EXPOSURE OF CANADIAN ABORIGINAL PEOPLES TO METHYLMERCURY

Aboriginal peoples living a traditional lifestyle are potentially expo sed to contaminants, such as methylmercury (MeHg), which bioaccumulate in aquatic ecosystems. A preliminary analysis of testing of Canadian indigenous people for MeHg from 1970 to 1992 is outlined. By December 1992, 71,842 tests of 38,571 individuals had been carried out in 514 n ative communities across Canada. Of these, 8,847 individuals (23%) had blood, or blood equivalent, MeHg levels greater than 20 mu g/l and 60 8 (1.6%) had levels over 100 mu g/l. Clinical examinations offered to all with levels greater than 100 mu g/l in blood, but were unable to p roduce a definitive diagnosis. In an attempt to ascertain fetal exposu re, 2,405 umbilical cord blood samples were taken. In about half of th ese cases the samples were paired with maternal levels. Of the cord sa mples 523 (21.8%) were found to have levels discussion of the assessme nt of risk from exposure to MeHg in this population is presented as ar e the initial results of the 20 year retrospective analysis including seasonal exposure patterns and trends in exposure levels. Probable fut ure intiatives based on this analysis are noted.