National analysis of trace elements in ground water, streams, stream and reservoir sediment, and fish and clam tissue across the United States

http://water.usgs.gov/nawqa/trace/

Trace elements are inorganic chemicals occurring in small amounts in nature. This web site of the National Water Quality Assessment links to U.S. data, publications, news, and other sites on trace metals, metalloids and radionuclides in water.

by National Water Quality Assessment Program (Sponsor) and Colorado Water Science Center (Sponsor)