| concentrations of arsenic, cadmium, copper, lead, selenium, and zinc in fish from the mississippi river basin, 1995. | fish were collected in late 1995 from 34 national contaminant biomonitoring program (ncbp) stations and 12 national water quality assessment program (nawqa) stations in the mississippi river basin (mrb), and in late 1996 from a reference site in west virginia. the ncbp sites represented key points (dams, tributaries, etc.) in the largest rivers of the mrb. the nawqa sites were typically on smaller rivers and were selected to represent dominant land uses in their watersheds. the west virginia sit ... | 2004 | 15887377 |