Changes in metal speciation in a sediment core from an acidified Black Forest lake.

Wildsee a small cirque lake in northern Black Forest, Fed. Rep. Germany. The recent acidification history was reconstructed by means of the paleolimnological diatom approach. Furthermore, the bonding stability of selected metals (Al, Fe, Pb, Zn, and Cd) within the sediment core has been evaluated by applying sequential chemical extraction, which differentiates between residual, labile and intermediate compounds. Increases in total concentrations of Al, Pb, and Zn as well as losses in bonding strength of these metals appear to be caused by acidification Cd appears to be derived principally from direct deposition on the lake and its catchment rather than from acidification-mediated soil release.Wildsee is a small cirque lake in northern Black Forest, Fed. Rep. Germany. The recent acidification history was reconstructed by means of the paleolimnological diatom approach. Furthermore, the bonding stability of selected metals (Al, Fe, Pb, Zn, and Cd) within the sediment core has been evaluated by applying sequential chemical extraction, which differentiates between residual, labile and intermediate compounds. Increases in total concentrations of Al, Pb, and Zn as well as losses in bonding strength of these metals appear to be caused by acidification. Cd appears to be derived principally from direct deposition on the lake and its catchment rather than from acidification-mediated soil release