Bed sediments and fish tissues were collected from 23 stream sites representing various land uses in the South Platte River Basin at low flow during the summers of 1992 and 1993 as part of the U.S. Geological Survey's National Water-Quality Assessment Program Bed sediments and fish livers were analyzed for selected trace-element concentrations.
Concentrations of most trace elements in bed sediments decreased with increasing distance from the mountains to the plains. Arsenic, cadmium, copper, iron, lead, manganese, and zinc concentrations were highest in bed sediments in mountainous mining areas. In the plains, concentrations of aluminum, selenium, and vanadium were highest in urban land-use settings, whereas arsenic, chromium, nickel, and silver concentrations were highest in mixed land-use settings, Concentrations of manganese and strontium were highest in bed sediments in agricultural land-use settings. Currently (1994), there are no national standards for trace-element concentrations in bed sediment to assess the environmental implications of these data.
Trace-element concentrations in fish livers exceeded the U.S. Environmental Protection Agency's suggested maximum levels for chromium, copper, selenium, and zinc at all sites in the basin, although these standards are based on whole fish samples. The suggested maximum level for cadmium was exceeded in 52 percent of brown trout and common carp, and vanadium concentrations exceeded the maximum level in 27 percent of the common carp.
Concentrations of aluminum, cadmium, chromium, copper, iron, manganese, and molybdenum were highest in brown trout (cold-water fish associated with mountain streams). Concentrations of aluminum, cadmium, vanadium, and zinc were highest in common carp (warm-water fish associated with plains streams) obtained from agricultural land-use settings, whereas in the mixed land-use setting, iron, molybdenum, and strontium were highest in carp.
1 U.S. Geological Survey, Box 25046, MS 415, Denver Federal Center, Lakewood, CO 80225