Variations in suspended sediment and associated trace element concentrations in selected riverine cross sections

Detailed sampling and subsequent analyses of riverine suspended sediment obtained from six rivers in the United States indicate substantial differences in suspended sediment concentrations and possibly in some associated trace elements, depending on whether depth- and width-integrated, point, or pumping samples are used. In addition, the data from time-series, depth-integrated sampling indicate that there can be substantial short-term (on the order of 20-30 min) spatial and/or temporal variations in suspended-sediment concentrations. Despite this, major element concentrations are remarkably stable both spatially and temporally. Trace element concentrations are generally stable; however, some spatial and temporal variations may occur.