Transfer of 137Cs into fish in small forest lakes

The transfer of 137Cs into fish in seepage and drainage lakes from 1988 to 1992 was analysed using linear regression. Empirical results for 137Cs in lake water and fish were used to calculate concentration factors (CFs). In the drainage lakes the CF decreased during the study period by 9% per year whereas in the seepage lakes the CF increased significantly by 4.3% per year. The transfer of 137Cs into pike was significantly (1.6 times) higher than that into perch. The CF increased on average by 3.4% for each 1-cm increase in the median size of perch. The relationship between the water chemistry and the CF differed between clear-water seepage and brown-water drainage lakes.