Transfer of 137Cs from water to fish is not linear in two northern lakes

Abstract

Empirical data on the behavior of radionuclides in the biosphere are needed for validating radioecological models. In this study, data collected from two lakes in Northern Finland were used to investigate the transfer of 137Cs from lake water into fish during a 20-year period after the Chernobyl nuclear power plant accident. The results indicated that transfer of 137Cs in the food chains investigated is nonlinear: the water-to-fish concentration ratios (CRs) decreased with increasing 137Cs concentration in water. Major deviation from linearity (constant CR) commonly assumed in radioecological modeling was observed only at low 137Cs concentrations in water. Other findings of potential importance for radioecological models were that 137Cs concentrations were threefold higher in piscivores than in non-piscivores and that no differences in 137Cs uptake were found between the two piscivorous species (pike and perch) studied or between three non-piscivorous species (vendace, white fish, and roach) representing different feeding habits (planktivore, benthivore, and mixed diet).