Richard Luthy

All Publications

• Feasibility evaluation of a blended cover with activated carbon for in-situ stabilization of DDT in sediment. Journal of contaminant hydrology Cho, Y., Pauken, B. J., Tovkach, A. E., Fringer, O. B., Monismith, S. G., Luthy, R. G. 2024; 267: 104445

  Abstract

  Activated carbon (AC) sediment amendment is an in-situ remediation technology in which the applied AC immobilizes organic contaminant flux from sediments, thereby reducing contaminant bioavailability and associated risks. While various studies have demonstrated the feasibility of in-situ AC treatment, hesitation to apply this technology exists due to limited experience under field-specific scour conditions and hydrodynamic forces. To address this concern, we conducted a feasibility study for an AC-blended cover at the Lauritzen Channel of the United Heckathorn Superfund Site in Richmond, California, United States, which was contaminated with dichlorodiphenyltrichloroethane and its metabolites (DDx) as well as dieldrin. Vessel activities causing sediment disturbance were identified as key factors for remedy selection. A blended cover with AC and coarse materials was designed to withstand varied hydrodynamic conditions and AC stability was tested in a current flume. The cover comprised medium-size gravel (D50=15mm, D90=19mm) with 4% granular AC by weight. Flume erosion studies showed minimal AC loss (1-2% of total AC) under shear forces of 9-31Pa, which was equivalent to or exceeded the estimated worst-case erosional conditions in the channel induced by a hypothetical, stationary tugboat propelling at high power thrust. The treatability performance of the engineered blended cover design was evaluated through mesocosm studies using site sediment and various cover options. Post-treatment assessments on days 5 and 145 showed rapid reductions in freely dissolved (Cfree) DDx and dieldrin in the blended cover layers and surface water. For example, by day 145, Cfree DDx was reduced by over 98%, meeting US EPA remedial goals for the site. It is concluded that the combination of both stability and performance testing demonstrates that an engineered blended cover-AC design would be a feasible remedial option at the site, and that this testing approach can be applied to evaluate in-situ treatment in other sediment cleanup activities.

  View details for DOI 10.1016/j.jconhyd.2024.104445

  View details for PubMedID 39423551

• Flow rate and kinetics of trace organic contaminants removal in black carbon-amended engineered media filters for improved stormwater runoff treatment. Water research Pritchard, J. C., Hawkins, K. M., Cho, Y. M., Spahr, S., Higgins, C. P., Luthy, R. G. 2024; 258: 121811

  Abstract

  Urban stormwater runoff is considered a key component of future water supply portfolios for water-stressed cities. Beneficial use of runoff, such as capture for recharge of drinking water aquifers, relies on improved stormwater treatment. Many dissolved constituents, including metals and trace organic contaminants (TrOCs) such as hydrophilic pesticides and poly- and perfluoroalkyl substances (PFASs), are of concern due to their toxicity, persistence, prevalence in stormwater runoff, and poor removal in conventional stormwater control measures. This study explores the operational flow rate limitations of black carbon (BC)-amended engineered media filters for removal of a wide suite of dissolved metals and TrOCs and provides validation for a previously developed predictive TrOC transport model. Column experiments were conducted with face velocities of 40 and 60 cm h-1 to assess Douglas Fir-based biochar and regenerated activated carbon (RAC) filter performance in light of media-contaminant removal kinetic limitations. This study found that increasing the face velocity in BC-amended filters to 40 and 60 cm h-1, which are representative of field conditions, decreased the removal of total suspended solids, turbidity, dissolved hydrophilic TrOCs, and PFASs when expressed as volume treated relative to previous studies conducted at 20 cm h-1. Dissolved metals and hydrophobic TrOCs removal were not substantially affected by the increased flow rates. A predictive 1-d intraparticle pore diffusion-limited sorption model with sorption and effective tortuosity parameters determined previously from experiments conducted at 20 cm h-1 was validated for these higher flow rates. This work provides insights to the kinetic limitations of contaminant removal within biochar and RAC filters and implications for stormwater filter design and operation.

  View details for DOI 10.1016/j.watres.2024.121811

  View details for PubMedID 38833811

• Controlling saturation to improve per- and polyfluoroalkyl substance (PFAS) removal in biochar-amended stormwater bioretention systems ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Hawkins, K., Pritchard, J., Struck, S., Cho, Y., Luthy, R. G., Higgins, C. P. 2024

  View details for DOI 10.1039/d3ew00767g

  View details for Web of Science ID 001198143700001

• Water Supply Planning in the Face of Drought and Ecosystem Flows: Examining the Impact of the Bay-Delta Plan on Bay Area Water Supply. Environmental science & technology Gile, B. C., Sherris, A. R., Holmes, R. T., Fendorf, S., Luthy, R. G. 2024

  Abstract

  In California, recent Bay-Delta Plan legislation attempts to balance water supply and ecosystem protection by requiring 40% of the flow to remain in-stream in the Tuolumne River from February through June. Serious questions remain about what this means for the Bay Area water supply, especially during drought. Our work develops a new approach to analyze how in-stream flow policy coupled with climate change could impact regional water supply over the coming decades. Results show that the new in-stream flow demand would exceed urban water deliveries in a typical year. In wet years, water supply performance is minimally impacted, but in drought, the policy can lead to less water in storage, delayed reservoir recovery, and increased time at critically low storage. Storage impact exceeding 50 000 acre-feet (60 million m3) is anticipated with at least 18% frequency, demonstrating that, climate uncertainty notwithstanding, this impact must be planned for and managed to ensure a reliable future water supply.

  View details for DOI 10.1021/acs.est.3c07398

  View details for PubMedID 38390867

• Inducing Evapotranspiration Reduction in an Engineered Natural System to Manage Saltcedar in Riparian Areas of Arid Environments WATER Solis, J. C., Bawazir, A., Tanzy, B. F., Luthy, R. G., Jeon, S. 2024; 16 (1)

  View details for DOI 10.3390/w16010053

  View details for Web of Science ID 001141422800001

• Predicting PFAS and Hydrophilic Trace Organic Contaminant Transport in Black Carbon-Amended Engineered Media Filters for Improved Stormwater Runoff Treatment. Environmental science & technology Pritchard, J. C., Cho, Y. M., Hawkins, K. M., Spahr, S., Higgins, C. P., Luthy, R. G. 2023

  Abstract

  Improved stormwater treatment is needed to prevent toxic and mobile contaminant transport into receiving waters and allow beneficial use of stormwater runoff. In particular, safe capture of stormwater runoff to augment drinking water supplies is contingent upon removing dissolved trace organic contaminants (TrOCs) not captured by conventional stormwater control measures. This study builds upon a prior laboratory-based column study investigating biochar and regenerated activated carbon (RAC) amendment for removing hydrophilic trace organic contaminants (HiTrOCs) and poly- and perfluoroalkyl substances (PFASs) from stormwater runoff. A robust contaminant transport model framework incorporating time-dependent flow and influent concentration is developed and validated to predict HiTrOC and PFAS transport in biochar- and RAC-amended stormwater filters. Specifically, parameters fit using a sorption-retarded intraparticle pore diffusion transport model were validated using data further along the depth of the column and compared to equilibrium batch isotherms. The transport model and fitted parameters were then used to estimate the lifetime of a hypothetical stormwater filter in Seal Beach, CA, to be 35 ± 6 years for biochar- and 51 ± 17 years for RAC-amended filters, under ideal conditions with no filter clogging. This work offers insights on the kinetics of HiTrOC and PFAS transport within biochar and RAC filters and on the impact of filter design on contaminant removal performance and longevity.

  View details for DOI 10.1021/acs.est.3c01260

  View details for PubMedID 37699564

• Urban stormwater capture for water supply: look out for persistent, mobile and toxic substances ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Mutzner, L., Zhang, K., Luthy, R. G., Arp, H. H., Spahr, S. 2023

  View details for DOI 10.1039/d3ew00160a

  View details for Web of Science ID 001032240300001

• Obituary Perry L. McCarty 1931-2023 NATURE SUSTAINABILITY Criddle, C. S., Luthy, R. G., Rittmann, B. E., Shin, C. 2023

  View details for DOI 10.1038/s41893-023-01183-9

  View details for Web of Science ID 001026600900003

• Black Carbon-Amended Engineered Media Filters for Improved Treatment of Stormwater Runoff. ACS environmental Au Pritchard, J. C., Hawkins, K. M., Cho, Y., Spahr, S., Struck, S. D., Higgins, C. P., Luthy, R. G. 2023; 3 (1): 34-46

  Abstract

  Urban stormwater runoff is a significant driver of surface water quality impairment. Recently, attention has been drawn to potential beneficial use of urban stormwater runoff, including augmenting drinking water supply in water-stressed areas. However, beneficial use relies on improved treatment of stormwater runoff to remove mobile dissolved metals and trace organic contaminants (TrOCs). This study assesses six engineered media mixtures consisting of sand, zeolite, high-temperature gasification biochar, and regenerated activated carbon (RAC) for removing a suite of co-contaminants comprising five metals, three herbicides, four pesticides, a corrosion inhibitor, six per- and polyfluoroalkyl substances (PFASs), five polychlorinated biphenyls (PCBs), and six polycyclic aromatic hydrocarbons (PAHs). This long-term laboratory-scale column study uses a novel approach to generate reproducible synthetic stormwater that incorporates catch basin material and straw-derived dissolved organic carbon. Higher flow conditions (20 cm hr-1), larger sized media (0.42-1.68 mm), and downflow configuration with outlet control increase the relevance of this study to better enable implementation in the field. Biochar- and RAC-amended engineered media filters removed nearly all of the TrOCs in the effluent over the course of three months of continuous flow (480 empty bed volumes), while sample ports spaced at 25% and 50% along the column depth provide windows to observe contaminant transport. Biochar provided greater benefit to TrOC removal than RAC on a mass basis. This study used relatively high concentrations of contaminants and low biochar and RAC content to observe contaminant transport. Performance in the field is likely to be significantly better with higher biochar- and RAC-content filters and lower ambient stormwater contaminant concentrations. This study provides proof-of-concept for biochar- and RAC-amended engineered media filters operated at a flow rate of 20 cm hr-1 for removing dissolved TrOCs and metals and offers insights on the performance of biochar and RAC for improved stormwater treatment and field trials.

  View details for DOI 10.1021/acsenvironau.2c00037

  View details for PubMedID 36691657

• Dissolved Methane Recovery and Trace Contaminant Fate Following Mainstream Anaerobic Treatment of Municipal Wastewater. ACS ES&T engineering Galdi, S. M., Szczuka, A., Shin, C., Mitch, W. A., Luthy, R. G. 2023; 3 (1): 121-130

  Abstract

  Anaerobic treatment of municipal wastewater with the staged anaerobic fluidized bed membrane bioreactor (SAF-MBR) shows promise to transform secondary wastewater treatment into an energy-positive process. However, the dissolved methane in SAF-MBR effluent needs to be recovered to reach net energy positive. To recover this methane for energy generation, an air stripping system was constructed downstream of a pilot-scale SAF-MBR facility and operated for over 80 days. The process removed 98% of effluent dissolved methane, and with the addition of intermittent disinfection recovered an average of 90% of the dissolved methane. The exit gas from air-stripping comprised 1.5-2.5% methane and could be utilized by blending with biogas produced from primary solids digestion and the SAF-MBR in an on-site combustion process. The direct energy costs for air stripping methane are <1% of the energy recoverable from the dissolved methane, not accounting for siloxane or sulfide scrubbing. Only siloxanes were observed at levels impacting combustion in this study, with 1.6 mg Si/m3 present in the blended biogas and air stripping mixture. The fate of a subset of trace organic contaminants was examined across the air stripping unit to check for aerobic degradation by methanotrophs or other opportunistic aerobes. Only 1,4-dioxane and benzotriazole showed statistically significant removal among 17 compounds screened, with 0.53 ± 0.13 and 0.34 ± 0.15 fraction removal, respectively. Our results indicate that air stripping is an energy efficient and robust technology for dissolved methane removal and onsite utilization for heat and electricity generation from anaerobic treatment of municipal wastewater.

  View details for DOI 10.1021/acsestengg.2c00256

  View details for PubMedID 36660091

• Use of pilot-scale geomedia-amended biofiltration system for removal of polar trace organic and inorganic contaminants from stormwater runoff. Water research Teixido, M., Charbonnet, J. A., LeFevre, G. H., Luthy, R. G., Sedlak, D. L. 2022; 226: 119246

  Abstract

  Stormwater runoff capture and groundwater recharge can provide a sustainable means of augmenting the local water resources in water-stressed cities while simultaneously mitigating flood risk, provided that these processes do not compromise groundwater quality. We developed and tested for one year an innovative pilot-scale stormwater treatment train that employs cost-effective engineered geomedia in a continuous-flow unit-process system to remove contaminants from urban runoff during aquifer recharge. The system consisted of an iron-enhanced sand filter for phosphate removal, a woodchip bioreactor for nitrate removal coupled to an aeration step, and columns packed with different configurations of biochar- and manganese oxide-containing sand to remove trace metals and persistent, mobile, and toxic trace organic contaminants. During conditioning with authentic stormwater runoff over an extended period (8 months), the woodchip bioreactor removed 98% of the influent nitrate (9g-N m-3 d-1), while phosphate broke through the iron-enhanced sand filter. During the challenge test (4 months), geomedia removed more than 80% of the mass of metals and trace organic compounds. Column hydraulic performance was stable during the entire study, and the weathered biochar and manganese oxide were effective at removing trace organic contaminants and metals, respectively. Under conditions likely encountered in the field, sustained nutrient removal is probable, but polar organic compounds such as 2,4-D could breakthrough after about a decade for conditions at the study site.

  View details for DOI 10.1016/j.watres.2022.119246

  View details for PubMedID 36288663

• Performance of biochars for the elimination of trace organic contaminants and metals from urban stormwater ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Spahr, S., Teixido, M., Gall, S. S., Pritchard, J. C., Hagemann, N., Helmreich, B., Luthy, R. G. 2022

  View details for DOI 10.1039/d1ew00857a

  View details for Web of Science ID 000791977800001

• Integrated Water Management at the Peri-Urban Interface: A Case Study of Monterey, California WATER Gile, B. C., Sciuto, P. A., Ashoori, N., Luthy, R. G. 2020; 12 (12)

  View details for DOI 10.3390/w12123585

  View details for Web of Science ID 000603508500001

• Urban Water Revolution: Sustainable Water Futures for California Cities JOURNAL OF ENVIRONMENTAL ENGINEERING Luthy, R. G., Wolfand, J. M., Bradshaw, J. L. 2020; 146 (7)

  View details for DOI 10.1061/(ASCE)EE.1943-7870.0001715

  View details for Web of Science ID 000536128900004

• Biochar-augmented biofilters to improve pollutant removal from stormwater - can they improve receiving water quality? ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Boehm, A. B., Bell, C. D., Fitzgerald, N. M., Gallo, E., Higgins, C. P., Hogue, T. S., Luthy, R. G., Portmann, A. C., Ulrich, B. A., Wolfand, J. M. 2020; 6 (6): 1520–37

  View details for DOI 10.1039/d0ew00027b

  View details for Web of Science ID 000540808000001

• Hydrophilic trace organic contaminants in urban stormwater: occurrence, toxicological relevance, and the need to enhance green stormwater infrastructure ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Spahr, S., Teixido, M., Sedlak, D. L., Luthy, R. G. 2020; 6 (1): 15–44

  View details for DOI 10.1039/c9ew00674e

  View details for Web of Science ID 000503799700003

• Biochar-augmented biofilters (BIOCHARge) to improve pollutant removal from stormwater: Can they improve receiving water quality? Boehm, A., Luthy, R., Wolfand, J., Higgins, C., Hogue, T., Fitzgerald, N., Kranner, B., Eisenstein, W., Ulrich, B. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061500790

• Enhanced removal of hydrophilic organic contaminants from urban stormwater in biochar-amended biofilters Spahr, S., Teixido, M., Sedlak, D., Luthy, R. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061500777

• Enhanced removal of urban stormwater runoff contaminants using biochar and manganese oxide-coated sand geomedia in a sequential biofiltration system Teixido, M., Spahr, S., Luthy, R., Sedlak, D. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061500744

• Urban stormwater to enhance water supply Luthy, R. AMER CHEMICAL SOC. 2019

  View details for Web of Science ID 000525061500738

• Global diversity and biogeography of bacterial communities in wastewater treatment plants NATURE MICROBIOLOGY Wu, L., Ning, D., Zhang, B., Li, Y., Zhang, P., Shan, X., Zhang, Q., Brown, M., Li, Z., Van Nostrand, J. D., Ling, F., Xiao, N., Zhang, Y., Vierheilig, J., Wells, G. F., Yang, Y., Deng, Y., Tu, Q., Wang, A., Zhang, T., He, Z., Keller, J., Nielsen, P. H., Alvarez, P. J., Criddle, C. S., Wagner, M., Tiedje, J. M., He, Q., Curtis, T. P., Stahl, D. A., Alvarez-Cohen, L., Rittmann, B. E., Wen, X., Zhou, J., Acevedo, D., Agullo-Barcelo, M., Andersen, G. L., de Araujo, J., Boehnke, K., Bond, P., Bott, C. B., Bovio, P., Brewster, R. K., Bux, F., Cabezas, A., Cabrol, L., Chen, S., Etchebehere, C., Ford, A., Frigon, D., Sanabria Gomez, J., Griffin, J. S., Gu, A. Z., Habagil, M., Hale, L., Hardeman, S. D., Harmon, M., Horn, H., Hu, Z., Jauffur, S., Johnson, D. R., Keucken, A., Kumari, S., Leal, C., Lebrun, L. A., Lee, J., Lee, M., Lee, Z. P., Li, M., Li, X., Liu, Y., Luthy, R. G., Mendonca-Hagler, L. C., Rodriguez de Menezes, F., Meyers, A. J., Mohebbi, A., Oehmen, A., Palmer, A., Parameswaran, P., Park, J., Patsch, D., Reginatto, V., de los Reyes, F. L., Noyola Robles, A., Rossetti, S., Sidhu, J., Sloan, W. T., Smith, K., de Sousa, O., Stephens, K., Tian, R., Tooker, N. B., De los Cobos Vasconcelos, D., Wakelin, S., Wang, B., Weaver, J. E., West, S., Wilmes, P., Woo, S., Wu, J., Wu, L., Xi, C., Xu, M., Yan, T., Yang, M., Young, M., Yue, H., Zhang, Q., Zhang, W., Zhang, Y., Zhou, H., Brown, M., Global Water Microbiome Consortium 2019; 4 (7): 1183–95

  View details for DOI 10.1038/s41564-019-0426-5

  View details for Web of Science ID 000480348200014

• Urban Stormwater to Enhance Water Supply ENVIRONMENTAL SCIENCE & TECHNOLOGY Luthy, R. G., Sharvelle, S., Dillon, P. 2019; 53 (10): 5534–42

  View details for DOI 10.1021/acs.est.8b05913

  View details for Web of Science ID 000469288100003

• Evaluation of pilot-scale biochar-amended woodchip bioreactors to remove nitrate, metals, and trace organic contaminants from urban stormwater runoff WATER RESEARCH Ashoori, N., Teixido, M., Spahr, S., LeFevre, G. H., Sedlak, D. L., Luthy, R. G. 2019; 154: 1–11

  View details for DOI 10.1016/j.watres.2019.01.040

  View details for Web of Science ID 000462104100001

• Occurrence of Urban-Use Pesticides and Management with Enhanced Stormwater Control Measures at the Watershed Scale ENVIRONMENTAL SCIENCE & TECHNOLOGY Wolfand, J. M., Seller, C., Bell, C. D., Cho, Y., Oetjen, K., Hogue, T. S., Luthy, R. G. 2019; 53 (7): 3634–44

  Abstract

  Urban-use pesticides are of increasing concern as they are widely used and have been linked to toxicity of aquatic organisms. To assess the occurrence and treatment of these pesticides in stormwater runoff, an approach combining field sampling and watershed-scale modeling was employed. Stormwater samples were collected at four locations in the lower San Diego River watershed during a storm event and analyzed for fipronil, three of its degradation products, and eight pyrethroids. All 12 compounds were detected with frequency ranging from 50 to 100%. Field results indicate pesticide pollution is ubiquitous at levels above toxicity benchmarks and that runoff may be a major pollutant source to urban surface waters. A watershed-scale stormwater model was developed, calibrated using collected data, and evaluated for pesticide storm load and concentrations under several management scenarios. Modeling results show that enhanced stormwater control measures, such as biochar-amended biofilters, reduce both pesticide storm load and toxicity benchmark exceedances, while conventional biofilters reduce the storm load but provide minimal toxicity benchmark exceedance reduction. Consequently, biochar amendment has the potential to broadly improve water quality at the watershed scale, particularly when meeting concentration-based metrics such as toxicity benchmarks. This research motivates future work to demonstrate the reliability of full-scale enhanced stormwater control measures to treat pollutants of emerging concern.

  View details for DOI 10.1021/acs.est.8b05833

  View details for Web of Science ID 000463679600030

  View details for PubMedID 30900451

• Quantifying the temperature dependence of nitrate reduction in woodchip bioreactors: experimental and modeled results with applied case-study ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Halaburka, B. J., LeFevre, G. H., Luthy, R. G. 2019; 5 (4): 782–97

  View details for DOI 10.1039/c8ew00848e

  View details for Web of Science ID 000462942400014

• Modeling Cost, Energy, and Total Organic Carbon Trade-Offs for Stormwater Spreading Basin Systems Receiving Recycled Water Produced Using Membrane-Based, Ozone-Based, and Hybrid Advanced Treatment Trains ENVIRONMENTAL SCIENCE & TECHNOLOGY Bradshaw, J. L., Ashoori, N., Osorio, M., Luthy, R. G. 2019; 53 (6): 3128–39

  View details for DOI 10.1021/acs.est.9b00184

  View details for Web of Science ID 000462098000022

• Modeling Cost, Energy, and Total Organic Carbon Trade-Offs for Stormwater Spreading Basin Systems Receiving Recycled Water Produced Using Membrane-Based, Ozone-Based, and Hybrid Advanced Treatment Trains. Environmental science & technology Bradshaw, J. L., Ashoori, N., Osorio, M., Luthy, R. G. 2019; 53 (6): 3128–39

  Abstract

  To address water scarcity, cities are pursuing options for augmenting groundwater recharge with recycled water. Ozone-based treatment trains comprising ozone and biologically activated carbon potentially offer cost-effective alternatives to membrane-based treatment, the standard process for potable reuse in numerous countries. However, regulations in multiple states effectively limit the extent to which ozone-based treatment alone can produce recycled water for groundwater recharge. To investigate the trade-offs between treatment costs and regulatory constraints, this study presents methods for modeling and optimizing designs for (1) producing recycled water using membrane-based treatment, ozone-based treatment, and hybrid treatment trains comprising ozone-based treatment with a membrane sidestream, and (2) delivering that water to stormwater spreading basins. We present a case study of Los Angeles, CA, to demonstrate the model's application under realistic conditions, including regulations that limit spreading recycled water based on its concentration of total organic carbon and theextent of dilution. While the membrane-based treatment train exhibits economies of scale, we demonstrate how regulatory constraints create a diseconomies of scale effect for hybrid treatment systems because larger scales necessitate a higher proportion of recycled water undergo membrane treatment. Nevertheless, relative to membrane-based treatment, we identify opportunities for ozone-based or hybrid treatment trains to reduce treatment costs and energy use by up to 62% and 59%, respectively, for systems with up to 1 m3/s (23 million gallons per day) mean water recycling rate, potentially lowering the barrier for decentralized water recycling systems. This modeling approach could inform planning and policy regarding recycled water projects for groundwater recharge through spreading basins and, with additional modification, other potable reuse applications.

  View details for PubMedID 30702865

• System Modeling, Optimization, and Analysis of Recycled Water and Dynamic Storm Water Deliveries to Spreading Basins for Urban Groundwater Recharge WATER RESOURCES RESEARCH Bradshaw, J. L., Osorio, M., Schmitt, T. G., Luthy, R. G. 2019; 55 (3): 2446–63

  View details for DOI 10.1029/2018WR024411

  View details for Web of Science ID 000464660000035

• Evaluation of pilot-scale biochar-amended woodchip bioreactors to remove nitrate, metals, and trace organic contaminants from urban stormwater runoff. Water research Ashoori, N., Teixido, M., Spahr, S., LeFevre, G. H., Sedlak, D. L., Luthy, R. G. 2019; 154: 1–11

  Abstract

  Stormwater is increasingly being valued as a freshwater resource in arid regions and can provide opportunities for beneficial reuse via aquifer recharge if adequate pollutant removal can be achieved. We envision a multi-unit operation approach to capture, treat, and recharge (CTR) stormwater using low energy, cost-effective technologies appropriate for larger magnitude, less frequent events. Herein, we tested nutrient, metal, and trace organic contaminant removal of a pilot-scale CTR system in the laboratory using biochar-amended woodchip bioreactors following eight months of aging under field conditions with exposure to real stormwater. Replicate columns with woodchips and biochar (33% by weight), woodchips and straw, or woodchips only were operated with continuous, saturated flow for eight months using water from a watershed that drained an urban area consisting of residential housing and parks in Sonoma, California. After aging, columns were challenged for five months by continuous exposure to synthetic stormwater amended with 50 mug L-1 of six trace organic contaminants (i.e., fipronil, diuron, 1H-benzotriazole, atrazine, 2,4-D, and TCEP) and five metals (Cd, Cu, Ni, Pb, Zn) frequently detected in stormwater in order to replicate the treatment unit operation of a CTR system. Throughout the eight-month aging and five-month challenge experiment, nitrate concentrations were below the detection limit after treatment (i.e., <0.05 mg N L-1). The removal efficiencies for metals in all treatments were >80% for Ni, Cu, Cd, and Pb. For Zn, about 50% removal occurred in the woodchip-biochar systems while the other systems achieved about 20% removal. No breakthrough of the trace organic compounds was observed in any biochar-containing columns. Woodchip columns without biochar removed approximately 99% of influent atrazine and 90% of influent fipronil, but exhibited relatively rapid breakthrough of TCEP, 2,4-D, 1H-benzotriazole, and diuron. The addition of straw to the woodchip columns provided no significant benefit compared to woodchips alone. Due to the lack of breakthrough of trace organics in the biochar-woodchip columns, we estimated column breakthrough with a diffusion-limited sorption model. Results of the model indicate breakthrough for the trace organics would occur between 10,000 and 32,000 pore volumes. Under ideal conditions this could be equivalent to decades of service, assuming failure by other processes (e.g., clogging, biofouling) does not occur. These results indicate that multiple contaminants can be removed in woodchip-biochar reactors employed in stormwater treatment systems with suitable flow control and that the removal of trace organic contaminants is enhanced significantly by addition of biochar.

  View details for PubMedID 30763870

• Benzotriazole Uptake and Removal in Vegetated Biofilter Mesocosms Planted with Carex praegracilis WATER Pritchard, J., Cho, Y., Ashoori, N., Wolfand, J. M., Sutton, J. D., Carolan, M. E., Gamez, E., Doan, K., Wiley, J. S., Luthy, R. G. 2018; 10 (11)

  View details for DOI 10.3390/w10111605

  View details for Web of Science ID 000451736300112

• Activated carbon amendment for treatment of sediment contaminated with DDT and other hydrophobic organic pollutants concentrated 10-100x more than prior studies Pritchard, C., Cho, Y., Luthy, R. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447609100420

• Additive remediation effectiveness of activated carbon amendment on fungal degradation of fluorene and its heteroatomic analogs: Dibenzofuran, dibenzothiophene, and carbazole Zhang, Z., Cho, Y., Wolfand, J., Choi, Y., Luthy, R. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447609100423

• HOC mass transfer modeling with consideration of bioturbation and on-going sediment influx Cho, Y., Werner, D., Choi, Y., Luthy, R. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447609100421

• Harnessing woodchips to remove pharmaceuticals and anticorrosive substances Tseng, Y., Lai, W., Tung, H., Luthy, R., Lin, A. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000447609100374

• Multiple Pathways to Bacterial Load Reduction by Stormwater Best Management Practices: Trade-Offs in Performance, Volume, and Treated Area ENVIRONMENTAL SCIENCE & TECHNOLOGY Wolfand, J. M., Bell, C. D., Boehm, A. B., Hogue, T. S., Luthy, R. G. 2018; 52 (11): 6370–79

  Abstract

  Stormwater best management practices (BMPs) are implemented to reduce microbial pollution in runoff, but their removal efficiencies differ. Enhanced BMPs, such as those with media amendments, can increase removal of fecal indicator bacteria (FIB) in runoff from 0.25-log10 to above 3-log10; however, their implications for watershed-scale management are poorly understood. In this work, a computational model was developed to simulate watershed-scale bacteria loading and BMP performance using the Ballona Creek Watershed (Los Angeles County, CA) as a case study. Over 1400 scenarios with varying BMP performance, percent watershed area treated, BMP treatment volume, and infiltrative capabilities were simulated. Incremental improvement of BMP performance by 0.25-log10, while keeping other scenario variables constant, reduces annual bacterial load at the outlet by a range of 0-29%. In addition, various simulated scenarios provide the same FIB load reduction; for example, 75% load reduction is achieved by diverting runoff from either 95% of the watershed area to 25 000 infiltrating BMPs with 0.5-log10 removal or 75% of the watershed area to 75 000 infiltrating BMPs with 1.5-log10 removal. Lastly, simulated infiltrating BMPs provide greater FIB reduction than noninfiltrating BMPs at the watershed scale. Results provide new insight on the trade-offs between BMP treatment volume, performance, and distribution.

  View details for DOI 10.1021/acs.est.8600408

  View details for Web of Science ID 000434892900032

  View details for PubMedID 29676892

• Enhanced removal of nutrients and trace organic contaminants from urban runoff using biochar and manganese oxide-coated sand geomedia in capture, treatment, and recharge systems Teixido, M., Charbonnet, J., Ashoori, N., Luthy, R., Sedlak, D. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000435539900721

• Harvesting urban stormwater runoff for water supply Luthy, R., Spahr, S., Ashoori, N., Planes, M., Sedlak, D. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000435539900619

• Connecting recycled water to spreading basins for combined operation and greater water supply resiliency Bradshaw, J., Ashoori, N., Gonzalez, M., Schmitt, T., Luthy, R. AMER CHEMICAL SOC. 2018

  View details for Web of Science ID 000435539901138

• Bioturbation facilitates DDT sequestration by activated carbon against recontamination by sediment deposition. Environmental toxicology and chemistry Lin, D., Cho, Y., Tommerdahl, J. P., Werner, D., Luthy, R. G. 2018

  Abstract

  We evaluated bioturbation as a facilitator for in situ treatment with a thin layer of activated carbon to treat dichlorodiphenyltrichloroethane (DDT)-contaminated sediment and contaminant influx by sediment deposition. Using the freshwater worm Lumbriculus variegatus as a bioturbator, microcosm time-series studies were conducted for 4 mo and monitored for DDT flux and porewater concentration profiles by polyethylene passive samplers. With bioturbators present, the thin-layer activated carbon amendment reduced DDT flux by >90% compared with the same simulated scenario without activated carbon amendment. In contrast, a clean sediment cap without activated carbon was ineffective in reducing flux when bioturbation was present. In simulated scenarios with contaminant influx through deposition of contaminated sediment, bioturbation facilitated in situ activated carbon treatment, reducing 4-mo DDT flux by 77% compared with the same scenario without bioturbation. Porewater concentration profiles and activated carbon dose profiles confirmed effective mixing of activated carbon particles down to 1-cm depth. A mass transfer model was developed to predict flux with consideration of bioturbation and sediment deposition processes. Predicted flux values were consistent with experimental results and confirm that bioturbation activity helps reduce DDT sediment-to-water fluxes in activated carbon-treated sediment with recontamination by contaminated sediment deposition. To our knowledge, this is the first study to combine experimental and modeling results showing how bioturbation enhances activated carbon amendment effectiveness against ongoing contaminant influx by sediment deposition. Environ Toxicol Chem 2018;9999:1-9. © 2018 SETAC.

  View details for PubMedID 29521428

• Assessment of hydrophobic organic contaminant availability in sediments after sorbent amendment and its complete removal ENVIRONMENTAL POLLUTION Wu, Y., Cho, Y., Luthy, R. G., Kim, K., Jung, J., Gala, W. R., Choi, Y. 2017; 231: 1380–87

  Abstract

  Sorbents amended to sediments in situ for sequestration of hydrophobic organic contaminants (HOCs) may be swept away from the treated sites due to hydrodynamic forces applied to the sediment surface. The purpose of this study is to examine the possibility of recovery of HOC availability in sorbent-amended sediment after complete removal of the sorbent. Sediment contact with an easily separable model sorbent Tenax beads for 28 days in a slurry phase resulted in 74-98% reduction in polycyclic aromatic hydrocarbon and polychlorinated biphenyl availability compared to the untreated controls. HOC availability in the sorbent-treated sediment slightly increased by sorbent removal and after one month of mixing in a slurry phase because the slowly-desorbing HOC fraction was released and repartitioned back to the sediment, partially replenishing the rapidly-desorbing HOC fraction. However, HOC availability did not further increase during an extended mixing period of 12 months suggesting that the repartitioning process was not an infinite source. HOC availability after the 12-month post-treatment mixing for the sorbent-treated sediment was 53-97% lower than that of the untreated sediment because of the combined effect of HOC mass removal from sediment (with the sorbent) and incomplete recovery of available HOC fraction in the sorbent-treated sediment.

  View details for PubMedID 28943348

• Modeling and Optimization of Recycled Water Systems to Augment Urban Groundwater Recharge through Underutilized Stormwater Spreading Basins ENVIRONMENTAL SCIENCE & TECHNOLOGY Bradshaw, J. L., Luthy, R. G. 2017; 51 (20): 11809–19

  Abstract

  Infrastructure systems that use stormwater and recycled water to augment groundwater recharge through spreading basins represent cost-effective opportunities to diversify urban water supplies. However, technical questions remain about how these types of managed aquifer recharge systems should be designed; furthermore, existing planning tools are insufficient for performing robust design comparisons. Addressing this need, we present a model for identifying the best-case design and operation schedule for systems that deliver recycled water to underutilized stormwater spreading basins. Resulting systems are optimal with respect to life cycle costs and water deliveries. Through a case study of Los Angeles, California, we illustrate how delivering recycled water to spreading basins could be optimally implemented. Results illustrate trade-offs between centralized and decentralized configurations. For example, while a centralized Hyperion system could deliver more recycled water to the Hansen Spreading Grounds, this system incurs approximately twice the conveyance cost of a decentralized Tillman system (mean of 44% vs 22% of unit life cycle costs). Compared to existing methods, our model allows for more comprehensive and precise analyses of cost, water volume, and energy trade-offs among different design scenarios. This model can inform decisions about spreading basin operation policies and the development of new water supplies.

  View details for PubMedID 28953372

• Toolset for assessment of natural recovery from legacy contaminated sediment: Case study of Pallanza Bay, Lake Maggiore, Italy. Water research Lin, D., Cho, Y., Oen, A., Eek, E., Tommerdahl, J. P., Luthy, R. G. 2017; 121: 109-119

  Abstract

  The aim of this study was to develop a toolset that can be used by site managers to assess and monitor natural attenuation processes in sediments contaminated with legacy hydrophobic organic contaminants. The toolset is composed of sediment traps to measure quality and deposition rate of incoming sediment under different hydrodynamic conditions, sediment cores to show trends in sediment bed concentrations over time, and passive samplers attached to a porewater probe frame to assess the mobility of buried contaminants and possible contaminant flux from sediment. These three tools were used together for the first time to assess the mobility of dichlorodiphenyltrichloroethane (DDT) contaminants in sediment in Pallanza Bay, Lake Maggiore, Italy. Depositing sediment and sediment cores were consistent in showing that DDT-contaminated sediment is undergoing burial by cleaner sediment. Elevated DDT concentrations from historical contamination seemed to be effectively buried and immobilized by ongoing deposition by cleaner sediment, because the positive flux from the elevated DDT concentration in the sediment porewater should not advance towards the sediment surface. The monitoring toolset introduced in this study enabled us to more effectively assess ongoing natural attenuation processes and provide more risk relevant data than traditional methods used in monitored natural recovery projects, such as bulk sediment concentrations from sediment cores. Our field assessment results suggest that incoming sediment from the Toce River have reduced DDT concentrations in the sediment compared to historic levels, and will continue to do so in locations where higher DDT concentrations are found within the bioactive layer.

  View details for DOI 10.1016/j.watres.2017.05.024

  View details for PubMedID 28525783

• Evaluation of Mechanistic Models for Nitrate Removal in Woodchip Bioreactors ENVIRONMENTAL SCIENCE & TECHNOLOGY Halaburka, B. J., Lefevre, G. H., Luthy, R. G. 2017; 51 (9): 5156-5164

  Abstract

  Woodchip bioreactors (WBRs) are increasingly being applied to remove nitrate from runoff. In this study, replicate columns with aged woodchips were subjected to a range of measured flow rates and influent nitrate concentrations with an artificial stormwater matrix. Dissolved oxygen (DO), nitrate, and dissolved organic carbon (DOC) were measured along the length of the columns. A multispecies reactive transport model with Michaelis-Menten kinetics was developed to explain the concentration profiles of DO, nitrate, and DOC. Four additional models were developed based on simplifying assumptions, and all five models were tested for their ability to predict nitrate concentrations in the experimental columns. Global sensitivity analysis and constrained optimization determined the set of parameters that minimized the root-mean-squared error (RMSE) between the model and the experimental data. A k-fold validation test revealed no statistical difference in RMSE for predicting nitrate concentrations between a zero-order model and the other multispecies reactive transport models tested. Additionally, the multispecies reactive transport models demonstrated no significant differences in predicting DO and DOC concentrations. These results suggest that denitrification in an aged woodchip bioreactor at constant temperature can effectively be modeled using zero-order kinetics when nitrate concentrations are >2 mg-N L(-1). A multispecies model may be used if predicting DOC or DO concentrations is desired.

  View details for DOI 10.1021/acs.est.7b01025

  View details for Web of Science ID 000400723200046

  View details for PubMedID 28394589

• Optimization of urban groundwater recharge systems that infiltrate combined stormwater and recycled water through surface spreading basins Bradshaw, J., Luthy, R. AMER CHEMICAL SOC. 2017

  View details for Web of Science ID 000430569100631

• Benzotriazole (BT) and BT plant metabolites in crops irrigated with recycled water ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY Lefevre, G. H., Lipsky, A., Hyland, K. C., Blaine, A. C., Higgins, C. P., Luthy, R. G. 2017; 3 (2): 213-223

  View details for DOI 10.1039/c6ew00270f

  View details for Web of Science ID 000396002600003

• Performance of retrievable activated carbons to treat sediment contaminated with polycyclic aromatic hydrocarbons JOURNAL OF HAZARDOUS MATERIALS Choi, Y., Wu, Y., Sani, B., Luthy, R. G., Werner, D., Kim, E. 2016; 320: 359-367

  Abstract

  The feasibility of sediment treatment by magnetized and textile forms of activated carbon (AC) is evaluated in a laboratory well-mixed condition, targeting removal of polycyclic aromatic hydrocarbons (PAHs) from contaminated sediments by amendment of the AC and subsequent AC retrieval. In water, the apparent PAH sorption coefficients for magnetized ACs are comparable to those for a non-magnetized AC, while the textile form of AC exhibits smaller values, which is likely due to the slow PAH sorption kinetics resulting from its thickness. When the magnetized ACs are added in a sediment slurry, the apparent PAH sorption coefficients generally become somewhat smaller than those determined in water, suggesting the sorption attenuation effect by dissolved and/or colloidal organic matter for the ACs. Still, treatment of a PAH-contaminated sediment by 5 dry wt% of the magnetized ACs substantially reduces polyethylene sampler uptakes (by 88-89%). By analyzing PAHs after magnetic separation of the AC particles and sediment, it is shown that significant PAH mass removal can be achieved by the AC-sediment contact followed by AC retrieval. The feasibility of the sediment treatment is challenged by low magnetic particle collection efficiency (50-60%), suggesting that the durability of magnetic susceptibility of the magnetized ACs should be improved.

  View details for DOI 10.1016/j.jhazmat.2016.08.047

  View details for Web of Science ID 000385600700038

  View details for PubMedID 27566929

• Non-equilibrium passive sampling of hydrophobic organic contaminants in sediment pore-water: PCB exchange kinetics JOURNAL OF HAZARDOUS MATERIALS Choi, Y., Wu, Y., Luthy, R. G., Kang, S. 2016; 318: 579-586

  Abstract

  This study investigates the isotropic exchange kinetics of PCBs for polyethylene (PE) passive samplers in quiescent sediment and develops a novel non-equilibrium passive sampling method using PE with multiple thicknesses. The release and uptake kinetics of PCBs in quiescent sediment are reproduced by a 1-D diffusion model using sediment diffusion parameters fitted with the data from actual measurements. From the sediment diffusion parameters observed for uptake and release kinetics, it is seen that the uptake kinetics are distinctly slower than the release kinetics, most likely because of the sorption-desorption hysteresis of PCBs in the study sediment. Despite the presence of the anisotropic PCB exchange kinetics, a performance reference compound (PRC)-based method, which is grounded on the assumption of isotropic exchange kinetics, estimated the freely dissolved aqueous concentrations (Cfree) of PCBs in sediment pore-water with less than a factor of two error for the study sediment. The novel method developed in this study using PE with multiple thicknesses also gives reasonable estimates of Cfree, demonstrating its potential as another option for non-equilibrium passive sampling for hydrophobic organic contaminants in sediment pore-water.

  View details for DOI 10.1016/j.jhazmat.2016.07.045

  View details for Web of Science ID 000383003200064

  View details for PubMedID 27472074

• Escherichia coli Reduction by Bivalves in an Impaired River Impacted by Agricultural Land Use. Environmental science & technology Ismail, N. S., Tommerdahl, J. P., Boehm, A. B., Luthy, R. G. 2016; 50 (20): 11025-11033

  Abstract

  Fecal indicator bacteria (FIB) are leading causes of impaired surface waters. Innovative and environmentally appropriate best management practices are needed to reduce FIB concentrations and associated risk. This study examines the ability of the native freshwater mussel Anodonta californiensis and an invasive freshwater clam Corbicula fluminea to reduce concentrations of the FIB Escherichia coli in natural waters. Laboratory batch experiments were used to show bivalve species-specific E. coli removal capabilities and to develop a relationship between bivalve size and clearance rates. A field survey within an impaired coastal river containing both species of bivalves in an agricultural- and grazing-dominated area of the central coast of California showed a significant inverse correlation between E. coli concentration and bivalve density. An in situ field spiking and sampling study showed filtration by freshwater bivalves resulting in 1-1.5 log10 reduction of E. coli over 24 h, and calculated clearance rates ranged from 1.2 to 7.4 L hr(-1) bivalve(-1). Results of this study show the importance of freshwater bivalves for improving water quality through the removal of E. coli. While both native and invasive bivalves can reduce E. coli levels, the use of native bivalves through integration into best management practices is recommended as a way to improve water quality and protect and encourage re-establishment of native bivalve species that are in decline.

  View details for PubMedID 27616202

• Metabolization and degradation kinetics of the urban-use pesticide fipronil by white rot fungus Trametes versicolor. Environmental science. Processes & impacts Wolfand, J. M., Lefevre, G. H., Luthy, R. G. 2016; 18 (10): 1256-1265

  Abstract

  Fipronil is a recalcitrant phenylpyrazole-based pesticide used for flea/tick treatment and termite control that is distributed in urban aquatic environments via stormwater and contributes to stream toxicity. We discovered that fipronil is rapidly metabolized (t1/2 = 4.2 d) by the white rot fungus Trametes versicolor to fipronil sulfone and multiple previously unknown fipronil transformation products, lowering fipronil concentration by 96.5%. Using an LC-QTOF-MS untargeted metabolomics approach, we identified four novel fipronil fungal transformation products: hydroxylated fipronil sulfone, glycosylated fipronil sulfone, and two compounds with unresolved structures. These results are consistent with identified enzymatic detoxification pathways wherein conjugation with sugar moieties follows initial ring functionalization (hydroxylation). The proposed pathway is supported by kinetic evidence of transformation product formation. Fipronil loss by sorption, hydrolysis, and photolysis was negligible. When T. versicolor was exposed to the cytochrome P450 enzyme inhibitor 1-aminobenzotriazole, oxidation of fipronil and production of hydroxylated and glycosylated transformation products significantly decreased (p = 0.038, 0.0037, 0.0023, respectively), indicating that fipronil is metabolized intracellularly by cytochrome P450 enzymes. Elucidating fipronil transformation products is critical because pesticide target specificity can be lost via structural alteration, broadening classes of impacted organisms. Integration of fungi in engineered natural treatment systems could be a viable strategy for pesticide removal from stormwater runoff.

  View details for PubMedID 27722395

• Metabolism of the xenobiotic compound benzotriazole in Arabidopsis plants LeFevre, G., Lipsky, A., Mueller, C., Sattely, E., Luthy, R. AMER CHEMICAL SOC. 2016

  View details for Web of Science ID 000431460200721

• Engineered natural treatment systems at the food-energy-water nexus: The influence of vegetation on micropollutant fate LeFevre, G., Portmann, A., Luthy, R. AMER CHEMICAL SOC. 2016

  View details for Web of Science ID 000431460204473

• Metabolization and degradation kinetics of the urban-use pesticide fipronil by white rot fungi Trametes versicolo Wolfand, J., LeFevre, G., Luthy, R. AMER CHEMICAL SOC. 2016

  View details for Web of Science ID 000431460204494

• Plant Assimilation Kinetics and Metabolism of 2-Mercaptobenzothiazole Tire Rubber Vulcanizers by Arabidopsis ENVIRONMENTAL SCIENCE & TECHNOLOGY Lefevre, G. H., Portmann, A. C., Muller, C. E., Sattely, E. S., Luthy, R. G. 2016; 50 (13): 6762-6771

  Abstract

  2-Mercaptobenzothiazole (MBT) is a tire rubber vulcanizer found in potential sources of reclaimed water where it may come in contact with vegetation. In this work, we quantified the plant assimilation kinetics of MBT using Arabidopsis under hydroponic conditions. MBT depletion kinetics in the hydroponic medium with plants were second order (t1/2 = 0.52 to 2.4 h) and significantly greater than any abiotic losses (>18 times faster; p = 0.0056). MBT depletion rate was related to the initial exposure concentration with higher rates at greater concentrations from 1.6 μg/L to 147 μg/L until a potentially inhibitory level (1973 μg/L) lowered the assimilation rate. 9.8% of the initial MBT mass spike was present in the plants after 3 h and decreased through time. In-source LC-MS/MS fragmentation revealed that MBT was converted by Arabidopsis seedlings to multiple conjugated-MBT metabolites of differential polarity that accumulate in both the plant tissue and hydroponic medium; metabolite representation evolved temporally. Multiple novel MBT-derived plant metabolites were detected via LC-QTOF-MS analysis; proposed transformation products include glucose and amino acid conjugated MBT metabolites. Elucidating plant transformation products of trace organic contaminants has broad implications for water reuse because plant assimilation could be employed advantageously in engineered natural treatment systems, and plant metabolites in food crops could present an unintended exposure route to consumers.

  View details for DOI 10.1021/acs.est.5b04716

  View details for Web of Science ID 000379366300022

  View details for PubMedID 26698834

• Reductive dehalogenation of disinfection byproducts by an activated carbon-based electrode system WATER RESEARCH Li, Y., Kemper, J. M., Datuin, G., Akey, A., Mitch, W. A., Luthy, R. G. 2016; 98: 354-362

  Abstract

  Low molecular weight, uncharged, halogenated disinfection byproducts (DBPs) are poorly removed by the reverse osmosis and advanced oxidation process treatment units often applied for further treatment of municipal wastewater for potable reuse. Granular activated carbon (GAC) treatment effectively sorbed 22 halogenated DBPs. Conversion of the GAC to a cathode within an electrolysis cell resulted in significant degradation of the 22 halogenated DBPs by reductive electrolysis at -1 V vs. Standard Hydrogen Electrode (SHE). The lowest removal efficiency over 6 h electrolysis was for trichloromethane (chloroform; 47%) but removal efficiencies were >90% for 13 of the 22 DBPs. In all cases, DBP degradation was higher than in electrolysis-free controls, and degradation was verified by the production of halides as reduction products. Activated carbons and charcoal were more effective than graphite for electrolysis, with graphite featuring poor sorption for the DBPs. A subset of halogenated DBPs (e.g., haloacetonitriles, chloropicrin) were degraded upon sorption to the GAC, even without electrolysis. Using chloropicrin as a model, experiments indicated that this loss was attributable to the partial reduction of sorbed chloropicrin from reducing equivalents in the GAC. Reducing equivalents depleted by these reactions could be restored when the GAC was treated by reductive electrolysis. GAC treatment of an advanced treatment train effluent for potable reuse effectively reduced the concentrations of chloroform, bromodichloromethane and dichloroacetonitrile measured in the column influent to below the method detection limits. Treatment of the GAC by reductive electrolysis at -1 V vs. SHE over 12 h resulted in significant degradation of the chloroform (63%), bromodichloromethane (96%) and dichloroacetonitrile (99%) accumulated on the GAC. The results suggest that DBPs in advanced treatment train effluents could be captured and degraded continuously by reductive electrolysis using a GAC-based cathode.

  View details for DOI 10.1016/j.watres.2016.04.019

  View details for Web of Science ID 000376805500039

  View details for PubMedID 27124125

• Measuring and Modeling Organochlorine Pesticide Response to Activated Carbon Amendment in Tidal Sediment Mesocosms ENVIRONMENTAL SCIENCE & TECHNOLOGY Thompson, J. M., Hsieh, C., Hoelen, T. P., Weston, D. P., Luthy, R. G. 2016; 50 (9): 4769-4777

  Abstract

  Activated carbon (AC) sediment amendment for hydrophobic organic contaminants (HOCs) is attracting increasing regulatory and industrial interest. However, mechanistic and well-vetted models are needed. Here, we conduct an 18 month field mesocosm trial at a site containing dichlorodiphenyltrichloroethane (DDT) and chlordane. Different AC applications were applied and, for the first time, a recently published mass transfer model was field tested under varying experimental conditions. AC treatment was effective in reducing DDT and chlordane concentration in polyethylene (PE) samplers, and contaminant extractability by Arenicola brasiliensis digestive fluids. A substantial AC particle size effect was observed. For example, chlordane concentration in PE was reduced by 93% 6 months post-treatment in the powdered AC (PAC) mesocosm, compared with 71% in the granular AC (GAC) mesocosm. Extractability of sediment-associated DDT and chlordane by A. brasiliensis digestive fluids was reduced by at least a factor of 10 in all AC treatments. The model reproduced the relative effects of varying experimental conditions (particle size, dose, mixing time) on concentrations in polyethylene passive samplers well, in most cases within 25% of experimental observations. Although uncertainties such as the effect of long-term AC fouling by organic matter remain, the study findings support the use of the model to assess long-term implications of AC amendment.

  View details for DOI 10.1021/acs.est.5b05669

  View details for Web of Science ID 000375521400021

  View details for PubMedID 27040592

• COMPETING MECHANISMS FOR PERFLUOROALKYL ACID ACCUMULATION IN PLANTS REVEALED USING AN ARABIDOPSIS MODEL SYSTEM ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Mueller, C. E., Lefevre, G. H., Timofte, A. E., Hussain, F. A., Sattely, E. S., Luthy, R. G. 2016; 35 (5): 1138-1147

  Abstract

  Perfluoroalkyl acids (PFAAs) bioaccumulate in plants, presenting a human exposure route if present in irrigation water. Curiously, accumulation of PFAAs in plant tissues is greatest for both the short-chain and long-chain PFAAs, generating a U-shaped relationship with chain length. In the present study, the authors decouple competing mechanisms of PFAA accumulation using a hydroponic model plant system (Arabidopsis thaliana) exposed to a suite of 10 PFAAs to determine uptake, depuration, and translocation kinetics. Rapid saturation of root concentrations occurred for all PFAAs except perfluorobutanoate, the least-sorptive (shortest-chain) PFAA. Shoot concentrations increased continuously, indicating that PFAAs are efficiently transported and accumulate in shoots. Tissue concentrations of PFAAs during depuration rapidly declined in roots but remained constant in shoots, demonstrating irreversibility of the translocation process. Root and shoot concentration factors followed the U-shaped trend with perfluoroalkyl chain length; however, when normalized to dead-tissue sorption, this relationship linearized. The authors therefore introduce a novel term, the "sorption normalized concentration factor," to describe PFAA accumulation in plants; because of their hydrophobicity, sorption is the determining factor for long-chain PFAAs, whereas the shortest-chain PFAAs are most effectively transported in the plant. The present study provides a mechanistic explanation for previously unexplained PFAA accumulation trends in plants and suggests that shorter-chained PFAAs may bioaccumulate more readily in edible portions.

  View details for DOI 10.1002/etc.3251

  View details for Web of Science ID 000374547500014

• Competing mechanisms for perfluoroalkyl acid accumulation in plants revealed using an Arabidopsis model system. Environmental toxicology and chemistry Müller, C. E., Lefevre, G. H., Timofte, A. E., Hussain, F. A., Sattely, E. S., Luthy, R. G. 2016; 35 (5): 1138-1147

  Abstract

  Perfluoroalkyl acids (PFAAs) bioaccumulate in plants, presenting a human exposure route if present in irrigation water. Curiously, accumulation of PFAAs in plant tissues is greatest for both the short-chain and long-chain PFAAs, generating a U-shaped relationship with chain length. In the present study, the authors decouple competing mechanisms of PFAA accumulation using a hydroponic model plant system (Arabidopsis thaliana) exposed to a suite of 10 PFAAs to determine uptake, depuration, and translocation kinetics. Rapid saturation of root concentrations occurred for all PFAAs except perfluorobutanoate, the least-sorptive (shortest-chain) PFAA. Shoot concentrations increased continuously, indicating that PFAAs are efficiently transported and accumulate in shoots. Tissue concentrations of PFAAs during depuration rapidly declined in roots but remained constant in shoots, demonstrating irreversibility of the translocation process. Root and shoot concentration factors followed the U-shaped trend with perfluoroalkyl chain length; however, when normalized to dead-tissue sorption, this relationship linearized. The authors therefore introduce a novel term, the "sorption normalized concentration factor," to describe PFAA accumulation in plants; because of their hydrophobicity, sorption is the determining factor for long-chain PFAAs, whereas the shortest-chain PFAAs are most effectively transported in the plant. The present study provides a mechanistic explanation for previously unexplained PFAA accumulation trends in plants and suggests that shorter-chained PFAAs may bioaccumulate more readily in edible portions.

  View details for DOI 10.1002/etc.3251

  View details for PubMedID 26383989

• Decision-making framework for the application of in-situ activated carbon amendment to sediment. Journal of hazardous materials Choi, Y., Cho, Y., Gala, W. R., Hoelen, T. P., Werner, D., Luthy, R. G. 2016; 306: 184-192

  Abstract

  This study provides a decision-support framework and a design methodology for preliminary evaluation of field application of in-situ activated carbon (AC) amendment to sediment to control the (bio)availability of hydrophobic organic contaminants. The decision-making framework comprises four sequential steps: screening assessment, input parameter determination, model prediction, and evaluation for process optimization. The framework allows the application of state-of-the-art experimental and modeling techniques to assess the effectiveness of the treatment under different field conditions and is designed for application as a part of a feasibility study. Through a stepwise process it is possible to assess the effectiveness of in-situ AC amendment with a proper consideration of different site conditions and application scenarios possible in the field. The methodology incorporates the effect of various parameters on performance including: site-specific kinetic coefficients, varied AC dose and particle size, sediment and AC sorption parameters, and pore-water velocity. The modeling framework allows comparison of design alternatives for treatment optimization and estimation of long-term effectiveness over a period of 10-20 years under slow mass transfer in the field.

  View details for DOI 10.1016/j.jhazmat.2015.12.019

  View details for PubMedID 26736169

• Development of a novel non-equilibrium passive sampling method using polyethylene with multiple thicknesses Kim, K., Jung, J., Choi, Y., Luthy, R. AMER CHEMICAL SOC. 2016

  View details for Web of Science ID 000431905701113

• Discovery of benzotriazole and novel plant metabolites in Arabidopsis and food crops LeFevre, G., Lipsky, A., Sattely, E., Higgins, C., Hyland, K., Luthy, R. AMER CHEMICAL SOC. 2016

  View details for Web of Science ID 000431905700575

• Secondary environmental impacts of remedial alternatives for sediment contaminated with hydrophobic organic contaminants JOURNAL OF HAZARDOUS MATERIALS Choi, Y., Thompson, J. M., Lin, D., Cho, Y., Ismail, N. S., Hsieh, C., Luthy, R. G. 2016; 304: 352-359

  Abstract

  This study evaluates secondary environmental impacts of various remedial alternatives for sediment contaminated with hydrophobic organic contaminants using life cycle assessment (LCA). Three alternatives including two conventional methods, dredge-and-fill and capping, and an innovative sediment treatment technique, in-situ activated carbon (AC) amendment, are compared for secondary environmental impacts by a case study for a site at Hunters Point Shipyard, San Francisco, CA. The LCA results show that capping generates substantially smaller impacts than dredge-and-fill and in-situ amendment using coal-based virgin AC. The secondary impacts from in-situ AC amendment can be reduced effectively by using recycled or wood-based virgin AC as production of these materials causes much smaller impacts than coal-based virgin AC. The secondary environmental impacts are highly sensitive to the dredged amount and the distance to a disposal site for dredging, the capping thickness and the distance to the cap materials for capping, and the AC dose for in-situ AC amendment. Based on the analysis, this study identifies strategies to minimize secondary impacts caused by different remediation activities: optimize the dredged amount, the capping thickness, or the AC dose by extensive site assessments, obtain source materials from local sites, and use recycled or bio-based AC.

  View details for DOI 10.1016/j.jhazmat.2015.09.069

  View details for Web of Science ID 000367699200039

• Secondary environmental impacts of remedial alternatives for sediment contaminated with hydrophobic organic contaminants. Journal of hazardous materials Choi, Y., Thompson, J. M., Lin, D., Cho, Y. M., Ismail, N. S., Hsieh, C. H., Luthy, R. G. 2016; 304: 352-9

  Abstract

  This study evaluates secondary environmental impacts of various remedial alternatives for sediment contaminated with hydrophobic organic contaminants using life cycle assessment (LCA). Three alternatives including two conventional methods, dredge-and-fill and capping, and an innovative sediment treatment technique, in-situ activated carbon (AC) amendment, are compared for secondary environmental impacts by a case study for a site at Hunters Point Shipyard, San Francisco, CA. The LCA results show that capping generates substantially smaller impacts than dredge-and-fill and in-situ amendment using coal-based virgin AC. The secondary impacts from in-situ AC amendment can be reduced effectively by using recycled or wood-based virgin AC as production of these materials causes much smaller impacts than coal-based virgin AC. The secondary environmental impacts are highly sensitive to the dredged amount and the distance to a disposal site for dredging, the capping thickness and the distance to the cap materials for capping, and the AC dose for in-situ AC amendment. Based on the analysis, this study identifies strategies to minimize secondary impacts caused by different remediation activities: optimize the dredged amount, the capping thickness, or the AC dose by extensive site assessments, obtain source materials from local sites, and use recycled or bio-based AC.

  View details for DOI 10.1016/j.jhazmat.2015.09.069

  View details for PubMedID 26590871

• Predicted effectiveness of in-situ activated carbon amendment for field sediment sites with variable site- and compound-specific characteristics JOURNAL OF HAZARDOUS MATERIALS Choi, Y., Cho, Y., Luthy, R. G., Werner, D. 2016; 301: 424-432

  Abstract

  A growing body of evidence shows that the effectiveness of in-situ activated carbon (AC) amendment to treat hydrophobic organic contaminants (HOCs) in sediments can be reliably predicted using a mass transfer modeling approach. This study analyzes available field data for characterizing AC-sediment distribution after mechanical mixing of AC into sediment. Those distributions are used to develop an HOC mass transfer model that accounts for plausible heterogeneities resulting from mixing of AC into sediment. The model is applied to ten field sites in the U.S. and Europe with 2-3 representative HOCs from each site using site- and HOC-specific model parameters collected from the literature. The model predicts that the AC amendment reduces the pore-water HOC concentrations by more than 95% fifteen years after AC deployment for 18 of the 25 total simulated cases when the AC is applied at doses of 1.5 times sediment total organic carbon content with an upper limit of 5 dry wt%. The predicted effectiveness shows negative correlation with the HOC octanol-water partitioning coefficients and the sediment-water distribution coefficients, and positive correlation with the effectiveness calculated based on equilibrium coefficients of sediment and AC, suggesting the possibility for use of the values for screening-level assessments.

  View details for DOI 10.1016/j.jhazmat.2015.09.016

  View details for Web of Science ID 000367407200046

• Predicted effectiveness of in-situ activated carbon amendment for field sediment sites with variable site- and compound-specific characteristics. Journal of hazardous materials Choi, Y., Cho, Y. M., Luthy, R. G., Werner, D. 2016; 301: 424-32

  Abstract

  A growing body of evidence shows that the effectiveness of in-situ activated carbon (AC) amendment to treat hydrophobic organic contaminants (HOCs) in sediments can be reliably predicted using a mass transfer modeling approach. This study analyzes available field data for characterizing AC-sediment distribution after mechanical mixing of AC into sediment. Those distributions are used to develop an HOC mass transfer model that accounts for plausible heterogeneities resulting from mixing of AC into sediment. The model is applied to ten field sites in the U.S. and Europe with 2-3 representative HOCs from each site using site- and HOC-specific model parameters collected from the literature. The model predicts that the AC amendment reduces the pore-water HOC concentrations by more than 95% fifteen years after AC deployment for 18 of the 25 total simulated cases when the AC is applied at doses of 1.5 times sediment total organic carbon content with an upper limit of 5 dry wt%. The predicted effectiveness shows negative correlation with the HOC octanol-water partitioning coefficients and the sediment-water distribution coefficients, and positive correlation with the effectiveness calculated based on equilibrium coefficients of sediment and AC, suggesting the possibility for use of the values for screening-level assessments.

  View details for DOI 10.1016/j.jhazmat.2015.09.016

  View details for PubMedID 26410271

• Novel Probe for in Situ Measurement of Freely Dissolved Aqueous Concentration Profiles of Hydrophobic Organic Contaminants at the Sediment-Water Interface ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Lin, D., Eek, E., Oen, A., Cho, Y., Cornelissen, G., Tommerdahl, J., Luthy, R. G. 2015; 2 (11): 320-324

  View details for DOI 10.1021/acs.estlett.5b00239

  View details for Web of Science ID 000364622800005

• Wastewater-effluent-dominated streams as ecosystem-management tools in a drier climate FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Luthy, R. G., Sedlak, D. L., Plumlee, M. H., Austin, D., Resh, V. H. 2015; 13 (9): 477-485

  View details for DOI 10.1890/150038

  View details for Web of Science ID 000364503100004

• Rapid Phytotransformation of Benzotriazole Generates Synthetic Tryptophan and Auxin Analogs in Arabidopsis. Environmental science & technology Lefevre, G. H., Müller, C. E., Li, R. J., Luthy, R. G., Sattely, E. S. 2015; 49 (18): 10959-10968

  Abstract

  Benzotriazoles (BTs) are xenobiotic contaminants widely distributed in aquatic environments and of emerging concern due to their polarity, recalcitrance, and common use. During some water reclamation activities, such as stormwater bioretention or crop irrigation with recycled water, BTs come in contact with vegetation, presenting a potential exposure route to consumers. We discovered that BT in hydroponic systems was rapidly (approximately 1-log per day) assimilated by Arabidopsis plants and metabolized to novel BT metabolites structurally resembling tryptophan and auxin plant hormones; <1% remained as parent compound. Using LC-QTOF-MS untargeted metabolomics, we identified two major types of BT transformation products: glycosylation and incorporation into the tryptophan biosynthetic pathway. BT amino acid metabolites are structurally analogous to tryptophan and the storage forms of auxin plant hormones. Critical intermediates were synthesized (authenticated by (1)H/(13)C NMR) for product verification. In a multiple-exposure temporal mass balance, three major metabolites accounted for >60% of BT. Glycosylated BT was excreted by the plants into the hydroponic medium, a phenomenon not observed previously. The observed amino acid metabolites are likely formed when tryptophan biosynthetic enzymes substitute synthetic BT for native indolic molecules, generating potential phytohormone mimics. These results suggest that BT metabolism by plants could mask the presence of BT contamination in the environment. Furthermore, BT-derived metabolites are structurally related to plant auxin hormones and should be evaluated for undesirable biological effects.

  View details for DOI 10.1021/acs.est.5b02749

  View details for PubMedID 26301449

• Urban Water-Supply Reinvention DAEDALUS Luthy, R. G., Sedlak, D. L. 2015; 144 (3): 72-82

  View details for DOI 10.1162/DAED_a_00343

  View details for Web of Science ID 000357859800008

• In situ sediment treatment using activated carbon: A demonstrated sediment cleanup technology. Integrated environmental assessment and management Patmont, C. R., Ghosh, U., LaRosa, P., Menzie, C. A., Luthy, R. G., Greenberg, M. S., Cornelissen, G., Eek, E., Collins, J., Hull, J., Hjartland, T., Glaza, E., Bleiler, J., Quadrini, J. 2015; 11 (2): 195-207

  Abstract

  This paper reviews general approaches for applying activated carbon (AC) amendments as an in situ sediment treatment remedy. In situ sediment treatment involves targeted placement of amendments using installation options that fall into two general approaches: 1) directly applying a thin layer of amendments (which potentially incorporates weighting or binding materials) to surface sediment, with or without initial mixing; and 2) incorporating amendments into a premixed, blended cover material of clean sand or sediment, which is also applied to the sediment surface. Over the past decade, pilot- or full-scale field sediment treatment projects using AC-globally recognized as one of the most effective sorbents for organic contaminants-were completed or were underway at more than 25 field sites in the United States, Norway, and the Netherlands. Collectively, these field projects (along with numerous laboratory experiments) have demonstrated the efficacy of AC for in situ treatment in a range of contaminated sediment conditions. Results from experimental studies and field applications indicate that in situ sequestration and immobilization treatment of hydrophobic organic compounds using either installation approach can reduce porewater concentrations and biouptake significantly, often becoming more effective over time due to progressive mass transfer. Certain conditions, such as use in unstable sediment environments, should be taken into account to maximize AC effectiveness over long time periods. In situ treatment is generally less disruptive and less expensive than traditional sediment cleanup technologies such as dredging or isolation capping. Proper site-specific balancing of the potential benefits, risks, ecological effects, and costs of in situ treatment technologies (in this case, AC) relative to other sediment cleanup technologies is important to successful full-scale field application. Extensive experimental studies and field trials have shown that when applied correctly, in situ treatment via contaminant sequestration and immobilization using a sorbent material such as AC has progressed from an innovative sediment remediation approach to a proven, reliable technology. Integr Environ Assess Manag 2015; 11:195-207. © 2014 The Authors. Published 2014 SETAC.

  View details for DOI 10.1002/ieam.1589

  View details for PubMedID 25323491

  View details for PubMedCentralID PMC4409844

• Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers. Environmental science & technology Thompson, J. M., Hsieh, C., Luthy, R. G. 2015; 49 (4): 2270-2277

  Abstract

  Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness.

  View details for DOI 10.1021/es504442s

  View details for PubMedID 25607420

• Improvement of Urban Lake Water Quality by Removal of Escherichia coli through the Action of the Bivalve Anodonta californiensis. Environmental science & technology Ismail, N. S., Dodd, H., Sassoubre, L. M., Horne, A. J., Boehm, A. B., Luthy, R. G. 2015; 49 (3): 1664-1672

  Abstract

  High levels of fecal indicator bacteria, such as Escherichia coli, can be indicative of poor water quality. The use of shellfish to reduce eutrophication has been proposed, but application of bivalves to reduce bacterial levels has not been extensively reported. Removal of E. coli by the native freshwater mussel Anodonta californiensis was studied using laboratory batch systems and field-based flow-through systems. Batch systems were utilized to determine the fate and inactivation of E. coli after uptake by the mussel. Batch experiments demonstrated that uptake patterns followed first order kinetics and E. coli was inactivated with less than 5% of the initial colonies recoverable in fecal matter or tissue. Flow-through systems located at an urban impaired lake in San Francisco, CA were utilized to determine uptake kinetics under environmentally relevant conditions. The bivalves maintained a 1-log removal of E. coli for the duration of exposure. The calculated uptake rates can be used in conjunction with hydrologic models to determine the number of bivalves needed to maintain removal of E. coli in different freshwater systems. The outcomes of this study support the use of native freshwater bivalves to achieve the co-benefits of rehabilitating a freshwater ecosystem and improving water quality via reduction of E. coli in contaminated freshwater systems.

  View details for DOI 10.1021/es5033212

  View details for PubMedID 25587628

• Issues of Governance, Policy, and Law in Managing Urban-Rural and Groundwater-Surface Water Connections Nelson, R., Bischel, H. N., Luthy, R. G., Thompson, B. H., Grafton, Q., Daniell, K. A., Nauges, C., Rinaudo, J. D., Chan, N. W. SPRINGER-VERLAG BERLIN. 2015: 463–88

  View details for DOI 10.1007/978-94-017-9801-3_22

  View details for Web of Science ID 000380452200022

• Assessment of the crop coefficient for saltgrass under native riparian field conditions in the desert southwest HYDROLOGICAL PROCESSES Bawazir, A. S., Luthy, R., King, J. P., Tanzy, B. F., Solis, J. 2014; 28 (25): 6163-6171

  View details for DOI 10.1002/hyp.10100

  View details for Web of Science ID 000346337400013

• Engagement at the Science-Policy Interface ENVIRONMENTAL SCIENCE & TECHNOLOGY Hering, J. G., Dzombak, D. A., Green, S. A., Luthy, R. G., Swackhamer, D. 2014; 48 (19): 11031-11033

  View details for DOI 10.1021/es504225t

  View details for Web of Science ID 000343016600005

• Engagement at the science-policy interface. Environmental science & technology Hering, J. G., Dzombak, D. A., Green, S. A., Luthy, R. G., Swackhamer, D. 2014; 48 (19): 11031-11033

  View details for DOI 10.1021/es504225t

  View details for PubMedID 25258185

• Uptake of Contaminants of Emerging Concern by the Bivalves Anodonta californiensis and Corbicula fluminea. Environmental science & technology Ismail, N. S., Müller, C. E., Morgan, R. R., Luthy, R. G. 2014; 48 (16): 9211-9219

  Abstract

  Uptake of seven contaminants regularly detected in surface waters and spanning a range of hydrophobicities (log D(ow) -1 to 5) was studied for two species of freshwater bivalves, the native mussel Anodonta californiensis and the invasive clam Corbicula fluminea. Batch systems were utilized to determine compound partitioning, and flow-through systems, comparable to environmental conditions in effluent dominated surface waters, were used to determine uptake and depuration kinetics. Uptake of compounds was independent of bivalve type. Log bioconcentration factor (BCF) values were correlated with log D(ow) for nonionized compounds with the highest BCF value obtained for triclocarban (TCC). TCC concentrations were reduced in the water column due to bivalve activity. Anionic compounds with low D(ow) values, i.e., clofibric acid and ibuprofen, were not removed from water, while the organic cation propranolol showed biouptake similar to that of TCC. Batch experiments supported compound uptake patterns observed in flow-through experiments. Contaminant removal from water was observed through accumulation in tissue or settling as excreted pseudofeces or feces. The outcomes of this study indicate the potential utility of bivalve augmentation to improve water quality by removing hydrophobic trace organic compounds found in natural systems.

  View details for DOI 10.1021/es5011576

  View details for PubMedID 25017714

• Use of bivalves in natural systems for removal of contaminants of emerging concern Ismail, N. S., Mueller, C. E., Morgan, R. R., Luthy, R. G. AMER CHEMICAL SOC. 2014

  View details for Web of Science ID 000349165105717

• Thin-layer AC placement for sequestering DDT contaminated sediment facilitated by bioturbation Lin, D., Cho, Y., Werner, D., Tommerdahl, J., Luthy, R. G. AMER CHEMICAL SOC. 2014

  View details for Web of Science ID 000349167400062

• Remedy performance monitoring at contaminated sediment sites using profiling solid phase microextraction (SPME) polydimethylsiloxane (PDMS) fibers (vol 16, pg 445, 2014) ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS Thomas, C., Lampert, D., Reible, D., Janssen, E., Luthy, R. G. 2014; 16 (8): 2049

  View details for Web of Science ID 000340081400027

• In Situ Sequestration of Hydrophobic Organic Contaminants in Sediments under Stagnant Contact with Activated Carbon. 1. Column Studies. Environmental science & technology Choi, Y., Cho, Y., Luthy, R. G. 2014; 48 (3): 1835-1842

  Abstract

  The effectiveness of activated carbon (AC) treatment to sequester hydrophobic organic contaminants in sediments under stagnant contact was comprehensively studied for the first time. Two years of column experiments were conducted to simulate field conditions with two study sediments contaminated with petroleum and polychlorinated biphenyls, respectively, and variations in AC-sediment contact times, initial AC mixing regimes and distribution, AC particle sizes, and pore-water flow. The benefit of AC treatment was gradually enhanced with time toward the end point of the treatment, where sorption equilibrium is established between sediment and AC. After two years of stagnant contact, the contaminant uptake in polyethylene passive samplers embedded in the columns was reduced by 95-99% for polycyclic aromatic hydrocarbons and 93-97% for polychlorinated biphenyls with 5 and 4 wt % AC dose, respectively, when AC was initially applied by mechanical mixing. These results verify that AC treatment can effectively control the availability of hydrophobic organic contaminants under stagnant conditions within a reasonable time frame following an initial distribution of AC into the sediment. The effectiveness of AC treatment was strongly dependent on AC particle size and AC distribution, while the effect of AC initial mixing regimes and pore-water flow was not pronounced.

  View details for DOI 10.1021/es403335g

  View details for PubMedID 24083415

• In Situ Sequestration of Hydrophobic Organic Contaminants in Sediments under Stagnant Contact with Activated Carbon. 2. Mass Transfer Modeling. Environmental science & technology Choi, Y., Cho, Y., Werner, D., Luthy, R. G. 2014; 48 (3): 1843-1850

  Abstract

  The validity of a hydrophobic organic contaminant mass transfer model to predict the effectiveness of in situ activated carbon (AC) treatment under stagnant sediment-AC contact is studied for different contaminants and sediments. The modeling results and data from a previous 24-month column experiment of uptake in polyethylene samplers are within a factor of 2 for parent- and alkylated-polycyclic aromatic hydrocarbons in petroleum-impacted sediment and factors of 3-10 for polychlorinated biphenyls. The model successfully reproduces the relative effects of AC-sediment contact time, contaminant properties, AC particle size, AC mixing regime, AC distribution, and hydraulic conditions observed in the sediment column experiments. The model tracks contaminant concentrations in different sediment compartments over time, which provides useful information on the contaminant sequestration by the added AC. Long-term projection of the effectiveness of AC amendment using the model shows that the effects of AC particle size and particle-scale heterogeneity in AC distribution are pronounced within a year or so. However, the effect of those factors becomes less significant after a much longer contact period (on the order of a decade or two), resulting in substantial reduction in pore-water concentrations, for example, greater than 99% for benz[a]anthracene, under various scenarios.

  View details for DOI 10.1021/es404209v

  View details for PubMedID 24410479

• Bioturbation Delays Attenuation of DDT by Clean Sediment Cap but Promotes Sequestration by Thin-Layered Activated Carbon ENVIRONMENTAL SCIENCE & TECHNOLOGY Lin, D., Cho, Y., Werner, D., Luthy, R. G. 2014; 48 (2): 1175-1183

  Abstract

  The effects of bioturbation on the performance of attenuation by sediment deposition and activated carbon to reduce risks from DDT-contaminated sediment were assessed for DDT sediment-water flux, biouptake, and passive sampler (PE) uptake in microcosm experiments with a freshwater worm, Lumbriculus variegatus. A thin-layer of clean sediment (0.5 cm) did not reduce the DDT flux when bioturbation was present, while a thin (0.3 cm) AC cap was still capable of reducing the DDT flux by 94%. Bioturbation promoted AC sequestration by reducing the 28-day DDT biouptake (66%) and DDT uptake into PE (>99%) compared to controls. Bioturbation further promoted AC-sediment contact by mixing AC particles into underlying sediment layers, reducing PE uptake (55%) in sediment compared to the AC cap without bioturbation. To account for the observed effects from bioturbation, a mass transfer model together with a biodynamic model were developed to simulate DDT flux and biouptake, respectively, and models confirmed experimental results. Both experimental measurements and modeling predictions imply that thin-layer activated carbon placement on sediment is effective in reducing the risks from contaminated sediments in the presence of bioturbation, while natural attenuation process by clean sediment deposition may be delayed by bioturbation.

  View details for DOI 10.1021/es404108h

  View details for Web of Science ID 000330205000042

  View details for PubMedID 24359108

• Recycled water for augmenting urban streams in mediterranean-climate regions: a potential approach for riparian ecosystem enhancement HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES Lawrence, J. E., Pavia, C. P., Kaing, S., Bischel, H. N., Luthy, R. G., Resh, V. H. 2014; 59 (3-4): 488-501

  View details for DOI 10.1080/02626667.2013.818221

  View details for Web of Science ID 000337085100004

• Economic and Ecological Costs and Benefits of Streamflow Augmentation Using Recycled Water in a California Coastal Stream ENVIRONMENTAL SCIENCE & TECHNOLOGY Halaburka, B. J., Lawrence, J. E., Bischel, H. N., Hsiao, J., Plumlee, M. H., Resh, V. H., Luthy, R. G. 2013; 47 (19): 10735-10743

  Abstract

  Streamflow augmentation has the potential to become an important application of recycled water in water scarce areas. We assessed the economic and ecological merits of a recycled water project that opted for an inland release of tertiary-treated recycled water in a small stream and wetland compared to an ocean outfall discharge. Costs for the status-quo scenario of discharging secondary-treated effluent to the ocean were compared to those of the implemented scenario of inland streamflow augmentation using recycled water. The benefits of the inland-discharge scenario were greater than the increase in associated costs by US$1.8M, with recreational value and scenic amenity generating the greatest value. We also compared physical habitat quality, water quality, and benthic macroinvertebrate community upstream and downstream of the recycled water discharge to estimate the effect of streamflow augmentation on the ecosystem. The physical-habitat quality was higher downstream of the discharge, although streamflow came in unnatural diurnal pulses. Water quality remained relatively unchanged with respect to dissolved oxygen, pH, and ammonia-nitrogen, although temperatures were elevated. Benthic macroinvertebrates were present in higher abundances, although the diversity was relatively low. A federally listed species, the California red-legged frog (Rana draytonii), was present. Our results may support decision-making for wastewater treatment alternatives and recycled water applications in Mediterranean climates.

  View details for DOI 10.1021/es305011z

  View details for Web of Science ID 000330094900004

  View details for PubMedID 23688175

• Design options for a more sustainable urban water environment. Environmental science & technology Luthy, R. G. 2013; 47 (19): 10719-20

  View details for DOI 10.1021/es403728p

  View details for PubMedID 24079919

• A Changing Framework for Urban Water Systems ENVIRONMENTAL SCIENCE & TECHNOLOGY Hering, J. G., Waite, T. D., Luthy, R. G., Drewes, J. E., Sedlak, D. L. 2013; 47 (19): 10721-10726

  Abstract

  Urban water infrastructure and the institutions responsible for its management have gradually evolved over the past two centuries. Today, they are under increasing stress as water scarcity and a growing recognition of the importance of factors other than the cost of service provision are forcing a reexamination of long-held ideas. Research and development that supports new technological approaches and more effective management strategies are needed to ensure that the emerging framework for urban water systems will meet future societal needs.

  View details for DOI 10.1021/es4007096

  View details for Web of Science ID 000330094900002

  View details for PubMedID 23650975

• Renewing Urban Streams with Recycled Water for Streamflow Augmentation: Hydrologic, Water Quality, and Ecosystem Services Management ENVIRONMENTAL ENGINEERING SCIENCE Bischel, H. N., Lawrence, J. E., Halaburka, B. J., Plumlee, M. H., Bawazir, A. S., King, J. P., McCray, J. E., Resh, V. H., Luthy, R. G. 2013; 30 (8): 455-479

  View details for DOI 10.1089/ees.2012.0201

  View details for Web of Science ID 000323206400006

• Hyporheic Zone in Urban Streams: A Review and Opportunities for Enhancing Water Quality and Improving Aquatic Habitat by Active Management ENVIRONMENTAL ENGINEERING SCIENCE Lawrence, J. E., Skold, M. E., Hussain, F. A., Silverman, D. R., Resh, V. H., Sedlak, D. L., Luthy, R. G., McCray, J. E. 2013; 30 (8): 480-501

  View details for DOI 10.1089/ees.2012.0235

  View details for Web of Science ID 000323206400007

• Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents ENVIRONMENTAL ENGINEERING SCIENCE Jasper, J. T., Nguyen, M. T., Jones, Z. L., Ismail, N. S., Sedlak, D. L., Sharp, J. O., Luthy, R. G., Horne, A. J., Nelson, K. L. 2013; 30 (8): 421-436

  Abstract

  Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe.

  View details for DOI 10.1089/ees.2012.0239

  View details for Web of Science ID 000323206400004

  View details for PubMedCentralID PMC3746285

• Polyethylene-Water Partitioning Coefficients for Parent- and Alkylated-Polycyclic Aromatic Hydrocarbons and Polychlorinated Biphenyls ENVIRONMENTAL SCIENCE & TECHNOLOGY Choi, Y., Cho, Y., Luthy, R. G. 2013; 47 (13): 6943-6950

  Abstract

  We report polyethylene (PE)-water partitioning coefficients (K(PE)) for 17 parent-polycyclic aromatic hydrocarbons (PAHs), 22 alkylated-PAHs, 3 perdeuterated parent-PAHs, and 100 polychlorinated biphenyl (PCB) congeners or coeluting congener groups. The K(PE) values for compounds in the same homologue group are within 0.2 log units for alkylated-PAHs but span up to an order of magnitude for PCBs, due to the greater contribution of the position of the substituents (i.e., chlorines for PCBs and alkyl groups for alkylated-PAHs) to the molecular structure. The K(PE) values in deionized water for parent- and alkylated-PAHs show a good correlation with a regression model employing the number of aromatic carbons (C(AR)) and aliphatic carbons (C(AL)) in each compound: log K(PE) = -0.241 + 0.313 C(AR) + 0.461 C(AL). The regression model is useful for the assessment of freely dissolved aqueous concentrations of alkylated-PAHs, which comprise a significant fraction of the total in petroleum-derived PAHs and in some pyrogenic PAH mixtures. For PCBs, experimentally determined octanol-water partitioning coefficients are the best predictor of the K(PE) values among the molecular parameters studied. The effect of salinity up to 20 or 30 parts per thousand is found to be relatively insignificant on K(PE) values for PAHs or PCBs, respectively.

  View details for DOI 10.1021/es304566v

  View details for Web of Science ID 000321521400029

  View details for PubMedID 23488618

• Measurement and Modeling of Activated Carbon Performance for the Sequestration of Parent- and Alkylated-Polycyclic Aromatic Hydrocarbons in Petroleum-Impacted Sediments ENVIRONMENTAL SCIENCE & TECHNOLOGY Choi, Y., Cho, Y., Gala, W. R., Luthy, R. G. 2013; 47 (2): 1024-1032

  Abstract

  We present a first comprehensive set of experiments that demonstrate the performance of activated carbon (AC) to reduce the availability of polycyclic aromatic hydrocarbons (PAHs) including alkylated-PAHs in petroleum-impacted sediments. The uptake in polyethylene samplers for total PAHs in a well-mixed sediment slurry was reduced up to 99% and 98% for petroleum-impacted sediments with oil contents of 1% and 2%, respectively, by treatment with 5% AC. The AC showed similar efficiency for parent-PAHs and a suite of alkylated-PAHs, which predominate over parent-PAHs in petroleum-impacted sediments. A mass transfer model was used to simulate the AC performance in a slurry phase with site-specific mass transfer parameters determined in this study. Comparison between the experimental data and simulation results suggested that dissolved organic matter and/or oil phase may have attenuated the AC performance by a factor of 5-6 for 75-300 μm AC with 5% dose at one month. The attenuation in AC performance became negligible with increase in AC-sediment slurry contact time to 12 months and with decrease in AC particle size. The results show the potential for AC amendment to sequester PAHs in petroleum-impacted sediments and the effect of contact time and AC particle size on the efficiency of the treatment.

  View details for DOI 10.1021/es303770c

  View details for Web of Science ID 000313667400045

  View details for PubMedID 23240641

• A Changing Framework for Urban Water Systems Environmental Science & Technology, ASAP Hering, Janet, G., Waite, T., David, Luthy, Richard, G., Drewes, Jorg, E., Sedlak, David, L. 2013

  View details for DOI 10.1021/es4007096

• Assessment of the crop coefficient for saltgrass under native riparian field conditions in the desert southwest Hydrological Processes Bawazir, A. S., Luthy, R., King, J. P., Tanzy, B. F., Solis, J. 2013

  View details for DOI 10.1002/hyp.10100

• Economic and Ecological Costs and Benefits of Streamflow Augmentation Using Recycled Water in a California Coastal Stream Environmental Science & Technology Halaburka, Brian, J., Lawrence, Justin, E., Bischel, Heather, N., Hsiao, J., Plumlee, Megan, H., Resh, Vincent, H., Luthy, Richard, G. 2013

  View details for DOI 10.1021/es305011z

• Hyporheic zone in urban streams: A review and opportunities for enhancing water quality and improving aquatic habitat by active management Environmental Engineering Science Lawrence, J. E., Skold, M. E., Hussain, F. A., Silverman, D. R., Resh, V. H., Sedlak, D. L., Luthy, Richard, G. 2013; 8 (30): 480-501

  View details for DOI 10.1089/ees.2012.0235

• Introduction: Reinventing Urban Water Infrastructure Environmental Engineering Science Sedlak, D. L., Drewes, J. E., Luthy, R. G. 2013; 30 (8): 393-394

  View details for DOI 10.1089/ees.2013.3008

• Design Options for a More Sustainable Urban Water Environment Environmental Science & Technology Luthy, R. G. 2013; 47 (19): 10719-10720

  View details for DOI 10.1021/es403728p

• Kinetics and pathways for the debromination of polybrominated diphenyl ethers by bimetallic and nanoscale zerovalent iron: Effects of particle properties and catalyst CHEMOSPHERE Zhuang, Y., Jin, L., Luthy, R. G. 2012; 89 (4): 426-432

  Abstract

  Polybrominated diphenyl ethers (PBDEs) are recognized as a new class of widely-distributed and persistent contaminants for which effective treatment and remediation technologies are needed. In this study, two kinds of commercially available nanoscale Fe(0) slurries (Nanofer N25 and N25S), a freeze-dried laboratory-synthesized Fe(0) nanoparticle (nZVI), and their palladized forms were used to investigate the effect of particle properties and catalyst on PBDE debromination kinetics and pathways. Nanofers and their palladized forms were found to debrominate PBDEs effectively. The laboratory-synthesized Fe(0) nanoparticles also debrominated PBDEs, but were slower due to deactivation by the freeze-drying and stabilization processes in the laboratory synthesis. An organic modifier, polyacrylic acid (PAA), bound on N25S slowed PBDE debromination by a factor of three to four compared to N25. The activity of palladized nZVI (nZVI/Pd) was optimized at 0.3 Pd/Fe wt% in our system. N25 could debrominate selected environmentally-abundant PBDEs, including BDE 209, 183, 153, 99, and 47, to end products di-BDEs, mono-BDEs and diphenyl ether (DE) in one week, while nZVI/Pd (0.3 Pd/Fe wt%) mainly resulted in DE as a final product. Step-wise major PBDE debromination pathways by unamended and palladized Fe(0) are described and compared. Surface precursor complex formation is an important limiting factor for palladized Fe(0) reduction as demonstrated by PBDE pathways where steric hindrance and rapid sequential debromination of adjacent bromines play an important role.

  View details for DOI 10.1016/j.chemosphere.2012.05.078

  View details for Web of Science ID 000307626000011

  View details for PubMedID 22732301

  View details for PubMedCentralID PMC3408778

• Assessment of Nontoxic, Secondary Effects of Sorbent Amendment to Sediments on the Deposit-Feeding Organism Neanthes arenaceodentata ENVIRONMENTAL SCIENCE & TECHNOLOGY Janssen, E. M., Choi, Y., Luthy, R. G. 2012; 46 (7): 4134-4141

  Abstract

  Activated carbon (AC) amendments to sediments were tested for nontoxic, secondary effects on survival, weight change, and energetic biomarkers of the deposit feeder Neanthes arenaceodentata. The tests employed silica sand, reference sediments, and contaminated sediments. Survival was not affected by the sediment type, the AC dose (20% versus 5%), or the AC particle size. Without additional food supply, exposure to untreated and AC-amended sediments resulted in similar reduction of weight and lipid content, with no difference between ingestible and noningestible AC. Overall, whether with or without AC, the organisms showed signs of starvation, as the organisms would most likely rely on organic surface deposits for their diet in the environments from which the sediments were collected. When additional food was supplied, the organisms grew significantly and maintained higher lipid and glycogen contents. However, when feeding on fish food, organisms grew less in AC amendments with slightly lower lipid and glycogen contents relative to organisms exposed to untreated sediment. Batch tests show that AC did not sorb sediment-associated nitrogen but sorbed nitrogen from fish food. Despite some effects of AC on these deposit feeders, absolute effects of AC amendments on growth and energy reserves were not significant.

  View details for DOI 10.1021/es204066g

  View details for Web of Science ID 000302850400070

  View details for PubMedID 22372688

• Kinetics and pathways for the debromination of polybrominated diphenyl ethers by bimetallic and nanoscale zerovalent iron: Effects of material properties and catalyst Zhuang, Y., Jin, L., Luthy, R. G. AMER CHEMICAL SOC. 2012

  View details for Web of Science ID 000324475105279

• Hunters Point seven-year narrative: In situ sequestration of HOCs in sediment by activated carbon sorbent amendment[p] Cho, Y., Choi, Y., Werner, D., Luthy, R. G. AMER CHEMICAL SOC. 2012

  View details for Web of Science ID 000324475104887

• Long-term monitoring and modeling of the mass transfer of polychlorinated biphenyls in sediment following pilot-scale in-situ amendment with activated carbon. Journal of contaminant hydrology Cho, Y., Werner, D., Choi, Y., Luthy, R. G. 2012; 129-130: 25-37

  Abstract

  The results of five years of post-treatment monitoring following in-situ activated carbon (AC) placement for stabilization of polychlorinated biphenyls (PCBs) at an inter-tidal mudflat adjacent to Hunters Point Shipyard, San Francisco Bay, CA, USA are reported in this paper. After five years, AC levels of the sediment cores were comparable to those at earlier sampling times. Passive sampler uptake validated the benefit of the AC amendment with a strong local sorbent dose-response relationship. The PCB uptakes in passive samplers decreased up to 73% with a 3.7 dry wt.% AC dose after five years, confirming the temporal enhancement of the amendment benefit from a 19% reduction with a 4.4% dose observed within one month. The long-term effectiveness of AC, the local AC dose response, the impact of fouling by NOM, the spatial heterogeneity of AC incorporation, and the effects of advective sediment pore-water movement are discussed with the aid of a PCB mass transfer model. Modeling and experimental results indicated that the homogeneous incorporation of AC in the sediment will significantly accelerate the benefit of the treatment.

  View details for DOI 10.1016/j.jconhyd.2011.09.009

  View details for PubMedID 22055155

• Long-term monitoring and modeling of the mass transfer of polychlorinated biphenyls in sediment following pilot-scale in-situ amendment with activated carbon JOURNAL OF CONTAMINANT HYDROLOGY Cho, Y., Werner, D., Choi, Y., Luthy, R. G. 2012; 129: 25-37

  Abstract

  The results of five years of post-treatment monitoring following in-situ activated carbon (AC) placement for stabilization of polychlorinated biphenyls (PCBs) at an inter-tidal mudflat adjacent to Hunters Point Shipyard, San Francisco Bay, CA, USA are reported in this paper. After five years, AC levels of the sediment cores were comparable to those at earlier sampling times. Passive sampler uptake validated the benefit of the AC amendment with a strong local sorbent dose-response relationship. The PCB uptakes in passive samplers decreased up to 73% with a 3.7 dry wt.% AC dose after five years, confirming the temporal enhancement of the amendment benefit from a 19% reduction with a 4.4% dose observed within one month. The long-term effectiveness of AC, the local AC dose response, the impact of fouling by NOM, the spatial heterogeneity of AC incorporation, and the effects of advective sediment pore-water movement are discussed with the aid of a PCB mass transfer model. Modeling and experimental results indicated that the homogeneous incorporation of AC in the sediment will significantly accelerate the benefit of the treatment.

  View details for DOI 10.1016/j.jconhyd.2011.09.009

  View details for Web of Science ID 000302437800005

• Intra-particle migration of mercury in granular polysulfide-rubber-coated activated carbon (PSR-AC) CHEMOSPHERE Kim, E., Masue-Slowey, Y., Fendorf, S., Luthy, R. G. 2012; 86 (6): 648-654

  Abstract

  The depth profile of mercuric ion after the reaction with polysulfide-rubber-coated activated carbon (PSR-AC) was investigated using micro-X-ray fluorescence (μ-XRF) imaging techniques and mathematical modeling. The μ-XRF results revealed that mercury was concentrated at 0-100 μm from the exterior of the particle after 3 months of treatment with PSR-AC in 10 ppm HgCl(2) aqueous solution. The μ-X-ray absorption near edge spectroscopic (μ-XANES) analyses indicated HgS as a major mercury species, and suggested that the intra-particle mercury transport involved a chemical reaction with PSR polymer. An intra-particle mass transfer model was developed based on either a Langmuir sorption isotherm with liquid phase diffusion (Langmuir model) or a kinetic sorption with surface diffusion (kinetic sorption model). The Langmuir model predicted the general trend of mercury diffusion, although at a slower rate than observed from the μ-XRF map. A kinetic sorption model suggested faster mercury transport, which overestimated the movement of mercuric ions through an exchange reaction between the fast and slow reaction sites. Both μ-XRF and mathematical modeling results suggest mercury removal occurs not only at the outer surface of the PSR-AC particle but also at some interior regions due to a large PSR surface area within an AC particle.

  View details for DOI 10.1016/j.chemosphere.2011.11.012

  View details for Web of Science ID 000301096200014

  View details for PubMedID 22133913

  View details for PubMedCentralID PMC3265622

• Sorption of Organic Compounds to Fresh and Field-Aged Activated Carbons in Soils and Sediments ENVIRONMENTAL SCIENCE & TECHNOLOGY Oen, A. M., Beckingham, B., Ghosh, U., Krusa, M. E., Luthy, R. G., Hartnik, T., Henriksen, T., Cornelissen, G. 2012; 46 (2): 810-817

  Abstract

  Activated carbon (AC) amendment to polluted sediment or soil is an emerging in situ treatment technique that reduces freely dissolved porewater concentrations and subsequently reduces the ecological and human health risk of hydrophobic organic compounds (HOCs). An important question is the capacity of the amended AC after prolonged exposure in the field. To address this issue, sorption of freshly spiked and native HOCs to AC aged under natural field conditions and fresh AC amendments was compared for one soil and two sediments. After 12-32 months of field aging, all AC amendments demonstrated effectiveness for reducing pore water concentrations of both native (30-95%) and spiked (10-90%) HOCs compared to unamended sediment or soil. Values of K(AC) for field-aged AC were lower than freshly added AC for spiked HOCs up to a factor of 10, while the effect was less for native HOCs. The different behavior in sorbing native HOCs compared to freshly spiked HOCs was attributed to differences in the sorption kinetics and degree of competition for sorption sites between the contaminants and pore-clogging natural organic matter. The implications of these findings are that amended AC can still be effective in sorbing additional HOCs some years following amendment in the field. Thus, a certain level of long-term sustainability of this remediation approach is observed, but conclusions for decade-long periods cannot be drawn solely based on the present study.

  View details for DOI 10.1021/es202814e

  View details for Web of Science ID 000299136200033

  View details for PubMedID 22128748

• Management Experiences and Trends for Water Reuse Implementation in Northern California ENVIRONMENTAL SCIENCE & TECHNOLOGY Bischel, H. N., Simon, G. L., Frisby, T. M., Luthy, R. G. 2012; 46 (1): 180-188

  Abstract

  In 2010, California fell nearly 300,000 acre-ft per year (AFY) short of its goal to recycle 1,000,000 AFY of municipal wastewater. Growth of recycled water in the 48 Northern California counties represented only 20% of the statewide increase in reuse between 2001 and 2009. To evaluate these trends and experiences, major drivers and challenges that influenced the implementation of recycled water programs in Northern California are presented based on a survey of 71 program managers conducted in 2010. Regulatory requirements limiting discharge, cited by 65% of respondents as a driver for program implementation, historically played an important role in motivating many water reuse programs in the region. More recently, pressures from limited water supplies and needs for system reliability are prevalent drivers. Almost half of respondents (49%) cited ecological protection or enhancement goals as drivers for implementation. However, water reuse for direct benefit of natural systems and wildlife habitat represents just 6-7% of total recycling in Northern California and few financial incentives exist for such projects. Economic challenges are the greatest barrier to successful project implementation. In particular, high costs of distribution systems (pipelines) are especially challenging, with $1 to 3 million/mile costs experienced. Negative perceptions of water reuse were cited by only 26% of respondents as major hindrances to implementation of surveyed programs.

  View details for DOI 10.1021/es202725e

  View details for Web of Science ID 000298762900026

  View details for PubMedID 22107126

• STRONG ASSOCIATIONS OF SHORT-CHAIN PERFLUOROALKYL ACIDS WITH SERUM ALBUMIN AND INVESTIGATION OF BINDING MECHANISMS ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Bischel, H. N., Macmanus-Spencer, L. A., Zhang, C., Luthy, R. G. 2011; 30 (11): 2423-2430

  Abstract

  Interactions of perfluoroalkyl acids (PFAAs) with tissue and serum proteins likely contribute to their tissue distribution and bioaccumulation patterns. Protein-water distribution coefficients (K(PW) ) based on ligand associations with bovine serum albumin (BSA) as a model protein were recently proposed as biologically relevant parameters to describe the environmental behavior of PFAAs, yet empirical data on such protein binding behavior are limited. In the present study, associations of perfluoroalkyl carboxylates (PFCAs) with two to 12 carbons (C₂-C₁₂) and perfluoroalkyl sulfonates with four to eight carbons (C₄, C₆, and C₈) with BSA are evaluated at low PFAA:albumin mole ratios and various solution conditions using equilibrium dialysis, nanoelectrospray ionization mass spectrometry, and fluorescence spectroscopy. Log K(PW) values for C₄ to C₁₂ PFAAs range from 3.3 to 4.3. Affinity for BSA increases with PFAA hydrophobicity but decreases from the C₈ to C₁₂ PFCAs, likely due to steric hindrances associated with longer and more rigid perfluoroalkyl chains. The C₄-sulfonate exhibits increased affinity relative to the equivalent chain-length PFCA. Fluorescence titrations support evidence that an observed dependence of PFAA-BSA binding on pH is attributable to conformational changes in the protein. Association constants determined for perfluorobutanesulfonate and perfluoropentanoate with BSA are on the order of those for long-chain PFAAs (K(a) ∼10⁶/M), suggesting that physiological implications of strong binding to albumin may be important for short-chain PFAAs.

  View details for DOI 10.1002/etc.647

  View details for Web of Science ID 000296230300005

  View details for PubMedID 21842491

• Partitioning of dissolved organic matter-bound mercury between a hydrophobic surface and polysulfide-rubber polymer WATER RESEARCH Kim, E., Luthy, R. G. 2011; 45 (17): 5441-5448

  Abstract

  This study investigated the role of dissolved organic matter on mercury partitioning between a hydrophobic surface (polyethylene, PE) and a reduced sulfur-rich surface (polysulfide rubber, PSR). Comparative sorption studies employed polyethylene and polyethylene coated with PSR for reactions with DOM-bound mercuric ions. These studies revealed that PSR enhanced the Hg-DOM removal from water when DOM was Suwannee River natural organic matter (NOM), fulvic acid (FA), or humic acid (HA), while the same amount of 1,3-propanedithiol-bound mercuric ion was removed by both PE and PSR-PE. The differences for Hg-DOM removal efficiencies between PE and PSR-PE varied depending on which DOM was bound to mercuric ion as suggested by the PE/water and PSR-PE/water partition coefficients for mercury. The surface concentrations of mercury on PE and PSR-PE with the same DOM measured by x-ray photoelectron spectroscopy were similar, which indicated the comparable amounts of immobilized mercury on PE and PSR-PE being exposed to the aqueous phase. With these observations, two major pathways for the immobilization reactions between PSR-PE and Hg-DOM were examined: 1) adsorption of Hg-DOM on PE by hydrophobic interactions between DOM and PE, and 2) addition reaction of Hg-DOM onto PSR by a complexation reaction between Hg and PSR. The percent contribution of each pathway was derived from a mass balance and the ratios among aqueous mercury, PE-bound Hg-DOM, and PSR-bound Hg-DOM concentrations. The results indicate strong binding of mercuric ion with both dissolved organic matter and PSR polymer. The FT-IR examination of Hg-preloaded-PSR-PEs after the reaction with DOM corroborated a strong interaction between mercuric ion and 1,3-propanedithiol compared to Hg-HA, Hg-FA, or Hg-NOM interactions.

  View details for DOI 10.1016/j.watres.2011.08.003

  View details for Web of Science ID 000295894600010

  View details for PubMedID 21872900

  View details for PubMedCentralID PMC3209504

• Reactive transport of neutral mercury species in polysulfide-rubber-coated activated carbon (PSR-AC) particle 242nd National Meeting of the American-Chemical-Society (ACS) Kim, E., Masue-Slowey, Y., Fendorf, S., Luthy, R. G. AMER CHEMICAL SOC. 2011

  View details for Web of Science ID 000299378302551

• PCB-INDUCED CHANGES OF A BENTHIC COMMUNITY AND EXPECTED ECOSYSTEM RECOVERY FOLLOWING IN SITU SORBENT AMENDMENT ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Janssen, E. M., Thompson, J. K., Luoma, S. N., Luthy, R. G. 2011; 30 (8): 1819-1826

  Abstract

  The benthic community was analyzed to evaluate pollution-induced changes for the polychlorinated biphenyl (PCB)-contaminated site at Hunters Point (HP) relative to 30 reference sites in San Francisco Bay, California, USA. An analysis based on functional traits of feeding, reproduction, and position in the sediment shows that HP is depauperate in deposit feeders, subsurface carnivores, and species with no protective barrier. Sediment chemistry analysis shows that PCBs are the major risk drivers at HP (1,570 ppb) and that the reference sites contain very low levels of PCB contamination (9 ppb). Different feeding traits support the existence of direct pathways of exposure, which can be mechanistically linked to PCB bioaccumulation by biodynamic modeling. The model shows that the deposit feeder Neanthes arenaceodentata accumulates approximately 20 times more PCBs in its lipids than the facultative deposit feeder Macoma balthica and up to 130 times more than the filter feeder Mytilus edulis. The comparison of different exposure scenarios suggests that PCB tissue concentrations at HP are two orders of magnitude higher than at the reference sites. At full scale, in situ sorbent amendment with activated carbon may reduce PCB bioaccumulation at HP by up to 85 to 90% under favorable field and treatment conditions. The modeling framework further demonstrates that such expected remedial success corresponds to exposure conditions suggested as the cleanup goal for HP. However, concentrations remain slightly higher than at the reference sites. The present study demonstrates how the remedial success of a sorbent amendment, which lowers the PCB availability, can be compared to reference conditions and traditional cleanup goals, which are commonly based on bulk sediment concentrations.

  View details for DOI 10.1002/etc.574

  View details for Web of Science ID 000293060900011

  View details for PubMedID 21560148

• Dehalogenation of Polybrominated Diphenyl Ethers and Polychlorinated Biphenyl by Bimetallic, Impregnated, and Nanoscale Zerovalent Iron ENVIRONMENTAL SCIENCE & TECHNOLOGY Zhuang, Y., Ahn, S., Seyfferth, A. L., Masue-Slowey, Y., Fendorf, S., Luthy, R. G. 2011; 45 (11): 4896-4903

  Abstract

  Nanoscale zerovalent iron particles (nZVI), bimetallic nanoparticles (nZVI/Pd), and nZVI/Pd impregnated activated carbon (nZVI/Pd-AC) composite particles were synthesized and investigated for their effectiveness to remove polybrominated diphenyl ethers (PBDEs) and/or polychlorinated biphenyls (PCBs). Palladization of nZVI promoted the dehalogenation kinetics for mono- to tri-BDEs and 2,3,4-trichlorobiphenyl (PCB 21). Compared to nZVI, the iron-normalized rate constants for nZVI/Pd were about 2-, 3-, and 4-orders of magnitude greater for tri-, di-, and mono-BDEs, respectively, with diphenyl ether as a main reaction product. The reaction kinetics and pathways suggest an H-atom transfer mechanism. The reaction pathways with nZVI/Pd favor preferential removal of para-halogens on PBDEs and PCBs. X-ray fluorescence mapping of nZVI/Pd-AC showed that Pd mainly deposits on the outer part of particles, while Fe was present throughout the activated carbon particles. While BDE 21 was sorbed onto activated carbon composites quickly, debromination was slower compared to reaction with freely dispersed nZVI/Pd. Our XPS and chemical data suggest about 7% of the total iron within the activated carbon was zerovalent, which shows the difficulty with in-situ synthesis of a significant fraction of zerovalent iron in the microporous material. Related factors that likely hinder the reaction with nZVI/Pd-AC are the heterogeneous distribution of nZVI and Pd on activated carbon and/or immobilization of hydrophobic organic contaminants at the adsorption sites thereby inhibiting contact with nZVI.

  View details for DOI 10.1021/es104312h

  View details for Web of Science ID 000291128700035

  View details for PubMedID 21557574

  View details for PubMedCentralID PMC3122486

• Saving water CHEMISTRY WORLD Smith, M., Luthy, R. 2011; 8 (6): 29-29

  View details for Web of Science ID 000293936500039

• In Situ Measurement of PCB Pore Water Concentration Profiles in Activated Carbon-Amended Sediment Using Passive Samplers ENVIRONMENTAL SCIENCE & TECHNOLOGY Oen, A. M., Janssen, E. M., Cornelissen, G., Breedveld, G. D., Eek, E., Luthy, R. G. 2011; 45 (9): 4053-4059

  Abstract

  Vertical pore water profiles of in situ PCBs were determined in a contaminated mudflat in San Francisco Bay, CA, 30 months after treatment using an activated carbon amendment in the upper layer of the sediment. Pore water concentrations were derived from concentrations of PCBs measured in two passive samplers; polyethylene (PE, 51 μm thick) and polyoxymethylene (POM, 17 μm thick) at different sediment depths. To calculate pore water concentrations from PCB contents in the passive samplers, an equilibrium approach and a first-order uptake model were applied, using five performance reference compounds to estimate pore water sampling rates. Vertical pore water profiles showed good agreement among the measurement and calculation methods with variations within a factor of 2, which seems reasonable for in situ measurements. The close agreements of pore water estimates for the two sampler materials (PE and POM) and the two methods used to translate uptake in samplers to pore water concentrations demonstrate the robustness and suitability of the passive sampling approach. The application of passive samplers in the sediment presents a promising method for site monitoring and remedial treatment evaluation of sorbent amendment or capping techniques that result in changes of pore water concentrations in the sediment subsurface.

  View details for DOI 10.1021/es200174v

  View details for Web of Science ID 000289819400038

  View details for PubMedID 21473574

• Drivers and challenges for nonpotable water reuse implementation and the emerging role of trace constituents 241st National Meeting and Exposition of the American-Chemical-Society (ACS) Luthy, R. G., Bischel, H. N., Simon, G., Frisby, T. M. AMER CHEMICAL SOC. 2011

  View details for Web of Science ID 000291982804387

• In-situ Sorbent Amendments: A New Direction in Contaminated Sediment Management ENVIRONMENTAL SCIENCE & TECHNOLOGY Ghosh, U., Luthy, R. G., Cornelissen, G., Werner, D., Menzie, C. A. 2011; 45 (4): 1163-1168

  View details for DOI 10.1021/es102694h

  View details for Web of Science ID 000287122400003

  View details for PubMedID 21247210

  View details for PubMedCentralID PMC3037809

• Toward Identifying the Next Generation of Superfund and Hazardous Waste Site Contaminants ENVIRONMENTAL HEALTH PERSPECTIVES Ela, W. P., Sedlak, D. L., Barlaz, M. A., Henry, H. F., Muir, D. C., Swackhamer, D. L., Weber, E. J., Arnold, R. G., Ferguson, P. L., Field, J. A., Furlong, E. T., Giesy, J. P., Halden, R. U., Henry, T., Hites, R. A., Hornbuckle, K. C., Howard, P. H., Luthy, R. G., Meyer, A. K., Saez, A. E., vom Saal, F. S., Vulpe, C. D., Wiesner, M. R. 2011; 119 (1): 6-10

  Abstract

  This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants.Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants.Superfund-relevant CECs can be characterized by specific attributes: They are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites.A need exists for a carefully considered and orchestrated expansion of programmatic and research efforts to identify, evaluate, and manage CECs of hazardous waste site relevance, including developing an evolving list of priority CECs, intensifying the identification and monitoring of likely sites of present or future accumulation of CECs, and implementing efforts that focus on a holistic approach to prevention.

  View details for DOI 10.1289/ehp.1002497

  View details for Web of Science ID 000285788900017

  View details for PubMedID 21205582

  View details for PubMedCentralID PMC3018501

• Immobilization of Hg(II) in water with polysulfide-rubber (PSR) polymer-coated activated carbon WATER RESEARCH Kim, E., Seyfferth, A. L., Fendorf, S., Luthy, R. G. 2011; 45 (2): 453-460

  Abstract

  An effective mercury removal method using polymer-coated activated carbon was studied for possible use in water treatment. In order to increase the affinity of activated carbon for mercury, a sulfur-rich compound, polysulfide-rubber (PSR) polymer, was effectively coated onto the activated carbon. The polymer was synthesized by condensation polymerization between sodium tetrasulfide and 1,2-dichloroethane in water. PSR-mercury interactions and Hg-S bonding were elucidated from x-ray photoelectron spectroscopy, and Fourier transform infra-red spectroscopy analyses. The sulfur loading levels were controlled by the polymer dose during the coating process and the total surface area of the activated carbon was maintained for the sulfur loading less than 2 wt%. Sorption kinetic studies showed that PSR-coated activated carbon facilitates fast reaction by providing a greater reactive surface area than PSR alone. High sulfur loading on activated carbon enhanced mercury adsorption contributing to a three orders of magnitude reduction in mercury concentration. μ-X-ray absorption near edge spectroscopic analyses of the mercury bound to activated carbon and to PSR on activated carbon suggests the chemical bond with mercury on the surface is a combination of Hg-Cl and Hg-S interaction. The pH effect on mercury removal and adsorption isotherm results indicate competition between protons and mercury for binding to sulfur at low pH.

  View details for DOI 10.1016/j.watres.2010.08.045

  View details for Web of Science ID 000286790500005

  View details for PubMedID 20965542

• ASSESSMENT OF FIELD-RELATED INFLUENCES ON POLYCHLORINATED BIPHENYL EXPOSURES AND SORBENT AMENDMENT USING POLYCHAETE BIOASSAYS AND PASSIVE SAMPLER MEASUREMENTS ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Janssen, E. M., Oen, A. M., Luoma, S. N., Luthy, R. G. 2011; 30 (1): 173-180

  Abstract

  Field-related influences on polychlorinated biphenyl (PCB) exposure were evaluated by employing caged deposit-feeders, Neanthes arenaceodentata, along with polyoxymethylene (POM) samplers using parallel in situ and ex situ bioassays with homogenized untreated or activated carbon (AC) amended sediment. The AC amendment achieved a remedial efficiency in reducing bioaccumulation by 90% in the laboratory and by 44% in the field transplants. In situ measurements showed that PCB uptake by POM samplers was greater for POM placed in the surface sediment compared with the underlying AC amendment, suggesting that tidal exchange of surrounding material with similar PCB availability as untreated sediment was redeposited in the cages. Polychlorinated biphenyls bioaccumulation with caged polychaetes from untreated sediment was half as large under field conditions compared with laboratory conditions. A biodynamic model was used to confirm and quantify the different processes that could have influenced these results. Three factors appeared most influential in the bioassays: AC amendment significantly reduces bioavailability under laboratory and field conditions; sediment deposition within test cages in the field partially masks the remedial benefit of underlying AC-amended sediment; and deposit-feeders exhibit less PCB uptake from untreated sediment when feeding is reduced. Ex situ and in situ experiments inevitably show some differences that are associated with measurement methods and effects of the environment. Parallel ex situ and in situ bioassays, passive sampler measurements, and quantifying important processes with a model can tease apart these field influences.

  View details for Web of Science ID 000285814200017

  View details for PubMedID 20872900

• Debromination of Polybrominated Diphenyl Ethers by Nanoscale Zerovalent Iron: Pathways, Kinetics, and Reactivity ENVIRONMENTAL SCIENCE & TECHNOLOGY Zhuang, Y., Ahn, S., Luthy, R. G. 2010; 44 (21): 8236-8242

  Abstract

  The debromination of selected polybrominated diphenyl ethers (PBDEs) by nanoscale zerovalent iron particles (nZVI) was studied to investigate the degradation pathways and the reaction kinetics of the PBDEs. The primary PBDE investigated was 2,3,4-tribromodiphenyl ether (BDE 21) to assess degradation pathways. nZVI could effectively debrominate the selected PBDEs into lower brominated compounds and diphenyl ether, a completely debrominated form of PBDEs. The susceptibility of the meta-bromine by nZVI was observed from the debromination tests for PBDEs with single-flanked (2,3-diBDE and 3,4-diBDE) and unflanked (three mono-BDEs) bromines. The stepwise debromination from n-bromo- to (n-1)-bromodiphenyl ether was observed as the dominant reaction process, although simultaneous multistep debromination seemed to be plausible for di-BDEs having two bromines adjacent on the same phenyl ring. The reaction rate constants were estimated by assuming the reaction between PBDEs and nZVI was a pseudo-first-order reaction and the rates decreased with fewer bromine substituents. The reaction rate constants were correlated with the heat of formation and the energy of the lowest unoccupied molecular orbital of the corresponding compounds, and these appear to be useful descriptors of relative reaction rates among PBDE homologue groups.

  View details for DOI 10.1021/es101601s

  View details for Web of Science ID 000283484000044

  View details for PubMedID 20923154

  View details for PubMedCentralID PMC2969174

• Simultaneous removal of mercury(II) and PCBs by polysulfide-rubber(PSR)-coated activated carbon Kim, E., Luthy, R. G. AMER CHEMICAL SOC. 2010

  View details for Web of Science ID 000208164702687

• Assessment of Advective Porewater Movement Affecting Mass Transfer of Hydrophobic Organic Contaminants in Marine Intertidal Sediment ENVIRONMENTAL SCIENCE & TECHNOLOGY Cho, Y., Werner, D., Moffett, K. B., Luthy, R. G. 2010; 44 (15): 5842-5848

  Abstract

  Advective porewater movement and molecular diffusion are important factors affecting the mass transfer of hydrophobic organic compounds (HOCs) in marsh and mudflat sediments. This study assessed porewater movement in an intertidal mudflat in South Basin adjacent to Hunters Point Shipyard, San Francisco, CA, where a pilot-scale test of sorbent amendment assessed the in situ stabilization of polychlorinated biphenyls (PCBs). To quantify advective porewater movement within the top 0-60 cm sediment layer, we used temperature as a tracer and conducted heat transport analysis using 14-day data from multidepth sediment temperature logging stations and one-dimensional heat transport simulations. The best-fit conditions gave an average Darcy velocity of 3.8cm/d in the downward vertical direction for sorbent-amended sediment with a plausible range of 0 cm/d to 8 cm/d. In a limiting case with no net advection, the best-fit depth-averaged mechanical dispersion coefficient was 2.2x10(-7) m2/s with a range of 0.9x10(-7) m2/s to 5.6x10(-7) m2/s. The Peclet number for PCB mobilization showed that molecular diffusion would control PCB mass transfer from sediment to sorbent particles for the case of uniform distribution of sorbent. However, the advective flow and mechanical dispersion in the test site would significantly benefit the stabilization effect of heterogeneously distributed sorbent by acting to smooth out the heterogeneities and homogenizing pollutant concentrations across the entire bioactive zone. These measurements and modeling techniques on intertidal sediment porewater transport could be useful for the development of more reliable mass transfer models for the prediction of contaminant release within the sediment bed, the movement of HOCs in the intertidal aquatic environment, and in situ sequestration by sorbent addition.

  View details for DOI 10.1021/es903583y

  View details for Web of Science ID 000280367200031

  View details for PubMedID 20608739

• Noncovalent Interactions of Long-Chain Perfluoroalkyl Acids with Serum Albumin ENVIRONMENTAL SCIENCE & TECHNOLOGY Bischel, H. N., Macmanus-Spencer, L. A., Luthy, R. G. 2010; 44 (13): 5263-5269

  Abstract

  Preferential distribution of long-chain perfluoroalkyl acids (PFAAs) in the liver, kidney, and blood of organisms highlights the importance of PFAA-protein interactions in PFAA tissue distribution patterns. A serum protein association constant may be a useful parameter to characterize the bioaccumulative potential and in vivo bioavailability of PFAAs. In this work, association constants (K(a)) and binding stoichiometries for PFAA-albumin complexes are quantified over a wide range of PFAA:albumin mole ratios. Primary association constants for perfluorooctanoate (PFOA) or perfluorononanoate (PFNA) with the model protein bovine serum albumin (BSA) determined via equilibrium dialysis are on the order of 10(6) M(-1) with one to three primary binding sites. PFNA was greater than 99.9% bound to BSA or human serum albumin (HSA) at a physiological PFAA:albumin mole ratio (<10(-3)), corresponding to a high protein-water distribution coefficient (log K(PW) > 4). Nanoelectrospray ionization mass spectrometry (nanoESI-MS) data reveal PFAA-BSA complexes with up to eight occupied binding sites at a 4:1 PFAA:albumin mole ratio. Association constants estimated by nanoESI-MS are on the order of 10(5) M(-1) for PFOA and PFNA and 10(4) M(-1) for perfluorodecanoate and perfluorooctanesulfonate. The results reported here suggest binding through specific high affinity interactions at low PFAA:albumin mole ratios.

  View details for DOI 10.1021/es101334s

  View details for Web of Science ID 000279304700070

  View details for PubMedID 20540534

• Measurement and Modeling of Polychlorinated Biphenyl Bioaccumulation from Sediment for the Marine Polychaete Neanthes arenaceodentata and Response to Sorbent Amendment ENVIRONMENTAL SCIENCE & TECHNOLOGY Janssen, E. M., Croteau, M., Luoma, S. N., Luthy, R. G. 2010; 44 (8): 2857-2863

  Abstract

  Bioaccumulation rates of polychlorinated biphenyls (PCBs) for the marine polychaete Neanthes arenaceodentata were characterized, including PCB uptake rates from water and sediment, and the effect of sorbent amendment to the sediment on PCB bioavailability, organism growth, and lipid content. Physiological parameters were incorporated into a biodynamic model to predict contaminant uptake. The results indicate rapid PCB uptake from contaminated sediment and significant organism growth dilution during time-series exposure studies. PCB uptake from the aqueous phase accounted for less than 3% of the total uptake for this deposit-feeder. Proportional increase of gut residence time and assimilation efficiency as a consequence of the organism's growth was assessed by PCB uptake and a reactor theory model of gut architecture. Pulse-chase feeding and multilabeled stable isotope tracing techniques proved high sediment ingestion rates (i.e., 6-10 times of dry body weight per day) indicating that such deposit-feeders are promising biological indicators for sediment risk assessment. Activated carbon amendment reduced PCB uptake by 95% in laboratory experiments with no observed adverse growth effects on the marine polychaete. Biodynamic modeling explained the observed PCB body burdens for N. arenaceodentata, with and without sorbent amendment.

  View details for DOI 10.1021/es901632e

  View details for Web of Science ID 000276556000020

  View details for PubMedID 20384377

• Polychlorinated Biphenyl Sorption and Availability in Field-Contaminated Sediments ENVIRONMENTAL SCIENCE & TECHNOLOGY Werner, D., Hale, S. E., Ghosh, U., Luthy, R. G. 2010; 44 (8): 2809-2815

  Abstract

  Traditional and new relationships of polychlorinated biphenyl (PCB) distribution among the solid phases, the free aqueous phase, and biolipids are comprehensively reviewed using seven well-characterized freshwater and marine sediments polluted with PCBs. The traditional relationship relating free aqueous concentration and biolipid concentration to sediment total organic carbon, compound octanol-water partitioning coefficient, and solid-phase contaminant concentration overestimates measured free aqueous concentrations and biolipid concentrations by mean factors of 8 and 33, respectively. By contrast, relationships based on measured free aqueous phase concentrations or the PCB mass fraction desorbed from sediment provide reasonable predictions of biolipid concentrations. Solid-phase concentration-based predictions perform better when sorption to amorphous organic matter and black carbon (BC) is distinguished. Contrary to previously published relationships, BC sorption appears to be linear for free aqueous PCB-congener concentrations in the picogram to microgram per liter range.

  View details for DOI 10.1021/es902325t

  View details for Web of Science ID 000276556000013

  View details for PubMedID 19961220

  View details for PubMedCentralID PMC2854002

• Debromination of polybrominated diphenyl ethers by nano-iron particles and carbon-supported nano-iron particles Zhuang, Y., Ahn, S., Luthy, R. G. AMER CHEMICAL SOC. 2010

  View details for Web of Science ID 000208189302442

• Binding of Perfluorocarboxylates to Serum Albumin: A Comparison of Analytical Methods ANALYTICAL CHEMISTRY MacManus-Spencer, L. A., Tse, M. L., Hebert, P. C., Bischel, H. N., Luthy, R. G. 2010; 82 (3): 974-981

  Abstract

  Perfluorochemicals are globally pervasive contaminants that are persistent, bioaccumulative, and toxic. Perfluorocarboxylic acids (PFCAs) with 8-13 carbons accumulate in the liver and blood of aquatic organisms; PFCA-protein interactions may explain this accumulation pattern. Here, the interactions between PFCAs with 8-11 carbons and serum albumin are examined using three experimental approaches: surface tension titrations, (19)F NMR spectroscopy, and fluorescence spectroscopy. Surface tension titrations indicate complex formation at high (mM) PFCA concentrations. Secondary association constants ranging from 10(2) to 10(4) M(-1) were determined from (19)F NMR titrations at high PFCA:albumin mole ratios. Fluorescence measurements indicate that PFCA-albumin interactions alter the protein conformation at low PFCA:albumin mole ratios (up to 5:1) and suggest two binding classes with association constants around 10(5) and 10(2) M(-1). While (19)F NMR and fluorescence provide both qualitative and quantitative information about PFCA-albumin interactions, surface tension provides only qualitative information. Limitations associated with instrumentation and methods require high PFCA concentrations in both surface tension and (19)F NMR experiments; in contrast, fluorescence allows for analysis of a wider range of PFCA concentrations and PFCA:albumin mole ratios. Results from this study indicate that fluorescence, though an indirect method, offers a more comprehensive picture of the nature of PFCA-albumin interactions.

  View details for DOI 10.1021/ac902238u

  View details for Web of Science ID 000273983700032

  View details for PubMedID 20039637

• Measurement and modeling of polychlorinated biphenylbioaccumulation from sediment for the marine polychaete Neanthes arenaceodentata and response to sorbent amendment Environmental Science & Technology Janssen, Elisabeth, M.L., Croteau, M., Luoma, Samuel, N., Luthy, Richard, G. 2010; 8 (44): 2857 - 2863
• Global diversity and biogeography of bacterial communities in wastewater treatment plants. Nature microbiology Wu, L., Ning, D., Zhang, B., Li, Y., Zhang, P., Shan, X., Zhang, Q., Brown, M., Li, Z., Van Nostrand, J. D., Ling, F., Xiao, N., Zhang, Y., Vierheilig, J., Wells, G. F., Yang, Y., Deng, Y., Tu, Q., Wang, A., Global Water Microbiome Consortium, Zhang, T., He, Z., Keller, J., Nielsen, P. H., Alvarez, P. J., Criddle, C. S., Wagner, M., Tiedje, J. M., He, Q., Curtis, T. P., Stahl, D. A., Alvarez-Cohen, L., Rittmann, B. E., Wen, X., Zhou, J., Acevedo, D., Agullo-Barcelo, M., Alvarez, P. J., Alvarez-Cohen, L., Andersen, G. L., de Araujo, J. C., Boehnke, K., Bond, P., Bott, C. B., Bovio, P., Brewster, R. K., Bux, F., Cabezas, A., Cabrol, L., Chen, S., Criddle, C. S., Deng, Y., Etchebehere, C., Ford, A., Frigon, D., Gomez, J. S., Griffin, J. S., Gu, A. Z., Habagil, M., Hale, L., Hardeman, S. D., Harmon, M., Horn, H., Hu, Z., Jauffur, S., Johnson, D. R., Keller, J., Keucken, A., Kumari, S., Leal, C. D., Lebrun, L. A., Lee, J., Lee, M., Lee, Z. M., Li, Y., Li, Z., Li, M., Li, X., Ling, F., Liu, Y., Luthy, R. G., Mendonca-Hagler, L. C., de Menezes, F. G., Meyers, A. J., Mohebbi, A., Nielsen, P. H., Ning, D., Oehmen, A., Palmer, A., Parameswaran, P., Park, J., Patsch, D., Reginatto, V., de Los Reyes, F. L., Rittmann, B. E., Robles, A. N., Rossetti, S., Shan, X., Sidhu, J., Sloan, W. T., Smith, K., de Sousa, O. V., Stahl, D. A., Stephens, K., Tian, R., Tiedje, J. M., Tooker, N. B., Tu, Q., Van Nostrand, J. D., De Los Cobos Vasconcelos, D., Vierheilig, J., Wagner, M., Wakelin, S., Wang, A., Wang, B., Weaver, J. E., Wells, G. F., West, S., Wilmes, P., Woo, S., Wu, L., Wu, J., Wu, L., Xi, C., Xiao, N., Xu, M., Yan, T., Yang, Y., Yang, M., Young, M., Yue, H., Zhang, B., Zhang, P., Zhang, Q., Zhang, Y., Zhang, T., Zhang, Q., Zhang, W., Zhang, Y., Zhou, H., Zhou, J., Wen, X., Curtis, T. P., He, Q., He, Z., Brown, M. 2019

  Abstract

  Microorganisms in wastewater treatment plants (WWTPs) are essential for water purification to protect public and environmental health. However, the diversity of microorganisms and the factors that control it are poorly understood. Using a systematic global-sampling effort, we analysed the 16S ribosomal RNA gene sequences from ~1,200 activated sludge samples taken from 269 WWTPs in 23 countries on 6 continents. Our analyses revealed that the global activated sludge bacterial communities contain ~1 billion bacterial phylotypes with a Poisson lognormal diversity distribution. Despite this high diversity, activated sludge has a small, global core bacterial community (n=28 operational taxonomic units) that is strongly linked to activated sludge performance. Meta-analyses with global datasets associate the activated sludge microbiomes most closely to freshwater populations. In contrast to macroorganism diversity, activated sludge bacterial communities show no latitudinal gradient. Furthermore, their spatial turnover is scale-dependent and appears to be largely driven by stochastic processes (dispersal and drift), although deterministic factors (temperature and organic input) are also important. Our findings enhance our mechanistic understanding of the global diversity and biogeography of activated sludge bacterial communities within a theoretical ecology framework and have important implications for microbial ecology and wastewater treatment processes.

  View details for PubMedID 31086312

• Sorption of dichlorodiphenyltrichloroethane (DDT) and its metabolites by activated carbon in clean water and sediment slurries WATER RESEARCH Hale, S. E., Tomaszewski, J. E., Luthy, R. G., Werner, D. 2009; 43 (17): 4336-4346

  Abstract

  Polyethylene-water partitioning coefficients (K(PE)) and mass transfer coefficients (k(PE)) for the ortho and para isomers of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolites dichlorodiphenyldichloroethane (DDD), dichlorodiphenyldichloroethylene (DDE) and, dichlorodiphenylmonochloroethylene (DDMU) were measured. These data were used to derive activated carbon (AC) sorption isotherms in clean water in the sub-nanogram per litre free aqueous concentration range for a virgin and a regenerated AC. The sorption strength of AC for DDT and its metabolites was very high and logarithmic values of the AC-water partitioning coefficients, logK(AC), ranged from 8.47 to 9.26. A numerical mass transfer model was calibrated with this data to interpret previously reported reductions in DDT uptake by semipermeable membrane devices after AC amendment of sediment from Lauritzen Channel, California, USA. The activated carbon-water partitioning coefficient values (K(AC)) measured in clean water systems appear to overestimate the AC sorption capacity in sediment up to a factor 32 for DDT and its metabolites at long contact time with fine-sized AC. Modelling results show decreased attenuation of the AC sorption capacity with increased sediment-AC contact time. We infer that increased resistance in mass transfer of DDTs to sorption sites in the microporous region likely caused by deposits of dissolved organic matter in the macro- and mesopores of AC appears to be the most relevant fouling mechanism. These results suggest that DDTs may diffuse through possible deposits of dissolved organic matter over time, implying that the effects of sediment on the sorption of DDTs by AC may be more kinetic than competitive.

  View details for DOI 10.1016/j.watres.2009.06.031

  View details for Web of Science ID 000270629500026

  View details for PubMedID 19595428

• Field Application of Activated Carbon Amendment for In-Situ Stabilization of Polychlorinated Biphenyls in Marine Sediment ENVIRONMENTAL SCIENCE & TECHNOLOGY Cho, Y., Ghosh, U., Kennedy, A. J., Grossman, A., Ray, G., Tomaszewski, J. E., Smithenry, D. W., Bridges, T. S., Luthy, R. G. 2009; 43 (10): 3815-3823

  Abstract

  We report results on the first field-scale application of activated carbon (AC) amendment to contaminated sediment for in-situ stabilization of polychlorinated biphenyls (PCBs). The test was performed on a tidal mud flat at South Basin, adjacent to the former Hunters Point Naval Shipyard, San Francisco Bay, CA. The major goals of the field study were to (1) assess scale up of the AC mixing technology using two available, large-scale devices, (2) validate the effectiveness of the AC amendment at the field scale, and (3) identify possible adverse effects of the remediation technology. Also, the test allowed comparison among monitoring tools, evaluation of longer-term effectiveness of AC amendment, and identification of field-related factors that confound the performance of in-situ biological assessments. Following background pretreatment measurements, we successfully incorporated AC into sediment to a nominal 30 cm depth during a single mixing event, as confirmed by total organic carbon and black carbon contents in the designated test plots. The measured AC dose averaged 2.0-3.2 wt% and varied depending on sampling locations and mixing equipment. AC amendment did not impact sediment resuspension or PCB release into the water column over the treatment plots, nor adversely impactthe existing macro benthic community composition, richness, or diversity. The PCB bioaccumulation in marine clams was reduced when exposed to sediment treated with 2% AC in comparison to the control plot Field-deployed semi permeable membrane devices and polyethylene devices showed about 50% reduction in PCB uptake in AC-treated sediment and similar reduction in estimated pore-water PCB concentration. This reduction was evident even after 13-month post-treatment with then 7 months of continuous exposure, indicating AC treatment efficacy was retained for an extended period. Aqueous equilibrium PCB concentrations and PCB desorption showed an AC-dose response. Field-exposed AC after 18 months retained a strong stabilization capability to reduce aqueous equilibrium PCB concentrations by about 90%, which also supports the long-term effectiveness of AC in the field. Additional mixing during or after AC deployment, increasing AC dose, reducing AC-particle size, and sequential deployment of AC dose will likely improve AC-sediment contact and overall effectiveness. The reductions in PCB availability observed with slow mass transfer under field conditions calls for predictive models to assess the long-term trends in pore-water PCB concentrations and the benefits of alternative in-situ AC application and mixing strategies.

  View details for DOI 10.1021/es802931c

  View details for Web of Science ID 000266046700066

  View details for PubMedID 19544893

• Field application of activated carbon amendment for in situ stabilization of PCBs in sediment Luthy, R. G., Cho, Y., Ghosh, U., Kennedy, A. J., Bridges, T. S. AMER CHEMICAL SOC. 2009

  View details for Web of Science ID 000207857804314

• The stability of marine sediments at a tidal basin in San Francisco Bay amended with activated carbon for sequestration of organic contaminants (vol 42, pg 15, 2008) WATER RESEARCH Zimmerman, J. R., Bricker, J. D., Jones, C., Dacunto, P. J., Street, R. L., Luthy, R. G. 2008; 42 (20): 5072-5072

  View details for DOI 10.1016/j.watres.2008.09.004

  View details for Web of Science ID 000262055900020

• Nitromusk compounds in San Francisco Bay sediments CHEMOSPHERE Rubinfeld, S. A., Luthy, R. G. 2008; 73 (6): 873-879

  Abstract

  Synthetic nitromusk fragrances are used in a wide variety of consumer products and can enter aquatic environments through wastewater effluent. Although nitromusks are known to be hydrophobic, little attention has been paid to their behavior in sediments. A sediment extraction method using sonication was developed and used to analyze samples from San Francisco Bay. Both musk xylene (MX) and musk ketone (MK) were found at low levels, with mean concentrations of 0.034 and 0.038ngg(-1), respectively. The highest concentrations were found in the southernmost region of the Bay. Samples were also analyzed from a nearby tidal channel fed by a wastewater treatment plant outfall. At this location both musk xylene and musk ketone were found at higher concentrations of 0.13-0.24ngg(-1) MX and 1.08-2.74ngg(-1) MK. A metabolite of musk xylene was also found at levels up to 4.08ngg(-1), suggesting that these metabolites may play an important role in the fate of nitromusk compounds. Concentrations of all three compounds were highest at the earliest of four sampling dates, and a geographic survey of sediments along the tidal channel showed that concentrations decreased rapidly with distance from the outfall and were close to background before the channel reached the Bay.

  View details for DOI 10.1016/j.chemosphere.2008.07.042

  View details for Web of Science ID 000260486600002

  View details for PubMedID 18783818

• Measuring and modeling reduction of DDT availability to the water column and mussels following activated carbon amendment of contaminated sediment WATER RESEARCH Tomaszewski, J. E., McLeod, P. B., Luthy, R. G. 2008; 42 (16): 4348-4356

  Abstract

  A 28-day accumulation study demonstrated the use of mussel uptake, passive samplers, and biodynamic modeling to measure the reduction of dichlorodiphenyltrichloroethane (DDT) availability in the water column after the addition of activated carbon to contaminated sediment. Sediment collected from Lauritzen Channel, Richmond, California (16.5mg total DDT/kg) was mixed with either virgin activated carbon or a reactivated carbon for one month, after which a 28-day laboratory exposure study was completed. Mussels (Mytilus edulis) suspended above activated carbon-treated sediment accumulated significantly less total DDT in soft tissue, 91% and 84% for virgin and reactivated carbon, respectively, as compared to untreated sediment. Mussel tissue concentrations correlated to concentrations in semipermeable membrane devices (SPMDs) and polyethylene devices (PEDs) suspended over the same sediments. A biodynamic model that incorporated DDT water concentrations, either analytically measured or estimated from PED uptake, described mussel accumulation over time. Thus, passive samplers in combination with biodynamic modeling may provide an important screening tool for assessment of filter-feeding uptake and ecological risk to water-dwelling organisms exposed to aqueous phase hydrophobic organic contaminants.

  View details for DOI 10.1016/j.watres.2008.07.016

  View details for Web of Science ID 000260757300015

  View details for PubMedID 18723202

• The stability of marine sediments at a tidal basin in San Francisco Bay amended with activated carbon for sequestration of organic contaminants WATER RESEARCH Zimmerman, J. R., Bricker, J. D., Jones, C., Dacunto, P. J., Street, R. L., Luthy, R. G. 2008; 42 (15): 4133-4145

  Abstract

  Recent laboratory studies show that adding activated carbon to marine sediments reduces the bioavailability of persistent organic contaminants, such as polychlorinated biphenyls, to benthic organisms. The present work investigates how mixing activated carbon into cohesive sediment affects the stability of sediment obtained from the intertidal zone at the Hunters Point Naval Shipyard Superfund site in South Basin, San Francisco Bay, CA. Our results show for these sediments that mixing activated carbon into sediment does not significantly affect stability of surface sediments, as measured by sediment erosion rate and critical shear stress for incipient motion, thus supporting the potential field application of this technique for in situ stabilization of persistent organic contaminants. Hydrodynamic modeling was used to estimate the maximum bottom shear stress encountered during high-wind storm events at the estuarine inlet from which the sediments were obtained. Comparison of estimated bottom shear stresses with measured critical shear stresses shows that surface sediments will not erode under normal, non-storm conditions. Bottom shear stresses caused by large waves under infrequent high-wind storm conditions may erode surface sediments for short periods of time. We conclude from sediment stability tests and hydrodynamic modeling that mixing activated carbon amendment with cohesive sediment at selected locations within South Basin will not reduce surface sediment stability nor result in significant erosion of treated sediments.

  View details for DOI 10.1016/j.watres.2008.05.023

  View details for Web of Science ID 000259919800013

  View details for PubMedID 18692860

• Field deployment of polyethylene devices to measure PCB concentrations in pore water of contaminated sediment ENVIRONMENTAL SCIENCE & TECHNOLOGY Tomaszewski, J. E., Luthy, R. G. 2008; 42 (16): 6086-6091

  Abstract

  Sediment pore water concentrations of polychlorinated biphenyls (PCBs) in a contaminated mudflat in San Francisco Bay, CA were determined by field-deployed polyethylene devices (PEDs). Sequential sampling of PEDs deployed in the field showed large differences in uptake rates and time to equilibrium compared to PEDs mixed with field-collected sediment in the laboratory. We demonstrate a modeling approach that involves the use of impregnated performance reference compounds (PRCs) and interpretation of the data either by PCB molar volume adjustment or environmental adjustment factors to measure pore water concentrations of 118 PCB congeners. Both adjustment methods predicted comparable sampling rates, and PCB pore water concentrations estimated by use of the molar volume adjustment method were similar to values analytically measured in pore waters from the laboratory and field. The utility of PEDs for sampling pore water in the field was evaluated at a tidal mudflat amended with activated carbon to sequester PCBs. Pore water concentrations decreased up to 60% within 18 months after activated carbon amendment, as compared to a mechanical-mixed control plot Results of this study illustrate PEDs provide an inexpensive, in situ method to measure total PCB contamination in sediment pore water using a small set of PRCs.

  View details for DOI 10.1021/es800582a

  View details for Web of Science ID 000258439600041

  View details for PubMedID 18767670

• Modeling PAH mass transfer in a slurry of contaminated soil or sediment amended with organic sorbents WATER RESEARCH Ahn, S., Werner, D., Luthy, R. G. 2008; 42 (12): 2931-2942

  Abstract

  A three-compartment kinetic partitioning model was employed to assess contaminant mass transfer and intraparticle diffusion in systems comprising dense slurries of polluted soil or aquifer sediment with or without sorbent amendments to sequester polycyclic aromatic hydrocarbons (PAHs). The model was applied to simulate temporal changes in aqueous and particle-bound PAH concentrations comparing different pollution sources (heavy oil or tar sludge) and various sorbent amendments (polyoxymethylene (POM), coke breeze, and activated carbon). For the model evaluation, all the parameters needed were directly measured from a series of experiments, allowing full calibration and verification of model predictions without parameter fitting. The numerical model reproduced two separate laboratory-scale experiments reasonably: PAH uptake in POM beads and PAH uptake by semipermeable membrane devices. PAH mass transfer was then simulated for various scenarios, considering different sorbent doses and mass transfer rates as well as biodegradation. Such model predictions provide a quick assessment tool for identifying mass transfer limitations during washing, stabilization, or bioslurry treatments of polluted soil or sediment in mixed systems. It appears that PAHs would be readily released from materials contaminated by small oil droplets, but not tar decanter sludge. Released PAHs would be sequestered rapidly by activated carbon amendment but to a much lesser extent by coke breeze. If sorbing black carbon is present in the slurries, POM pellets would not be effective as a sequestration amendment. High first-order biodegradation rates in the free aqueous phase, e.g., in the order of 0.001 s(-1) for phenanthrene, would be required to compete effectively with adsorption and mass transfer for strong sorbents.

  View details for DOI 10.1016/j.watres.2008.03.011

  View details for Web of Science ID 000257649100010

  View details for PubMedID 18456306

• Uptake of PAHs into polyoxymethylene and application to oil-soot (lampblack)-impacted soil samples CHEMOSPHERE Hong, L., Luthy, R. G. 2008; 72 (2): 272-281

  Abstract

  Polyoxymethylene (POM) is a polymeric material used increasingly in passive sampling of hydrophobic organic contaminants such as PAHs and PCBs in soils and sediments. In this study, we examined the sorption behavior of 12 PAH compounds to POM and observed linear isotherms spanning two orders of magnitude of aqueous concentrations. Uptake kinetic studies performed in batch systems for up to 54 d with two different volume ratios of POM-to-aqueous phase were evaluated with coupled diffusion and mass transfer models to simulate the movement of PAHs during the uptake process and to assess the physicochemical properties and experimental conditions that control uptake rates. Diffusion coefficients of PAHs in POM were estimated to be well correlated with diffusants' molecular weights as D(POM) proportional, variant(MW)(-3), descending from 2.3 x 10(-10) cm(2) s(-1) for naphthalene to 7.0 x 10(-11) cm(2) s(-1) for pyrene. The uptake rates for PAHs with log K(ow)<5.8 were controlled by the POM phase and the hydrophobicity of PAH compounds. For more hydrophobic PAH compounds, the aqueous boundary layer played an increasingly important role in determining the overall mass transfer rate. The POM partitioning technique was demonstrated to agree well with two other procedures for measuring PAH soil-water distribution coefficients in oil-soot (lampblack) containing soil samples.

  View details for DOI 10.1016/j.chemosphere.2008.01.028

  View details for Web of Science ID 000256737900018

  View details for PubMedID 18334261

• Aerobic biotransformation and fate of N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE) in activated sludge ENVIRONMENTAL SCIENCE & TECHNOLOGY Rhoads, K. R., Janssen, E. M., Luthy, R. G., Criddle, C. S. 2008; 42 (8): 2873-2878

  Abstract

  Processes affecting the fate of perfluorinated organics are of increasing concern due to the global dispersal, persistence, and bioaccumulation of these contaminants. The volatile compound N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE) and its phosphate esters have been used in protective surface coatings. In this report, we describe the fate of N-EtFOSE in aerobic batch assays. These assays were performed using undiluted activated sludge in serum bottles that were sealed to prevent the escape of N-EtFOSE and volatile transformation products. Separate assays were performed with N-EtFOSE and reported transformation products. N-EtFOSE degraded to N-ethyl perfluorooctane sulfonamido acetic acid (N-EtFOSAA) with an observed first-order rate of 0.99 +/- 0.08 day(-1) and a pseudosecond order rate of 0.26 +/- 0.02 L/mg VSS day(-1). N-EtFOSAA underwent further transformation at a slower rate (0.093 +/- 0.012 day(-1)) to N-ethylperfluorooctane sulfonamide (N-EtFOSA). N-EtFOSA then transformed to perfluorooctane sulfonamide (FOSA). FOSA transformed to perfluorooctane sulfinate (PFOSI), and PFOSI transformed to perfluorooctane sulfonate (PFOS). Perfluorooctanoic acid (PFOA) was not detected as a transformation product of any compound. Using the measured rate of N-EtFOSE biotransformation and literature values for phase partitioning and mass transfer in aeration basins, we modeled the fate of N-EtFOSE in a typical activated sludge aeration basin open to the atmosphere. The model predicts that 76% of the N-EtFOSE is stripped into the atmosphere, 5% sorbs to waste solids, 13% undergoes transformation to N-EtFOSAA, and 6% is discharged in the wastewater effluent.

  View details for DOI 10.1021/es702866c

  View details for Web of Science ID 000254890400033

  View details for PubMedID 18497137

• ANYL 155-Investigation of the binding of perfluorocarboxylates to a model serum protein: A comparison of analytical methods 235th American-Chemical-Society National Meeting MacManus-Spencer, L. A., Tse, M. L., Bische, H., Luthy, R. G. AMER CHEMICAL SOC. 2008

  View details for Web of Science ID 000271775100345

• Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon ENVIRONMENTAL SCIENCE & TECHNOLOGY McLeod, P. B., Luoma, S. N., Luthy, R. G. 2008; 42 (2): 484-490

  Abstract

  Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms.

  View details for DOI 10.1021/es070139a

  View details for Web of Science ID 000252317700030

  View details for PubMedID 18284151

• Field methods for amending marine sediment with activated carbon and assessing treatment effectiveness MARINE ENVIRONMENTAL RESEARCH Cho, Y., Smithenry, D. W., Ghosh, U., Kennedy, A. J., Millward, R. N., Bridges, T. S., Luthy, R. G. 2007; 64 (5): 541-555

  Abstract

  Previous laboratory studies have shown reductions in PCB bioavailability for sediments amended with activated carbon (AC). Here we report results on a preliminary pilot-scale study to assess challenges in scaling-up for field deployment and monitoring. The goals of the preliminary pilot-scale study at Hunters Point Shipyard (San Francisco, USA) were to (1) test the capabilities of a large-scale mixing device for incorporating AC into sediment, (2) develop and evaluate our field assessment techniques, and (3) compare reductions in PCB bioavailability found in the laboratory with well-mixed systems to those observed in the field with one-time-mixed systems. In this study we successfully used a large-scale device to mix 500kg of AC into a 34.4m(2) plot to a depth of 1ft, a depth that includes the majority of the biologically active zone. Our results indicate that after 7 months of AC-sediment contact in the field, the 28-day PCB bioaccumulation for the bent-nosed clam, Macoma nasuta, field-deployed to this AC-amended sediment was approximately half of the bioaccumulation resulting from exposure to untreated sediment. Similar PCB bioaccumulation reductions were found in laboratory bioassays conducted on both the bivalve, M. nasuta and the estuarine amphipod, Leptocheirus plumulosus, using sediment collected from the treated and untreated field plots one year after the AC amendment occurred. To further understand the long-term effectiveness of AC as an in situ treatment strategy for PCB-contaminated sediments under field conditions, a 3-year comprehensive study is currently underway at Hunters Point that will compare the effectiveness of two large-scale mixing devices and include both unmixed and mixed-only control plots.

  View details for DOI 10.1016/j.marenvres.2007.04.006

  View details for Web of Science ID 000251201400001

  View details for PubMedID 17570482

• Activated carbon amendment as a treatment for residual DDT in sediment from a superfund site in San Francisco Bay, Richmond, California, USA ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Tomaszewski, J. E., Werner, D., Luthy, R. G. 2007; 26 (10): 2143-2150

  Abstract

  Pesticide formulators formerly operating at Lauritzen Channel, a portion of San Francisco Bay near Richmond (CA, USA), caused contamination of sediment with dichlorodiphenyltrichloroethane (DDT). The present study evaluated the distribution of residual DDT in channel sediment six years following extensive remedial dredging. High DDT concentrations (up to 252 mg/ kg) were found in Young Bay Mud sampled across the channel. Particle analyses showed most of the contamination is contained in the clay/silt sediment fraction, and desorption tests showed that availability is greater for DDT metabolites than parent DDT. The present study examined the feasibility of using activated carbon amendment to sequester DDT from sediment, including an evaluation of reactivated carbon as a less costly alternative to virgin activated carbons. Treatment success of activated carbon amendment to sediment collected from Lauritzen Channel was measured by reductions in aqueous equilibrium concentrations and uptake in semipermeable membrane devices (SPMDs). Four different activated carbons were tested and, after one month of treatment with 3.2 weight % carbon, DDT aqueous equilibrium concentrations were reduced up to 83% and SPMD uptake was reduced up to 91%. Reactivated carbon was comparable with virgin carbons in all tests. Reduction in SPMD uptake of DDT by treatment with 3.2% reactivated carbon increased to 99% after 26 months of treatment. The effectiveness of activated carbon was dependent on the type, size, dose, and contact time. The results show the potential usefulness of activated carbon amendment as a follow-up remedial technology for management of residuals after dredging contaminated sediment.

  View details for Web of Science ID 000249528000015

  View details for PubMedID 17867891

• Bioaccumulation of perfluorochemicals in sediments by the aquatic oligochaete Lumbriculds variegatus ENVIRONMENTAL SCIENCE & TECHNOLOGY Higgins, C. P., McLeod, P. B., Macmanus-Spencer, L. A., Luthy, R. G. 2007; 41 (13): 4600-4606

  Abstract

  Bioaccumulation of perfluoroalkyl sulfonates, perfluorocarboxylates, and 2-(N-ethylperfluorooctane sulfonamido) acetic acid (N-EtFOSAA) from laboratory-spiked and contaminated field sediments was assessed using the freshwater oligochaete, Lumbriculus variegatus. Semistatic batch experiments were conducted to monitor the biological uptake of these perfluorochemicals (PFCs) over 56 days. The elimination of PFCs was measured as the loss of PFCs in L. variegatus exposed to PFC-spiked sediment for 28 days and then transferred to clean sediment. The resultant data suggest that PFCs in sediments are readily bioavailable and that bioaccumulation from sediments does not continually increase with increasing perfluorocarbon chain length. Perfluorooctane sulfonate (PFOS) and perfluorononanoate were the most bioaccumulative PFCs, as measured by laboratory-based estimated steady-state biota sediment accumulation factors (BSAFs) and BSAFs measured using contaminated field sediments. Elimination rate constants for perfluoroalkyl sulfonates and perfluorocaroboxylates were generally smaller than those previously measured for other organic contaminants. Last, a PFOS precursor, N-EtFOSAA, accumulated in the worm tissues and appeared to undergo biotransformation to PFOS and other PFOS precursors. This suggests that N-EtFOSAA, which has been detected in sediments and sludge often at levels exceeding PFOS, may contribute to the bioaccumulation of PFOS in aquatic organisms.

  View details for DOI 10.1021/es062792o

  View details for Web of Science ID 000247782500027

  View details for PubMedID 17695903

• Modeling sorption of anionic surfactants onto sediment materials: An a priori approach for perfluoroalkyl surfactants and linear alkylbenzene sulfonates ENVIRONMENTAL SCIENCE & TECHNOLOGY Higgins, C. P., Luty, R. G. 2007; 41 (9): 3254-3261

  Abstract

  A mechanistically derived model predicting the sorption of anionic surfactants to sediments was developed and evaluated for three classes of surfactants: perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and linear alkylbenzene sulfonates. The model includes both hydrophobic and electrostatic components and estimates the contribution of each to the sediment-water distribution coefficient (Kd) using Gibbs free energy terms. The hydrophobic free energy term was calculated from the aqueous solubilities of non-charged alkylbenzene or perfluoroalkane analogs and prior observations of increases in Kd values with increasing chain lengths. The electrostatic term was calculated from aqueous solution measurements using the non-ideal competitive adsorption Donnan (NICA-Donnan) model. The NICA-Donnan calculations were performed using parameters previously derived for generic humic acids. These two terms were coupled by multiplying by the fraction of organic carbon in the sediment, foc, and a single fitting parameter, Faccess, the volumetric fraction of organic carbon accessible to the sorbing surfactant. The combined model accurately predicted the sediment-water distribution coefficients for all three classes of anionic surfactants. In its current formulation, the model was unable to capture the slight degree of isotherm nonlinearity observed for these surfactants.

  View details for DOI 10.1021/es062449j

  View details for Web of Science ID 000246371100040

  View details for PubMedID 17539534

• Biological uptake of polychlorinated biphenyls by Macoma balthica from sediment amended with activated carbon ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY McLeod, P. B., Van den Heuvel-Greve, M. J., Luoma, S. N., Luthy, R. G. 2007; 26 (5): 980-987

  Abstract

  This work characterizes the efficacy of activated carbon amendment in reducing polychlorinated biphenyl (PCB) bioavailability to clams (Macoma balthica) from field-contaminated sediment (Hunters Point Naval Shipyard, San Francisco Bay, CA, USA). Test methods were developed for the use of clams to investigate the effects of sediment amendment on biological uptake. Sediment was mixed with activated carbon for one month. Bioaccumulation tests (28 d) were employed to assess the relationships between carbon dose and carbon particle size on observed reductions in clam biological uptake of PCBs. Extraction and cleanup protocols were developed for the clam tissue. Efficacy of activated carbon treatment was found to increase with both increasing carbon dose and decreasing carbon particle size. Average reductions in bioaccumulation of 22, 64, and 84% relative to untreated Hunters Point sediment were observed for carbon amendments of 0.34, 1.7, and 3.4%, respectively. Average bioaccumulation reductions of 41, 73, and 89% were observed for amendments (dose = 1.7% dry wt) with carbon particles of 180 to 250, 75 to 180, and 25 to 75 microm, respectively, in diameter, indicating kinetic phenomena in these tests. Additionally, a biodynamic model quantifying clam PCB uptake from water and sediment as well as loss through elimination provided a good fit of experimental data. Model predictions suggest that the sediment ingestion route contributed 80 to 95% of the PCB burdens in the clams.

  View details for Web of Science ID 000245749500021

  View details for PubMedID 17521146

• Availability of polycyclic aromatic hydrocarbons from lampblack-impacted soils at former oil-gas plant sites in California, USA ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Hong, L., Luthy, R. G. 2007; 26 (3): 394-405

  Abstract

  Lampblack-impacted soils at former oil-gas plant sites in California, USA, were characterized to assess the sorption of polycyclic aromatic hydrocarbons (PAHs) and the concentration-dependent effects of a residual oil tar phase on sorption mechanism and availability of PAHs. Nuclear magnetic resonance spectroscopy demonstrated similar aromaticity for both lampblack carbon and the oil tar phase, with pronounced resonance signals in the range of 100 to 150 ppm. Scanning-electron microscopic images revealed a physically distinct oil tar phase, especially at high concentrations in lampblack, which resulted in an organic-like film structure when lampblack particles became saturated with the oil tar. Sorption experiments were conducted on a series of laboratory-prepared lampblack samples to systematically evaluate influences of an oil tar phase on PAH sorption to lampblack. Results indicate that the sorption of PAHs to lampblack exhibits a competition among sorption phases at low oil tar contents when micro- and mesopores are accessible. When the oil tar content increases to more than 5 to 10% by weight, this tar phase fills small pores, reduces surface area, and dominates PAH sorption on lampblack surface. A new PAH partitioning model, Kd = KLB-C(1 - ftar)alpha + ftarKtar (alpha = empirical exponent), incorporates these effects in which the control of PAH partitioning transits from being dominated by sorption in lampblack (KLB-C) to absorption in oil tar (Ktar), depending on the fraction of tar (ftar). This study illustrates the importance of understanding interactions among PAHs, oil tar, and lampblack for explaining the differences in availability of PAHs among site soils and, consequently, for refining site-specific risk assessment and establishing soil cleanup levels.

  View details for Web of Science ID 000244241600003

  View details for PubMedID 17373502

• Sorption of perfluorinated surfactants on sediments ENVIRONMENTAL SCIENCE & TECHNOLOGY Higgins, C. P., Luthy, R. G. 2006; 40 (23): 7251-7256

  Abstract

  The sorption of anionic perfluorochemical (PFC) surfactants of varying chain lengths to sediments was investigated using natural sediments of varying iron oxide and organic carbon content. Three classes of PFC surfactants were evaluated for sorptive potential: perfluorocarboxylates, perfluorosulfonates, and perfluorooctyl sulfonamide acetic acids. PFC surfactant sorption was influenced by both sediment-specific and solution-specific parameters. Sediment organic carbon, rather than sediment iron oxide content, was the dominant sediment-parameter affecting sorption, indicating the importance of hydrophobic interactions. However, sorption also increased with increasing solution [Ca2+] and decreasing pH, suggesting that electrostatic interactions play a role. Perfluorocarbon chain length was the dominant structural feature influencing sorption, with each CF2 moiety contributing 0.50-0.60 log units to the measured distribution coefficients. The sulfonate moiety contributed an additional 0.23 log units to the measured distribution coefficient, when compared to carboxylate analogs. In addition, the perfluorooctyl sulfonamide acetic acids demonstrated substantially stronger sorption than perfluorooctane sulfonate (PFOS). These data should prove useful for modeling the environmental fate of this class of contaminants.

  View details for DOI 10.1021/es061000n

  View details for Web of Science ID 000242367100027

  View details for PubMedID 17180974

• Fluorochemical mass flows in a municipal wastewater treatment facility ENVIRONMENTAL SCIENCE & TECHNOLOGY Schultz, M. M., Higgins, C. P., Huset, C. A., Luthy, R. G., Barofsky, D. F., Field, J. A. 2006; 40 (23): 7350-7357

  Abstract

  Fluorochemicals have widespread applications and are released into municipal wastewater treatment plants via domestic wastewater. A field study was conducted at a full-scale municipal wastewater treatment plant to determine the mass flows of selected fluorochemicals. Flow-proportional, 24 h samples of raw influent, primary effluent, trickling filter effluent, secondary effluent, and final effluent and grab samples of primary, thickened, activated, and anaerobically digested sludge were collected over 10 days and analyzed by liquid chromatography electrospray-ionization tandem mass spectrometry. Significant decreases in the mass flows of perfluorohexane sulfonate and perfluorodecanoate occurred during trickling filtration and primary clarification, while activated sludge treatment decreased the mass flow of perfluorohexanoate. Mass flows of the 6:2 fluorotelomer sulfonate and perfluorooctanoate were unchanged as a result of wastewater treatment, which indicates that conventional wastewater treatment is not effective for removal of these compounds. A net increase in the mass flows for perfluorooctane and perfluorodecane sulfonates occurred from trickling filtration and activated sludge treatment. Mass flows for perfluoroalkylsulfonamides and perfluorononanoate also increased during activated sludge treatment and are attributed to degradation of precursor molecules.

  View details for DOI 10.1021/es061025m

  View details for Web of Science ID 000242367100041

  View details for PubMedID 17180988

  View details for PubMedCentralID PMC2556954

• Nanometer-scale chemical heterogeneities of black carbon materials and their impacts on PCB sorption properties: Soft X-ray spectromicroscopy study ENVIRONMENTAL SCIENCE & TECHNOLOGY Yoon, T. H., Benzerara, K., Ahn, S., Luthy, R. G., Tyliszczak, T., Brown, G. E. 2006; 40 (19): 5923-5929

  Abstract

  Synchrotron-based soft X-ray spectromicroscopy was used to probe nanometer-scale chemical heterogeneities of black carbon (BC) materials, including anthracite coal, coke, and activated carbon (AC), and to study their impact on the partitioning of one type of polychlorinated biphenyls (PCB-166: 2,3,4,4',5,6 hexachloro biphenyl) onto AC particles. Various carbon species (e.g., aromatic, ketonic/ phenolic, and carboxylic functional groups) were found in all of the BC materials examined, and impurities (e.g., carbonate and potassium ions in anthracite coal) were identified in nanometer-scale regions of these samples. We show that these chemical heterogeneities in AC particles influence their sorption of hydrophobic organic compounds (HOCs). PCB-166 was found to accumulate preferentially on AC particles with the highest content of aromatic functionalities. These new findings from X-ray spectromicroscopy have the following implications for the role of BC materials in the environment: (1) the functional groups of BC materials vary on a 25-nanometer scale, and so does the abundance of the HOCs; (2) molecular-level characterization of HOC sorption preferences on AC will lead to an improved understanding of AC sorption properties for the remediation of HOCs in soils and sediments.

  View details for DOI 10.1021/es060173+

  View details for Web of Science ID 000240826000022

  View details for PubMedID 17051780

• Human development is linked to multiple water body impairments along the California coast ESTUARIES AND COASTS Handler, N. B., Payran, A., Higgins, C. P., Luthy, R. G., Boehm, A. B. 2006; 29 (5): 860-870

  View details for Web of Science ID 000241837400015

• Implications for perfluorochemical ecotoxicology: Inhibition and induction of an efflux transporter in the marine mussel, Mytilus californianus Stevenson, C., Macmanus-Spencer, L. A., Luckenbach, T., Luthy, R. G., Epel, D. AMER CHEMICAL SOC. 2006: 608–608

  View details for Web of Science ID 000207781604539

• Modeling perfluorochemical surfactant sorption onto sediment materials: An a priori approach Higgins, C. P., Luthy, R. G. AMER CHEMICAL SOC. 2006: 614–614

  View details for Web of Science ID 000207781604545

• New perspectives on perfluorochemical ecotoxicology: inhibition and induction of an efflux transporter in the marine mussel, Mytilus californianus ENVIRONMENTAL SCIENCE & TECHNOLOGY Stevenson, C. N., Macmanus-Spencer, L. A., Luckenbach, T., Luthy, R. G., Epel, D. 2006; 40 (17): 5580-5585

  Abstract

  The toxicological effects of perfluoroalkyl acids on the p-glycoprotein (p-gp) cellular efflux transporter were investigated using the marine mussel Mytilus californianus as a model system. Four of the perfluoroalkyl acids studied exhibit chemosensitizing behavior, significantly inhibiting p-gp transporter activity. The inhibitory potency is maximal for the longer chain acids perfluorononanoate (PFNA) and perfluorodecanoate (PFDA), with average IC50 values of 4.8 and 7.1 microM, respectively. Results indicate that PFNA inhibits p-gp by an indirect mechanism, and this inhibition is reversible and accompanied by a rapid loss of PFNA from the tissue. In addition, PFNA induces expression of the p-gp transporter after a 2-h exposure, a stress response that may result in a metabolic cost to the organism. Given that most organisms, including humans, share efflux transporters as a first line of defense against toxicants, the results of this study may have broader implications for the ecotoxicology of perfluoroalkyl acids.

  View details for DOI 10.1021/es0602593

  View details for Web of Science ID 000240130200067

  View details for PubMedID 16999143

• Modeling polychlorinated biphenyl mass transfer after amendment of contaminated sediment with activated carbon ENVIRONMENTAL SCIENCE & TECHNOLOGY Werner, D., Ghosh, U., Luthy, R. G. 2006; 40 (13): 4211-4218

  Abstract

  The sorption kinetics and concentration of polychlorinated biphenyls (PCBs) in historically polluted sediment is modeled to assess a remediation strategy based on in situ PCB sequestration by mixing with activated carbon (AC). We extend our evaluation of a model based on intraparticle diffusion by including a biomimetic semipermeable membrane device (SPMD) and a first-order degradation rate for the aqueous phase. The model predictions are compared with the previously reported experimental PCB concentrations in the bulk water phase and in SPMDs. The simulated scenarios comprise a marine and a freshwater sediment, four PCB congeners, two AC grain sizes, four doses of AC, and comparison with laboratory experiments for up to 540 days of AC amendment slowly mixed with sediment. The model qualitatively reproduces the observed shifts in the PCB distribution during repartitioning after AC amendment but systematically overestimates the overall effect of the treatment in reducing aqueous and SPMD concentrations of PCBs by a factor of 2-6. For our AC application in sediment, competitive sorption of the various solutes apparently requires a reduction by a factor of 16 of the literature values for the AC-water partitioning coefficient measured in pure aqueous systems. With this correction, model results and measurements agree within a factor of 3. We also discuss the impact of the nonlinearity of the AC sorption isotherm and first-order degradation in the aqueous phase. Regular mixing of the sediment accelerates the benefit of the proposed amendment substantially. But according to our scenario, after AC amendment is homogeneously mixed into the sediment and then left undisturbed, aqueous PCB concentrations tend toward the same reduction after approximately 5 or more years.

  View details for DOI 10.1021/es052215k

  View details for Web of Science ID 000238645400032

  View details for PubMedID 16856737

• Treatment and containment of contaminated sediments NATO Advanced Research Workshop on Assessment and Remediation of Contaminated Sediments Tomaszewski, J. E., Smithenry, D. W., Cho, Y., Luthy, R. G., Lowry, G. V., Reible, D., Macek, T., Sura, M., Chrastilova, Z., Demnerova, K., Mackova, M., Pavlikova, D., Szekeres, M., Sylvestre, M. SPRINGER. 2006: 137–178

  View details for Web of Science ID 000240547100004

• Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon ENVIRONMENTAL SCIENCE & TECHNOLOGY Ahn, S., Werner, D., Karapanagioti, H. K., McGlothlin, D. R., Zare, R. N., Luthy, R. G. 2005; 39 (17): 6516-6526

  Abstract

  We report sorption isotherms and uptake kinetics for phenanthrene and pyrene with three organic model sorbents: polyoxymethylene (POM), coke, and activated carbon. We combine batch equilibration and kinetic experiments with the direct observation of the long-term diffusion of phenanthrene and pyrene as measured within cross-sectioned particles using microprobe laser-desorption laser-ionization mass spectroscopy (muL2MS). For POM pellets, the intraparticle concentration profiles predicted from kinetic batch experiments and a polymer diffusion model with spherical geometry are in agreement with the independent muL2MS measurements. For coke particles, the apparent diffusivities decreased with smaller particle size. These trends in diffusivities were described by a sorption-retarded pore diffusion model with a particle-size-dependent solid-water partitioning coefficient obtained from apparent equilibrium observed in the kinetic batch studies. For activated carbon, the muL2MS measurements showed faster radial diffusion of phenanthrene and pyrene into the particle interior than predicted from diffusion models based on a single sorption domain and diffusivity. A branched pore kinetic model, comprising polycyclic aromatic hydrocarbon (PAH) macropore diffusion with kinetic exchange of PAH between macroporous and microporous domains, fits the experimental observations better. Because of parallel macro- and microdiffusion processes, nonlinear sorption isotherms, and a concentration-dependent diffusivity, it is not possible to make independent parameter estimations for intraparticle diffusion in activated carbon using our present procedures.

  View details for DOI 10.1021/es050113o

  View details for Web of Science ID 000231723800035

  View details for PubMedID 16190207

• Physicochemical characterization of coke-plant soil for the assessment of polycyclic aromatic hydrocarbon availability and the feasibility of phytoremediation ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Ahn, S., Werner, D., Luthy, R. G. 2005; 24 (9): 2185-2195

  Abstract

  Coke oven site soil was characterized to assess the particle association and availability of polycyclic aromatic hydrocarbons (PAHs). We identified various carbonaceous materials including coal, coke, pitch, and tar decanter sludge. Most of the PAHs were associated with the polymeric matrix of tar sludge or hard pitch as discrete particles, coatings on soil mineral particles, or complex aggregates. The PAH availability from these particles was very low due to hindered diffusive release from solid tar or pitch with apparent diffusivities of 6 x 10(-15) for phenanthrene, 3 x 10(-15) for pyrene, and 1 x 10(-15) cm2/s for benzo[a]pyrene. Significant concentrations of PAHs were observed in the interior of solid tar aggregates with up to 40,000 mg/kg total PAHs. The release of PAHs from the interior of such particles requires diffusion over a substantial distance, and semipermeable membrane device tests confirmed a very limited availability of PAHs. These findings explain the results from three years of phytoremediation of the site soil, for which no significant changes in the total PAH concentrations were observed in the test plot samples. The observed low bioavailability of PAHs probably inhibited PAH phytoremediation, as diffusion-limited mass transfer would limit the release of PAHs to the aqueous phase.

  View details for Web of Science ID 000231341300010

  View details for PubMedID 16193745

• Preliminary field testing of activated carbon mixing and in situ stabilization of PCBs in sediment 230th National Meeting of the American-Chemical-Society Cho, Y., Smithenry, D. W., Luthy, R. G. AMER CHEMICAL SOC. 2005: U1591–U1591

  View details for Web of Science ID 000236797303186

• Use of black carbon to alter the bioavailability of contaminants in sediments 230th National Meeting of the American-Chemical-Society Millward, R. N., Burgess, R. M., Ho, K. T., Bridges, T. S., Lotufo, G. R., Luthy, R. G., Ghosh, U. AMER CHEMICAL SOC. 2005: U1508–U1508

  View details for Web of Science ID 000236797303018

• Effects of dose and particle size on activated carbon treatment to sequester polychlorinated biphenyls and polycyclic aromatic hydrocarbons in marine sediments ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Zimmerman, J. R., Werner, D., Ghosh, U., Millward, R. N., Bridges, T. S., Luthy, R. G. 2005; 24 (7): 1594-1601

  Abstract

  Recent laboratory studies show that mixing activated carbon with contaminated sediment reduces the chemical and biological availability of hydrophobic organic contaminants. In this study, we test the effects of varying the activated carbon dose and particle size in reducing the aqueous availability of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) and the uptake of PCBs by two benthic organisms. We mixed PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay (CA, USA), for one month with activated carbon, at doses of 0.34, 1.7, and 3.4% dry mass basis. We found that increasing the carbon dose increased the effectiveness in reducing PCB bioaccumulation. In 56-d uptake tests with the benthic organisms Neanthes arenaceodentata and Leptocheirus plumulosus, PCB bioaccumulation was reduced by 93 and 90%, respectively, with 3.4% carbon. Increasing the dose also increased the effectiveness in reducing PCB and PAH aqueous concentrations and uptake by semipermeable membrane devices and quiescent flux of PCBs to overlying water. Decreasing activated carbon particle size increased treatment effectiveness in reducing PCB aqueous concentration, and larger-sized activated carbon (400-1,700 microm) was ineffective with a contact period of one month. We invoke a numerical model based on intraparticle diffusion in sediment and activated carbon particles to help interpret our experimental results. This model was useful in explaining the trends for the effect of activated carbon dose and particle size on PCB aqueous concentrations in well-mixed systems.

  View details for Web of Science ID 000229960700003

  View details for PubMedID 16050574

• Improving Risk Assessments for Manufactured Gas Plant Soils by Measuring PAH Availability INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT Stroo, H. F., Nakles, D. V., Kreitinger, J. P., Loehr, R. C., Hawthorne, S. B., Luthy, R. G., Holman, H., LaPierre, A. 2005; 1 (3): 259-266

  Abstract

  Remediation of soils at oil-gas manufactured gas plant (MGP) sites is driven primarily by the human health risks posed by the carcinogenic polycyclic aromatic hydrocarbons (PAHs), particularly benzo[a]pyrene (BaP), that are associated with lampblack residues. Although PAHs on lampblack are tightly sorbed, risk assessments do not account for this reduced availability. A multi-investigator study of 7 oil-gas MGP site soil samples demonstrated that the dermal and ingestion absorption factors are far lower than current default assumptions used in risk assessments. Using these sample-specific absorption factors in standard risk assessment equations increased risk-based cleanup levels by a factor of 72 on average (with a range from 23 to 142 times the default level). The rapidly released fraction of the BaP in each sample, as measured by supercritical fluid extraction, was closely correlated (r2 = 0.96) to these calculated cleanup levels. The weight of evidence developed during this research indicates that the risks posed by PAHs on lampblack are far less than assumed when using default absorption factors and that a tiered evaluation protocol employing chemical analyses, chemical release data, and in vitro bioassays can be used to establish more realistic site-specific criteria.

  View details for DOI 10.1897/2004-009R.1

  View details for Web of Science ID 000209711900006

• Improving risk assessments for manufactured gas plant soils by measuring PAH availability. Integrated environmental assessment and management Stroo, H. F., Nakles, D. V., Kreitinger, J. P., Loehr, R. C., Hawthorne, S. B., Luthy, R. G., Holman, H., LaPierre, A. 2005; 1 (3): 259-266

  Abstract

  Remediation of soils at oil-gas manufactured gas plant (MGP) sites is driven primarily by the human health risks posed by the carcinogenic polycyclic aromatic hydrocarbons (PAHs), particularly benzo[a]pyrene (BaP), that are associated with lampblack residues. Although PAHs on lampblack are tightly sorbed, risk assessments do not account for this reduced availability. A multi-investigator study of 7 oil-gas MGP site soil samples demonstrated that the dermal and ingestion absorption factors are far lower than current default assumptions used in risk assessments. Using these sample-specific absorption factors in standard risk assessment equations increased risk-based cleanup levels by a factor of 72 on average (with a range from 23 to 142 times the default level). The rapidly released fraction of the BaP in each sample, as measured by supercritical fluid extraction, was closely correlated (r2 = 0.96) to these calculated cleanup levels. The weight of evidence developed during this research indicates that the risks posed by PAHs on lampblack are far less than assumed when using default absorption factors and that a tiered evaluation protocol employing chemical analyses, chemical release data, and in vitro bioassays can be used to establish more realistic site-specific criteria.

  View details for PubMedID 16639887

• Quantitative determination of perfluorochemicals in sediments and domestic sludge ENVIRONMENTAL SCIENCE & TECHNOLOGY Higgins, C. P., Field, J. A., Criddle, C. S., Luthy, R. G. 2005; 39 (11): 3946-3956

  Abstract

  Perfluorochemicals (PFCs) are the subject of increasingly intense environmental research. Despite their detection both in biota and in aqueous systems, little attention has been paid to the possible presence of this class of compounds in solid environmental matrixes. The limited available data indicate that some PFCs such as perfluorooctane sulfonate (PFOS) may strongly sorb to solids, and sewage sludge is widely suspected as a major sink of PFCs entering municipal waste streams. A quantitative analytical method was developed that consists of liquid solvent extraction of the analytes from sediments and sludge, cleanup via solid-phase extraction, and injection of the extracts with internal standards into a high-performance liquid chromatography (HPLC) system coupled to a tandem mass spectrometer (LC/MS/MS). The limits of detections of the method were analyte and matrix dependent, but ranged from 0.7 to 2.2 ng/g and 0.041 to 0.246 ng/g (dry weight) for sludge and sediment, respectively. A demonstration of the method was performed by conducting a limited survey of domestic sludge and sediments. The concentration of PFCs in domestic sludge ranged from 5 to 152 ng/g for total perfluorocarboxylates and 55 to 3370 ng/g for total perfluoroalkyl sulfonyl-based chemicals. Data from a survey of San Francisco Bay Area sediments suggest widespread occurrence of PFCs in sediments at the low ng/g to sub-ng/g level. Furthermore, substances that may be transformed to PFOS, such as 2-(N-ethylperfluorooctanesulfonamido) acetic acid (N-EtFOSAA) and 2-(N-methylperfluorooctanesulfonamido) acetic acid (N-MeFOSAA), are present in both sediments and sludge at levels often exceeding PFOS.

  View details for DOI 10.1021/es048245p

  View details for Web of Science ID 000229662200019

  View details for PubMedID 15984769

• The sequestration of PCBs in Lake Hartwell sediment with activated carbon WATER RESEARCH Werner, D., Higgins, C. P., Luthy, R. G. 2005; 39 (10): 2105-2113

  Abstract

  Recent laboratory studies with a marine sediment from a tidal mudflat in San Francisco Bay demonstrated that a low dose of activated carbon enhances the sequestration of PCBs and PAHs under well-mixed conditions. Here we compare activated carbon treatment for a freshwater sediment from a rural site, using PCB-contaminated sediment from Lake Hartwell, SC. An activated carbon dose of 2% of the dry sediment mass lowered total aqueous PCB concentrations by more than 95% after 1 month of treatment and more than 98% after 6 months. Aqueous PCB concentrations remained below detection limits following 18 months of sediment-carbon contact in slowly mixed systems. Uptake of PCBs into semipermeable membrane devices was reduced by 78%, 91% and 97% over 1, 6 and 18 months, respectively. These tests show that PCB sequestration with activated carbon improves with contact time and is not diminished by prolonged mixing with sediment. Desorption studies confirmed the sequestration, in which 74% of the total PCB mass could be desorbed from untreated Lake Hartwell sediment within 30 days as compared to only 7% after activated carbon treatment for 6 months. We compare these observations with marine sediment from San Francisco Bay and propose a conceptual model to rationalize how sediment properties relate to the reduction in aqueous PCB concentrations during activated carbon treatment.

  View details for DOI 10.1016/j.watres.2005.03.019

  View details for Web of Science ID 000230241200019

  View details for PubMedID 15922398

• Addition of activated carbon to sediments to reduce PCB bioaccumulation by a polychaete (Neanthes arenaceodentata) and an amphipod (Leptocheirus plumulosus) ENVIRONMENTAL SCIENCE & TECHNOLOGY Millward, R. N., Bridges, T. S., Ghosh, U., Zimmerman, J. R., Luthy, R. G. 2005; 39 (8): 2880-2887

  Abstract

  This work examines the effects of adding coke or activated carbon on the bioavailability of polychlorinated biphenyls (PCBs) in contaminated sedimentfrom South Basin at Hunters Point, San Francisco Bay. We show with 28-day sediment exposure tests that PCB bioaccumulation in a polychaete (Neanthes arenaceodentata) is reduced by 82% following 1-month contact of sediment with activated carbon and by 87% following 6-months contact of sediment with activated carbon. PCB bioaccumulation in an amphipod (Leptocheirus plumulosus) is reduced by 70% following 1-month contact of sediment with activated carbon and by 75% after 6-months contact of sediment with activated carbon. Adding coke had a negligible effect on reducing PCB bioaccumulation, probably because of the low specific surface area and the slow kinetics of PCB diffusion intothe solid coke particles. Reductions in congener bioaccumulation with activated carbon were inversely related to congener Kow, suggesting that the efficacy of activated carbon is controlled by the mass-transfer rate of PCBs from sediment and into activated carbon. We find that reductions in aqueous PCB concentrations in equilibrium with the sediment were similar to reductions in PCB bioaccumulation. While no lethality was observed following activated carbon addition, growth rates were reduced by activated carbon for the polychaete, but not for the amphipod, suggesting the need for further study of the potential impacts of activated carbon on exposed communities. The study suggests that treatment of the biologically active layer of contaminated sediments with activated carbon may be a promising in-situ technique for reducing the bioavailability of sediment-associated PCBs and other hydrophobic organic compounds.

  View details for DOI 10.1021/es048768x

  View details for Web of Science ID 000228428900066

  View details for PubMedID 15884389

• Soft x-ray spectromicroscopy study of carbonaceous materials: Characterization of their chemical heterogeneities in sub-micrometer scale 229th National Meeting of the American-Chemical-Society (ACS) Yoon, T. H., Benzerara, K., Ahn, S. W., Luthy, R. G., Tyliszczak, T., Brown, G. E. AMER CHEMICAL SOC. 2005: U860–U860

  View details for Web of Science ID 000228177706191

• Response to comment on "Addition of carbon sorbents to reduce PCB and PAH: Bioavailability in marine sediments: Physicochemical tests" ENVIRONMENTAL SCIENCE & TECHNOLOGY Zimmerman, J. R., Luthy, R. G., Ghosh, U., Millward, R. N., Bridges, T. S. 2005; 39 (4): 1199-1200

  View details for DOI 10.1021/es047983a

  View details for Web of Science ID 000227001700039

• Effect of oil on polychlorinated biphenyl phase partitioning during land biotreatment of impacted sediment JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE McNamara, S. W., Ghosh, U., Dzombak, D. A., Weber, A. S., Smith, J. R., Luthy, R. G. 2005; 131 (2): 278-286

  View details for DOI 10.1061/(ASCE)0733-9372(2005)131:2(278)

  View details for Web of Science ID 000226388200013

• Sorbent wicking device for sampling hydrophobic organic compounds in unsaturated soil pore water. I: Design and hydraulic characteristics JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE McNamara, S. W., Luthy, R. G. 2005; 131 (1): 11-20

  View details for DOI 10.1061/(ASCE)0733-9372(2005)131:1(11)

  View details for Web of Science ID 000225818800003

• Improving Risk Assessments for Manufactured Gas Plant Soils Integrated Environmental Assessment and Management Stroo, Hans, F., Nakles, David, V., Kreitinger, Joseph, P., Loehr, Raymond, C., Hawthorne, Steven, B., Luthy, Richard, G. 2005; 1 (3): 259-266
• Sorbent wicking device for sampling hydrophobic organic compounds in unsaturated soil pore water. II: Chemical capture, recovery, and analysis JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE McNamara, S. W., Luthy, R. G. 2005; 131 (1): 21-28

  View details for DOI 10.1061/(ASCE)0733-9372(2005)131:1(21)

  View details for Web of Science ID 000225818800004

• Thermal program desorption mass spectrometry of PAHs from mineral and organic surfaces ENVIRONMENTAL ENGINEERING SCIENCE Talley, J. W., Ghosh, U., Furey, J. S., Tucker, S. G., Luthy, R. G. 2004; 21 (6): 647-660

  View details for Web of Science ID 000225201700001

• Addition of carbon sorbents to reduce PCB and PAH bioavailability in marine sediments: Physicochemical tests ENVIRONMENTAL SCIENCE & TECHNOLOGY Zimmerman, J. R., Ghosh, U., Millward, R. N., Bridges, T. S., Luthy, R. G. 2004; 38 (20): 5458-5464

  Abstract

  The addition of activated carbon as particulate sorbent to the biologically active layer of contaminated sediment is proposed as an in-situ treatment method to reduce the chemical and biological availability of hydrophobic organic contaminants (HOCs) such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). We report results from physicochemical experiments that assess this concept. PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay, CA, was contacted with coke and activated carbon for periods of 1 and 6 months. Sediment treated with 3.4 wt % activated carbon showed 92% and 84% reductions in aqueous equilibrium PCB and PAH concentrations, 77% and 83% reductions in PCB and PAH uptake by semipermeable membrane devices (SPMD), respectively, and reductions in PCB flux to overlying water in quiescent systems up to 89%. Adding coke to contaminated sediment did not significantly decrease aqueous equilibrium PCB concentrations nor PCB or PAH availability in SPMD measurements. Coke decreased PAH aqueous equilibrium concentrations by 38-64% depending on coke dose and particle size. The greater effectiveness of activated carbon as compared to coke is attributed to its much greater specific surface area and a pore structure favorable for binding contaminants. The results from the physicochemical tests suggest that adding activated carbon to contaminated field sediment reduces HOC availability to the aqueous phase. The benefit is manifested relatively quickly under optimum contact conditions and improves in effectiveness with contact time from 1 to 6 months. Activated carbon application is a potentially attractive method for in-situ, nonremoval treatment of marine sediment contaminated with HOCs.

  View details for DOI 10.1021/es034992v

  View details for Web of Science ID 000224519500034

  View details for PubMedID 15543751

• Effects of particulate carbonaceous matter on the bioavailability of benzo[a]pyrene and 2,2 ',5,5 '-tetrachlorobiphenyl to the clam, Macoma balthica ENVIRONMENTAL SCIENCE & TECHNOLOGY McLeod, P. B., van den Heuvel-Greve, M. J., Allen-King, R. M., Luoma, S. N., Luthy, R. G. 2004; 38 (17): 4549-4556

  Abstract

  We investigated the bioavailability via diet of spiked benzo[a]pyrene (BaP) and 2,2',5,5'-tetrachlorobiphenyl (PCB-52) from different carbonaceous (non-carbonate, carbon containing) particle types to clams (Macoma balthica) collected from San Francisco Bay. Our results reveal significant differences in absorption efficiency between compounds and among carbonaceous particle types. Absorption efficiency for PCB-52 was always greater than that for BaP bound to a given particle type. Among particles, absorption efficiency was highest from wood and diatoms and lowest from activated carbon. Large differences in absorption efficiency could not be simply explained by comparatively small differences in the particles' total organic carbon content. BaP and PCB-52 bound to activated carbon exhibited less than 2% absorption efficiency and were up to 60 times less available to clams than the same contaminants associated with other types of carbonaceous matter. These results suggest that variations in the amount and type of sediment particulate carbonaceous matter, whether naturally occurring or added as an amendment, will have a strong influence on the bioavailability of hydrophobic organic contaminants. This has important implications for environmental risk assessment, sediment management, and development of novel remediation techniques.

  View details for DOI 10.1021/es049893b

  View details for Web of Science ID 000223678900021

  View details for PubMedID 15461162

• Granular activated carbon treatment of contaminated sediment to reduce PCB availability and biouptake. Meeting of the Division of Chemical Toxicology of the American-Chemical-Society held at the 228th National Meeting of the American-Chemical-Society McLeod, P. B., Zimmerman, J. R., Werner, D., Smithenry, D. W., Luthy, R. G. AMER CHEMICAL SOC. 2004: U618–U618

  View details for Web of Science ID 000223712802449

• Microbial transformations of perfluorinated organics. Meeting of the Division of Chemical Toxicology of the American-Chemical-Society held at the 228th National Meeting of the American-Chemical-Society Fu, Q. S., Rhoads, K. R., Higgins, C. P., Luthy, R. G., Criddle, C. S. AMER CHEMICAL SOC. 2004: U609–U609

  View details for Web of Science ID 000223712802392

• Effects of thiocyanate on the formation of free cyanide during chlorination and ultraviolet disinfection of publicly owned treatment works secondary effluent WATER ENVIRONMENT RESEARCH Zheng, A. P., Dzombak, D. A., Luthy, R. G. 2004; 76 (3): 205-212

  Abstract

  Cyanide has been detected in effluent of some publicly owned treatment works (POTWs) at levels exceeding influent concentration. Thiocyanate (SCN-) is a cyanide-related compound encountered in most POTW influents and may be decomposed to free cyanide (CN-) under some circumstances. Effects of SCN- on the formation of cyanide during chlorination and UV disinfection were studied through a laboratory study with synthetic solutions and POTW secondary effluent. Results indicated that CN- was detected in SCN- solutions after chlorination in which the chlorine dose or reaction time was not sufficient to destroy SCN-completely, thus ensuring no residual chlorine to destroy any CN-produced. It was also found that SCN can be broken down to yield cyanide by UV irradiation. In addition, SCN- was observed to cause significant positive error in the conventional total cyanide analysis technique involving acidic distillation and colorimetric measurement when nitrate was present in the sample.

  View details for Web of Science ID 000222451500003

  View details for PubMedID 15338691

• Effects of nitrosation on the formation of cyanide in publicly owned treatment works secondary effluent WATER ENVIRONMENT RESEARCH Zheng, A. P., Dzombak, D. A., Luthy, R. G. 2004; 76 (3): 197-204

  Abstract

  Cyanide has been detected in the effluents of some publicly owned treatment works (POTWs) at levels exceeding the influent concentration. The presence of nitrite ion (NO2-) as a common constituent in domestic wastewater effluents may play an important role in the formation of cyanide through reaction with certain kinds of organic compounds, especially aromatic compounds. Laboratory studies with seven organic compounds (aniline. p-toluidine, phenol, 1,2,4-trihydroxybenzene, L-serine, glycine, and benzoic acid) revealed that cyanide can be formed by reaction of nitrite with some of these compounds. The most substantial free cyanide (HCN. CN-) production observed at 25 degrees C was 0.15 mg/L from reaction of 0.01 mM 1.2.4-trihydroxybenze with 5 mg/L nitrite for 72 hours. Substantial free cyanide formation was also observed at pH 2-4 in experiments with POTW effluents when reactive organics and nitrite were both added to wastewater. Formation of cyanide through nitrosation was strongly pH dependent, being most significant at low pH (2 to 4) and negligible at neutral-to-high pH. This result points to nitrous acid (HNO2) as being more reactive than the dissociated NO2- ion. The reaction of these nitrite species with organics also occurs in conventional analyses for total cyanide which involve distillation under strongly acidic conditions. Sufficient sample pretreatment with sulfamic acid at the time of sampling, not at the time of analysis. is highly recommended to prevent biasing analytical measurement of total cyanide in POTW effluents.

  View details for Web of Science ID 000222451500002

  View details for PubMedID 15338690

• Formation of free cyanide and cyanogen chloride from chloramination of publicly owned treatment works secondary effluent: Laboratory study with model compounds WATER ENVIRONMENT RESEARCH Zheng, A. P., Dzombak, D. A., Luthy, R. G. 2004; 76 (2): 113-120

  Abstract

  The potential generation of cyanide species in wastewater upon chlorination in the presence of residual ammonia (resulting in chloramine formation) was investigated in experiments with synthetic solutions and publicly owned treatment works (POTW) secondary effluent. This study demonstrated that low concentrations (approximately 5 to 25 microg/L as cyanide) of cyanogen chloride (CNCI), a highly toxic cyanide species not measured in total or free cyanide analyses, could be detected as a result of chloramination reactions in POTW secondary effluent. The potential for chloramination of nitrogen-bearing organic compounds to yield CNCl and/or free cyanide was demonstrated in experiments with synthetic solutions spiked with selected precursor organics: L-serine, benzene, catechin, and humic acid. The amino acid L-serine yielded the largest concentrations of CNCI upon chloramination. Additionally, detectable cyanide (approximately 10 microg/L) was observed in solutions of L-serine and in POTW secondary effluent that was chloraminated followed by dechlorination to prevent destruction of any free cyanide produced. Thus, chlorination of POTW secondary effluent containing residual ammonia can lead to chloramination of organic compounds and the resulting production of CNCl and free cyanide.

  View details for Web of Science ID 000221290800004

  View details for PubMedID 15168842

• The occurrence of cyanide formation in six full-scale publicly owned treatment works WATER ENVIRONMENT RESEARCH Zheng, A. P., Dzombak, D. A., Luthy, R. G., Kavanaugh, M. C., Deeb, R. A. 2004; 76 (2): 101-112

  Abstract

  This paper presents results from an intensive monitoring program implemented at six full-scale publicly owned treatment works (POTWs) to investigate the fate and formation of cyanide in wastewater treatment processes, with a focus on chlorination and dechlorination processes. A review of historical monitoring data for cyanide species in these POTWs was also conducted. This POTW monitoring program provided a database for the investigation of cyanide formation in wastewater secondary treatment. Data from participating POTWs showed evidence of cyanide formation in this 1-year monitoring effort, although the cyanide formation pattern varied significantly from one plant to another and among seasons. Generally, the chlorination of thiocyanate (SCN-) seems to be the most important mechanism for the formation of cyanide in wastewater treatment processes, especially in chlorination and dechlorination. This hypothesis is supported by the findings of a related laboratory study of mechanisms of cyanide formation in POTWs. It is recommended that POTWs monitor SCN in influent and secondary effluent to identify its presence and adjust chlorine dose appropriately.

  View details for Web of Science ID 000221290800003

  View details for PubMedID 15168841

• Release of polychlorinated to water under biphenyls from river sediment low-flow conditions: Laboratory assessment. JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE Ortiz, E., Luthy, R. G., Dzombak, D. A., Smith, J. R. 2004; 130 (2): 126-135

  View details for DOI 10.1061/(ASCE)0733-9372(2004)130:2(126)

  View details for Web of Science ID 000188370200003

• Microscale association of organic contaminants to sediment particles and implications for risk management. 226th National Meeting of the American-Chemical-Society Ghosh, U., Zimmerman, J. R., McLeod, P. B., Luthy, R. G., Milward, R. N., Bridges, T. S. AMER CHEMICAL SOC. 2003: U514–U514

  View details for Web of Science ID 000187062402486

• PAH sorption mechanism and partitioning behavior in lampblack-impacted soils from former oil-gas plant sites ENVIRONMENTAL SCIENCE & TECHNOLOGY Hong, L., Ghosh, U., Mahajan, T., Zare, R. N., Luthy, R. G. 2003; 37 (16): 3625-3634

  Abstract

  This study assessed polycyclic aromatic hydrocarbon (PAH) association and aqueous partitioning in lampblack-impacted field soils from five sites in California that formerly housed oil-gas process operations. Lampblack is the solid residue resulting from the decomposition of crude oil at high temperatures in the gas-making operation and is coated or impregnated with oil gasification byproducts, among which PAHs are the compounds of the greatest regulatory concern. A suite of complementary measurements investigated the character of lampblack particles and PAH location and the associated effects on PAH partitioning between lampblack and water. PAH analyses on both whole samples and density-separated components demonstrated that 81-100% of PAHs in the lampblack-impacted soils was associated with lampblack particles. FTIR, 13C NMR, and SEM analyses showed that oil-gas lampblack solids comprise primarily aromatic carbon with soot-like structures. A free-phase aromatic oil may be present in some of the lampblack soils containing high PAH concentrations. Comparable long-term aqueous partitioning measurements were obtained with an air-bridge technique and with a centrifugation/alum flocculation procedure. Large solid/water partition coefficient (Kd) values were observed in samples exhibiting lower PAH and oil levels, whereas smaller Kd values were measured in lampblack samples containing high PAH levels. The former result is in agreement with an oil-soot partitioning model, and the latter is in agreement with a coal tar-water partitioning model. Lampblack containing high PAH levels appears to exhaust the sorption capacity of the soot-carbon, creating a free aromatic oil phase that exhibits partitioning behavior similar to PAHs in coal tar. This study improves mechanistic understanding of PAH sorption on aged lampblack residuals at former oil-gas sites and provides a framework for mechanistic assessment of PAH leaching potential and risk from such site materials.

  View details for DOI 10.1021/es0262683

  View details for Web of Science ID 000184803700022

  View details for PubMedID 12953875

• Contaminant bioavailability in soil and sediment ENVIRONMENTAL SCIENCE & TECHNOLOGY Ehlers, L. J., Luthy, R. G. 2003; 37 (15): 295A-302A

  View details for Web of Science ID 000184501900023

  View details for PubMedID 12966964

• PCB and PAH speciation among particle types in contaminated harbor sediments and effects on PAH bioavailability ENVIRONMENTAL SCIENCE & TECHNOLOGY Ghosh, U., Zimmerman, J. R., Luthy, R. G. 2003; 37 (10): 2209-2217

  Abstract

  This research provides particle-scale understanding of PCB and PAH distribution in sediments obtained from three urban locations in the United States: Hunters Point, CA; Milwaukee Harbor, WI; and Harbor Point, NY. The sediments comprised mineral grains (primarily sand, silt, and clays) and carbonaceous particles (primarily coal, coke, charcoal, pitch, cenospheres, and wood). The carbonaceous sediment fractions were separated from the mineral fractions based on their lower density and were identified by petrographic analysis. In all three sediments, carbonaceous particles contributed 5-7% of the total mass and 60-90% of the PCBs and PAHs. The production of carbonaceous particles is not known to be associated with PCB contamination, and it is very unlikely that these particles can be the source of PCBs in the environment Thus, it appears that carbonaceous particles preferentially accumulate PCBs acting as sorbents in the aqueous environment if PCBs are released directly to the sediment or if deposited as airborne soot particles. Aerobic bioslurry treatment resulted in negligible PAH loss from the carbonaceous coal-derived material in Milwaukee Harbor sediment but resulted in 80% of the PAHs being removed from carbonaceous particles in Harbor Point sediment. Microscale PAH extraction and analysis revealed that PAHs in Harbor Point sediment were associated mainly with coal tar pitch residue. PAHs present in semisolid coal tar pitch are more bioavailable than PAHs sorbed on carbonaceous particles such as coal, coke, charcoal, and cenosphere. Results of this study illustrate the importance of understanding particle-scale association of hydrophobic organic contaminants for explaining bioavailability differences among sediments.

  View details for DOI 10.1021/es020833k

  View details for Web of Science ID 000182866000025

  View details for PubMedID 12785527

• Evaluation and testing of analytical methods for cyanide species in municipal and industrial contaminated waters ENVIRONMENTAL SCIENCE & TECHNOLOGY Zheng, A. P., Dzombak, D. A., Luthy, R. G., Sawyer, B., Lazouskas, W., Tata, P., Delaney, M. F., Zilitinkevitch, L., Sebroski, J. R., Swartling, R. S., Drop, S. M., Flaherty, J. M. 2003; 37 (1): 107-115

  Abstract

  Total cyanide analysis by distillation is used most commonly to assess cyanide content of water samples. This manual method is robust but slow and provides no information about cyanide speciation, a significant limitation in that cyanide species have substantially different toxicity characteristics. Seven alternative methods for the analysis of cyanide species or groups of species were evaluated in reagent water and five different contaminated water matrices, including five species-specific methods--weak acid dissociable (WAD) cyanide, free cyanide by microdiffusion, available cyanide, automated WAD cyanide by thin film distillation, metal cyanides by ion chromatography--and two automated techniques for total cyanide--total cyanide bythin film distillation and total cyanide by low-power UV digestion. The species-specific cyanide analytical techniques achieved low, ppb-level detection limits and exhibited satisfactory accuracy and precision for most contaminated waters. Analysis of low concentrations of cyanide species in raw wastewater was problematical for the available cyanide and ion chromatography methods, which experienced significant interference problems and/or low recoveries. There was recovery of significant diffusible cyanide in microdiffusion tests with nickel-cyanide-spiked samples, reflecting dissociation of this weak metal-cyanide complex during the test and demonstrating that the test can recover some fraction of WAD cyanide in addition to free cyanide. The automated total cyanide methods, which involve UV digestion, achieved low detection limits for most waters but exhibited low recoveries for some waters.

  View details for DOI 10.1021/es0258273

  View details for Web of Science ID 000180246200033

  View details for PubMedID 12542298

• Bioterrorism and water security ENVIRONMENTAL SCIENCE & TECHNOLOGY Luthy, R. G. 2002; 36 (7): 123A-123A

  View details for Web of Science ID 000174789200002

  View details for PubMedID 11999032

• Particle-scale understanding of the bioavailability of PAHs in sediment ENVIRONMENTAL SCIENCE & TECHNOLOGY Talley, J. W., Ghosh, U., Tucker, S. G., Furey, J. S., Luthy, R. G. 2002; 36 (3): 477-483

  Abstract

  This study reports results of sediment bioslurry treatment and earthworm bioaccumulation for polycyclic aromatic hydrocarbon (PAH) contaminants found in sediment dredged from Milwaukee Harbor. A significant finding was that bioslurry treatment reduced PAHs on the sediment clay/silt fraction but not on the sediment coal-derived fraction and that PAH reduction in the clay/silt fraction correlated with substantial reduction in earthworm PAH bioaccumulation. These findings are used to infer PAH bioavailability from characterization of particle-scale PAH distribution, association, and binding among the principal particle fractions in the sediment. The results are consistent with work showing that the sediment comprised two principal particle classes for PAHs, coal-derived and clay/silt, each having much different PAH levels, release rates, and desorption activation energies. PAH sorption on coal-derived particles is associated with minimal biodegradation, slow release rates, and high desorption activation energies, while PAH sorption on clay/silt particles is associated with significant potential biodegradability, relatively fast release rates, and lower desorption activation energies. These characteristics are attributed to fundamental differences in the organic matter to which the PAHs are sorbed. Although the majority of the PAHs are found preferentially on coal-derived particles, the PAHs on the clay/silt sediment fraction are more mobile and available, and thus potentially of greater concern. This study demonstrates that a suite of tests comprising both bioassays and particle-scale investigations provide a basis to assess larger-scale phenomena of biotreatment of PAH-impacted sediments and bioavailability and potential toxicity of PAH contaminants in sediments. Improved understanding of contaminant bioavailability aids decision-making on the effectiveness of biotreatment of PAH-impacted sediments and the likelihood for possible reuse of dredged sediments as reclaimed soil or fill.

  View details for DOI 10.1021/es010897f

  View details for Web of Science ID 000173626900041

  View details for PubMedID 11871564

• Microscale detection of polychlorinated biphenyls using two-step laser mass spectrometry INTERNATIONAL JOURNAL OF MASS SPECTROMETRY Mahajan, T. B., Ghosh, U., Zare, R. N., Luthy, R. G. 2001; 212 (1-3): 41-48

  View details for Web of Science ID 000173003600007

• Particle-scale investigation of PAH desorption kinetics and thermodynamics from sediment ENVIRONMENTAL SCIENCE & TECHNOLOGY Ghosh, U., Talley, J. W., Luthy, R. G. 2001; 35 (17): 3468-3475

  Abstract

  Dredged sediment from Milwaukee Harbor showed two primary classes of particles in the <2 mm size range: a lighter-density coal- and wood-derived fraction with 62% of total PAHs and a heavier-density sand, silt, and clay fraction containing the remaining 38% of the PAHs. Room-temperature PAH desorption kinetic studies on separated sediment fractions revealed slow desorption rates for the coal-derived particles and fast desorption rates for the clay/silt particles. The effect of temperature on PAH release was measured by thermal program desorption mass spectrometry to investigate the desorption activation energies for PAHs on the different sediment particles. Three activated diffusion-based models and an activated first-order rate model were used to describe the thermal desorption of PAHs for four molecular weight classes. PAH binding with the coal-derived particles was associated with high activation energies, typically in the range of 115-139 kJ/mol. PAHs bound to the clay/silt material had much lower activation energy, i.e., in the range of 37-41 kJ/ mol for molecular weight 202. Among the desorption models tested, a spherical diffusion model with PAHs located like a rind on the outer 1-3 microm region best described the PAH thermal desorption response for coal-derived particles. This internal PAH distribution pattern on coalderived particles is based on prior direct measurement of PAH locations at the subparticle scale. These studies reveal that heterogeneous particle types in sediment exhibit much different amounts and binding of PAHs. PAHs associated with coal-derived particles aged over several decades in the field appear to be far from reaching an equilibrium sorption state due to the extremely slow diffusivities through the polymer-like coal matrix. These results provide an improved mechanistic perspective for the understanding of PAH mobility and bioavailability in sediments.

  View details for DOI 10.1021/es0105820

  View details for Web of Science ID 000170824300021

  View details for PubMedID 11563648

• Succession of phenotypic, genotypic, and metabolic community characteristics during in vitro bioslurry treatment of polycyclic aromatic hydrocarbon-contaminated sediments APPLIED AND ENVIRONMENTAL MICROBIOLOGY Ringelberg, D. B., Talley, J. W., Perkins, E. J., Tucker, S. G., Luthy, R. G., Bouwer, E. J., Fredrickson, H. L. 2001; 67 (4): 1542-1550

  Abstract

  Dredged harbor sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) was removed from the Milwaukee Confined Disposal Facility and examined for in situ biodegradative capacity. Molecular techniques were used to determine the successional characteristics of the indigenous microbiota during a 4-month bioslurry evaluation. Ester-linked phospholipid fatty acids (PLFA), multiplex PCR of targeted genes, and radiorespirometry techniques were used to define in situ microbial phenotypic, genotypic, and metabolic responses, respectively. Soxhlet extractions revealed a loss in total PAH concentrations of 52%. Individual PAHs showed reductions as great as 75% (i.e., acenapthene and fluorene). Rates of (14)C-PAH mineralization (percent/day) were greatest for phenanthrene, followed by pyrene and then chrysene. There was no mineralization capacity for benzo[a]pyrene. Ester-linked phospholipid fatty acid analysis revealed a threefold increase in total microbial biomass and a dynamic microbial community composition that showed a strong correlation with observed changes in the PAH chemistry (canonical r(2) of 0.999). Nucleic acid analyses showed copies of genes encoding PAH-degrading enzymes (extradiol dioxygenases, hydroxylases, and meta-cleavage enzymes) to increase by as much as 4 orders of magnitude. Shifts in gene copy numbers showed strong correlations with shifts in specific subsets of the extant microbial community. Specifically, declines in the concentrations of three-ring PAH moieties (i.e., phenanthrene) correlated with PLFA indicative of certain gram-negative bacteria (i.e., Rhodococcus spp. and/or actinomycetes) and genes encoding for naphthalene-, biphenyl-, and catechol-2,3-dioxygenase degradative enzymes. The results of this study suggest that the intrinsic biodegradative potential of an environmental site can be derived from the polyphasic characterization of the in situ microbial community.

  View details for Web of Science ID 000167865500022

  View details for PubMedID 11282603

  View details for PubMedCentralID PMC92767

• Microprobe laser mass spectrometry studies of polycyclic aromatic hydrocarbon distributions on harbor sediments and coals ISRAEL JOURNAL OF CHEMISTRY Gillette, J. S., Ghosh, U., Mahajan, T. B., Zare, R. N., Luthy, R. G. 2001; 41 (2): 105-110

  View details for Web of Science ID 000172703700005

• Microscale PAH location ano association with organic matter and effects on biotreatment and bioaccumulation. Luthy, R. G., Ghosh, U., Gillette, J. S., Zare, R. N., Talley, J. W., Tucker, S. AMER CHEMICAL SOC. 2000: U337–U337

  View details for Web of Science ID 000166091201755

• Microscale location, characterization, and association of polycyclic aromatic hydrocarbons on harbor sediment particles ENVIRONMENTAL SCIENCE & TECHNOLOGY Ghosh, U., Gillette, J. S., Luthy, R. G., Zare, R. N. 2000; 34 (9): 1729-1736

  View details for Web of Science ID 000086794500033

• Theoretical study of hydrogen abstraction from ethane by small radicals. Senosiain, J. P., Musgrave, C. B., GOLDEN, D. M. AMER CHEMICAL SOC. 2000: U325–U325

  View details for Web of Science ID 000087246201772

• Direct observation of polycyclic aromatic hydrocarbons on geosorbents at the subparticle scale ENVIRONMENTAL SCIENCE & TECHNOLOGY Gillette, J. S., Luthy, R. G., Clemett, S. J., Zare, R. N. 1999; 33 (8): 1185-1192

  View details for Web of Science ID 000079974600007

• Organic phase resistance to dissolution of polycyclic aromatic hydrocarbon compounds ENVIRONMENTAL SCIENCE & TECHNOLOGY ORTIZ, E., Kraatz, M., Luthy, R. G. 1999; 33 (2): 235-242

  View details for Web of Science ID 000078213600005

• Organic Phase Resistance to Dissolution of Polycyclic Aromatic Hydrocarbon Compounds Environmental Science and Technology Ortiz, E., Kraatz, M., Luthy, R., G. 1999; 2 (33): 235-242
• In situ measurement of PCB availability in unsaturated soils 5th International In Situ and On-Site Bioremediation Symposium McNamara, S., Luthy, R. G. BATTELLE PRESS. 1999: 241–246

  View details for Web of Science ID 000082417000040

• Equilibrium precipitation and dissolution of iron cyanide solids in water ENVIRONMENTAL ENGINEERING SCIENCE Ghosh, R. S., Dzombak, D. A., Luthy, R. G. 1999; 16 (4): 293-313

  View details for Web of Science ID 000081086100006

• Equilibrium Precipitation and Dissolution of Iron Cyanide Solids in Water Environmental Engineering Science Ghosh, R., S., Dzombak, D., A., Luthy, R., G. 1999; 16: 293-313
• Biodegradation kinetics of naphthalene in nonaqueous phase liquid-water mixed batch systems: Comparison of model predictions and experimental results BIOTECHNOLOGY AND BIOENGINEERING Ghoshal, S., Luthy, R. G. 1998; 57 (3): 356-366

  Abstract

  A model is formulated to describe dissolution of naphthalene from an insoluble nonaqueous phase liquid (NAPL) and its subsequent biodegradation in the aqueous phase in completely mixed batch reactors. The physicochemical processes of equilibrium partitioning and mass transfer of naphthalene between the NAPL and aqueous phases were incorporated into the model. Biodegradation kinetics were described by Monod's microbial growth kinetic model, modified to account for the inhibitory effects of 1,2-naphthoquinone formed during naphthalene degradation under certain conditions. System parameters and biokinetic coefficients pertinent to the NAPL-water systems were determined either by direct measurement or from nonlinear regression of the naphthalene mineralization profiles obtained from batch reactor tests with two-component NAPLs comprised of naphthalene and heptamethylnonane. The NAPLs contained substantial mass of naphthalene, and naphthalene biodegradation kinetics were evaluated over the time required for near complete depletion of naphthalene from the NAPL. Model predictions of naphthalene mineralization time profiles compared favorably to the general trends observed in the data obtained from laboratory experiments with the two-component NAPL, as well as with two coal tars obtained from the subsurface at contaminated sites and composed of many different PAHs (polycyclic aromatic hydrocarbon compounds). The effects of varying the NAPL mass and the naphthalene mole fractions in the NAPL are discussed. It was observed that the time to achieve a given percent removal of naphthalene does not change significantly with the initial mass of naphthalene in a fixed volume of the NAPL. Significant changes in the mineralization profiles are observed when the volume (and mass) of NAPL in the system is changed.

  View details for Web of Science ID 000070987000012

  View details for PubMedID 10099212

• Sequestration of hydrophobic organic contaminants by geosorbents ENVIRONMENTAL SCIENCE & TECHNOLOGY Luthy, R. G., Aiken, G. R., Brusseau, M. L., Cunningham, S. D., Gschwend, P. M., Pignatello, J. J., Reinhard, M., Traina, S. J., Weber, W. J., Westall, J. C. 1997; 31 (12): 3341-3347

  View details for Web of Science ID A1997YJ88200024

• Mass transfer and bioavailability of PAH compounds in coal tar NAPL-slurry systems .1. Model development ENVIRONMENTAL SCIENCE & TECHNOLOGY Ramaswami, A., Luthy, R. G. 1997; 31 (8): 2260-2267

  View details for Web of Science ID A1997XN75800042

• Mass transfer and bioavailability of PAH compounds in coal tar NAPL-slurry systems .2. Experimental evaluations ENVIRONMENTAL SCIENCE & TECHNOLOGY Ramaswami, A., Ghoshal, S., Luthy, R. G. 1997; 31 (8): 2268-2276

  View details for Web of Science ID A1997XN75800043

• Dissolution of PCB congeners from an Aroclor and an Aroclor/hydraulic oil mixture WATER RESEARCH Luthy, R. G., Dzombak, D. A., SHANNON, M. J., UNTERMAN, R., Smith, J. R. 1997; 31 (3): 561-573

  View details for Web of Science ID A1997WM12100022

• Aqueous Solubility of PCB Congeners from an Aroclor and an Aroclor/Hydraulic Oil Mixture Water Research Luthy, R., G., Dzombak, D., A., Shannon, M., J.R., Unterman, R., Smith, J., R. 1997; 3 (31): 561-573
• PAH-bioavailability from NAPLs and significance for soil biotreatment 4th International In Situ and On-Site Bioremediation Symposium Kraatz, M., ORTIZ, E., Luthy, R. G. BATTELLE PRESS. 1997: 669–674

  View details for Web of Science ID A1997BH89W00147

• Measuring and Modeling Physico-Chemical Limitations to Bioavailability and Biodegradation, Chapter 78 Manual of Environmental Microbiology Adeel, Z., Luthy, R., G. edited by Sabatini, D., A., Knox, R., C., Harwell, J., H. American Society for Microbiology, ASM Press Washington, DC.. 1997
• Measuring and Modeling Physico-Chemical Limitations to Bioavailability and Biodegradation Manual of Environmental Microbiology Laha, S. edited by Huang, C., P., O’Melia, C., R., Morgan, J., J. American Society for Microbiology, ASM Press Washington, DC.. 1997: 339–362
• Mass Transfer and Bioavailability of PAH Compounds in Coal Tar NAPL-Slurry Systems: 2. Experimental Evaluations Environmental Science and Technology Ramaswami, A., Ghoshal, S., Luthy, R., G. 1997; 8 (31): 2268-2276
• Mass Transfer and Bioavailability of PAH Compounds in Coal Tar NAPL-Slurry Systems: 1. Model Development Environmental Science and Technology Ramaswami, A., Luthy, R., G. 1997; 8 (31): 2260-2267
• Bioavailability of hydrophobic organic compounds from nonaqueous-phase liquids: The biodegradation of naphthalene from coal tar Department-of-Defense Tri-Service Workshop on Bioavailability of Organic Contaminants in Soils and Sediments Ghoshal, S., Luthy, R. G. WILEY-BLACKWELL. 1996: 1894–1900

  View details for Web of Science ID A1996VR11800006

• Biodegradation of naphthalene from coal tar and heptamethylnonane in mixed batch systems ENVIRONMENTAL SCIENCE & TECHNOLOGY Ghoshal, S., Ramaswami, A., Luthy, R. G. 1996; 30 (4): 1282-1291

  View details for Web of Science ID A1996UC41300053

• Chemical characterization of coal tar-water interfacial films ENVIRONMENTAL SCIENCE & TECHNOLOGY Nelson, E. C., Ghoshal, S., Edwards, J. C., Marsh, G. X., Luthy, R. G. 1996; 30 (3): 1014-1022

  View details for Web of Science ID A1996TX75100059

• Biodegradation of Naphthalene from Coal Tar and Heptamethylnonane in Mixed Batch Systems Environmental Science and Technology Ghoshal, S., Ramaswami, A., Luthy, R., G. 1996; 30 (4): 1282-1291
• Chemical Characterization of Coal Tar-Water Interfacial Films Environmental Science and Technology Nelson, E., C., Ghoshal, S., Edwards, J., C., Marsh, G., X., Luthy, R., G. 1996; 30 (3): 1014-1022
• Bioavailability of Hydrophobic Organic Compounds from Nonaqueous Phase Liquids: The Biodegradation of Naphthalene from Coal Tar Environmental Toxicology and Chemistry Goshal, S., Luthy, R., G. 1996; 15 (11): 1894-1990
• MODELING TRANSPORT OF MULTIPLE ORGANIC-COMPOUNDS - SEGREGATED TRANSPORT-SORPTION SOLUBILIZATION NUMERICAL TECHNIQUE WATER RESOURCES RESEARCH Adeel, Z., Luthy, R. G., Edwards, D. A. 1995; 31 (8): 2035-2045

  View details for Web of Science ID A1995RM64400019

• SORPTION AND TRANSPORT KINETICS OF A NONIONIC SURFACTANT THROUGH AN AQUIFER SEDIMENT ENVIRONMENTAL SCIENCE & TECHNOLOGY Adeel, Z., Luthy, R. G. 1995; 29 (4): 1032-1042

  View details for Web of Science ID A1995QP70900035

  View details for PubMedID 22176412

• Modeling Transport of Multiple Organic Compounds: Segregated Transport-Sorption/Solubilization Numerical Technique Water Resources Research Adeel, Z., Luthy, R., G., Edwards, D., A. 1995; 31 (8): 2035-2045
• BIODEGRADATION OF NAPHTHALENE IN AQUEOUS NONIONIC SURFACTANT SYSTEMS APPLIED AND ENVIRONMENTAL MICROBIOLOGY Liu, Z. B., Jacobson, A. M., Luthy, R. G. 1995; 61 (1): 145-151

  Abstract

  The principal objective of this study was to quantify the bioavailability of micelle-solubilized naphthalene to naphthalene-degrading microorganisms comprising a mixed population isolated from contaminated waste and soils. Two nonionic surfactants were used, an alkylethoxylate, Brij 30 (C12E4), and an alkylphenol ethoxylate, Triton X-100 (C8PE9.5). Batch experiments were used to evaluate the effects of aqueous, micellized nonionic surfactants on the microbial mineralization of naphthalene and salicylic acid, an intermediate compound formed in the pathway of microbial degradation of naphthalene. The extent of solubilization and biodegradation under aerobic conditions was monitored by radiotracer and spectrophotometric techniques. Experimental results showed that surfactant concentrations above the critical micelle concentration were not toxic to the naphthalene-degrading bacteria and that the presence of surfactant micelles did not inhibit mineralization of naphthalene. Naphthalene solubilized by micelles of Brij 30 or Triton X-100 in liquid media was bioavailable and degradable by the mixed culture of bacteria.

  View details for Web of Science ID A1995PY86700024

  View details for PubMedID 7887597

• Biodegradation of naphthalene from coal tar: An assessment of the potential for slurry treatment at MGP sites National Conference on Innovative Technologies for Site Remediation and Hazardous Waste Management Ghoshal, S., Luthy, R. G. AMER SOC CIVIL ENGINEERS. 1995: 211–218

  View details for Web of Science ID A1995BE31D00028

• SURFACTANT SOLUBILIZATION OF PHENANTHRENE IN SOIL-AQUEOUS SYSTEMS AND ITS EFFECTS ON BIOMINERALIZATION Symposium on Aquatic Chemistry - Interfacial and Interspecies Processes, at the 203rd National Meeting of the American-Chemical-Society Laha, S., Liu, Z. B., Edwards, D. A., Luthy, R. G. AMER CHEMICAL SOC. 1995: 339–361

  View details for Web of Science ID A1995BC44Q00017

• Biodegradation of naphthalene from nonaqueous-phase liquids 3rd International In Situ and On-Site Bioreclamation Symposium Ghoshal, S., Ramaswami, A., Luthy, R. G. BATTELLE PRESS. 1995: 75–82

  View details for Web of Science ID A1995BG31V00010

• CONCENTRATION-DEPENDENT REGIMES IN SORPTION AND TRANSPORT OF A NONIONIC SURFACTANT IN SAND-AQUEOUS SYSTEMS Symposium on Surfactant-Enhanced Subsurface Remediation - Emerging Technologies, at the 207th National Meeting of the American-Chemical-Society Adeel, Z., Luthy, R. G. AMER CHEMICAL SOC. 1995: 38–53

  View details for Web of Science ID A1995BD63V00004

• Concentration-Dependent Regimes in Sorption and Transport of a Nonionic Surfactant in Sand/Aqueous Systems Surfactant-Enhanced Remediation and Subsurface Contamination: Emerging Technologies Emerging Technologies Ramaswami, A., Luthy, R., G. edited by Hurst, C., J. American Chemical Society Symposium. 1995: 712–729
• Concentration-Dependent Regimes in Sorption and Transport of a Nonionic Surfactant in Sand/Aqueous Systems Adeel, A., Luthy, R., G. edited by Sabatini, D., A., Knox, R., C., Harwell, J., H. 1995
• Surfactant Solubilization of Phenanthrene in Soil-Aqueous Systems and Its Effect on Biomineralization Aquatic Chemistry: Interfacial and Interspecies Processes Ramaswami, A., Luthy, R., G. edited by Hurst, C., J. American Chemical Society, Advances in Chemistry. 1995: 712–729
• Biodegradation of Naphthalene in Aqueous Nonionic Surfactant Systems Applied and Environmental Microbiology Liu, Z., Jacobson, A., M., Luthy, R., G. 1995; 61 (1): 145-151
• DISTRIBUTION OF NONIONIC SURFACTANT AND PHENANTHRENE IN A SEDIMENT AQUEOUS SYSTEM ENVIRONMENTAL SCIENCE & TECHNOLOGY Edwards, D. A., Adeel, Z., Luthy, R. G. 1994; 28 (8): 1550-1560

  View details for Web of Science ID A1994PA22100032

  View details for PubMedID 22165943

• SEMIEMPIRICAL THERMODYNAMIC MODELING OF LIQUID-LIQUID PHASE-EQUILIBRIA - COAL-TAR DISSOLUTION IN WATER-MISCIBLE SOLVENTS ENVIRONMENTAL SCIENCE & TECHNOLOGY Peters, C. A., Luthy, R. G. 1994; 28 (7): 1331-1340

  View details for Web of Science ID A1994NU80800024

  View details for PubMedID 22176327

• REMEDIATING TAR-CONTAMINATED SOILS AT MANUFACTURED-GAS PLANT SITES ENVIRONMENTAL SCIENCE & TECHNOLOGY Luthy, R. G., Dzombak, D. A., Peters, C. A., Roy, S. B., Ramaswami, A., Nakles, D. V., Nott, B. R. 1994; 28 (6): A266-A276

  View details for Web of Science ID A1994NP27700005

• Additions and corrections: interfacial films in coal tar nonaqueous-phase liquid-water systems. Environmental science & technology Luthy, R. G., Ramaswami, A., Ghoshal, S., Merkel, W. 1994; 28 (4): 756-?

  View details for DOI 10.1021/es00053a600

  View details for PubMedID 22196563

• Experimental Data and Modeling for Surfactant Micelles, HOCs and Soil Journal of Environmental Engineering, ASCE. Edwards, D., A., Liu, Z., Luthy, R., G. 1994; 120 (1): 23-41
• MASS-TRANSFER AND BIODEGRADATION OF PAH COMPOUNDS FROM COAL-TAR WATER SCIENCE AND TECHNOLOGY RAMASWMI, A., Ghoshal, S., Luthy, R. G. 1994; 30 (7): 61-70

  View details for Web of Science ID A1994QH65800010

• EXPERIMENTAL-DATA AND MODELING FOR SURFACTANT MICELLES, HOCS, AND SOIL JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE Edwards, D. A., Liu, Z. B., Luthy, R. G. 1994; 120 (1): 23-41

  View details for Web of Science ID A1994MT21600003

• SURFACTANT SOLUBILIZATION OF ORGANIC-COMPOUNDS IN SOIL/AQUEOUS SYSTEMS JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE Edwards, D. A., Liu, Z. B., Luthy, R. G. 1994; 120 (1): 5-22

  View details for Web of Science ID A1994MT21600002

• Surfactant-Enhanced Bioremediation of Polynuclear Aromatic Hydrocarbons in Coke Waste Handbook of Bioremediation Sanseverino, J., Graves, D., A., Leavitt, M., E., Gupta, S., K., Luthy, R., G. edited by Wise, D., L., Trantolo, D., J. Marcel-Dekker, NY. 1994: 345–372
• Semiempirical Thermodynamic Modeling of Liquid-Liquid Phase Equilibria Coal Tar Dissolution in Water-Miscible Solvents Environmental Science and Technology Peters, C., A., Luthy, R., G. 1994; 28 (7): 1331-1340
• Semi-Continuous Evaporation Model for Leachate Treatment Process Evaluation Environmental Progress Marks, A., L., Luthy, R., G., Diwekar, U., M. 1994; 13 (4): 278-289
• Mass Transfer and Biodegradation of PAH Compounds from Coal Tar Water Science and Technology Ramaswami, A., Ghoshal, S., Luthy, R., G. 1994; 30 (7): 61-70
• Surfactant Solubilization of Organic Compounds in Soil/Aqueous Systems Journal of Environmental Engineering, ASCE. Edwards, D., A., Liu, Z., Luthy, R., G. 1994; 120 (1): 5-22
• Landfill Leachate Treatment by Evaporation Journal of Environmental Engineering, ASCE Birchler, D., R., Milke, M., W., Marks, A., L., Luthy, R., G. 1994; 120 (5): 1109-1131
• Distribution of Nonionic Surfactant and Phenanthrene in Sediment/Aqueous Systems Environmental Science and Technology Edwards, D., A., Adeel, Z., Luthy, R., G. 1994; 28 (8): 1550-1560
• Remediating Tar-Contaminated Soils at Manufactured Gas Plant Sites Environmental Science and Technology Luthy, R., R., Dzombak, D., A., Peters, C., A., Roy, S., B., Ramaswami, A., Nakles, D., V. 1994; 28 (6): 266A-276A
• INTERFACIAL FILMS IN COAL-TAR NONAQUEOUS-PHASE LIQUID WATER-SYSTEMS ENVIRONMENTAL SCIENCE & TECHNOLOGY Luthy, R. G., Ramaswami, A., Ghoshal, S., Merkel, W. 1993; 27 (13): 2914-2918

  View details for Web of Science ID A1993MJ95600041

• COAL-TAR DISSOLUTION IN WATER-MISCIBLE SOLVENTS - EXPERIMENTAL EVALUATION ENVIRONMENTAL SCIENCE & TECHNOLOGY Peters, C. A., Luthy, R. G. 1993; 27 (13): 2831-2843

  View details for Web of Science ID A1993MJ95600031

• Coal Tar Solubilization in Water-Miscible Solvents: Experimental Data Environmental Science and Technology Peters, C., A., Luthy, R., G. 1993; 27 (13): 2831-2843
• Interfacial Films in Coal Tar Nonaqueous-Phase Liquid-Water Systems Environmental Science and Technology Luthy, R., G., Ramaswami, A., Ghoshal, S., Merkel, W. 1993; 27 (13): 2914-2918
• EFFECTS OF NONIONIC SURFACTANTS ON THE SOLUBILIZATION AND MINERALIZATION OF PHENANTHRENE IN SOIL-WATER SYSTEMS BIOTECHNOLOGY AND BIOENGINEERING Laha, S., Luthy, R. G. 1992; 40 (11): 1367-1380

  Abstract

  The solubilization and mineralization of (14)C-phenanthrene in soil-water systems was examined with several commercially available surface-active agents, viz., an alkyl ethoxylate C(12)E(4); two alkylphenol ethoxylate surfactants: C(8)PE(9.5) and C(9)PE(10.5); two sorbitan ethoxylate surfactants: the sorbitan monolaurate (Tween 20) and the sorbitan monooleate (Tween 80); two pairs of nonionic ethoxylate surfactant mixtures: C(12)E(4)/C(12)E(23) at a 1:1 ratio, and C(12-15)E(3)/C(12-15)E(9) at a 1:3 ratio; and two surfactants possessing relatively high critical micelle concentration (CMC) values and low aggregation numbers: CHAPS and octyglucoside. Surface tension experiments were performed to evaluate surfactant sorption onto soil and the surfactant doses required to attain the CMC in the soil-water systems. Surfactant solubilization of (14)C-phenanthrene commenced with the onset of micellization. The addition of surface-active agents was observed not to be beneficial to the microbial mineralization of phenanthrene in the soil-water systems and, for supra-CMC surfactant doses, phenanthrene mineralization was completely inhibited for all the surfactants tested. A comparison of solubilization, surface tension, and mineralization data confirms that the inhibitory effect on microbial degradation of phenanthrene is related to the CMC of the surfactant in the presence of soil. Additional tests demonstrated the recovery of mineralization upon dilution of surfactant concentration to sub-CMC levels, and a relatively high exit rate for phenanthrene from micelles. These tests suggest that the inhibitory effect is probably related to a reversible physiological surfactant micelle-bacteria interaction, possibly through partial complexing or release of membrane material with disrupting membrane lamellar structure. This study indicates that nonionic surfactant solubilization of sorbed hydrophobic organic compounds from soil may not be beneficial for the concomitant enhancement of soil bioremediation. Additional work is needed to address physicochemical processes for bioavailability enhancement, and effects of solubilizing agents on microorganisms for remediation and treatment of hydrophobic organic compounds and nonaqueous phase liquids.

  View details for Web of Science ID A1992JY04600010

  View details for PubMedID 18601093

• SORPTION OF NONIONIC SURFACTANTS ONTO SOIL WATER RESEARCH Liu, Z. B., Edwards, D. A., Luthy, R. G. 1992; 26 (10): 1337-1345

  View details for Web of Science ID A1992JM77300007

• Sorption of Nonionic Surfactants onto Soil Water Research Liu, Z., Edwards, D., A., Luthy, R., G. 1992; 26 (10): 1337-1345
• SOLUBILIZATION AND BIODEGRADATION OF HYDROPHOBIC ORGANIC-COMPOUNDS IN SOIL AQUEOUS SYSTEMS WITH NONIONIC SURFACTANTS SYMP ON TRANSPORT AND REMEDIATION OF SUBSURFACE CONTAMINANTS, AT THE 65TH ANNUAL COLLOID AND SURFACE SCIENCE SYMP OF THE AMERICAN CHEMICAL SOC Edwards, D. A., Laha, S., Liu, Z. B., Luthy, R. G. AMER CHEMICAL SOC. 1992: 159–168

  View details for Web of Science ID A1992BV75D00014

• INTERACTIONS BETWEEN NONIONIC SURFACTANT MONOMERS, HYDROPHOBIC ORGANIC-COMPOUNDS AND SOIL 16TH BIENNIAL CONF OF THE INTERNATIONAL ASSOC ON WATER POLLUTION RESEARCH AND CONTROL : WATER QUALITY INTERNATIONAL 92 Edwards, D. A., Liu, Z., Luthy, R. G. IWA PUBLISHING. 1992: 147–58

  View details for Web of Science ID A1992JZ39500017

• NONIONIC SURFACTANT SORPTION ONTO SOIL 16TH BIENNIAL CONF OF THE INTERNATIONAL ASSOC ON WATER POLLUTION RESEARCH AND CONTROL Liu, Z., Edwards, D. A., Luthy, R. G. IWA PUBLISHING. 1992: 2337–40

  View details for Web of Science ID A1992KA66900088

• ENHANCING POLYNUCLEAR AROMATIC UPTAKE INTO BULK SOLUTION WITH AMPHIPHILIC COLLOIDAL AGGREGATES 16TH BIENNIAL CONF OF THE INTERNATIONAL ASSOC ON WATER POLLUTION RESEARCH AND CONTROL Edwards, D. A., Liu, Z., Luthy, R. G. IWA PUBLISHING. 1992: 2341–44

  View details for Web of Science ID A1992KA66900089

• SOLUBILIZATION AND BIODEGRADATION OF HYDROPHOBIC ORGANIC-COMPOUNDS IN SOIL AQUEOUS SYSTEMS WITH NONIONIC SURFACTANTS ACS SYMPOSIUM SERIES Edwards, D. A., Laha, S., Liu, Z. B., Luthy, R. G. 1992; 491: 159-168

  View details for Web of Science ID A1992HX62500014

• Solubilization and Biodegradation of Hydrophobic Organic Compounds in Soil-Aqueous Systems with Nonionic Surfactants American Chemical Society Symposium Series No. 491, Transport and Remediation of Subsurface Contaminants: Colloidal, Interfacial and Surfactant Phenomena Sanseverino, J., Graves, D., A., Leavitt, M., E., Gupta, S., K., Luthy, R., G. edited by Wise, D., L., Trantolo, D., J. 1992: 345–372
• Effects of Nonionic Surfactants on the Solubilization and Mineralization of Phenanthrene in Soil-Water Systems Biotechnology and Bioengineering Laha, S., Luthy, R., G. 1992; 40 (11): 1367-1380
• Future Concerns in Environmental Engineering Graduate Education Journal of Professional Issues in Engineering Education and Practice, ASCE Luthy, R., G., Bella, D., A., Hunt, J., R., Johnson Jr., J., H., Lawler, D., F., O'Melia, C., R. 1992; 118 (4): 361-380
• Interactions Between Nonionic Surfactant Monomers, Hydrophobic Organic Compounds and Soil Water Science and Technology Edwards, D., A., Liu, Z., Luthy, R., G. 1992; 26 (1-2): 147-158
• INHIBITION OF PHENANTHRENE MINERALIZATION BY NONIONIC SURFACTANTS IN SOIL-WATER SYSTEMS ENVIRONMENTAL SCIENCE & TECHNOLOGY Laha, S., Luthy, R. G. 1991; 25 (11): 1920-1930

  View details for Web of Science ID A1991GM84800019

• Inhibition of Mineralization of Phenanthrene in Soil-Water Systems with Nonionic Surfactants Environmental Science and Technology Laha, S., Luthy, R., G. 1991; 25 (11): 1920-1930
• SURFACTANT SOLUBILIZATION OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN SOIL-WATER SUSPENSIONS 15TH BIENNIAL CONF OF THE INTERNATIONAL ASSOC ON WATER POLLUTION RESEARCH AND CONTROL Liu, Z. B., LAHA, S. L., Luthy, R. G. IWA PUBLISHING. 1991: 475–85

  View details for Web of Science ID A1991EN77200054

• SOLUBILIZATION OF POLYCYCLIC AROMATIC-HYDROCARBONS IN MICELLAR NONIONIC SURFACTANT SOLUTIONS ENVIRONMENTAL SCIENCE & TECHNOLOGY Edwards, D. A., Luthy, R. G., Liu, Z. B. 1991; 25 (1): 127-133

  View details for Web of Science ID A1991EP99100019

• Surfactant Enhanced Solubility of Hydrophobic Organic Compounds in Water and in Soil-Water Systems Organic Substances and Sediments in Water Edwards, D., A., Liu, Z., Luthy, R., G. edited by Baker, R., A. Lewis Publishers. 1991: 383–405
• Surfactant Solubilization of Polycyclic Aromatic Hydrocarbon Compounds in Soil-Water Suspensions Water Science and Technology Liu, Z., Laha, S., Luthy, R., G. 1991; 23: 475-485
• Bioremediation--Promises and Problems Editorial, Research Journal Water Pollution Control Federation Luthy, R., G. 1991; 63 (2)
• Solubilization of Polycyclic Aromatic Hydrocarbons in Micellar Nonionic Surfactant Solutions Environmental Science and Technology Edwards, D., A., Luthy, R., G., Liu, Z. 1991; 25 (1): 127-133
• OXIDATION OF ANILINE AND OTHER PRIMARY AROMATIC-AMINES BY MANGANESE-DIOXIDE ENVIRONMENTAL SCIENCE & TECHNOLOGY Laha, S., Luthy, R. G. 1990; 24 (3): 363-373

  View details for Web of Science ID A1990CQ96100016

• Solving Groundwater Contamination Problems through Graduate Education in Environmental Engineering Water Environment and Technology Luthy, R., G., Benjamin, M., M. 1990; 2 (1): 48-57
• Oxidation of Aniline and Other Primary Aromatic Amines by Manganese Dioxide Environmental Science and Technology Laha, S., Luthy, R., G. 1990; 24 (3): 363-373
• Environmental Research: A Clearer Focus Across a Broader Horizon Environmental Science and Technology Luthy, R., G., Small, M., J. 1990; 24 (11): 1620-1623
• Personnel and Research Shortages: Policy Recommendations for the Environmental Professions Environment Luthy, R., G. 1989; 31 (3): 4
• Destruction of Iron-Complexed Cyanide by Alkaline Hydrolysis Water Science and Technology Robuck, S., J., Luthy, R., G. 1989; 21: 547-558
• MICROBIAL FERROUS IRON OXIDATION IN ACIDIC SOLUTION JOURNAL WATER POLLUTION CONTROL FEDERATION Smith, J. R., Luthy, R. G., Middleton, A. C. 1988; 60 (4): 518-530

  View details for Web of Science ID A1988M967500014

• Microbial Degradation of Acenaphthene and Naphthalene Under Denitrification Conditions in Soil-Water Systems Applied and Environmental Microbiology Mihelcic, J., R., Luthy, R., G. 1988; 54: 1188-1198
• Biodegradation Kinetics of Naphthalene in Nonaqueous Phase Liquid-Water Mixed Batch Systems: Comparison of Model Predictions and Experimental Results Biotechnology and Bioengineering Ghoshal, S., Luthy, R., G. 1988; 57 (3): 356-366
• Degradation of Polycyclic Aromatic Hydrocarbon Compounds Under Various Redox Conditions in Soil-Water Systems Applied and Environmental Microbiology Mihelcic, J., R., Luthy, R., G. 1988; 54: 1182-1187
• Complexation of Metals with Hydantoins Water Research Pavlovich, G., Z., Luthy, R., G. 1988; 23 (3): 327-336
• Microbial Ferrous Iron Oxidation in Acidic Solution Journal Water Pollution Control Federation Smith, J., R., Luthy, R., G., Middleton, A., W. 1988; 60 (4): 518-530
• Cementation of Cadmium on Zinc Water Science and Technology Luthy, R., G. 1987; 19: 1083-1088
• Effect of Organic Solvent on Sorption of Aromatic Solutes onto Soils Journal of Environmental Engineering, ASCE Fu, J., K., Luthy, R., G. 1986; 112 (2): 346-366
• Adsorption of Lead and Zinc on Blast Furnace Iron Oxide Solids Journal Water Pollution Control Federation Mihelcic, J., R., Luthy, R., G. 1986; 58 (3): 242-249
• Blast Furnace Recycle Scrubber Water Quality and Reactions of Lead and Zinc Journal Water Pollution Control Federation Luthy, R., G., Sable, E., R., McMichael, F., C. 1986; 58 (3): 250-260
• Aromatic Compound Solubility in Solvent/Water Mixtures Journal of Environmental Engineering, ASCE Fu, J., K., Luthy, R., G. 1986; 112 (2): 328-345
• Prediction of Aromatic Solute Partition Coefficients Using the UNIFAC Group Contribution Model Environmental Science and Technology Campbell, J., R., Luthy, R., G. 1985; 19 (10): 980-985
• PREDICTION OF AROMATIC SOLUTE PARTITION-COEFFICIENTS USING THE UNIFAC GROUP CONTRIBUTION MODEL ENVIRONMENTAL SCIENCE & TECHNOLOGY Campbell, J. R., Luthy, R. G. 1985; 19 (10): 980-985

  View details for Web of Science ID A1985ART3800019

• Calcium Sulfate Solubility in Organic-Laden Wastewater Journal of Environmental Engineering, ASCE Banz, I., Luthy, R., G. 1985; 111 (3): 317-335
• Discussion: Equilibrium Adsorption of Polycyclic Aromatic Hydrocarbons from Water onto Activated Carbon Environmental Science and Technology Walters, R., W., Luthy, R., G. 1985; 19 (9): 870-871
• Equilibrium Adsorption of Polycyclic Aromatic Hydrocarbons from Water onto Activated Carbon Environmental Science and Technology Walters, R., W., Luthy, R., G. 1984; 18 (6): 395-403
• EQUILIBRIUM ADSORPTION OF POLYCYCLIC AROMATIC-HYDROCARBONS FROM WATER ONTO ACTIVATED CARBON ENVIRONMENTAL SCIENCE & TECHNOLOGY Walters, R. W., Luthy, R. G. 1984; 18 (6): 395-403

  View details for Web of Science ID A1984ST45000006

  View details for PubMedID 22247939

• Liquid-Suspended Solid Phase Partitioning of Polycyclic Aromatic Hydrocarbons in Coal Coking Wastewaters Water Research Walters, R., W., Luthy, R., G. 1984; 18 (7): 795-809
• Measurement and Prediction of Distribution Coefficients for Aromatic Solutes Environmental Science and Technology Campbell, J., R., Luthy, R., G., Carrondo, M., J.T. 1983; 17 (10): 582-590
• MEASUREMENT AND PREDICTION OF DISTRIBUTION COEFFICIENTS FOR WASTEWATER AROMATIC SOLUTES ENVIRONMENTAL SCIENCE & TECHNOLOGY Campbell, J. R., Luthy, R. G., Carrondo, M. J. 1983; 17 (10): 582-590

  View details for Web of Science ID A1983RJ87200009

  View details for PubMedID 22288702

• REMOVAL OF ORGANIC CONTAMINANTS FROM COAL CONVERSION PROCESS CONDENSATES JOURNAL WATER POLLUTION CONTROL FEDERATION Luthy, R. G., STAMOUDIS, V. C., Campbell, J. R., Harrison, W. 1983; 55 (2): 196-207

  View details for Web of Science ID A1983QA38100013

• DEMINERALIZATION FOR REUSE OF COAL CONVERSION CONDENSATES INDUSTRIAL & ENGINEERING CHEMISTRY PROCESS DESIGN AND DEVELOPMENT Campbell, J. R., Luthy, R. G., Dzombak, D. A. 1983; 22 (3): 496-503

  View details for Web of Science ID A1983QV10800026

• Biological Oxidation of Organic Constituents in Tar Sand Combustion Process Water Biotechnology and Bioengineering Torpy, M., F., Luthy, R., G. 1983; XXV: 3163-3176
• Demineralization for Reuse of Coal Conversion Condensates Industrial and Engineering Chemistry: Process Design and Development Campbell, J., R., Luthy, R., G. 1983; 22 (3): 496-503
• Removal of Organic Contaminants from Coal Conversion Condensates Journal Water Pollution Control Federation Luthy, R., G., Stamoudis, V., C., Campbell, J., R., Harrison, W. 1983; 55 (2): 196-207
• Chemical Equilibria in Split-Treatment Softening of Water Journal American Water Works Association Zipf, K., Luthy, R., G. 1981; 73 (6): 304-311
• The Problem of Water Reuse in Coke Production Wastewater Reuse Luthy, R., G. edited by Middlebrooks, E., J. Ann Arbor Science Publishers, Inc.. 1981: 501–520
• Treatment of Coal Coking and Coal Gasification Wastewaters Journal Water Pollution Control Federation Luthy, R., G. 1981; 53 (3): 325-339
• Determination of Biological Removal of Organic Constituents in Quench Waters from High-BTU Coal Gasification Pilot Plants Water Research Stamoudis, V., C., Luthy, R., G. 1980; 14 (8): 1143-1156
• DETERMINATION OF BIOLOGICAL REMOVAL OF ORGANIC-CONSTITUENTS IN QUENCH WATERS FROM HIGH-BTU COAL-GASIFICATION PILOT PLANTS WATER RESEARCH STAMOUDIS, V. C., Luthy, R. G. 1980; 14 (8): 1143-1156

  View details for Web of Science ID A1980KD13600029

• The Production, Management and Chemistry of Coal Gasification Wastewaters Analytical Methods for Coal and Coal Products Luthy, R., G., Carter, M., J. edited by Baker, R., A. Academic Press. 1980: 137–167
• Biological Treatment of a Coal Gasification Process Wastewater Water Research Luthy, R., G., T, J. 1980; 14 (9): 1269-1282
• Biological Treatment of Synthetic Fuel Wastewater Journal of the Environmental Engineering Division ASCE Luthy, R., G., Sekel, D., J., Tallon, J., T. 1980; 106 (EE3): 609-629
• Leach Characteristics of Coal Gasification Process Char Journal of the Environmental Engineering Division, ASCE Luthy, R., G., Vassiliou, P., Carter, M., J. 1980; 106 (EE1): 81-103
• Biological Oxidation of Coke Plant Effluent Journal of the Environmental Engineering Division ASCE Luthy, R., G., Jones, L., D. 1980; 106 (EE4): 847-851
• Kinetics of Reaction of Cyanide and Reduced Sulfur Species in Aqueous Solution Environmental Science and Technology Luthy, R., G., Bruce Jr., S., G. 1979; 13 (12): 1481-1487
• KINETICS OF REACTION OF CYANIDE AND REDUCED SULFUR SPECIES IN AQUEOUS-SOLUTION ENVIRONMENTAL SCIENCE & TECHNOLOGY Luthy, R. G., Bruce, S. G. 1979; 13 (12): 1481-1487

  View details for Web of Science ID A1979HW20200015

• CYANIDE AND THIOCYANATE IN COAL-GASIFICATION WASTEWATERS JOURNAL WATER POLLUTION CONTROL FEDERATION Luthy, R. G., Bruce, S. G., Walters, R. W., Nakles, D. V. 1979; 51 (9): 2267-2282

  View details for Web of Science ID A1979HJ73100009

• Leaching Characteristics of Coal Gasification Process Ash and Char Proceedings of Symposium on Contaminants and Sediments, Chapter 9 Edwards, D., A., Laha, S., Liu, Z., Luthy, R., G. edited by Sabatini, D., A., Knox, R., C. Ann Arbor Science Publishers, Inc.. 1979: 159–168
• Cyanide and Thiocyanate in Coal Gasification Wastewaters Journal Water Pollution Control Federation Luthy, R., G., Bruce, S., G., Walters, R., W., Nakles, D., V. 1979; 51 (9): 2267-2282
• Removal of Emulsified Oil with Organic Coagulants and Dissolved Air Flotation Journal Water Pollution Control Federation Luthy, R., G., Selleck, R., E., Galloway, T., R. 1978; 50 (2): 331-346
• Surface Properties of Petroleum Refinery Waste Oil Emulsions Environmental Science and Technology Luthy, R., G., Selleck, R., E., Galloway, T., R. 1977; 12 (11): 1211-1217
• Underwater Construction Survey The Military Engineer Ciani, J., B., Brackett, R., L., Luthy, R., G. 1972; 62 (421): 315-318