Cesium-137 distribution patterns in bottom sediments of beaver ponds in small rivers in the north of the Volga upland, European Russia

Abstract

Bottom sediments of beaver ponds in small rivers of the study region are accumulators of artificial radioisotopes, in particular cesium-137. The concentration of artificial radioisotopes is directly proportional to the content of organic matter in these sediments, the flow of dead organic matter to the bottom of the ponds themselves and to their coastal zone. The research also shows that the average concentration of cesium-137 in the bottom sediments of beaver ponds is many times less than its average content in the soils of near-water-divide surfaces of the interfluves of the studied rivers that are not affected by the processes of their erosive washout. These soil concentrations of 137Cs reflecting their regional level after atmospheric fallout following global nuclear weapons tests and, above all, the Chernobyl accident in 1986. The indicated ratio of radiocesium concentrations in soils Water 2025, 17, 503 17 of 21 and bottom sediments is valid only relative to modern beaver ponds formed in the last one and a half to two decades