Estimating recent sedimentation rates using 210 PB on the example of morphologically complex lake (Upper Lake Raduńskie, N Poland)

Upper Lake Raduńskie is a classical channel lake with a typical complexity of lake basin morphology. This study presents the results of 210Pb measurements in four cores of recent sediments taken from different parts of the lake. The unsupported 210Pb activity plotted on a logarithmic scale against the cumulative dry mass decreased almost linearly. Sedimentation rates were determined from the mean slope of the profile (CF:CS model). A diversity of calculated values was significant, the highest value was found in the core RAD02/6 located in the deepest part of the lake. Both 210Pb inventories and fluxes were higher than that expected from atmospheric fallout estimated for this part of Europe. Factors influencing differences between atmospheric fallout and sediment record may include inputs from the catchment and sediment focusing, which seems to be the main reason of sedimentation rates diversity in morphologically complex lakes.