I am interested in the exposure and effects of contaminants including current-use pesticides and other endocrine active compounds on fish and wildlife with a focus on amphibian populations.
I am an environmental organic chemist who has been working with the USGS since 2004. My current research focuses on the occurrence, fate and effects of emerging contaminants including current-use pesticides in the environment. I am the lead for the Amphibian Research and Monitoring Initiative's Contaminants Project, the project coordinator of the "EDC effects on fish and wildlife in the Cheseapeake Bay Watershed" project through the Contaminants Biology Program, and a member of the Toxic Substances Hydrology Program's Pesticide Fate Research Team.
Education and Certifications
BS in Chemistry from the University of Alabama in Huntsville in 1999
MSPH in Environmental Health Science from the University of South Carolina in 2003
Science and Products
Drinking Water and Wastewater Infrastructure Science Team
USGS Integrates Findings about Endocrine-Disrupting Compounds in the Chesapeake Watershed
Inorganic and Organic Chemical Mixtures Detected in both Public and Private Tap Water in Cape Cod, Massachusetts
Nationwide Occurrence
Occurrence of toxic contaminant mixtures in surface water and groundwater in agricultural watersheds of the Chesapeake Bay
Per- and Polyfluoroalkyl Substances (PFAS) in Residential Tap Water: Source-to-Tap Science for Underserved Communities
Environmental Health Program Drinking Water Science
Mixtures of Organic and Inorganic Chemicals Characterized in Water from the Taps of Residences in the Greater Chicago Area— Science to Understand Contaminant Exposures in Drinking Water
Amphibians Exposed to Oil and Gas Co-Produced Wastewaters: Differentiating the Actual and the Perceived Inorganic Contaminant Hazards — Prairie Pothole Region
Sublethal Effects of Contaminants in Aquatic Food Webs—Research Challenges and Considerations for Future Studies
Pre-listing Science Support in the Northeast
Pilot Study Provides Information on Contaminant Exposure from Tap Water at Residential and Workplace Sites in the United States
Target-Chemical Concentrations and Microbiological Results for Assessment of Mixed Contaminant and Biological Exposures in Bottled Water, 2020
Pesticide residues in passive samplers and bee tissue from Conservation Reserve Program fields across an agricultural gradient in eastern Iowa, USA, 2019
Current-use pesticides, nutrients, chloride, and metals in ponds and stormwater basins of the New Jersey Pinelands, 2018-20
Target-Chemical Concentration Results for Assessment of Mixed-Organic/Inorganic Chemical and Biological Exposures in North Dakota and South Dakota Tapwater, 2019
Concentrations of organic and inorganic constituents in tapwater samples from California in 2020-21 (ver. 3, September 2022)
Current use pesticides in larval amphibian tissues, amphibian pathogen and wetland sediment screening data from three northeastern National Wildlife Refuges, 2013-2014
Metal concentrations in sediment and amphibian tissues from wetlands sampled across the United States
Pesticide concentrations in surface waters of the Sacramento Valley rice-growing regions, 2010
Estrogen equivalents of surface water and smallmouth bass estrogenic biomarker data in New Jersey, 2016-2017
Nutrients, estrogenicity, and fecal indicators in surface water collected from wetlands in the Klamath Marsh National Wildlife Refuge, Oregon, 2017-2018
Chloride in water, metals in sediment and amphibian tissues and amphibian capture information from wetlands in the Williston Basin of Montana and North Dakota, 2015-2017
Current-use pesticides and emerging amphibian pathogens in natural ponds, excavated ponds, and stormwater basins from 24 sites varying in land-use classifications throughout the New Jersey Pinelands, 2014-2016
Juxtaposition of intensive agriculture, vulnerable aquifers, and mixed chemical/microbial exposures in private-well tapwater in northeast Iowa
Wild bee exposure to pesticides in conservation grasslands increases along an agricultural gradient: A tale of two sample types
Bottled water contaminant exposures and potential human effects
Estrogenic activity response to best management practice implementation in agricultural watersheds in the Chesapeake Bay watershed
Tapwater exposures, effects potential, and residential risk management in Northern Plains Nations
Potential health effects of contaminant mixtures from point and nonpoint sources on fish and frogs in the New Jersey Pinelands
Power analysis for detecting the effects of best management practices on reducing nitrogen and phosphorus fluxes to the Chesapeake Bay watershed, USA
Site- and individual-level contaminations affect infection prevalence of an emerging infectious disease of amphibians
Food, beverage, and feedstock processing facility wastewater: A unique and underappreciated source of contaminants to U.S. streams
The statistical power to detect regional temporal trends in riverine contaminants in the Chesapeake Bay Watershed, USA
Integrated science for the study of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the environment—A strategic science vision for the U.S. Geological Survey
Juvenile African clawed frogs (Xenopus laevis) express growth, metamorphosis, mortality, gene expression, and metabolic changes when exposed to thiamethoxam and clothianidin
Non-USGS Publications**
**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.
Science and Products
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Drinking Water and Wastewater Infrastructure Science Team
The team studies toxicants and pathogens in water resources from their sources, through watersheds, aquifers, and infrastructure to human and wildlife exposures. That information is used to develop decision tools that protect human and wildlife health.USGS Integrates Findings about Endocrine-Disrupting Compounds in the Chesapeake Watershed
Issue: Studies in the Chesapeake Bay Watershed have documented the exposure of fish to toxic contaminants including endocrine-disrupting compounds (EDCs) - compounds which can alter normal hormonal function in organisms. Given the importance of fisheries to the economic and environmental health of the Watershed, observed endocrine disruption and fish kills in the Watershed have raised public and...Inorganic and Organic Chemical Mixtures Detected in both Public and Private Tap Water in Cape Cod, Massachusetts
Multiple detections of regulated and unregulated chemical (inorganic, organic) analytes or elements were detected in both privately and publicly supplied tap water samples from 20 residences in Cape Cod, Massachusetts that share a common source of water.Nationwide Occurrence
A National-scale approach is used to examine and analyze per- and polyfluoroalkyl substances (PFAS) prevalence and magnitude in watersheds and aquifers. As an initial step to fill known science gaps in the understanding of human and wildlife exposure, the team will provide a snapshot of PFAS in drinking water paired with bioaccumulation in fish and wildlife near known or suspected sources of...Occurrence of toxic contaminant mixtures in surface water and groundwater in agricultural watersheds of the Chesapeake Bay
Issue The widespread use of pesticides and fertilizers, application of biosolids and manure, and large-scale animal feeding operations result in contaminant mixtures occurring in streams and rivers (figure 1). These nonpoint sources are affected by multiple processes (such as stream discharge, seasonality and management practices) that influence contaminant occurrence in surface and groundwater...Per- and Polyfluoroalkyl Substances (PFAS) in Residential Tap Water: Source-to-Tap Science for Underserved Communities
Per- and polyfluoroalkyl substances (PFAS) were detected at low levels in treated drinking water samples from residential taps in the Greater Chicago Area. This study is part of a larger approach to provide an understanding of contaminant mixtures in residential tap water across the Nation including underserved communities in rural, urban, and tribal areas.Environmental Health Program Drinking Water Science
Drinking water in the United States rarely is tested for contaminants and pathogens at the tap, where human exposure can occur. In this special issue, we present the science to help understand contaminants and pathogens in drinking water at business and residential taps.Mixtures of Organic and Inorganic Chemicals Characterized in Water from the Taps of Residences in the Greater Chicago Area— Science to Understand Contaminant Exposures in Drinking Water
As a component of ongoing research with a coalition of partners, including the U.S. Geological Survey U.S. Environmental Protection Agency, National Institute of Environmental Health Sciences, Colorado School of Mines, University of Illinois Chicago, and University of South Carolina, water was collected from the taps of 45 Chicago-area residences and analyzed for 540 organic and 35 inorganic...Amphibians Exposed to Oil and Gas Co-Produced Wastewaters: Differentiating the Actual and the Perceived Inorganic Contaminant Hazards — Prairie Pothole Region
Chloride and metals in oil and gas co-produced wastewaters (often referred to as brines) are commonly perceived as contaminant hazards for biota. Amphibian abundance in the Prairie Pothole Region affected by historic oil and gas co-produced wastewaters was lower in wetlands with high concentrations of chloride indicating an actual contaminant hazard. Metals detected in sediments and amphibian...Sublethal Effects of Contaminants in Aquatic Food Webs—Research Challenges and Considerations for Future Studies
U.S. Geological Survey (USGS) and academic scientists partnered to identify challenges and provide considerations for future scientific study designs to advance our understanding of the often subtle sublethal effects of contaminants on individuals, populations, communities, and entire aquatic food webs.Pre-listing Science Support in the Northeast
The background information required to support listing decisions is not always current or available, and additional information or tools to model potential future condition can greatly improve the confidence in Species Status Assessments. We are working closely with multiple partners to provide updated information, model potential outcomes, and identify key uncertainties relevant to amphibian and...Pilot Study Provides Information on Contaminant Exposure from Tap Water at Residential and Workplace Sites in the United States
The U.S. Geological Survey (USGS), in collaboration with National Institutes of Health, U.S. Environmental Protection Agency, and academia, completed a pilot study to provide information on contaminant exposure from tap water at 26 locations including public and private supplies. Public-supply tap water generally met enforceable standards for those compounds with standards. Samples consisted of... - Data
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Target-Chemical Concentrations and Microbiological Results for Assessment of Mixed Contaminant and Biological Exposures in Bottled Water, 2020
This data release contains concentration and quality-assurance results for inorganic, organic analytes and microbiological pathogens collected from 30 different commercial bottled water sources. Samples were processed on July 20 and August 17, 2020 at the New Jersey Water Science Center and analyzed at various U.S. Geological Survey laboratories. Samples were analyzed for nutrients, cations and anPesticide residues in passive samplers and bee tissue from Conservation Reserve Program fields across an agricultural gradient in eastern Iowa, USA, 2019
This data release includes sampling location, pesticide concentrations in passive samplers (silicone bands) and bees foraging in Conservation Reserve Program fields. Sampling took place during July and August of 2019. Fields were located on private land managed for the U.S. Department of Agriculture Conservation Reserve Program in eastern central Iowa, U.S.A.Current-use pesticides, nutrients, chloride, and metals in ponds and stormwater basins of the New Jersey Pinelands, 2018-20
The data presented in this data release include concentrations of current-use pesticides, nutrients, chloride, and metals in surface water collected from 60 wetlands including natural ponds, excavated ponds (Xponds), and stormwater basins in the New Jersey Pinelands, 2018-20. Site information, basic water-quality parameters, and method information also are included.Target-Chemical Concentration Results for Assessment of Mixed-Organic/Inorganic Chemical and Biological Exposures in North Dakota and South Dakota Tapwater, 2019
Concentration and quality assurance results for organic compounds and bioassay endocrine activity results analyzed at the U.S. Geological Survey National Water Quality Laboratory, Denver, Colorado, Organic Chemistry Research Laboratory, Sacramento, California, the Organic Geochemistry Research Laboratory, Lawrence, Kansas, and the U.S. Environmental Protection Agency, Office of Research and DeveloConcentrations of organic and inorganic constituents in tapwater samples from California in 2020-21 (ver. 3, September 2022)
This dataset contains the trace elements, cations, anions, disinfection by-products, per- and polyfluoroalkyl substances (PFAS), pharmaceutical and pesticide concentration results for the tapwater study conducted in California, November, 2020 through May, 2021. Trace elements, cations and anions were analyzed at the U.S. Geological Survey Redox Chemistry Laboratory in Boulder, Colorado. The disiCurrent use pesticides in larval amphibian tissues, amphibian pathogen and wetland sediment screening data from three northeastern National Wildlife Refuges, 2013-2014
The data include concentrations of current use pesticides in tissues of larval wood frog (Lithobates sylvaticus) and spotted salamander (Ambystoma maculatum) and the presence of ranavirus in wood frogs and spotted salamanders from three northeastern National Wildlife Refuges sampled in 2013 and 2014. The data also include estrogenicity, protein phosphatase 2A inhibition and a suite of 15 major andMetal concentrations in sediment and amphibian tissues from wetlands sampled across the United States
The data presented include concentrations of 10 metals in sediments and composite larval amphibian tissues from 20 wetlands across the United States. Sixteen of the wetlands were sampled in 2019 and four were sampled in 2015-2016. Where possible both larval anurans (frogs and toads) and salamanders were collected from each wetland. The data also include information on metal concentrations in amphiPesticide concentrations in surface waters of the Sacramento Valley rice-growing regions, 2010
Surface water samples were collected from four stream/agricultural drain sites in the Sacramento Valley of California to measure pesticides commonly applied to rice. Samples were collected weekly from May through August 2010 to capture the rice pesticide application season. Water samples were filtered (0.7 ?m) and extracted via solid-phase extraction. Additionally, the filter paper was solvent extEstrogen equivalents of surface water and smallmouth bass estrogenic biomarker data in New Jersey, 2016-2017
The data were gathered as a preliminary assessment of estrogenicity under base-flow conditions at over 100 sites (lakes and streams) throughout New Jersey followed by more targeted sampling of smallmouth bass at nine sites with varying levels of estrogenicity. In 2016, 102 sites (lakes and streams) for the preliminary estrogenicity assessment were selected utilizing compiled results of previous moNutrients, estrogenicity, and fecal indicators in surface water collected from wetlands in the Klamath Marsh National Wildlife Refuge, Oregon, 2017-2018
The data was gathered to determine the effects of cattle grazing on wetland water quality in the Klamath National Wildlife Refuge in Oregon. Surface water samples from sites representing a range of grazing histories were collected between June and October in 2017 and 2018. Samples were analyzed for nutrients (ammonia, nitrate plus nitrite, nitrite and orthophosphate), total coliforms, E. coli, entChloride in water, metals in sediment and amphibian tissues and amphibian capture information from wetlands in the Williston Basin of Montana and North Dakota, 2015-2017
The data presented includes chloride concentration and specific conductance in surface water collected from 33 wetlands in the Williston Basin of Montana and North Dakota, 2015-2017 as well as count data for three species of amphibians captured at each wetland. Data also includes concentrations of metals in bed sediment and larval amphibians collected from 32 and 12 wetlands, respectively in 2015-Current-use pesticides and emerging amphibian pathogens in natural ponds, excavated ponds, and stormwater basins from 24 sites varying in land-use classifications throughout the New Jersey Pinelands, 2014-2016
Water, sediment, anuran food (leaf litter and detritus) and whole body larval amphibian composites were analyzed for over 100 current-use pesticides from 24 wetlands representing land-use gradients in the New Jersey Pinelands, USA during 2014-2016. Emerging amphibian pathogens, Ranavirus and Batrachochytrium dendrobatidis (Bd) were also assessed in individual larvae at the 24 wetlands. Tables in t - Multimedia
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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 landscapesWild bee exposure to pesticides in conservation grasslands increases along an agricultural gradient: A tale of two sample types
Conservation efforts have been implemented in agroecosystems to enhance pollinator diversity by creating grassland habitat, but little is known about the exposure of bees to pesticides while foraging in these grassland fields. Pesticide exposure was assessed in 24 conservation grassland fields along an agricultural gradient at two time points (July and August) using silicone band passive samplersBottled 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/micrEstrogenic activity response to best management practice implementation in agricultural watersheds in the Chesapeake Bay watershed
Best management practices (BMPs) have been predominantly used throughout the Chesapeake Bay watershed (CBW) to reduce nutrients and sediments entering streams, rivers, and the bay. These practices have been successful in reducing loads entering the estuary and have shown the potential to reduce other contaminants (pesticides, hormonally active compounds, pathogens) in localized studies and modeledTapwater 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) intervePotential health effects of contaminant mixtures from point and nonpoint sources on fish and frogs in the New Jersey Pinelands
Aquatic ecosystems convey complex contaminant mixtures from anthropogenic pollution on a global scale. Point (e.g., municipal wastewater) and nonpoint sources (e.g., stormwater runoff) are both drivers of contaminant mixtures in aquatic habitats. The objectives of this study were to identify the contaminant mixtures present in surface waters impacted by both point and nonpoint sources, to determinPower analysis for detecting the effects of best management practices on reducing nitrogen and phosphorus fluxes to the Chesapeake Bay watershed, USA
In 2010 the U.S. Environmental Protection Agency established the Total Maximum Daily Load (TMDL) which is a “pollution diet” that aims to reduce the amount of nitrogen and phosphorus entering the Chesapeake Bay, the largest estuary in the United States, by 25 and 24% percent, respectively. To achieve this goal the TMDL requires the implementation of Best Management Practices (BMPs), which are acceSite- and individual-level contaminations affect infection prevalence of an emerging infectious disease of amphibians
Emerging infectious disease outbreaks are one of multiple stressors responsible for amphibian declines globally. In the northeastern United States, ranaviral diseases are prevalent in amphibians and other ectothermic species, but there is still uncertainty as to whether their presence is leading to population level effects. Further, there is also uncertainty surrounding the potential interactionsFood, 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 asByEcosystems, Water Resources, 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 LaboratoryThe statistical power to detect regional temporal trends in riverine contaminants in the Chesapeake Bay Watershed, USA
Chemical contamination of riverine ecosystems is largely a result of urbanization, industrialization, and agricultural activities occurring on adjacent terrestrial landscapes. Land management activities (e.g., Best Management Practices) are an important tool used to reduce point and non-point sources of pollution. However, the ability to confidently make inferences about the efficacy of land managIntegrated science for the study of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the environment—A strategic science vision for the U.S. Geological Survey
Concerns related to perfluoroalkyl and polyfluoroalkyl substances (PFAS) in sources of drinking water and in natural and engineered environments have captured national attention over the last few decades. This report provides an overview of the science gaps that exist in the fields of study related to PFAS that are relevant to the U.S. Geological Survey mission and identifies opportunities where tJuvenile African clawed frogs (Xenopus laevis) express growth, metamorphosis, mortality, gene expression, and metabolic changes when exposed to thiamethoxam and clothianidin
Neonicotinoids (NEO) represent the main class of insecticides currently in use, with thiamethoxam (THX) and clothianidin (CLO) primarily applied agriculturally. With few comprehensive studies having been performed with non-target amphibians, the aim was to investigate potential biomarker responses along an adverse outcome pathway of NEO exposure, whereby data were collected on multiple biologicalNon-USGS Publications**
Brander, S. M., He, G., Smalling, K. L., Denison, M. S. and Cherr, G. N. (2012), The in vivo estrogenic and in vitro anti-estrogenic activity of permethrin and bifenthrin. Environmental Toxicology and Chemistry, 31: 2848–2855Brander SM, Connon RE, He G, Hobbs JA, Smalling KL, et al. (2013) From ‘Omics to Otoliths: Responses of an Estuarine Fish to Endocrine Disrupting Compounds across Biological Scales. PLoS ONE 8(9): e74251. doi: 10.1371/journal.pone.0074251Smalling, K.L and Aelion, C.M., 2006, Biological and chemical transformation of atrazine in coastal aquatic sediments, Chemosphere, 62: 188-196.Pulster, E. L., Smalling, K. L., Zolman, E., Schwacke, L. and Maruya, K. A. (2009), Persistent organochlorine pollutants and toxaphene congener profiles in bottlenose dolphins (Tursiops truncatus) frequenting the Turtle/Brunswick River Estuary, Georgia, USA. Environmental Toxicology and Chemistry, 28: 1390–1399**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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