Radiocaesium concentration factors of Chernobyl-contaminated fish: a studyof the influence of potassium, and "blind" testing of a previously developed model

The radiocaesium concentration factors (CF) of different fish species in 10 lakes in Russia, Belarus and Ukraine were measured between 6 and 11 yr aft er the Chernobyl accident. Clear inverse relations were observed between fi sh CF and lakewater K+ concentration. Perch (a predatory species) had CFs w hich were two times higher than non-predatory fish. No differences in CFs w ere observed between different species of non-predatory fish. An empirical model for the prediction of radiocaesium CFs in fish (Rowan & Rasmussen, 19 94) was blind-tested against our measurements. The model predictions, based on measurements of K+ and suspended solids concentrations in the lakewater , were in good agreement with measured values. Our observations, however, i mplied a stronger effect of K+ on CF than that used in the Rowan and Rasmus sen (1994) model. Further improvements in models could also be made by acco unting for the effect of fish size on CF. (C) 2000 Elsevier Science Ltd. Al l rights reserved.