Depth Variability and Fractionation of Fe, Mn, Cu and Pb in Sediments from Bosten Lake in Xinjiang, Northwest China

Abstract

The abundance and layered evolution vs. depth of dissolved and solid species of Mn, Fe, Cu and Pb were investigated both in extracted porewaters and in sedimentary solid materials. The chemical speciations between five geochemical phases (exchangeable fraction, carbonate fraction, Fe/Mn oxide fraction, organic fraction, and the residual) versus depth of the heavy metals (Mn, Fe, Cu and Pb) were gotten using five-step sequential extraction procedures. The concentration of metals in porewaters and of sedimentary solid phases was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Heavy metal concentrations do not have distinct patterns along the depth. In Bosten Lake, the total concentrations of Cu is relative plentiful. Sedimentary Mn, Fe, Cu and Pb are found mainly in the residual fraction (7096%). According to the Risk Assessment Code (RAC), these sediments are Mn at between low and medium risk, Fe at no risk, Cu and Pb at low risk.