Abstract

In a large-scale investigation the decrease of the activity concentration of 137Cs in foodstuffs after the widespread Chernobyl fallout was determined. At different times after the deposition in 1986 more than 1000 samples of various foodstuffs in Austria were taken and investigated with regard to their activity concentration. The investigation showed that in the first year after deposition, the activity concentration decreased to about 6-10% (milk, fruit), and 3-6%, respectively (grain, potatoes, vegetables) of the values in the fallout maximum. The calculated effective half-lives are significantly shorter than observed after nuclear weapon test series and result in a smaller long-term exposure than estimated before. The effective ingestion dose in the 50 years following of a one-time nuclear fallout amounts to about 1.3 times of the first year ingestion dose. In 2002, the ingestion dose in Austria amounts to 2.24 microSv (adult), or 0.88 microSv (5-year infant) respectively, which is less than 0.5% of the ingestion dose of the first year and amounts to 0.7% of the ingestion dose from natural radionuclides.