Activity concentration measurements of selected radionuclides in seals from Canadian Arctic.

The activity concentrations of naturally occurring radionuclides (such as Ra, Pb and Po) and long lived Cs were measured in a total of 119 tissue samples (43 blubber, 43 liver, and 33 muscle samples) from 40 ringed seals and 4 bearded seals collected in the Arviat area of Canada during the fall of 2014. Activity concentration of Po was measured in all seal liver and muscle samples individually. The average Po activity concentrations were 25 ± 7.6 Bq/kg fresh weight (fw) in muscle and 211 ± 58 Bq/kg fw in liver for ringed seals, and 20 ± 6.1 Bq/kg fw in muscle and 231 ± 150 Bq/kg fw in liver for bearded seals. Due to insufficient sample material for most samples collected, gamma counting for radioactive caesium and radiochemical analysis for Ra and Pb were performed for pooled samples. Activity concentrations of Pb and Ra were generally below detection limits. While Cs activity concentration was not detectable, Cs activity concentration was detected in muscle and liver samples. On average, the Cs activity concentrations were 0.25 ± 0.05 and 0.12 ± 0.04 Bq/kg fw in muscle and liver samples of ringed seals, and 0.11 ± 0.02 and 0.10 ± 0.03 Bq/kg fw in muscle and liver samples of bearded seals, respectively. Neither Po nor Cs were detected in the blubber samples. This study confirmed that Po is the dominant contributor to radiation doses resulting from seal consumption. Man-made contaminant Cs only contributes less than 0.01% of the total ingestion dose obtained from Arviat seals.