[Assessment of factors determining the dynamics of pollution by Cs-137 of agricultural production after the Chernobyl AES accident].

Analysis of the dynamics of 137Cs content in the main kinds of plant and animal products obtained on the basis of a separate farm located at 40-50 km to the north from Chernobyl NPP has shown that in 1987-1991 the decrease of 137Cs transfer from soil to agricultural crops was on the average 2--4-fold, and for milk--6--7-fold during the pasture period and 10-fold--during stabling one. The half-life periods of decrease of 137Cs constant in the main kinds of plant production vary from 2.1 to 5.9 years; for milk this parameter equals to 1.4 years in the pasture period, and in the stabling one--2.8 years. The main contribution (67-80%) to the decrease of 137Cs transfer to plant products is made by biogeochemical processes causing decrease of mobility of 137Cs in soil; as for agrochemical countermeasures, these contribute 20--33%. Decrease of contamination of milk, on the contrary, is mainly due to realization of countermeasures--contribution of the latter reaches 60%.