The Toxic Substances Hydrology (Toxics) Program is investigating factors and processes that control the transport and fate of contaminants in unsaturated zones (the zone in the subsurface between the land surface and underlying aquifers). Toxics Program scientists are developing methods for measuring and modeling the transport and fate of many different types of contaminants in the unsaturated zone. Such measurement tools, interpretive approaches, and modeling packages are needed for the design and management of waste-disposal facilities, to understand how nonpoint-source contaminants are transported to ground water, the cleanup of contaminated sites, and the monitoring of remediation systems. The unsaturated zone is particularly important at sites in the arid western United States that are being relied upon to isolate a significant portion of the Nation's radioactive and other hazardous wastes for periods up to thousands of years. The information presented on this page cuts across lines drawn by individual investigations and projects so that information on contaminant transport in surface-water can be presented in one place.
Investigations and Research Activities
Thermocouple psychrometer installation for evaluating an evapotranspiration landfill cover at Fort Carson, Colorado.
Science Feature Articles
- Multimodel analysis of anisotropic diffusive tracer-gas transport in a deep arid unsaturated zone: Green, C.T., Walvoord, M.A., Andraski, B.J., Striegl, R.G., and Stonestrom, D.A., 2015, Water Resources Research, doi:10.1002/2014WR016055.
Soil moisture probes and tensiometers installed in the side of a pit for monitoring a tracer test in the unsaturated zone at the Bemidji Crude Oil Spill Research Site, Minnesota. Note black oil-contaminated sand on pit walls.