Fallout and exposure of the population in Austria after the Chernobyl accident / Fallout und Exposition der Bevölkerung in Österreich nach dem Reaktorunfall in Tschernobyl

Abstract

The fallout situation in Austria after the Chernobyl accident is described and compared to that in neighboring countries. The plume from the destroyed power plant caused an exposure of the population in the first year of 0.55 mSv on the average, of which about 0.1 mSv were caused by external exposure, 0.03 mSv by inhalation, and 0.42 mSv by ingestion. Despite these low exposure values several measures were adopted in Austria, the effects of which are given in this paper. Only three measures (feeding restrictions for fresh grass, a ban on marketing fresh vegetables, and selection of low-activity milk in dairies) resulted in substantial dose reduction effects of about 30% of the total exposure to be expected. The time course in activity concentration in foodstuffs relevant to countermeasures is described. Also, the differences in exposure of the population by ingestion as estimated from foodstuff and whole body measurements is discussed. The decrease in activity concentration in foodstuffs after the direct contamination phase, which is characterized by an effective half-life of about 2 years in the period up to now, is discussed. This decrease in Cs availability results at present in an exposure of approximately 0.5% of initial values, equivalent to about 5 μSv per annum or approximately 0.15% of the natural background radiation exposure in Austria