Exposure to mercury in Canada: A multimedia analysis

A thorough assessment of Canadian exposure to mercury (Hg) has not been undertaken since 1970. A multimedia approach was used to update estimates of Hg exposure to members of the general population in Canada, based on currently available information. Adult Canadians have an estimated intake of all Hg species via all routes of 7.7μg/day (0.11μg/kg body weight/day), which equated to an absorbed dose of 5.3μg/day (0.076μg/kg bw/day). Fish consumption accounts for much of this exposure (27% of intake, 40% of absorbed dose), in the form of methylmercury. However, dental amalgam appears to account for a greater proportion of total Hg exposure than fish consumption. Exposure from amalgam was estimated for intake and absorbed doses (of Hg⁰) at 2.81 and 2.25μg/day, respectively. This represents 36% of total Hg intake and 42% of absorbed dose. Hg²⁺ arises principally from foods other than fish. Intake of Hg²⁺ by adults was determined to be 1.82μg/day and absorbed dose only 0.18μg/day. Exposures for four other age groups of the population were also evaluated.