A study on the levels of radioactivity in fish samples from the experimental lakes area in Ontario, Canada.

Abstract To better understand background radiation levels in country foods, a total of 125 fish samples were collected from three lakes (Lake 226, Lake 302 and Lake 305) in the Experimental Lakes Area (ELA) in Ontario of Canada during the summer of 2014. Concentrations of naturally occurring radionuclides ( 226 Ra, 210 Pb and 210 Po) as well as anthropogenic radionuclides ( 134 Cs and 137 Cs) were measured. This study confirmed that 210 Po is the dominant contributor to radiation doses resulting from fish consumption. While concentrations of 210 Pb and 226 Ra were below conventional detection limits, 210 Po was measured in almost all fish samples collected from the ELA. The average concentration was about 1.5 Bq/kg fresh weight (fw). None of the fish samples analysed in this study contained any detectable levels of 134 Cs. An average 137 Cs level of 6.1 Bq/kg fw was observed in freshwater fishes harvested in the ELA, almost twice that of samples measured in the National Capital Region of Canada in 2014 and more than 20 times higher than the levels observed in marine fish harvested from the Canadian west coast in 2013 and 2014. However, it is important to note that the concentrations of 137 Cs in fish samples from these inland lakes are considered very low from a radiological protection perspective. The resulting radiation dose for people from fish consumption would be a very small fraction of the annual dose from exposure to natural background radiation in Canada. The results indicate that fishes from inland lakes do not pose a radiological health concern.