Anthropogenic and natural radionuclides in caribou and muskoxen in the Western Alaskan Arctic and marine fish in the Aleutian Islands in the first half of 2000s

Abstract

A number of caribou and muskoxen samples from the western Alaskan Arctic and fish samples from the Aleutian Islands were collected between 1998 and 2006 and analyzed for anthropogenic (Sr-90 and Cs-137) and natural radionculides (K-40, (210)pb and Ra-226), as part of the radiological assessment for the regional subsistence hunting communities in the first half of 2000s. We examined the relationship between the activities of these nuclides with the size of the fish. In caribou samples, concentration of Sr-90 in muscle was below the detection limit of 0.14 Bq kg(-1) and Cs-137 concentration in bones was below the detection limit of 0.15 Bq kg(-1). Cs-137 activity varied over an order of magnitude in caribou muscle samples with an average value of 2.5 Bq/kg wet wt. Average Cs-137 activity in muskoxen muscle was found to be 9.7 Bq/kg wet wt. However, there were a little variation (less than 60%) in (210)pb, (40) K, and Ra-226 in both muscle and bone of both caribou and muskoxen. The activities of total Pb-210 in caribou and muskox bones were found to be 1-2 orders of magnitude higher than that of parent-supported Pb-210 indicating the potential for dating of bones of terrestrial mammals (time elapsed since the death of the animal) based on the excess Pb-210 method exists. in fish muscle samples, Cs-137 activity varied from below detection limit to 154 mBq/kg wet wt. and its content increased with the size of the fish due to its transfer through the food chain. Among the seven fish species investigated, Pb-210 activities varied almost an order of magnitude: however, K-40 and Ra-226 activities varied less than a factor of two. Total annual effective dose due to Sr-90 and Cs-137 from the ingestion of those terrestrial and marine meats was estimated to be negligible (ca. 9 mu SV/a) compared to the natural radio-nuclides present thus posing negligible radiological threat to humans. (C) 2011 Elsevier B.V. All rights reserved.