Mercury accumulation, previously considered a risk for aquatic ecosystems, is also found in many wildlife species living on the land, according to a new report published by the Biodiversity Research Institute (BRI) in partnership with The Nature Conservancy (the Conservancy).
Background:
Mercury is a pollutant that is cause for concern at local, regional, and
global scales. While areas of high contamination (known as biological
mercury hotspots) may occur near mercury-emitting sources, often they do
not depending on the mercury species being present. Because mercury released into the atmosphere can circle the world
before being deposited, wildlife living in habitats located far from
point sources of mercury can still be at risk.
In the United States, mercury becomes an air pollutant largely through
emissions from coal-fired power plants; in some areas, cement plants and
mining related industries also add to mercury pollution. Airborne
mercury eventually returns to the earth in rain, snow, and fog droplets,
as well as in dry form. Under the right conditions, mercury is
transformed into methylmercury, an organic toxin that becomes magnified
as it is ingested up the food chain.
The human health effects of mercury contamination are well documented;
adverse effects include impacts on cardiovascular health, IQ, workplace
productivity, and motor control. Similarly, mercury negatively affects wildlife populations by hindering behavior and reproduction.
Past investigations have emphasized adverse impacts to fish-eating
wildlife, such as common loons, bald eagles, and river otters. Although great strides
have been made to reduce mercury released into the air and water from
human activities, the new BRI report illustrates that high levels of mercury persist in many wildlife species distributed across many habitat types.
The new BRI report:
Hidden Risk: Mercury in Terrestrial Systems of the Northeast
highlights BRI’s scientific findings on high levels of mercury
contamination in songbirds and bats throughout 11 northeastern states from Maine to Virginia. More than 50 researchers contributed to the information in this report,
which illustrates the continued interest in advancing our understanding
of the impacts of air pollution—in particular mercury—on nature and
people.
“While the risk of mercury to people is well known—there are more than
3,700 fish consumption advisories issued in the U.S.—we are still
learning about mercury’s effects on wildlife,” says David C. Evers,
Ph.D., BRI’s executive director and chief scientist. “Mercury
accumulation has many implications for the health and survival of
wildlife species across habitats, not just those that live and feed in
aquatic habitats. Our research has found that mercury concentrations in
animals that live in terrestrial environments are significant enough to
cause physiological and reproductive harm. This knowledge is creating a
major paradigm shift in ecotoxicological research, assessment,
monitoring, management, and policy.”
The Hidden Risk Report documents,
for the first time, elevated levels of mercury in a new group of animals—terrestrial invertivores—that until now has largely been ignored in mercury investigations. Among the findings:
- Current
environmental mercury loads have the ability to significantly reduce
reproductive success in several songbird species of conservation concern
in the northeastern U.S., including the saltmarsh sparrow and rusty
blackbird;
- Bats also build up significant body burdens of
mercury; individuals from multiple species from all 10 areas sampled in
the northeastern U.S. exceeded the subclinical threshold for changes to
neurochemistry;
- Mercury loading in songbirds is not only
restricted during the breeding season; for some species, such as the
northern waterthrush, high levels of mercury accumulate during migration
and in tropical wintering grounds.
Hidden Risk presents findings from at-risk habitats, and associated
indicator species are identified based on the species’ level of
conservation concern, relative abundance, and ability to build up
mercury in the body. The report demonstrates the significant costs of
mercury to wildlife that were not factored into previous cost/benefit
analyses.
“While air pollution impacts people and nature on public and private
lands, the good news is that when action has been taken to reduce
mercury emissions, the results are very promising,” says Dr. Timothy
Tear, New York director of science for the Conservancy. “Research has
shown that reduction in mercury levels do make a difference to
dramatically and quickly reverse mercury contamination trends in fish
and wildlife. Reducing this neurotoxin from the environment will benefit
wildlife and people.”
Hidden Risk outlines a number of management actions that can be taken
to reduce the mercury risk in various terrestrial ecosystems, ranging
from cleaning up legacy dump sites to reducing atmospheric deposition.
The U.S. Environmental Protection Agency (EPA) has recently finalized
the Mercury and Air Toxics Standards (MATS) Rule that requires
coal-fired power plants to update their mercury pollution control
technologies, and this report highlights the importance of tracking the
biological implications of this rule through better national and
international monitoring programs. The report also calls for the
establishment of critical loads for air-borne contaminants that are
based upon preserving healthy ecosystems. Critical loads identify the
maximum level of pollutant deposition that ecosystems can handle before
harmful effects occur.
Air pollution continues to be an important
area of environmental concern. The recent U.S. EPA MATS ruling and
release of the National Acid Precipitation Assessment Program Report to
Congress: An Integrated Assessment underscore the fact that although
efforts to reduce air pollution in the United States are working, there
is still much more work to be done.
Source: Adapted from
The Nature Conservancy
The cited and other related reports
D.C. Evers, A.K. Jackson, T.H. Tear and C.E. Osborne.
Hidden Risk: Mercury in Terrestrial Ecosystems of the Northeast. Biodiversity Research Institute. Gorham, Maine (2012) 33 pages.
C. Osborne, D. Evers, M. Duron, N. Schoch, D. Yates, O. Lane, D. Buck, I. Johnson, and J. Franklin.
Mercury Contamination Within Terrestrial Ecosystems in New England and Mid-Atlantic States: Profiles of Soil, Invertebrates, Songbirds, and Bats. BRI Report 2011-09.
Available from Researchgate G.M. Lovett, T.H. Tear. 2008.
Threats from Above: Air Pollution Impacts on Ecosystems and Biological Diversity in the Eastern United States.
The Nature Conservancy and the Cary Institute of Ecosystem Studies.
Related EVISA Resources EVISA Link database: Environmental cycling of mercury EVISA Link database: Environmental mercury pollution
Related EVISA News (newest first)
December 19, 2011: Anthropogenic Mercury Releases Into the Atmosphere from Ancient to Modern Time June 17, 2009: 'Surprisingly High Levels' of Methylmercury Contamination found in Groundwater May 3, 2009: Ocean mercury on the rise March 11, 2007: Methylmercury contamination of fish warrants worldwide public warning February 18, 2007: New research results suggest that mercury hotspots in the northeastern US are home made October 9, 2006: Linking atmospheric mercury to methylmercury in fish September 13, 2005: Regulating Mercury Emissions from Power Plants: Will It Protect Our Health? April 3, 2005: Dissension on the best way to fight mercury pollutionlast time modified: May 17, 2024
