[en] This paper presents the results of radioactivity studies of environmental factors such as surface water, sediment, aquatic vegetation and soil. The concentrations of ¹³⁷Cs, ⁹⁰Sr, ³H, U, Ca and Mg in water samples were determined by radiochemical and chemical methods. Gamma-spectrometric analyses were performed for all the samples. The analysis showed a decrease in concentrations of ¹³⁷Cs in water, aquatic vegetation and sediment, but a constant level of ¹³⁷Cs activity in soil (0-5 cm depth). The average concentrations of ⁹⁰Sr, ³H, U Ca and Mg were about 7 mBq/l, 11 Bq/l, 0.6 μg/l 60 mg/l and 11 mg/l, respectively. (author) 12 refs.; 7 figs.; 3 tabs