Environmental Health - Toxic Substances Hydrology Program

Toxic Substances Hydrology Program Investigations

The USGS Toxic Substances Hydrology Program has studies focused on issues of national concern including contaminants associated with unconventional oil and gas and uranium extractions, home and personal-care products, agricultural production, industrial processes.

USGS scientist collecting water samples and measuring water field properties

Chemical Mixtures and Environmental Effects

The USGS is investigating the occurrence and environmental effects of complex mixtures of both natural and man-made chemicals in environmental waters.

USGS scientist with equipment used to inject fluids for a bioaugmentation experiment

Chlorinated Solvents in Fractured-Rock Aquifers

The USGS is investigating the hydrological, geochemical, and microbiological processes controlling contaminant fate in fractured-rock aquifers. Long-term field experiments are currently conducted at a former aircraft engine test facility in West Trenton, New Jersey, where high concentrations of trichloroethene persist in sedimentary rocks despite two decades of groundwater pumping and treatment.

Four sample bottels filled with leachate

Contaminants of Emerging Concern in the Environment

The USGS is conducting source-to-receptor research on a broad range of chemical and microbial contaminants including pharmaceuticals, personal care products, pathogens, antibiotic resistant genes, and natural toxins that are not commonly considered in environmental research but have the potential to impact environmental health.

USGS scientists collecting a water sample from a well at the USGS Bemidji Research Site

Crude Oil Contamination in the Shallow Subsurface

This investigation focuses on the long-term persistence in soils and groundwater of petroleum hydrocarbon spills, including crude oil and refined petroleum fuels. The study site near Bemidji, MN, is a laboratory for developing site assessment tools and understanding chemical changes affecting human and environmental health that occur during natural attenuation of petroleum hydrocarbons.

Graph, sampling depth in meters on left, oxygen concentration in micromoles per kilogram on right.
The location of the maximum methylmercury concentration at depth in the Pacific Ocean was the first evidence noted by the researchers pointing to the new methylation cycle. The graphic shows sampling depth on the left (in meters), and oxygen concentration on the right (in micromoles per kilogram of seawater [µmol/kg]) along a north-south latitudinal transect in the eastern North Pacific Ocean. The specific depth of maximal methylmercury concentration was consistently found at the ocean depth where the most rapid loss of oxygen was also observed. The process linking these two observations is microbial decomposition of "ocean rain", which is settling algae produced near the surface of the ocean. The decomposition process consumes oxygen from the water, but also leads to unintended methylmercury production.
-- from the Effect of Mercury on Aquatic Ecosystems Investigation
USGS scientist lifting a sample bottle from ice hole

Fate and Effects of Wastes from Unconventional Oil and Gas Development

This study is assessing the environmental health risks associated with wastes from unconventional oil and gas development by characterizing waste materials, identifying potential environmental pathways, and evaluating the potential effects on organisms from exposure to unintended waste releases.

USGS scientists collecting gas samples from the unsaturated zone

Low-Level Radioactive and Mixed- Hazardous Wastes

The objective of research at the Amargosa Desert Research Site, Nevada, is to improve understanding of processes controlling the migration and fate of contaminants in arid environments, and the environmental-health implications of disposed radioactive and industrial waste.


Mercury in Aquatic Ecosystems

This investigation focuses on understanding mercury sources, pathways and key processes in the environment, with particular emphasis on mercury methylation and accumulation in aquatic ecosystems.

USGS scientist collecting a water-quality sample from Zollner Creek, Oregon

Pesticide Contamination and Environmental Exposure

The USGS is developing methods to measure new pesticides and their byproducts in environmental media, conducting studies on the fate of these chemicals, and assessing exposure and potential effects on fish, wildlife, and human health.

A USGS scientist prepares a tracer solution in a gas-tight bladder.
A USGS scientist prepares a tracer solution in a gas-tight bladder that will be pumped into a zone of nitrate-containing groundwater to monitor the production and consumption of nitric oxide dissolved in groundwater. USGS scientists and their colleagues have developed a method to measure the rates at which inorganic nitrogen compounds, such as nitrate and nitrite, transform in groundwater.
-- from the Cape Cod Site
White tanks used to hold the tracer injection solutions with tubing going to injection wells

Sewage-Contaminated Ground Water

The USGS is investigating a wastewater plume in a shallow aquifer near Cape Cod, Massachusetts, to increase the understanding of the physical, chemical, and microbiological processes that affect the fate and transport of contaminants in groundwater.

View of Cement Creek, a mining impacted stream in Colorado

Watershed Contamination from Metal and Uranium Mining

The goal of this investigation is to provide improved information and tools to support decisions related to management, risk assessment, remediation planning, and mitigation of the effects of hard-rock metal mining and uranium mining on watersheds and ecosystems.


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