Determination of heavy metals in suspended matter in the storage lake ?Bitterfelder Muldestausee?

Abstract

Dissolved and particulate trace elements have been determined in 400 samples of both the inflow and the outflow waters of the storage lake “Bitterfelder Muldestausse” in order to investigate the sedimentation of 22 elements transported by the highly polluted Mulde River, an affluent of the river Elbe. Inductively coupled plasma mass spectrometry (ICP-MS) has been used to analyse filtered water samples because of its multielemental capabilities, the excellent detection limits, the wide linear calibration range and the high speed of analysis. A special leaching procedure has been employed for the very low amounts of the suspended matter collected from each water sample. The dissolved material has been also analysed by ICP-MS. Testing of the procedure employed by the analysis of a standard reference material (SRM BCR 146) and use of the standard addition method has resulted in both a good precision (1–7%) and accuracy. Despite the wide variation in the composition of the suspended matter samples the concentrations of the heavy metals in sediment samples and in the suspended matter have been found to be comparable. A balance of sedimentation has been calculated based on the mean values of concentrations of all elements investigated in both the water and suspended matter samples of the inflow and outflow. Results from this first study show that the storage lake acts as a sedimentation trap for Zn, Cu, Pb, Ni, Cr, Cd, U and Co.