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James L Gray, PhD

James Gray is a Research Chemist for the USGS Water Resources Mission Area.

Science and Products

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Collaborative Science Provides Understanding of Contaminants in Bottled Water-an Increasingly Common Alternate Drinking Water Source

U.S. Geological Survey researchers and public health experts collaborated to determine what contaminants occur in bottled water, which is an increasingly common alternate drinking water source, to broaden their understanding of human exposure to contaminants in drinking water supply chains. Bottled water, like public-supply and private-well tap water supply chains, contained multiple organic...
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Ecosystems Mission Area, Environmental Health Program
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Collaborative Science Provides Understanding of Contaminants in Bottled Water-an Increasingly Common Alternate Drinking Water Source

U.S. Geological Survey researchers and public health experts collaborated to determine what contaminants occur in bottled water, which is an increasingly common alternate drinking water source, to broaden their understanding of human exposure to contaminants in drinking water supply chains. Bottled water, like public-supply and private-well tap water supply chains, contained multiple organic...
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Small stream traversing a field

Study Provides a Data Resource for Per- and Polyfluoroalkyl Substances in Streams Within Iowa Agricultural Watersheds

Per- and polyfluoroalkyl substances (PFAS) were detected in streams within agricultural areas (an often-unmeasured landscape) across Iowa. The data from this study provide one resource to understand the extent of PFAS concentrations in water resources from diverse landscapes throughout the United States.
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
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Study Provides a Data Resource for Per- and Polyfluoroalkyl Substances in Streams Within Iowa Agricultural Watersheds

Per- and polyfluoroalkyl substances (PFAS) were detected in streams within agricultural areas (an often-unmeasured landscape) across Iowa. The data from this study provide one resource to understand the extent of PFAS concentrations in water resources from diverse landscapes throughout the United States.
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Image of land application of municipal biosolids in Orange County, NC.

Commonly Used Chemicals Transported to Agricultural Field through Municipal Biosolids Application

Commonly used chemicals (including fragrances, detergents, fire retardants, plasticizers, and antibacterials) transferred to wastewater treatment plants were detected in municipal wastewater biosolids applied to agricultural field plots and subsequently detected in the runoff transported from the plots during precipitation events.
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
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Commonly Used Chemicals Transported to Agricultural Field through Municipal Biosolids Application

Commonly used chemicals (including fragrances, detergents, fire retardants, plasticizers, and antibacterials) transferred to wastewater treatment plants were detected in municipal wastewater biosolids applied to agricultural field plots and subsequently detected in the runoff transported from the plots during precipitation events.
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Emerging contaminant data at wastewater treatment facilities, municipal water supplies, surface water and lake sites in the northeastern United States, 2009-2018 (ver. 1.1, January 2023)

Over 300 samples were collected in New York, Vermont, and Massachusetts from wastewater treatment facilities (20 locations), drinking water facilities (9 locations), streams (53 locations), lakes (2 locations), a bay (1 location), and a POCIS (Polar Organic Chemical Integrative Sampler) blank sample between April 2009 and October 2018. This data release provides chemistry data for over 400 analyt
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New York Water Science Center

Water-quality data for a statewide assessment of per- and polyfluoroalkyl substances (PFAS) study in Iowa, 2019-2020

Data were collected at 60 surface water and two effluent sites across Iowa in 2019-2020 by staff from the U.S. Geological Survey Central Midwest Water Science Center. Samples were submitted to the National Water Quality Laboratory in Denver, Colorado, and were analyzed for per- and polyfluoroalkyl substances.
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Central Midwest Water Science Center
Filter Total Items: 43

Per- and polyfluoroalkyl substances (PFAS) in United States tapwater: Comparison of underserved private-well and public-supply exposures and associated health implications

Drinking-water quality is a rising concern in the United States (US), emphasizing the need to broadly assess exposures and potential health effects at the point-of-use. Drinking-water exposures to per- and poly-fluoroalkyl substances (PFAS) are a national concern, however, there is limited information on PFAS in residential tapwater at the point-of-use, especially from private-wells. We conducted
Authors
Kelly Smalling, Kristin M. Romanok, Paul M. Bradley, Matthew Connor Morriss, James L. Gray, Leslie K. Kanagy, Stephanie Gordon, Brianna Williams, Sara Breitmeyer, Daniel Jones, Laura A. DeCicco, Collin Eagles-Smith, Tyler Wagner
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Ecosystems Mission Area, Water Resources Mission Area, Cooperative Research Units, Forest and Rangeland Ecosystem Science Center, New Jersey Water Science Center, South Atlantic Water Science Center (SAWSC), Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center, Utah Water Science Center

Exposures and potential health implications of contaminant mixtures in linked source water, finished drinking water, and tapwater from public-supply drinking water systems in Minneapolis/St. Paul area, USA

Continued improvements in drinking-water quality characterization and treatment/distribution infrastructure are required to address the expanding number of documented environmental contaminants. To better understand the variability in contaminant exposures from the drinking water resource (surface and groundwater), through the distribution process, to the point-of-use (tapwater), in 2019 a synopti
Authors
Kelly Smalling, Paul Bradley, Kristin Romanok, Sarah M. Elliott, Jane de Lambert, Michael J. Focazio, Stephanie Gordon, James L. Gray, Leslie K. Kanagy, Michelle Hladik, Keith Loftin, R. Blaine McCleskey, Elizabeth Medlock-Kakaley, Mary C. Cardon, Nicola Evans, Christopher P. Weis
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Water Resources Mission Area, New Jersey Water Science Center

Juxtaposition of intensive agriculture, vulnerable aquifers, and mixed chemical/microbial exposures in private-well tapwater in northeast Iowa

In the United States and globally, contaminant exposure in unregulated private-well point-of-use tapwater (TW) is a recognized public-health data gap and an obstacle to both risk-management and homeowner decision making. To help address the lack of data on broad contaminant exposures in private-well TW from hydrologically-vulnerable (alluvial, karst) aquifers in agriculturally-intensive landscapes
Authors
Paul Bradley, Dana W. Kolpin, Darrin A. Thompson, Kristin Romanok, Kelly Smalling, Sara Breitmeyer, Mary C. Cardon, David M. Cwiertny, Nicola Evans, R. William Field, Michael J. Focazio, Laura E. Beane Freeman, Carrie E Givens, James L. Gray, Gordon L. Hager, Michelle Hladik, Jonathan N. Hoffman, Rena R. Jones, Leslie K. Kanagy, Rachael F. Lane, R. Blaine McCleskey, Danielle Medgyesi, Elizabeth Medlock-Kakaley, Shannon M. Meppelink, Michael T. Meyer, Diana A. Stavreva, Mary H. Ward
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Water Resources Mission Area, California Water Science Center, Kansas Water Science Center, New Jersey Water Science Center, South Atlantic Water Science Center (SAWSC), Central Midwest Water Science Center, Upper Midwest Water Science Center

Contaminant exposure and transport from three potential reuse waters within a single watershed

Global demand for safe and sustainable water supplies necessitates a better understanding of contaminant exposures in potential reuse waters. In this study, we compared exposures and load contributions to surface water from the discharge of three reuse waters (wastewater effluent, urban stormwater, and agricultural runoff). Results document substantial and varying organic-chemical contribution to
Authors
Jason R. Masoner, Dana W. Kolpin, Isabelle M. Cozzarelli, Paul Bradley, Brian Arnall, Kenneth J. Forshay, James L. Gray, Justin F. Groves, Michelle Hladik, Laura E. Hubbard, Luke R. Iwanowicz, Jeanne B. Jaeschke, Rachael F. Lane, R. Blaine McCleskey, Bridgette F. Polite, David A. Roth, Michael Pettijohn, Michaelah C. Wilson
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Water Resources Mission Area, Environmental Health Program, Eastern Ecological Science Center, Colorado Water Science Center, California Water Science Center, Central Midwest Water Science Center, Geology, Energy & Minerals Science Center, Kansas Water Science Center, Oklahoma-Texas Water Science Center, South Atlantic Water Science Center (SAWSC), Upper Midwest Water Science Center, Reston Biogeochemical Processes in Groundwater Laboratory

Bottled water contaminant exposures and potential human effects

Bottled water (BW) consumption in the United States and globally has increased amidst heightened concern about environmental contaminant exposures and health risks in drinking water supplies, despite a paucity of directly comparable, environmentally-relevant contaminant exposure data for BW. This study provides insight into exposures and cumulative risks to human health from inorganic/organic/micr
Authors
Paul Bradley, Kristin Romanok, Kelly Smalling, Michael J. Focazio, Nicola Evans, Suzanne C. Fitzpatrick, Carrie E Givens, Stephanie Gordon, James L. Gray, Emily M. Green, Dale W. Griffin, Michelle Hladik, Leslie K. Kanagy, John T. Lisle, Keith Loftin, R. Blaine McCleskey, Elizabeth Medlock-Kakaley, Ana Navas-Acien, David A. Roth, Paul F. South, Christopher P. Weis
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Water Resources Mission Area, California Water Science Center, Kansas Water Science Center, New Jersey Water Science Center, South Atlantic Water Science Center (SAWSC), St. Petersburg Coastal and Marine Science Center, Upper Midwest Water Science Center

Tapwater exposures, effects potential, and residential risk management in Northern Plains Nations

In the United States (US), private-supply tapwater (TW) is rarely monitored. This data gap undermines individual/community risk-management decision-making, leading to an increased probability of unrecognized contaminant exposures in rural and remote locations that rely on private wells. We assessed point-of-use (POU) TW in three northern plains Tribal Nations, where ongoing TW arsenic (As) interve
Authors
Paul Bradley, Kristin Romanok, Kelly Smalling, Michael J. Focazio, Robert Charboneau, Christine Marie George, Ana Navas-Acien, Marcia O'Leary, Reno Red Cloud, Tracy Zacher, Sara Breitmeyer, Mary C. Cardon, Christa K. Cuny, Guthrie Ducheneaux, Kendra Enright, Nicola Evans, James L. Gray, David E. Harvey, Michelle Hladik, Leslie K. Kanagy, Keith Loftin, R. Blaine McCleskey, Elizabeth Medlock-Kakaley, Shannon M. Meppelink, Joshua F. Valder, Christopher P. Weis
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Water Resources Mission Area, South Atlantic Water Science Center (SAWSC)

Food, beverage, and feedstock processing facility wastewater: A unique and underappreciated source of contaminants to U.S. streams

Process wastewaters from food, beverage, and feedstock facilities, although regulated, are an under-investigated environmental contaminant source. Food process wastewaters (FPWWs) from 23 facilities in 17 U.S. states were sampled and documented for a plethora of chemical and microbial contaminants. Of the 576 analyzed organics, 184 (32%) were detected at least once, with concentrations as large as
Authors
Laura E. Hubbard, Dana W. Kolpin, Carrie E Givens, Bradley D. Blackwell, Paul Bradley, James L. Gray, Rachael F. Lane, Jason R. Masoner, R. Blaine McCleskey, Kristin Romanok, Mark W. Sandstrom, Kelly Smalling, Daniel L. Villeneuve
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Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Central Midwest Water Science Center, Kansas Water Science Center, New Jersey Water Science Center, Pennsylvania Water Science Center, South Atlantic Water Science Center (SAWSC), Upper Midwest Water Science Center, National Water Quality Laboratory

A comprehensive statewide spatiotemporal stream assessment of per- and polyfluoroalkyl substances (PFAS) in an agricultural region of the United States

Public concern regarding per- and polyfluoroalkyl substances (PFAS) has grown substantially in recent years. In addition, research has documented multiple potential agriculture-related release pathways for PFAS (e.g., biosolids and livestock manure). Nevertheless, little research on the environmental prevalence of PFAS has been conducted in agricultural regions of the United States. To fill this g

Authors
Dana W. Kolpin, Laura E. Hubbard, D.M. Cwiertny, Shannon M. Meppelink, D.A. Thompson, James L. Gray
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Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Energy Resources Program, Environmental Health Program, Toxic Substances Hydrology, Central Midwest Water Science Center

Pilot-scale expanded assessment of inorganic and organic tapwater exposures and predicted effects in Puerto Rico, USA

A pilot-scale expanded target assessment of mixtures of inorganic and organic contaminants in point-of-consumption drinking water (tapwater, TW) was conducted in Puerto Rico (PR) to continue to inform TW exposures and corresponding estimations of cumulative human-health risks across the US. In August 2018, a spatial synoptic pilot assessment of than 524 organic, 37 inorganic, and select microbiolo
Authors
Paul Bradley, Ingrid Y. Padilla, Kristin Romanok, Kelly Smalling, Michael J. Focazio, Sara Breitmeyer, Mary C. Cardon, Justin M. Conley, Nicola Evans, Carrie E Givens, James L. Gray, L. Earl Gray, Phillip C. Hartig, Michelle Hladik, Christopher P. Higgins, Luke R. Iwanowicz, Rachael F. Lane, Keith Loftin, R. Blaine McCleskey, Carrie A. McDonough, Elizabeth Medlock-Kakaley, Shannon M. Meppelink, Christopher P. Weis, Vickie S. Wilson
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Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, South Atlantic Water Science Center (SAWSC), National Water Quality Laboratory

Public and private tapwater: Comparative analysis of contaminant exposure and potential risk, Cape Cod, Massachusetts, USA

BackgroundHumans are primary drivers of environmental contamination worldwide, including in drinking-water resources. In the United States (US), federal and state agencies regulate and monitor public-supply drinking water while private-supply monitoring is rare; the current lack of directly comparable information on contaminant-mixture exposures and risks between private- and public-supplies under
Authors
Paul Bradley, Denis R. LeBlanc, Kristin Romanok, Kelly Smalling, Michael J. Focazio, Mary C. Cardon, Jimmy Clark, Justin M. Conley, Nicola Evans, Carrie E Givens, James L. Gray, L. Earl Gray, Phillip C. Hartig, Christopher P. Higgins, Michelle Hladik, Luke R. Iwanowicz, Keith Loftin, R. Blaine McCleskey, Carrie A. McDonough, Elizabeth Medlock-Kakaley, Christopher P. Weis, Vickie S. Wilson
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Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, California Water Science Center, Eastern Ecological Science Center, New England Water Science Center, New Jersey Water Science Center, South Atlantic Water Science Center (SAWSC), Upper Midwest Water Science Center, National Water Quality Laboratory

Landfill leachate contributes per-/poly-fluoroalkyl substances (PFAS) and pharmaceuticals to municipal wastewater

Widespread disposal of landfill leachate to municipal sewer infrastructure in the United States calls for an improved understanding of the relative organic-chemical contributions to the wastewater treatment plant (WWTP) waste stream and associated surface-water discharge to receptors in the environment. Landfill leachate, WWTP influent, and WWTP effluent samples were collected from three landfill-
Authors
Jason R. Masoner, Dana W. Kolpin, Isabelle M. Cozzarelli, Kelly L. Smalling, Stephanie Bolyard, Jennifer Field, Edward T. Furlong, James L. Gray, Duncan Lozinski, Debra Reinhart, Alix Rodowa, Paul M. Bradley
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Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Oklahoma-Texas Water Science Center, National Water Quality Laboratory, Reston Biogeochemical Processes in Groundwater Laboratory

Mixed organic and inorganic tapwater exposures and potential effects in greater Chicago area, USA

Safe drinking water at the point of use (tapwater, TW) is a public-health priority. TW exposures and potential human-health concerns of 540 organics and 35 inorganics were assessed in 45 Chicago area United States (US) homes in 2017. No US Environmental Protection Agency (EPA) enforceable Maximum Contaminant Level(s) (MCL) were exceeded in any residential or water treatment plant (WTP) pre-distrib
Authors
Paul Bradley, Maria Argos, Dana W. Kolpin, Shannon M. Meppelink, Kristin Romanok, Kelly Smalling, Michael J. Focazio, Joshua M. Allen, Julie E. Dietze, Michael J. Devito, Ariel Donovan, Nicola Evans, Carrie E. Givens, James L. Gray, Christopher P. Higgins, Michelle Hladik, Luke Iwanowicz, Celeste A. Journey, Rachael F. Lane, Zachary Laughrey, Keith A. Loftin, R. Blaine McCleskey, Carrie A. McDonough, Elizabeth K Medlock Kakaley, Michael T. Meyer, Andrea Holthouse-Putz, Susan D Richardson, Alan Stark, Christopher P. Weis, Vickie S. Wilson, Abderrahman Zehraoui
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Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, South Atlantic Water Science Center (SAWSC), National Water Quality Laboratory

Non-USGS Publications**

Verplanck, P. L., Furlong, E. T., Gray, J. L., Phillips, P. J., Wolf, R. E., & Esposito, K. (2010). Evaluating the Behavior of Gadolinium and Other Rare Earth Elements through Large Metropolitan Sewage Treatment Plants. Environmental Science & Technology, 44(10), 3876-3882. doi:10.1021/es903888t
Furlong, E. T., Gray, J. L., Quanrud, D. M., Teske, S. S., Esposito, K., Marine, J., . . . Phillips, P. J. (2010). The Estrogenicity of Biosolids in Four Full-Scale Wastewater Treatment Plants in the United States. Proceedings of the Water Environment Federation, 2010(15), 2236-2240. doi:10.2175/193864710798159354
Vajda, A. M., Barber, L. B., Gray, J. L., Lopez, E. M., Woodling, J. D., & Norris, D. O. (2008). Reproductive Disruption in Fish Downstream from an Estrogenic Wastewater Effluent. Environmental Science & Technology, 42(9), 3407-3414. doi:10.1021/es0720661
Kolodziej, E. P., Gray, J. L., & Sedlak, D. L. (2003). Quantification Of Steroid Hormones With Pheromonal Properties In Municipal Wastewater Effluent. Environmental Toxicology and Chemistry, 22(11), 2622. doi:10.1897/03-42
Sedlak, D. L., Pinkston, K. E., Gray, J. L., & Kolodziej, E. P. (2003). Approaches for Quantifying the Attenuation of Wastewater-Derived Contaminants in the Aquatic Environment. CHIMIA International Journal for Chemistry, 57(9), 567-569. doi:10.2533/000942903777679055
Sedlak, D. L., Gray, J. L., & Pinkston, K. E. (2000). Peer Reviewed: Understanding Microcontaminants in Recycled Water. Environmental Science & Technology, 34(23). doi:10.1021/es003513e

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

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