ATMOSPHERIC PARTICULATE AND XENON RADIOISOTOPES MONITORING OVER CANADA AND HEALTH IMPACT ESTIMATION BEFORE AND AFTER THE FUKUSHIMA NUCLEAR ACCIDENT

: This article presents the results of atmospheric radioactivity monitoring obtained by three Canadian radiation monitoring stations before, after and during Fukushima-Daiichi accident. It includes 210Pb, 212Pb and 7Be (naturally occurring radionuclides) and 131I, 132I, 129Te, 129mTe, 132Te, 134Cs, 136Cs, 137Cs and 133Xe (Fukushima contaminants). The maximum activity concentrations were in range of 2.3-3.7 Bq/m3 for 133Xe; 2.0-4.4 mBq/m3 for 131I in aerosol form; 0.27-0.83 mBq/m3 for 137Cs depending on monitoring locations. The effective inhalation and cloudshine dose due to the Fukushima contaminants for an adult was estimated in range of 0.8-1.1 × 10-4 mSv, out of which the proportions of 133Xe and 131I were in range of 64-83% and 15-33%, respectively. During this period, the dose resulting from exposure to naturally occurring radionuclides was estimated in range of 0.60-1.8 × 10-3 mSv, one order of magnitude higher than those of the Fukushima contaminants. The dose impact from exposure to the Fukushima contaminants was negligible.