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.
Great Lakes Mercury Connections distills
key results from 35 new peer-reviewed
papers accepted in special issues of
two scientific journals
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
, published in
Springer's journal Ecotoxicology
. Also, new research indicates
that for some species of fish and wildlife in particular areas, mercury
concentrations may again be on the rise.
While the risk of elevated mercury concentrations to human health is
well known—all of the Great Lakes states and the province of Ontario
issued fish consumption advisories due to high mercury—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
and chief scientist 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. For example, we found that estimated mercury
concentrations in the blood of common loons were above levels that are
associated with at least 22 percent fewer fledged young in large areas
of the Great Lakes study region."
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).
"One of our core missions is to support the policymaking process
with good science," says Tim Eder, executive director of the Great Lakes
Commission. "This report represents a wealth of scientific knowledge
developed by some of North America's leading experts in this field. It
portrays the most accurate and well-documented picture yet of the impact
of mercury contamination on the Great Lakes environment."
The research details how mercury pollution is changing over time.
"When we analyzed lake sediments, we were surprised to see such a strong
connection between mercury loadings to the region and mercury emissions
in the region," says Charles Driscoll, Ph.D., University Professor of
Environmental Systems Engineering at Syracuse University and
co-principal investigator on the project. "We documented a 20 percent
decline in sediment mercury deposition from peak values around 1985.
This decline was concurrent with a 48 percent decline in mercury
emissions from sources in the Great Lakes region and a 17 percent
increase in global emissions, clearly illustrating the benefit of
controlling domestic emissions. It is likely that additional national
and regional air emission controls would result in further declines in
mercury contamination of the Great Lakes region as well as other areas
of the U.S. and Canada." Among other findings, the report points out
that the northern reaches of the Great Lakes region are particularly
sensitive to mercury and that, despite improvements, fish mercury
concentrations remain above the EPA human health criterion in these
"The decline in mercury contamination of fishery resources across
much of the Great Lakes region is very welcome news," says James G.
Wiener, Ph.D., Wisconsin Distinguished Professor at the University of
Wisconsin-La Crosse, and co-principal investigator in the study.
"However, the fish in many of the region's inland lakes and rivers
exceed important human and environmental health thresholds. For
instance, we looked at six commonly eaten game fish and found that
average mercury concentrations in these fishes exceeded the EPA human
health criterion in 61 percent of the study region." Dr. Wiener further
noted that some long-term mercury trends appear to be changing. "The
observations of recent increases in mercury concentrations in some fish
and wildlife populations in the region is also cause for concern,
because we do not understand why these increases are occurring."
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."
Great Lakes Mercury Connections has been officially released Tuesday, October 11 in Detroit at the Great Lakes Commission's 2011 Annual Meeting, and the
opening day of the first-ever "Great Lakes Week" event. Great Lakes Week
is bringing together representatives of the U.S. and Canadian
governments along with public and private groups to focus on finding
solutions to the most pressing environmental and economic challenges
facing the lakes.
Source: The above story is reprinted (with editorial adaptations) from materials provided by Springer Science+Business Media, via AlphaGalileo.
Biodiversity Research Institute
University of Wisconsin-La Crosse
Great Lakes Commission
BRI Report: Great Lakes Mercury Connections (distills key results from 35 new peer-reviewed papers accepted in special issues of two scientific journals:
Ecotoxicology, Vol. 20, No. 7 (October 2011). Special issue: Mercury in the Great Lakes. Guest editors: Evers DC and Wiener JG
United Nations Environment Programme (UNEP): Reducing Risks from Mercury
European Commission: Environment: Mercury
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last time modified: October 15, 2011