US Fish & Wildlife Service
Date of this Version
1991
Abstract
We conducted this project to assess the concentrations of natural and anthropogenic contaminants in fish of the Missouri River from the Nebraska/South Dakota border to Kansas City, Missouri. We collected 45 composite samples of eight fish species from nine locations on the river. We were unable to collect all species at all locations, but the collections allowed us to compare concentrations within trophic levels and at different locations. Comparisons in this project are based on concentrations in composites of fish that may have been of different ages. Also, the comparisons of different species should be treated with caution because' different species respond to contaminants in different ways and may have normal concentrations of metals or organic contaminants that differ from other species.
Fish from seven of the nine locations were analyzed for arsenic, mercury, selenium, and 11 other metals, for organochlorine compounds, and for aliphatic hydrocarbons. Fish from two of the sampling locations were analyzed only for organochlorines.
Aluminum, arsenic, cadmium, copper, manganese, and zinc concentrations in the fish samples were high enough to warrant further studies. Lead concentrations were high enough to warrant further study, especially downstream from Dakota City, Nebraska. Chromium and nickel concentrations were high relative to concentrations found in other locations. Beryllium, iron, mercury, selenium, and tellurium concentrations need not concern resource managers.
Chlordane and heptachlor concentrations were well below the geometric means from the National Contaminant Biomonitoring Program {NCBP}, but the total concentrations of those compounds exceeded the 1973 National Academy of Sciences and National Academy of Engineering {NAS/NAE} recommendation for protection of aquatic life in 14 of the 45 samples analyzed. Five of the samples were more than double the protection level. Most of the chlordane- and/or heptachlorcontaminated samples came from Blair, Nebraska or downstream. Half of the values exceeding the NAS/NAE recommendation were from Atchison, Kansas and Kansas City, Missouri.
Thirteen of the fish composites exceeded the 1984 NCBP nationwide mean dieldrin concentration in fish. Concentrations in a paddlefish from Blair, Nebraska and in the channel catfish and shovel nose sturgeon composites from Rulo, Nebraska exceeded the NAS/NAE recommendation for dieldrin concentration. In addition, the presence of aldrin in the shovel nose sturgeon sample from Rulo suggests recent inputs of the banned chemical into the Missouri River.
Comments
Published in Contaminant Report Number: R6/503M/91, 1-77, (1991)