Contaminant Transport Modeling

Metals, metalloids, and radionuclides all are trace elements that occur naturally in the Earth's crust. In small quantities many trace elements are essential for health in all living organisms, but some trace elements can be toxic or cause cancer, and some can bioaccumulate. The USGS investigates where and how trace elements make their way into our Nation's surface water and groundwater.

The sources, biogeochemistry, and ecotoxicology of selenium (Se) combine to produce a widespread potential for ecological risk such as deformities in birds and fish. Linking the understanding of source characteristics to a mechanistic, biodynamic dietary model of Se exposure on an ecosystem-scale improves the prediction of Se effects and its potential remediation.

More than 100 million people in the United States—about 35 percent of the population—receive their drinking water from public-supply wells. These systems can be vulnerable to contamination from naturally occurring constituents, such as radon, uranium and arsenic, and from commonly used manmade chemicals, such as fertilizers, pesticides, solvents, and gasoline hydrocarbons. Learn about the...

What is SPARROW? SPARROW (SPAtially Referenced Regression On Watershed attributes) is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as contaminant sources and environmental factors that affect rates of delivery to streams and in-stream processing. The core of the model consists of a nonlinear...

Selenium (Se) as a contaminant of ecosystems is bioaccumulative and causes reproductive effects in fish and wildlife. Ecosystem-scale Se modeling predicts Se bioaccumulation based on dietary biodynamics within site-specific food webs. The model can be used to forecast Se toxicity under different management or regulatory proposals or to translate a tissue guideline to a dissolved guideline.

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.

On August 5, 2015, U.S. EPA was conducting an investigation of the Gold King Mine near Silverton, Colorado. While excavating as part of the investigation, water began leaking from the mine tunnel, and about three million gallons of water and sediment were released into Cement Creek, a tributary of the Animas River. The USGS provided pre- and post-release water-quality and streamflow data from...

The USGS studies calcium carbonate mineral reactions in soils at the Amarigosa Desert Research Site (ADRS) near Beatty, Nevada, in order to better understand carbon dioxide transport to and from the soil surface, as well as sequestration of toxic elements in the soil.