The scope and intensity of mercury pollution in the Great Lakes region is much greater than previously reported, but additional mercury controls should bring needed improvement, according to a new summary of scientific research on the subject.
Despite general declines in mercury levels in the Great Lakes region over the past four decades, mercury concentrations still exceed human and ecological risk thresholds, especially in inland lakes and rivers, according to the report Great Lakes Mercury Connections: The Extent and Effects of Mercury Pollution in the Great Lakes Region, which summarizes 35 new scientific papers. Also, new research indicates that for some species of fish and wildlife in particular areas, mercury concentrations may again be on the rise.
New studies cited in the report suggest that adverse effects of mercury on the health of fish and wildlife occur at levels much lower than previously reported.
"The good news is that efforts to control mercury pollution have been very beneficial," says David C. Evers, Ph.D., executive director at Biodiversity Research Institute, and the principal investigator in the Great Lakes study. "However, as we broaden our investigations, we find that fish and wildlife are affected at lower mercury concentrations and across larger areas, and that impacts can be quite serious."
Great Lakes Mercury Connections distills key results from 35 peer-reviewed papers in special issues of two scientific journals: Ecotoxicology and Environmental Pollution. The report represents the work of more than 170 scientists, researchers, and resource managers who used more than 300,000 mercury measurements to document the impact and trends of mercury pollution on the Great Lakes region.
A collaboration of the Biodiversity Research Institute in Gorham, Maine, the Great Lakes Commission based in Ann Arbor, Michigan, and the University of Wisconsin-La Crosse, the project is the product of a binational, scientific synthesis sponsored by the Commission through its Great Lakes Air Deposition Program, funded by the U.S. Environmental Protection Agency (EPA).
Atmospheric emissions are the primary source of mercury deposition in the Great Lakes basin; the report projects that further controls on those emissions "are expected to lower mercury concentrations in the food web, yielding multiple benefits to fish, wildlife, and people in the Great Lakes region."