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

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 ( ⁹⁰Sr and ¹³⁷Cs) and natural radionculides ( ⁴⁰K, ²¹⁰Pb and ²²⁶Ra), 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 ⁹⁰Sr in muscle was below the detection limit of 0.14Bqkg ^-1 and ¹³⁷Cs concentration in bones was below the detection limit of 0.15Bqkg ^-1. ¹³⁷Cs activity varied over an order of magnitude in caribou muscle samples with an average value of 2.5Bq/kg wet wt. Average ¹³⁷Cs activity in muskoxen muscle was found to be 9.7Bq/kg wet wt. However, there were a little variation (less than 60%) in ²¹⁰Pb, ⁴⁰K, and ²²⁶Ra in both muscle and bone of both caribou and muskoxen. The activities of total ²¹⁰Pb in caribou and muskox bones were found to be 1-2 orders of magnitude higher than that of parent-supported ²¹⁰Pb indicating the potential for dating of bones of terrestrial mammals (time elapsed since the death of the animal) based on the excess ²¹⁰Pb method exists. In fish muscle samples, ¹³⁷Cs activity varied from below detection limit to 154mBq/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, ²¹⁰Pb activities varied almost an order of magnitude; however, ⁴⁰K and ²²⁶Ra activities varied less than a factor of two. Total annual effective dose due to ⁹⁰Sr and ¹³⁷Cs from the ingestion of those terrestrial and marine meats was estimated to be negligible (ca. 9μSV/a) compared to the natural radionuclides present thus posing negligible radiological threat to humans.