On the transport of Chernobyl radioactivity to Eastern Canada

A large number of radionuclides released by the Chernobyl nuclear reactor were detected in air and river water samples collected in the Quebec region of eastern Canada. Analysis of the data supports the view that three waves of airborne radioactivity entered eastern Canada between 6 May 1986 and the end of June 1986. The first two waves would have followed an Arctic route and arrived over Quebec on 6 May and around 14 May respectively. The third wave would have been carried by the prevailing winds across the Pacific Ocean and arrived over Quebec around 25-26 May. On 25 June and thereafter. Chernobyl radioactivity was undetectable in our air filters but was still being detected in the St Lawrence river in March 1987. (author)