Estimate of the dose due to 90Sr to the Austrian population after the Chernobyl accident.

In order to estimate the contribution of 90Sr to the exposure of the Austrian population, the ratio of 90Sr to 137Cs in 126 food samples and nine drinking water samples was determined. From this and the average activity concentration of 137Cs in each type of food as obtained by the measurement of some 100,000 food samples after the Chernobyl accident, a good estimate of the average activity concentration of 90Sr in these food items could be obtained. Samples were investigated at various times after the accident to take into account possible changes with time in the 90Sr-activity concentration and its ratio to 137Cs. Also, pre-Chernobyl samples were measured to estimate the relative contribution of the reactor accident and the fallout of the atomic bomb testing to the intake of 90Sr. Assuming average food consumption, the intake of 90Sr for an adult person amounted to 168 Bq in the first year and 115 Bq in the second year after the accident, resulting in an effective dose equivalent of 5.9 muSv and 4.0 muSv, respectively. This is a minor fraction of the dose due to the ingestion of Cs isotopes, which amounted to 360 muSv in the first year and 97 muSv in the second year. For the one-year-old infant, a 90Sr intake of 96 Bq (10.5 muSv) in the first year and 65 Bq (7.1 muSv) in the second year is estimated. Approximately 50% of the intake in the first year and 70% of that in the second year are due to 90Sr from nuclear weapons testing.