RADIOCESIUM TRANSFER TO MAN FROM MOOSE AND ROE DEER IN SWEDEN

Studies of radiocaesium in the forest ecosystems in Sweden resulted in aggregated transfer factors quantified for the transfer of Cs-137 from soil to moose and roe deer. These aggregated transfer factors were 0.02 m2 kg-1 for moose and 0.05 m2 kg-1 for roe deer. There seems to be no decrease in the Cs-137 activity concentrations in moose harvested in our research area and therefore we suggest the use of the physical half-life of Cs-137 (30 years) as the effective ecological half-life. The time-integrated transfer of Cs-137 from the Chernobyl fall-out to man by moose in Sweden was calculated and found to be 115 GBq, corresponding to 1500 man Sv for moose. The time-integrated transfer by roe deer to man was estimated to be between 25-48 GBq, corresponding to 327-620 man Sv for roe deer. The annual transfer of Cs-137 to man by moose has varied between 2.0-2.7 GBq, corresponding to 27-34 man Sv. Depending on the group studied, the mean annual transfer of Cs-137 can be calculated to be from about 250 to 43000 Bq. For example, the mean annual transfer of Cs-137 by moose to hunters and their families in Gavle commune, the most affected commune in Sweden, was estimated to be about 26000 Bq, corresponding to 0.34 mSv.