No abstract

The edible parts of several species of fish and other marine organisms inhabiting the Calcasieu River/Lake, Louisiana were analyzed for Cd, Cr, Cu, Pb, Hg, Ag, Zn and As. Concentrations of all metals measured in both intra and interspecies showed no significant variation with sample location. Differences in elemental concentrations were related to organism mobility and not to site-specific variations in metal loadings. Different species of finfish contained only trace amounts of Cd (0.02-0.08), Ag (less than 0.01-0.3), Pb (less than 0.2-0.5), and As (less than 0.1-0.3) mg kg(-1). Concentrations of Cu and Cr were highly variable, in contrast to Zn, which was present in relatively constant amounts across all species (28 +/- mg kg(-1). Sessile organisms such as oysters had the highest concentrations of heavy metals, including Cd. Periphyton and zooplankton were the only groups that showed differences in metal concentrations with sampling location.

The heavy metals Cd, Cr, Cu, Pb, Hg, Ag, and Zn, and the metalloid As were measured in surface sediments at permanent stations located in the Calcasieu River/Lake Complex . The relationships among metal concentrations in different areas of the system were investigated to determine sources, source strength, and transport . The point-source inputs of heavy metals were assumed to be industrial outfalls (Bayou d'Inde) and sewage outfalls (Bayou d'Inde and Contraband Bayou) . Although these inputs have not seriously affected the entire river/lake system, stressed regions exist within each bayou .The background levels of arsenic and heavy metals were : 0 .60 (As), 0.3 to 1 .4 (Cd), 25 (Cr), 10 (Cu), 15 (Pb), < 0.05 (Hg), 0.07 (Ag), and 40 mg kg-' (Zn) . Stations near sewage outfalls and industrial outfalls had increased metal concentrations above these background levels, but the increases were restricted to the regions near the outfalls . The metals discharged into the bayous were not being transported to the remainder of the river/lake complex .