Ecological Half-time of Radiocaesium From the Chernobyl Accident and from Nuclear Weapons Fallout as Measured in a South Swedish Population

INTRODUCTION The aim of this study was to investigate the time variation of the whole-body burden levels of Cs in a south Swedish population after the Chernobyl fallout in 1986 (1, 2) and to compare the results with data obtained from the same reference group during the 1960s and 70s (3, 4, 5), as well as with contemporary studies on other Swedish populations. Radiocaesium from the nuclear weapons fallout consisted almost solely of Cs (6) and it was estimated that the intake of dairy and beef products accounted for a large part of the Cs intake in the Lund reference group (4), which is in accordance with international observations (7). Between 1960 and 1980 the cumulated deposition of fallout Cs from atmospheric bomb tests was about 2 kBq m in the Lund region (8, 9), which is in reasonable agreement with results from similar latitudes in the northern hemisphere except for areas with very high precipitation (10, 11). The ground deposition levels from the Chernobyl fallout in the province of Skåne was typically 1 kBq m (9), which is low in comparison with most other regions in Sweden (11). Furthermore the aggregate transfer of caesium from soil deposition to man through the ingestion of contaminated foodstuffs was calculated based on detailed deposition data in the region (9) in combination with the results of in vivo concentration in the control group.