Barbara Mahler is a Research Hydrologist and Communications Coordinator for the USGS Water Mission Area. Her research interests include fate and transport of contaminated sediment, and karst hydrology and water quality.
Barbara has Masters and doctoral degrees in Geology from the University of Texas, where she studied with Dr. Philip Bennett. The emphasis of her graduate research was the geochemistry of karst aquifers. Her doctoral research focused on sediment transport through karst aquifers and its potential to serve as a vector for contaminant transport. After completing her Ph.D. in 1997, she spent 1 year as an NSF/NATO International Postdoc in Montpellier, France, studying transport of sediment and bacteria in karst.
Currently Barbara is a geochemist with the NWQP Regional Stream Quality Assessment (RSQA) study, and the Communications Coordinator for the USGS National Water Quality Program (NWQP). Her research has highlighted the role played by coal-tar-based pavement sealants in contributing polycyclic aromatic hydrocarbons (PAHs) to the environment, for which was was awarded the USGS Meritorious Service Award in 2017. Her publications in the field of karst have included analysis of pesticide breakthrough curves in spring flow, use of nitrate as a tracer of recent recharge, and use of principal components analysis to investigate nutrient dynamics in karst. She has been an Associate Editor for the Journal of Hydrology, and is a member of the IAH Karst Hydrogeology Commission.
Barbara is a Research Fellow at the University of Texas Jackson School of Geosciences. She regularly serves on the committees of Masters and Ph.D. students and teaches courses at the university. She is a regular reviewer for numerous scientific journals, including Science, Nature, Journal of Hydrology, Hydrogeology Journal, Environmental Science and Technology, and Journal of Contaminant Hydrology.
Science and Products
USGS Streamgaging Network
The USGS Groundwater and Streamflow Information Program supports the collection and (or) delivery of both streamflow and water-level information at approximately 8,500 sites and water-level information alone for more than 1,700 additional sites. The data are served online—most in near realtime—to meet many diverse needs.
Urban Land Use and Water Quality
Wherever you live, there’s a creek or stream near you. The eighty percent of Americans who live in metropolitan areas are often unaware of the network of urban creeks—many teeming with life—that weaves through our cities and town. Nowhere are the environmental changes associated with urban development more evident than in urban streams.
NWQP Water-Quality Topics
From chloride to corrosivity, from pesticides to PAHs, find the most recent National Water Quality Program (NWQP) science on these topics and effects on surface water, groundwater, and ecology. Informative web pages provide an overview and links to related web pages, publications, maps, news, and data.
Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Sealcoat is the black, viscous liquid applied to many asphalt parking lots, driveways, and playgrounds in North America to protect and enhance the appearance of the underlying asphalt. Coal-tar-based pavement sealcoat is a potent source of polycyclic aromatic hydrocarbon (PAH) contamination in urban and suburban areas and a potential concern for human health and aquatic life.
Water-Quality Quick Links
Looking for data? Maps? Use the links below to quickly access some of the most frequently visited USGS web pages on water quality.
National Water-Quality Project Sampling Methods
USGS National Water Quality Assessment (NAWQA) studies require analyses of stream and bed-sediment samples for major ions, nutrients, sediments, and organic contaminants that are consistent across time and space. Procedures have been designed specifically to produce information that is comparable among studies in different parts of the Nation.
Water-Quality Trends
Is water quality getting better or worse? Answering this deceptively simple question has been a fundamental objective of the USGS National Water-Quality Assessment Project’s research. Learn about trends in contaminants in the nation’s streams and rivers, trends in contaminants that collect in the bed sediment of streams and lakes, and changes in the quality of the nation’s groundwater.
Sediment-Associated Contaminants
Stream, river, and lake bed sediment are reservoirs for many contaminants. These contaminants include some “legacy” contaminants, like DDT, PCBs, and chlordane, and chemicals currently in use, like the insecticide bifenthrin and many flame retardants. Learn about techniques used to study sediment-associated contaminants and their importance to aquatic biota.
USGS Research: PAHs and Coal-Tar-Based Pavement Sealcoat
Coal-tar-based pavement sealant is a potent source of polycyclic aromatic hydrocarbons (PAHs), as documented by the USGS and other researchers.Coal-tar-based sealcoat products typically are 20 to 35% coal tar or coal-tar pitch—these materials are known human carcinogens that contain high concentrations of PAHs and related chemicals. Coal-tar-based pavement sealcoat typically contains 35,000 to 200...
Webinar: Karst, Critters, and Climate Change: A Multidisciplinary Evaluation of Karst Species Vulnerability to Climate Change
View this webinar to learn how scientists are exploring the vulnerability of karst species to climate change.
Evaluating the Impacts of Climate Extremes on Karst Hydrology and Species Vulnerability
Karst aquifers—formed when the movement of water dissolves bedrock—are critical groundwater resources in North America. Water moving through these aquifers carves out magnificent caves, sinkholes, and other formations. These formations are home to high concentrations of rare and endangered species, but the hydrological conditions that support these species can change rapidly. Managing these ecosys...
Science and Products
- Science
USGS Streamgaging Network
The USGS Groundwater and Streamflow Information Program supports the collection and (or) delivery of both streamflow and water-level information at approximately 8,500 sites and water-level information alone for more than 1,700 additional sites. The data are served online—most in near realtime—to meet many diverse needs.Urban Land Use and Water Quality
Wherever you live, there’s a creek or stream near you. The eighty percent of Americans who live in metropolitan areas are often unaware of the network of urban creeks—many teeming with life—that weaves through our cities and town. Nowhere are the environmental changes associated with urban development more evident than in urban streams.NWQP Water-Quality Topics
From chloride to corrosivity, from pesticides to PAHs, find the most recent National Water Quality Program (NWQP) science on these topics and effects on surface water, groundwater, and ecology. Informative web pages provide an overview and links to related web pages, publications, maps, news, and data.Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Sealcoat is the black, viscous liquid applied to many asphalt parking lots, driveways, and playgrounds in North America to protect and enhance the appearance of the underlying asphalt. Coal-tar-based pavement sealcoat is a potent source of polycyclic aromatic hydrocarbon (PAH) contamination in urban and suburban areas and a potential concern for human health and aquatic life.Water-Quality Quick Links
Looking for data? Maps? Use the links below to quickly access some of the most frequently visited USGS web pages on water quality.National Water-Quality Project Sampling Methods
USGS National Water Quality Assessment (NAWQA) studies require analyses of stream and bed-sediment samples for major ions, nutrients, sediments, and organic contaminants that are consistent across time and space. Procedures have been designed specifically to produce information that is comparable among studies in different parts of the Nation.Water-Quality Trends
Is water quality getting better or worse? Answering this deceptively simple question has been a fundamental objective of the USGS National Water-Quality Assessment Project’s research. Learn about trends in contaminants in the nation’s streams and rivers, trends in contaminants that collect in the bed sediment of streams and lakes, and changes in the quality of the nation’s groundwater.Sediment-Associated Contaminants
Stream, river, and lake bed sediment are reservoirs for many contaminants. These contaminants include some “legacy” contaminants, like DDT, PCBs, and chlordane, and chemicals currently in use, like the insecticide bifenthrin and many flame retardants. Learn about techniques used to study sediment-associated contaminants and their importance to aquatic biota.USGS Research: PAHs and Coal-Tar-Based Pavement Sealcoat
Coal-tar-based pavement sealant is a potent source of polycyclic aromatic hydrocarbons (PAHs), as documented by the USGS and other researchers.Coal-tar-based sealcoat products typically are 20 to 35% coal tar or coal-tar pitch—these materials are known human carcinogens that contain high concentrations of PAHs and related chemicals. Coal-tar-based pavement sealcoat typically contains 35,000 to 200...Webinar: Karst, Critters, and Climate Change: A Multidisciplinary Evaluation of Karst Species Vulnerability to Climate Change
View this webinar to learn how scientists are exploring the vulnerability of karst species to climate change.Evaluating the Impacts of Climate Extremes on Karst Hydrology and Species Vulnerability
Karst aquifers—formed when the movement of water dissolves bedrock—are critical groundwater resources in North America. Water moving through these aquifers carves out magnificent caves, sinkholes, and other formations. These formations are home to high concentrations of rare and endangered species, but the hydrological conditions that support these species can change rapidly. Managing these ecosys... - Data
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