Coloured rain dust from Sahara Desert is still radioactive

A coloured rain event originating from the Sahara Desert occurred on April 9, 2000 at Thessaloniki, Northern Greece (40°38′N, 22°58′E). The radioactive nuclides that were determined in a coloured rain dust sample were 137Cs of Chernobyl origin, 7Be of cosmogenic origin and 40K of terrestrial origin. Cesium-137 still remained 14 years after the Chernobyl accident, reaching 26.6 Bq kg−1 in the coloured rain dust.