ABSTRACT
Bottom sediments play an important role both as a sink where contaminants can be stored and as a source of these contaminants to the overlying water and to biota. Sediments have only been considered as non-point sources of environmental contaminants. Under certain conditions, some in-place pollutants are likely to be an important source for the water body. The map of the distribution of V concentrations indicates the likely sources for the element. The loadings from all of these sources may include the sediment burden, bacteria and viruses, and adsorbed and dissolved contaminants such as metals or organo-xenobiotics. Atmospheric loading, a major non-point source of contaminants, includes chemicals in rain, dry deposition, and snowpack runoff, and all of these may reflect long-range transport of contaminants from many human activities. Contaminants which enter as dissolved atoms or molecules are removed from the water column through such chemical processes as precipitation and coprecipitation and such biological processes as uptake by biota.
