Evaluation of range of internal dose from 137Cs and 90Sr in milk and meat in Lithuania in 1965-2003

Abstract

One of the tasks of radiation protection is dose estimation for the population from different sources of exposure. The relevant source is daily food. Calculation of average annual effective dose caused by activity concentrations of 90Sr and 137Cs in milk and meat is based on the measured activity concentrations of 90Sr and 137Cs in milk and meat sampled in Lithuania and on the annual consumption. Dynamics of the dose was analyzed using correlation tests. Regression curves using 3-6 degree of polynoms show the decrease of the annual effective dose during period analyzed. 137Cs in milk causes higher dose than 90Sr, but regression curve is less complicated in case of 90Sr in milk. Dose caused by 137Cs in milk in 1986 reaches the maximum value (up to 30 µSv). Average annual effective dose caused by 137Cs in milk is in range of 5-7 µSv since 1990, caused by 90Sr in milk – in range of 5–6 µSv since 1972. Average annual effective dose caused by 137Cs in meat was higher than caused by 90Sr during 1965–2003. Since 1987 dose caused by 137Cs in meat is in the range 1–2 µSv, dose caused by 90Sr – less than 1 µSv since 1970. The increase of annual effective dose caused by the activity concentrations of 137Cs in the meat is observed during year 1986 (up to 4 µSv), but it is less than dose in the year 1966 (more than 8 µSv).