Global transport rates of 137Cs and 239+240Pu originating from the Nagasaki A-bomb in 1945 as determined from analysis of Canadian Arctic ice cores

Abstract

Recent advancements in analytical technology make it possible for artificial radionuclides released from nuclear explosions to be detected in Arctic ice core layers. The fission product, 137Cs, and the unexpended fission material, 239+240Pu, originating from the Nagasaki A-bomb of August 1945, were measured by collecting 10 ice cores on the Agassiz ice cap, Ellesmere Island, Canada. The deposition rates were 0·020 mBq cm -2 for 137Cs and 0·0016 mBq cm -2 for 239+240Pu, originating from Nagasaki. Assuming the radionuclides, excluding the amount fissioned from the explosion and deposi-ted as local fallout, are deposited evenly throughout the Northern Hemisphere, 67% of the expected amount of 137Cs reached the Arctic while 1·1% of 239+240Pu reached the Arctic. The results suggest that different transport mechanisms exist for various contaminants in the global transport system.