The Dynamics of the Transfer of Caesium-137 to Animal Fodder in Areas of Russia Affected by the Chernobyl Accident and Resulting from the Consumption of Milk and Milk Products

Abstract

Data on the concentration of ¹³⁷Cs in animal fodder from collective farms in Russia on which no countermeasures were applied following the Chernobyl accident have been evaluated for the period 1987 to 1994. The aggregated transfer factor (Bq.kg^-1 per Bq.m^-2) was found to increase in the order fodder beet < maize < perennial grasses < natural grasses and decreased with increasing clay content in the soil. Effective half-lives for ¹³⁷Cs of between 1 and 3 years have been calculated for the period up to 1989. From 1989 onwards the data are somewhat more variable and effective half-lives between 3 and 10 years are observed. Mean individual effective doses in 1987 from the consumption of milk and milk products produced from cattle fed on a typical diet of fodder crops produced on sandy soils are calculated as 3.1, 3.3 and 4.0 µSv per kBq.m^-2 for Russia, Belarus and the Ukraine respectively, with 95% confidence intervals for the three Republics jointly of 2.2 to 6.0 µSv per kBq.m^-2. The corresponding values are some three times higher for production on peat soils and about ten times lower in the case of clay soils.