Spatial and vertical distribution of 137Cs activity concentrations in lake sediments of Turawa Lake (Poland)

The main objective of this research was to study the spatial and vertical distribution of Cs-137 activity concentrations in the bottom sediments of Turawa Lake 32 years after the Chernobyl fallout to investigate possible factors responsible for the post-fallout migration and accumulation of Cs-137 in the selected reservoir. The results demonstrated a strong relationship between the increasing Cs-137 and K-40 activity concentrations and the decreasing grain size of sediments. Significant amounts of Cs-137 were detected in the bottom sediments deposited in the deeper parts of the reservoir (especially near the dam). Therefore, this research showed that Turawa Lake can be an important trap for sediments polluted with Cs-137. Moreover, disturbed vertical distribution of Cs-137 activity concentrations in the sediment columns collected from the littoral zone of this lake was observed, which is probably related to the bottom erosion intensified by wind-wave action, bioturbations, and water-level fluctuations. In the profundal zone, the vertical distribution of Cs-137 activity concentrations was undisturbed, which indicates stable sedimentation conditions in this part of Turawa Lake.

Automated summary

The research revealed a negative correlation between Cs-137 activity concentrations and sediment grain size, with significant amounts of Cs-137 detected in the deeper parts of the lake bottom. Turawa Lake may serve as a significant trap for Cs-137 polluted sediments.