A study on arsenic and the heavy metals in the Mulde river system

Analyses of water, suspended particulate matter, and sediment for the area drained by the river Mulde (Germany) for the early 90's show a high level of pollution in several sections of the river system. This was caused primarily by mining, and industrial and urban activity. The influence of the extreme "100-year- flood" into the Mulde and Elbe river systems as a result of the extremely high precipitation in the ore mountains (Erzgebirge) in August 2002 was studied. During the flood, large amounts of strongly polluted sediments were transported into the Freiberger Mulde and Zwickauer Mulde, and deposited on the flooded areas and along river banks in the Vereinigte Mulde. Concentrations of As and heavy metals in the flood sediments of the Freiberger Mulde were found to be very high. This is due primarily to waste dump leaching into the polluted part of the river near Freiberg. Studies in such strongly polluted area show that there is a permanent supply of pollutants from point and diffuse sources, and new sediments with the same level of pollution are formed in the river system. The study of the Bitterfelder Mulde river reservoir documents its function as a sink for suspended matter and heavy metals in the lower Mulde and Elbe system, even at extremely high flow rates. As a result of the flooding of the Lake Goitsche, large amounts of sediment were observed, particularly in the first subbasin Dobern. The deposited sediments contained large concentrations of As and heavy metals.