FALLOUT AND EXPOSURE OF THE POPULATION IN AUSTRIA AFTER THE CHERNOBYLACCIDENT

The fallout situation in Austria after the Chernobyl accident is descr ibed and compared to that in neighboring countries. The plume from the destroyed power plant caused an exposure of the population in the fir st 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 ingestio n. Despite these low exposure values several measures were adopted in Austria, the effects of which are given in this paper. Only three meas ures (feeding restrictions for fresh grass, a ban on marketing fresh v egetables, 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 foodstuff s relevant to countermeasures is described. Also the differences in ex posure of the population by ingestion as estimated from foodstuff and whole body measurements is discussed. The decrease in activity concent ration in foodstuffs after the direct contamination phase, which is ch aracterized by an effective half-life of about 2 years in the period u p to now, is discussed. This decrease in Cs availability results at pr esent in an exposure of approximately 0.5% of initial values, equivale nt to about 5 mu Sv per annum or approximately 0.15% of the natural ba ckground radiation exposure in Austria.