A: The U.S. Geological Survey's Toxic Substances Hydrology (Toxics) Program has done studies of the cycling of toxic substances in aquatic environments that have been used by regulatory agencies to develop water-quality criteria for streams and other water bodies. Information on water-quality criteria can be found at:

• U.S. Environmental Protection Agency's National Recommended Water-Quality Criteria -- A collection of tables containing recommended water quality criteria for the protection of aquatic life and human health for approximately 150 pollutants.

Back to FAQ index