Land use influence on Cs-137 levels in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.)

The environmental influence on Chernobyl-derived (137)Cs levels in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) was revealed using partial least-squares regression (PLS). The 53 environmental predictors used describe land use in catchment areas, various catchment area and lake characteristics, lake water chemistry, and fish stock composition. The study showed a profound effect of land use on the (137)Cs levels in fish. Radiocaesium deposited on arable land was retained in the soil to a greater extent than was (137)Cs deposited on wetlands, which more easily leached out to the lake ecosystems. The (137)Cs deposition close to the lakes had a more pronounced effect on (137)Cs levels in the fish than did more distant deposition. The radiocaesium bioavailability is mainly governed by lake water cation content, as hardwater lakes had significantly lower (137)Cs content in fish. Resuspension of (137)Cs contaminated sediments only had a limited influence on the observed levels in fish. (C) 2001 Elsevier Science Ltd. All rights reserved.