Dynamics of 137Cs concentrations in meat of farm animals in the districts of the Bryansk region affected after the Chernobyl acciden

Data on dynamics in 137Cs concentration in muscles of farm animals obtained by the organizations of the Ministry of Agriculture of Russia in the areas of the Bryansk region affected after the Chernobyl accident have not been practically generalized so far. The aim of this study was to analyse the data of radioecological monitoring of 137Cs content in meat of farm animals in the south-western districts of the Bryansk region subjected to intensive contamination after the Chernobyl accident. Materials and Methods: The data on the 137Cs concentrations in 27519 samples of farm animal meat collected by the organizations of the Ministry of Agriculture of Russia in the period from 1986 to 2013 were analysed. Determination of 137Cs in samples was carried out by gamma-spectrometric method. Results and Discussion: The dynamics of 137Cs content in animal muscle tissue were largely determined by the specific protective measures implemented in agricultural production. In the initial year following the accident, the average half-life was 116 days for beef and 99 days for pork. Between 1987 and 1992, the effective half-life ranged from 1.5 to 1.6 years. After 1993, the decline in 137Cs levels in animal muscles slowed significantly, with half-lives extending to 9.8 years for beef and 16.1 years for pork. The rate of contamination decrease differed between meat produced in the public and private sectors, as well as between beef and pork.