Geographic and vertical distribution of Cs-137 in soils in Canada

Levels of Cs-137 from weapons fallout on non-cultivated soils in Quebec and in several northern sites elsewhere in Canada are presented. The activity of Cs-137 was measured at 33 sites. The superficial activity levels ranged from 701 to 5055 Bq/m2 with an overall mean of 2513 ± 1099 Bq/m2. The activities were found to be approximately normally distributed. The Cs-137 deposition levels peaked in Quebec around 54 ° north and they are correlated with precipitation rates. Their frequency distribution is closer to a normal rather than a lognormal distribution. The specific activities ranged from 0.2 to 212 Bq/kg with an overall mean of 38 ± 52 Bq/kg.