Total selenium and selenium (IV) in the James River estuary and southern Chesapeake Bay

Abstract

The concentrations of total selenium (Se) and Se (IV) were determined in the surface waters of 30 stations located in the James River and southern Chesapeake Bay. The concentrations of total Se and Se (IV) ranged from 0·28 to 1·91 nM and from 0·07 to 1·36 nM, respectively, between salinities of 31·78 and 0·06‰. The concentration of Se (VI), calculated as the difference between the concentrations of total Se and Se (IV), ranged from 0·08 to 0·67 nM. While total Se seemed to be conservative in this study area at salinities above 0·36‰, Se (IV) might have been removed during estuarine mixing. The removal of Se (IV) occurred primarily at salinities below 4‰ possibly via the oxidation of Se (IV) to Se (VI).