The team analysed the sediment profiles along 190 kilometres of the Spree from the Spreewald to the estuary. Even 90 kilometres downstream, the influences of open-cast mining could be detected. However, the substances are transported and deposited differently due to their individual properties and chemical reactions.
The amounts of iron and trace metals decreased with increasing distance in the sediment while sulphate concentrations remained high even along the 190 kilometres. Nickel and cobalt are co-precipitated with iron and bound in the sediment – so their concentration decreased faster along the river. The strongly diminished but still present mining signature in urban Berlin is replaced by an urban signature characterised by high levels of zinc, chromium, lead, and copper.
Polluted sediments can influence material cycles and living organisms
"Our measurements show that the sediments from the Spree are enriched with iron, nickel and cobalt. This can affect living organisms in the river," expresses Giulia Friedland, first author of the study. "The input of iron into the sediment can also influence material cycles, such as the availability of phosphorus and turnover processes of organic carbon," adds Michael Hupfer, who led the study.
The study took place within the framework of the GRS microcluster "Signatures of highly disturbed landscapes – a case study of post-mining landscapes", in which the BTU Cottbus-Senftenberg and the IGB jointly train doctoral students.
The video shows the River Spree from the source in Saxony to the mouth in River Havel. It gives an introduction to anthropogenic impacts (lignite mining and urban influences) on River Spree and field work methods (water and sediment sampling) frequently used by our Department of Chemical Analytics and Biogeochemistry.