Trace elements in water, fish and sediment from Tuskegee Lake, Southeastern USA

Abstract

The concentrations of trace elements in water, sediment and fish samples from Tuskegee Lake located in Southeastern United States were investigated in this study. The Lake is utilized both as a source for municipal drinking water, and for recreational fishing. The water quality characteristics over two sampling periods, the speciation of metals in the Lake sediments, the risk to water column contamination and levels of heavy metals in largemouth bass (Micropterus salmoides) samples from the Lake were evaluated. The Lake water quality characteristics were mostly below the recommended drinking water standards by the United States Environmental Protection Agency (US EPA) and the European Union (EU) except for aluminum, iron, manganese and thallium. In addition, the average values of Cr, As, Mn, Zn and Cl− in the water samples analyzed were higher than the respective reference values for fresh water. To study the speciation of metals in the Lake sediments, ten elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn) in four grain sizes (< 710 µm 250 µm, < 250 µm 75 µm, < 75 µm 53µm, and < 53 µm) were subjected to sequential extractions. Irrespective of grain size, the elements analyzed were distributed in both the non-residual and residual phases except Ni that was found only in the residual fraction. The potential risk to Lake water contamination was highest downstream (Sites 1 and 2) based on the calculated global contamination factors. From the calculated individual contamination factors, Mn and Pb followed by Zn, Cu, Cr, Co and V posed the highest risk to water contamination. Based on this study, the human health risks for heavy metals in fish caught from Tuskegee Lake are low for now, and irrespective of the source of fish, concentrations of metals in muscle tissues were all below the recommended Food and Agriculture Organization (FAO) maximum limits for Pb (0.5 mg Kg−1), Cd (0.5 mg Kg−1), Cu (30 mg Kg−1), and Zn (30 mg Kg−1) in fish Contamination factors