Electron Paramagnetic Resonance Measurements of Lifetime Doses in Teeth of Durham Region Residents, Ontario

Abstract

Abstract The Canadian Nuclear Safety Commission (CNSC) and Ontario Power Generation (OPG) determined the total dose contribution of nuclear power plants in Durham Region populations by analyzing environmental samples from the surrounding areas of both nuclear generating stations (Pickering and Darlington). However, the total doses from the various sources were unknown in Durham Region populations, Ontario. Electron paramagnetic resonance (EPR) dosimetry with tooth enamel has been successfully established as an effective tool for gamma dose assessment for chronic and acute exposures in individuals, groups, or populations to reconstruct the absorbed dose down to 30 mGy. This study collected the extracted teeth from people of different ages in Durham Region, Ontario, and analyzed them using the x-band continuous wave (CW) EPR spectrometer. The total dose rate from the natural and anthropogenic sources was 1.9721 mSv y−1. The anthropogenic dose rate from the various sources was 0.6341 mSv y−1, about 47.39% of the natural background dose (1.338 mSv y−1) in Durham Region, Ontario. The combined anthropogenic doses from these sources were lower than the local background dose in Durham Region and lower than the regulatory annual effective dose limit of 1 mSv y−1 in Canada. Based on these data, this study concluded that the anthropogenic dose contribution was lower than the regulatory limit to the local populations.