DISTRIBUTION OF CS-137(CS-134) IN LAKE-SEDIMENTS FROM MONDSEE (AUSTRIA) BEFORE AND AFTER THE CHERNOBYL ACCIDENT

Profile studies on lake sediments from Mondsee (Austria) show Cs-137-activities deposited during several days in May 1986 after the Chernobyl reactor accident, which are about 5-10 times higher than those caused by the atomic weapon tests during all the years since 1952. Remarkable differences occur between these both contamination events considering the areal distribution of the Cs-137 deposition at the lake bottom. Gammaspectroscopic measurements of the new Cs-137 content in the upper sediment layers - now marked additionally with Cs-134 - reveal different penetration depths down to 5 cm independent of the sedimentation rate at the same site.