The fallout in Sweden of radiocesium from nuclear weapons tests during the 1960's (137Cs) and from the Chernobyl accident in 1986 (134Cs and 137Cs) has transferred to humans through different ecological pathways. Data from whole-body burden measurements of 134Cs, 137Cs, and 40K in various Swedish populations between 1964 and 2002 have been compiled. This database enables an evaluation of the temporal and geographical dependence of the transfer of radiocesium from ground deposition to humans and the associated absorbed dose. The body burdens of 137Cs gradually decrease after the peak values reached in 1965 from nuclear weapons fallout and in 1987 from the Chernobyl fallout, but at a varying rate depending on the population. Assuming a dual exponential decrease, a short-term component of typically 1–2 y and a long-term component of 5–10 y are found in urban populations in Sweden. Among reindeer herders and hunters the effective ecological half-time is mono-exponential with a half-time of 5–7 y. The estimated time-integrated effective dose to an individual during a period of 50 y from the Chernobyl fallout is, on average, approximately 10 mSv for reindeer herders, which is 10–100 times higher than the estimated dose received by urban populations in the three major Swedish urban areas (Malmö, Göteborg, and Stockholm).
* Department of Radiation Physics, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden; † Swedish Radiation Protection Authority, SE-171 16 Stockholm, Sweden; ‡ Swedish Defence Research Agency, SE-901 82 Umeå, Sweden; § Department of Radiation Physics, Göteborg University, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
For correspondence or reprints contact: Christopher L. Rääf, Department of Radiation Physics, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden, or email at email@example.com.
(Manuscript received 13 June 2005; revised manuscript received 29 July 2005, accepted 29 November 2005)