Introduction: Research Hydrologist/Ecologist with the South Atlantic Water Science Center focused on understanding environmental contaminant mixture exposures and real versus perceived effects to human and environmental health.
Paul is project lead, along with Kelly Smalling, of the Drinking-Water and Wastewater Infrastructure Integrated Science Team of the Ecosystems Mission, Environmental Health Program. His research focuses on human exposures to and potential effects of inorganic, organic, and microbial contaminant mixtures in drinking water at the point of use and on anthropogenic contaminant mixtures as ecosystem stressors.
Professional Experience
1988–present: Research Ecologist/Hydrologist, U.S. Geological Survey
Expertise:
• Contaminant mixtures
• Drinking water
• Water quality
• Environmental health
Education and Certifications
B.S., Applied Biology, Georgia Institute of Technology, Atlanta, Georgia
M.S., Applied Biology, Georgia Institute of Technology, Atlanta, Georgia
Ph.D., Physiological Ecology, University of South Carolina, Columbia, South Carolina
Science and Products
Coproduced Science Linking Environmental and Public-Health Data to Evaluate Drinking Water Arsenic Exposure on Birth Outcomes
Drinking Water and Wastewater Infrastructure Science Team
Inorganic and Organic Chemical Mixtures Detected in both Public and Private Tap Water in Cape Cod, Massachusetts
Nationwide Occurrence
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
Ongoing Research to Characterize the Complexity of Chemical Mixtures in Water Resources—Urban Stormwater
Pilot Study Provides Information on Contaminant Exposure from Tap Water at Residential and Workplace Sites in the United States
Sources of Contaminants to Congaree National Park—USGS and National Park Service Working Together
Study Highlights the Complexity of Chemical Mixtures in United States Streams
Recovery of Stream and Adjacent Groundwater After Wastewater Treatment Facility Closure
Target-Chemical Concentrations and Microbiological Results for Assessment of Mixed Contaminant and Biological Exposures in Bottled Water, 2020
Target-Chemical Concentration Results for Assessment of Mixed-Organic/Inorganic Chemical and Biological Exposures in North Dakota and South Dakota Tapwater, 2019
Inorganic 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)
Target-Chemical Concentration Results of Mixed-Organic/Inorganic Chemical Exposures in Puerto Rico Tapwater, 2017 to 2018
Pesticide and Pharmaceutical Exposure Data for Select Streams within Great Smoky Mountains National Park, 2019
Microbial Source Tracking Marker Concentrations in Congaree National Park in 2017-2019, South Carolina, USA
Target-Chemical Concentration Results of Mixed-Organic/Inorganic Chemical Exposures in Cape Cod, Massachusetts Tapwater, 2018
Concentrations of Pesticide, Pharmaceutical, and Organic Wastewater Contaminants from a Multi-Regional Assessment of Wadeable USA Streams, 2014-17
Pesticide and transformation product concentrations and risk quotients in U.S. headwater streams
Cyanotoxin Concentration and Phytoplankton Community Composition Data for Surface Water Samples Collected at Lake Mattamuskeet National Wildlife Refuge, North Carolina during summer 2015
Water-, Sediment-, and Biological-Quality Data for Waters Receiving Runoff from Five Bridges in South Carolina, 2013 to 2018
Juxtaposition of intensive agriculture, vulnerable aquifers, and mixed chemical/microbial exposures in private-well tapwater in northeast Iowa
Contaminant exposure and transport from three potential reuse waters within a single watershed
Bottled water contaminant exposures and potential human effects
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
Rapid implementation of high-frequency wastewater surveillance of SARS-CoV-2
Ecological consequences of neonicotinoid mixtures in streams
Arsenic in private well water and birth outcomes in the United States
Temporal variability in TiO2 engineered particle concentrations in rural Edisto River
Food, beverage, and feedstock processing facility wastewater: A unique and underappreciated source of contaminants to U.S. streams
Integrated science for the study of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the environment—A strategic science vision for the U.S. Geological Survey
Assessing the ecological functionality and integrity of natural ponds, excavated ponds and stormwater basins for conserving amphibian diversity
Science and Products
- Science
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Coproduced Science Linking Environmental and Public-Health Data to Evaluate Drinking Water Arsenic Exposure on Birth Outcomes
U.S. Geological Survey (USGS) scientists teamed up with public-health epidemiologists to probe for associations between arsenic in drinking water and human-birth outcomes. They reported a modest inverse relation between birth weight and arsenic exposure. Findings indicate that future research efforts using individual-level exposure data such as measured arsenic concentrations in tap water could...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.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...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...Ongoing Research to Characterize the Complexity of Chemical Mixtures in Water Resources—Urban Stormwater
A multiagency reconnaissance study of chemicals in urban stormwater, sampled from pipes or ditches during 50 runoff events at 21 sites in 17 states across the United States, demonstrated that stormwater runoff contains complex mixtures of chemicals including polycyclic aromatic hydrocarbons, pesticides, and pharmaceuticals that are indicative of multiple sources in the watershed.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...Sources of Contaminants to Congaree National Park—USGS and National Park Service Working Together
A National Park Service (NPS) and U.S. Geological Survey (USGS) study determined the concentrations, potential for degradation, and potential for aquatic and terrestrial animal exposure to organic contaminants in water and sediment within the flood-plain/aquatic environments of Congaree National Park which is located downstream from urban and agricultural areas.Study Highlights the Complexity of Chemical Mixtures in United States Streams
A new study highlights the complexity of chemical mixtures in streams and advances the understanding of wildlife and human exposure to complex chemical mixtures.Recovery of Stream and Adjacent Groundwater After Wastewater Treatment Facility Closure
The hydrology and chemistry of a wastewater-impacted stream and adjacent groundwater responded rapidly (had fewer chemicals at lower concentrations) following wastewater treatment facility shutdown. However, the adjacent shallow groundwater remained a continuing source of some wastewater-derived contaminants to the stream at least 1 year post-shutdown. - 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 anTarget-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 DeveloInorganic Concentration Results for Assessment of Mixed Organic/Inorganic Chemical and Biological Exposures in North Dakota and South Dakota Tapwater, 2019
This data set reports results for inorganic constituents analyzed at the Redox Chemistry Laboratory in Boulder, Colorado, for the 2019 tapwater study conducted in North Dakota and South Dakota, USA. This project is part of the U.S. Geological Survey, Ecosystems Mission Area, Environmental Health Water and Wastewater Infrastructure Program.Concentrations 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 disiTarget-Chemical Concentration Results of Mixed-Organic/Inorganic Chemical Exposures in Puerto Rico Tapwater, 2017 to 2018
This dataset provides the water-quality results for organic and inorganic concentrations analyzed from samples collected at domestic and commercial tapwater faucets and one spring, sourced in Puerto Rico. Samples were collected in October, 2017 and August and December, 2018 from 19 locations. Samples were analyzed at various U.S. Geological Survey laboratories: the National Water Quality LaboratorPesticide and Pharmaceutical Exposure Data for Select Streams within Great Smoky Mountains National Park, 2019
This dataset included the concentration results (in nanograms per liter) for 328 pharmaceutical and pesticide compounds analyzed within the Great Smoky Mountain National Park, Tennessee and North Carolina, in 2019. Two samples were collected (July and September) at 15 locations within the park, and one location at the park boundary. Samples were analyzed at the National Water Quality Laboratory (NMicrobial Source Tracking Marker Concentrations in Congaree National Park in 2017-2019, South Carolina, USA
The dataset contains quantitative polymerase chain reaction data for microbial source tracking markers screened on water samples collected from streams and rivers within and bounding Congaree National Park from samples collected throughout the year from December 2017 through June 2019. The number of samples collected per event ranged from 4-16 over the span of 11 sample events.Target-Chemical Concentration Results of Mixed-Organic/Inorganic Chemical Exposures in Cape Cod, Massachusetts Tapwater, 2018
This dataset provides the water-quality results for organic and inorganic concentrations analyzed from samples collected at residential tapwater faucets, sourced from private drinking water wells in Cape Cod, Massachusetts. Samples were collected in July and August, 2018 from 20 locations. Samples were analyzed at various U.S. Geological Survey laboratories: the National Water Quality Laboratory iConcentrations of Pesticide, Pharmaceutical, and Organic Wastewater Contaminants from a Multi-Regional Assessment of Wadeable USA Streams, 2014-17
Human-use pharmaceutical, pesticide, and wastewater indicator compounds were analyzed at the U.S. Geological Survey, National Water Quality Laboratory, Denver, Colorado, in wadeable streams in 4 Regional Stream Quality Assessments: Northeast (NESQA), Southeast (SESQA), Pacific Northwest (PNSQA) and California (CSQA). Multiple (with few exceptions) samplings occurred at each site, during base flow,Pesticide and transformation product concentrations and risk quotients in U.S. headwater streams
This dataset includes a subset of previously released pesticide data (Morace and others, 2020) from the U.S. Geological Survey (USGS) National Water Quality Assessment Program (NAWQA) Regional Stream Quality Assessment (RSQA) project and the corresponding hazard index results calculated using the R package toxEval, which are relevant to Mahler and others, 2020. Pesticide and transformation productCyanotoxin Concentration and Phytoplankton Community Composition Data for Surface Water Samples Collected at Lake Mattamuskeet National Wildlife Refuge, North Carolina during summer 2015
Data release including concentrations of cyanotoxins and phytoplankton community composition data for water samples collected from the Lake Mattamuskeet National Wildlife Refuge in North Carolina during 2015.Water-, Sediment-, and Biological-Quality Data for Waters Receiving Runoff from Five Bridges in South Carolina, 2013 to 2018
This dataset contains water-, sediment-, and biological-quality data collected immediately upstream and downstream from 5 bridges in 3 physiographic provinces (Piedmont, Upper Coastal Plain, and Lower Coast Plain) in South Carolina during periods of observable bridge-deck runoff during 2013 to 2018. The associated report (Journey and others, 2020, "Effects of Stormwater Runoff from Selected Bridge - 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 landscapesContaminant 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 toBottled 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/micrTapwater 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 determinRapid implementation of high-frequency wastewater surveillance of SARS-CoV-2
There have been over 507 million cases of COVID-19, the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulting in 6 million deaths globally. Wastewater surveillance has emerged as a valuable tool in understanding SARS-CoV-2 burden in communities. The National Wastewater Surveillance System (NWSS) partnered with the United States Geological Survey (USGS) to imEcological consequences of neonicotinoid mixtures in streams
Neonicotinoid mixtures are common in streams worldwide, but corresponding ecological responses are poorly understood. We combined experimental and observational studies to narrow this knowledge gap. The mesocosm experiment determined that concentrations of the neonicotinoids imidacloprid and clothianidin (range of exposures, 0 to 11.9 μg/liter) above the hazard concentration for 5% of species (0.0Arsenic in private well water and birth outcomes in the United States
BackgroundPrenatal exposure to drinking water with arsenic concentrations >50 μg/L is associated with adverse birth outcomes, with inconclusive evidence for concentrations ≤50 μg/L. In a collaborative effort by public health experts, hydrologists, and geologists, we used published machine learning model estimates to characterize arsenic concentrations in private wells—federally unregulated for driTemporal variability in TiO2 engineered particle concentrations in rural Edisto River
Titanium dioxide (TiO2) is widely used in engineered particles including engineered nanomaterial (ENM) and pigments, yet its occurrence, concentrations, temporal variability, and fate in natural environmental systems are poorly understood. For three years, we monitored TiO2 concentrations in a rural river basin (Edisto River, < 1% urban land cover) in South Carolina, United States. The total conceFood, 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 LaboratoryIntegrated 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 tAssessing the ecological functionality and integrity of natural ponds, excavated ponds and stormwater basins for conserving amphibian diversity
Wetlands provide ecological functionality by maintaining and promoting regional biodiversity supporting quality habitat for aquatic organisms. Globally, habitat loss, fragmentation and degradation due to increases in agricultural activities and urban development have reduced or altered geographically isolated wetlands, thus reducing biodiversity. The objective of this study was to assess the relat - News