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1D - Soil and Sediment Contamination (TU9/4) Persistent organic pollutants (POPs) in sediments of reservoir lakes in the Ruhr Valley, Germany. Regier, Annette1, Schwark, Lorenz1, 1 University of Cologne, Cologne, NRW, Germany ABSTRACT- The Ruhr Valley, NW-Germany, is one of the largest industrialised areas in Europe. For centuries it has been famous for coal mining, metal processing industry and the corresponding environmental pollution. However, during the last decades emissions have been decreasing. On the one hand because most processing plants and mines ceased operation on the other hand because legislation forced industry to diminish emissions. Sediments act as sinks for hydrophobic organic contaminants and can be seen as archives of historic pollution. Dated sediments from 2 reservoir lakes along the Ruhr River have been analysed. Persistent organic pollutants (POPs) belonging to various compound classes, including PCBs and PAHs, have been detected. Historical trends of PCB loading show higher levels between 1950 and 1990 with a maximum around 1970. PCB congener analysis reveals that penta- and hexachlorinated biphenyls are present throughout the cores. Sediments accumulated around peak concentrations are dominated by the tri- and tetrachlorinated biphenyls, which are main constituents of hydraulic fluids used in coal mining. PAHs in the reservoir sediments originate from combustion sources as well as uncombusted fossil fuels. Diagentic PAH are important in sediments deposited before damming of the river. The maximum of PAH contamination dates back to 1955. Older sediments show medium but strongly variable concentrations. After 1960 concentrations decrease rapidly. PAH source apportionment by alkyl homologue distributions (AHD) reveals a domination of alkylated PAHs over parent compounds from the mid 50s to the mid 80s suggesting predominantly fossil fuel input. Before and after this period contribution from combustion sources dominate. Decreasing sediment concentrations and distribution pattern of principle contaminants reveal the joint effects of technical improvements and environmental legislation. Key words: persistent organic pollutants, reservoir sediments, PAH, PCB |
