Radiocesium in Canadian game Birds Harvested during 1989-95

A historic data set containing unpublished measurements of ¹³⁷Cs (radiocesium) in 238 pooled samples of pectoral muscle from 1892 birds representing 37 species was analyzed in order to determine if (i) birds were contaminated due to global weapons fallout and/or the Chernobyl accident, (ii) to understand baseline ¹³⁷Cs levels in birds across the country by examining potential effects of trophic position and geophysical region, and (iii) to determine if the harvested birds were safe to eat. Current work is taking advantage of this data set to improve capabilities to assess the impacts of releases of radionuclides on food chains of species harvested as country food. Samples obtained from 173 locations across Canada (including locations in the Arctic), mostly during the fall hunting seasons between 1989 and 1995, were analyzed by gamma spectrometry and decay-corrected for the date of collection. Various methods of correlating measurements with environmental ¹³⁷Cs levels and species' habits were explored in order to determine environmental radiological transfer factors. All ¹³⁷Cs measurements in the samples were much lower than the Health Canada (2018) guidance level for ¹³⁷Cs (1000 Bq kg^-1); therefore, there was no evidence of a human health risk with respect to radiocesium. Environmental transfer factors for six different foraging groups were determined.