CONTENT AND DISTRIBUTION OF Cs-137 IN ORGANS AND TISSUES OF THE RIVER OTTAR INHABITING THE TERRITORY OF THE BELARUSIAN SECTOR OF THE CHERNOBYL NUCLEAR POWER PLANT EXCLUSION ZONE

This study has been conducted for the first time (from 2016 to 2024). Previously, no studies on the content and distribution of Cs-137 in the organs and tissues of the river otter in biotopes on the territory of the Polesie State Radiation and Ecological Reserve were conducted. Radiation and ecological monitoring of the reserve includes observation and control of the state of the near zone of the Chernobyl NPP contaminated with radionuclides, obtaining basic information for assessing and forecasting the general radioecological situation. Radionuclides that entered the external environment were actively involved in biological migration chains, due to which radionuclides began accumulating in the organs and tissues of animals inhabiting natural biogeocenoses. Our studies show that the river otter is characterized by a tendency – the higher is the density of contamination in the territory, the higher the content of 137Cs in tissues and organs. In the Borshchevka and Krasnosel'ye biotope, a high 137Cs content in the river otter is observed in muscle tissue (2070±301.1 Bq/kg) and fur (1867±421.6 Bq/kg), and a low one in the liver (259±74.1 Bq/kg). In the Kulazhina biotope, a high 137Cs content in the river otter is observed in muscle tissue (3201±402.6 Bq/kg) and fur (2041±333.5 Bq/kg), and a low content is in the liver (546±101.1 Bq/kg). In the Khvoshchevka and Vyura biotope, a high 137Cs content in the river otter is observed in the liver (1246.39±202.2 Bq/kg) and muscle tissue (893±104.4 Bq/kg), and a low – in the fur (523.5±120.8 Bq/kg) and lungs (427.5±113.7 Bq/kg). In the Orevichi biotope, high 137Cs content in the river otter is observed in the kidneys (2771±430.3 Bq/kg) and liver (2571±301.1 Bq/kg), and low – in the adrenal glands (890±190.5 Bq/kg). In the Semennitsa biotope, a high 137Cs content in the river otter is observed in the endocrine glands (744±175.2 Bq/kg) and muscle tissue (645±105.4 Bq/kg), and a low – in the lung (207±81.3 Bq/kg).