Projecting Fish Mercury Levels in the Province of Ontario, Canada and the Implications for Fish and Human Health

Fish mercury levels appear to be increasing in Ontario, Canada, which covers a wide geographical area and contains about 250 000 lakes including a share of the North American Great Lakes. Here we project 2050 mercury levels in Ontario fish, using the recently measured levels and rates of changes observed during the last 15 years, and present potential implications for fish and human health. Percentage of northern Ontario waterbodies where sublethal effects of mercury on fish can occur may increase by 2050 from 60% to >98% for Walleye (WE), 44% to 59–70% for Northern Pike (NP), and 70% to 76–92% for Lake Trout (LT). Ontario waterbodies with unrestricted fish consumption advisories for the general population may deteriorate from 24–76% to