CALCULATION AND MATHEMATICAL-ANALYSIS OF ANNUAL MEAN EFFECTIVE DOSES DUE TO INTERNAL RADIATION IN CHILDREN OF THE KRASNOGORSK DISTRICT, BRYANSK REGION, RESIDING IN THE AREAS WITH DIFFERENT LEVELS OF RADIONUCLIDE CONTAMINATION WITH CS-137

Reconstructing the absorbed doses of external and internal radiation a nd determining the annual mean effective dose (AMED) is the requisite conditions for research analysis of the results of investigations of t he exposures of the population in the areas radioactively contaminated due to the Chernobyl accident. At present, internal radiation associa ted with the dietary intake of radionuclides makes a considerable cont ribution into the formation of AMED. In 1991-1993 field studies yielde d data on human radiation spectroscopy (HRS) in 2240 children of the K rasnogorsk District, Bryansk Region. Based on HRS measurements, calcul ation and mathematical analysis of AMED due to internal radiation were made. The empirical distribution of the number of children by the str ictly positive AMED due to internal radiation is (2)(chi) normally clo se to log-normal probability distributions. No clear-cut correlation e xisted between AMED due to internal radiation and the degree of soil r adionuclide contamination. In the areas whose soil is contaminated wit h Cs-137, less than 15 Ci/km. the mean AMED due to internal radiation is in the allowable range (as high as 0.5 mEq) or greater in the more contaminated areas. There are statistical deviations from the total me an AMED due to internal radiation in children born in some years (such as in 1991 and 1992), which is yet to be accounted for.