USGS Publications Warehouse

Abstract

Concentrations of metals and nonmetallic elements were measured in the less than 63-micrometer-sized fraction of streambed-sediment samples from 422 sites on first- and second-order streams in the lower Kansas River Basin of Kansas and Nebraska. Median concentrations were of the same order of magnitude as the geometric mean concentrations in soils of the western United States. Either threshold concentrations (based on normal-probability plots) or upper percentile classes (greater than 50 percent) of concentrations were determined for 14 metals, arsenic, and phosphorus. Samples with a concentration greater than the threshold concentration indicated possible enrichment with respect to that particular element. Concentrations of the transition metals, which included chromium, cobalt, copper, manganese, nickel, and vanadium, generally were larger in the southeastern part of the study unit where Permian and Pennsylvanian shale and limestone predominate. The largest concen- trations of alakali metals, potassium and sodium, mainly were in the northwestern part of the study unit, which is an area of Quaternary loess deposits irrigated with ground water. Larger concentrations of the alkaline-earth metal, barium, also were in the northwestern part of the study unit. Concentrations of the other alkaline-earth metals, calcium, magnesium, and strontium, were larger in the southern part of the basin, which is underlain by Permian and Pennsylvanian shale and limestone. The largest concentrations of arsenic and lead and were mainly in the southeastern part of the study unit. Large concentrations of phosphorus occurred in the northwestern part of the study unit and were associated with irrigated agriculture.