EXPOSURE OF CANADIAN ABORIGINAL PEOPLES TO METHYLMERCURY

Aboriginal peoples living a traditional lifestyle are potentially exposed 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 native communities across Canada. Of these, 8,847 individuals (23%) had blood, or blood equivalent, MeHg levels greater than 20 mu g/l and 608 (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 produce a definitive diagnosis. In an attempt to ascertain fetal exposure, 2,405 umbilical cord blood samples were taken. In about half of these cases the samples were paired with maternal levels. Of the cord samples 523 (21.8%) were found to have levels discussion of the assessment of risk from exposure to MeHg in this population is presented as are the initial results of the 20 year retrospective analysis including seasonal exposure patterns and trends in exposure levels. Probable future intiatives based on this analysis are noted.