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(T/MF152) Heavy metal speciation in lake sediments polluted by industrial and urban wastewater. Fekete, Ilona1, Heltai, György1, Kaemmerer, Michel2, Merlina, George2, Gavalda, David2, Revel, Jean-Claude2, 1 2 ABSTRACT- In a previous study it was reported that in the Gödöllô lake system an intensive sedimentation had been observed due to the release of biologically cleaned communal and industrial wastewater into the lakes. Sediment samples were analysed, and the accumulation of heavy metals and of other elements was detected. Given that these lakes are used for recreational purposes such as fishing, the estimation of the environmental risk is necessary. That is the reason why the sequential extraction procedure was carried out in order to define the chemical speciation of the metallic trace elements. It was carried out according to the three-step method recommended by the BCR supplemented with a preliminary and an additional step. This study showed that the origin of the elements does not influence the speciation since, whatever the lake, in the recent sediment the copper is essentially bound to the organic matter and the sulphides and the cadmium to the carbonates. Moreover, the alkaline pH of water explains the very slight mobility in metals and a limited bio availability. Key words: metal, sediment, speciation, extraction |
