摘要：The concentrations of trace elements (TEs), such as As, Cd, Co, Cr, Cu, Ni, Pb, and Zn, in the water and sediments of Tangipahoa River in Louisiana were investigated at five selected sampling locations along the river in July 2009. Some important physicochemical parameters (pH, EC, temperature, DO (dissolved oxygen), turbidity, TOC (total organic carbon), and DOC (dissolved organic carbon) and common anions (F-, Cl-, Br-, NO2-, SO42-, NO3-, and PO43-) of river water were analyzed, and the correlation coefficients of selected parameters with TE concentration were examined. The bioavailability and fractionation of TEs in sediment were evaluated using EDTA and BCR sequential extraction, respectively. The results showed that all measured TEs and common anions in water were below the current guidelines of USEPA and WHO for drinking water. Sediment was only contaminated by As at all sampling locations according to the Sediment Quality Guidelines (SQGs). Bioavailability of TEs in sediment obtained by EDTA extraction decreased in the order of Zn>Cd>Co>Pb> Ni>Cu>As>Cr. Zn was identified as a potential risk to aquatic organisms despite being below SQGs at its highest total and bioavailable concentration. The fractionation of all TEs obtained by BCR sequential extraction showed that the TE exchangeable fraction in sediment decreased in the order of Zn>Co>Ni>Cd>Cu>Cr>Pb≈As, which differs from that as evaluated by EDTA extraction. This difference was attributed to the variation of complexing potential of TEs with EDTA or CH3COOH used in the BCR extraction. The relationships of TE variation with partial water parameters showed strong positive or negative correlation. The results obtained in this study provided baseline information for future Tangipahoa River management and application.
关键词：Trace element; bioavailability; sediment; water; fractionation; Tangipahoa River
