The Situation of PCDD/Fs and Dioxin-like PCBs after the Flooding of River Elbe and Mulde in 2002

Following the Elbe and Mulde flooding in August 2002 a series of research and monitoring programmes were conducted to assess the contamination of the flooded areas with PCDD/Fs and related compounds and to identify related threats to the food chain. The present paper reports an overview of PCDD/F and dioxin-like PCB results obtained for soil samples from the floodplains and behind broken dikes, river sediments and feedstuff produced on the floodplains, and some products from animals fed with feedstuffs grown on the contaminated floodplains. The highest contamination levels in soil were found in periodically flooded pastureland riverside of the dikes. PCDD/Fs in most samples from pasture land exceeded the German threshold of 5 pg/g I-TEQ. Maximum concentrations in soil were up to 2100 pg/g I-TEQ. PCDD/Fs in agricultural soils, usually not flooded except during 2002, did not exceed the threshold of 40 pg/g. Maximum concentrations in soil were below 10 pg/g I-TEQ. PCDD/Fs in playgrounds and sporting areas did not exceed the threshold of 100 pg/g I-TEQ in soil, maximum concentrations were around 25 pg/g I-TEQ. Dioxin-like PCBs were of minor importance for the WHO-TEQ in soil and sediment but dominate the WHO-TEQ in Elbe fish. Monitoring, The soils behind broken dikes only affected by the 2002 flood were only marginally contaminated with PCDD/Fs. In contrast, most soils from the pasture lands riverside of the dikes, continuously affected by periodic flooding, revealed high contamination levels. This demonstrates that the 2002 flooding had only minor impact on the contamination of soils The downstream concentration profile of Elbe sediments and alluvial soils identifies the Germany rivers Mulde and Saale as important input sources. The related congener distribution suggests input from former metallurgic processing (magnesium) in the Mulde and Saale catchment. The downstream contamination profile in the sediments showed one order of magnitude lower PCDD/F levels and the peak contamination was located about 200 km further upstream when compared to the floodplains. Analytical surveys on feedstuffs cultivated on the contaminated floodplains did not reveal significant soil-grass transfer of PCDD/Fs, which indicates a low mobility of the PCDD/Fs present in the floodplains. However, co-ingestion of soil by grazing animals gave a clear signal of contaminant uptake and demonstrates the necessity of a careful agri-management of the floodplains of Elbe and Mulde.JRC.H.5-Rural, water and ecosystem resource