137Cs in fish of some lakes and rivers of the Bryansk region and north-west Russia in 1990–1992

Abstract

The 137Cs content was measured in the muscle tissue of different fish species from several lakes and rivers in the western Bryansk region (a zone of heavy radioactive pollution after the Chernobyl accident) and in lightly contaminated territories: the Vologda region and Karelia. The highest levels of 137Cs (up to 15 000–21 000 Bq/kg wet weight) were observed in crucian carp from Kozhany reservoir in the Bryansk region. The potassium content in water of this reservoir in low (0.4–1.4 mg/litre), and the level of 137Cs fallout in its vicinity was the highest in the Bryansk region (at about 1500 kBq/m 2). The minimum levels of 137Cs (2–3 Bq/kg w.w.) were found in fish of the Upper Volga basin. Fish from lakes generally contained more 137Cs (up to about ten times) than those from rivers, both in the heavily contaminated zone and in the lightly contaminated regions. The range of values (in Bq/kg w.w.) was: 2–10 in rivers of the upper Volga basin, 30–200 in lakes of north-west Russia (with a low potassium content in the water), 100–2300 in the Iput river (Bryansk region), and 200–21 000 in lakes of the Bryansk region. Between 1990 and 1992 there was no significant general decrease of 137Cs content in fish.