GORHAM, Maine â€“ 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). Hidden Risk: Mercury in Terrestrial Systems of the Northeast highlights the Instituteâ€™s scientific findings on high levels of mercury contamination in songbirds and bats throughout 11 northeastern states.
Hidden Risk is the most complete synthesis of songbird and bat mercury data in the Northeast published to date. This report documents, for the first time, elevated levels of mercury in a wide range of songbirds and bats living in a variety of terrestrial ecosystems in northeastern states from Maine to Virginia. Among the findings:
â€˘ 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;
â€˘ 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;
â€˘ 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.
Songbirds and bats, often referred to as insect eaters, are more accurately called invertivores because they eat a wide variety of invertebrate species such as spiders, snails, and worms, in addition to insects. â€śThe role of invertivores in the ecosystem has until now been largely ignored in mercury investigations,â€ť says Evers. â€śHowever, these species are more common, widespread, and sensitive to mercury contamination than previously known; studying the terrestrial food web can serve as an effective biological network of important indicators for people and wildlife.â€ť
Hidden Risk presents findings from at-risk habitats, and associated indicator species are identified based on the speciesâ€™ 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.
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 toxic effects of methylmercury may include both neurological and reproductive harm to wildlife, and to people who consume contaminated wildlife.
â€śWhile 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,â€ť says Tim Tear, New York director of science for the Conservancy. â€śResearch 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.â€ť
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.
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 pollutionâ€”in particular mercuryâ€”on nature and people.
Hidden Risk: Mercury in Terrestrial Systems of the Northeast and related materials are available online at http://www.briloon.org/hiddenrisk.
The mission of the Biodiversity Research Institute is to assess emerging threats to wildlife and ecosystems through collaborative research, and to use scientific findings to advance environmental awareness and inform decision makers. BRIâ€™s science programs include wetlands, mammal, raptor, waterfowl, migratory bird, marine bird, coastal bird, wildlife and renewable energy, and tropical programs. The Instituteâ€™s research efforts stretch throughout most of North and Central America, as well as across sites in South America, Russia, South Africa, and Europe. For more information visit www.briloon.org.
The mission of The Nature Conservancy is to conserve the lands and waters upon which all life depends. The Conservancy accomplishes its mission through a collaborative approach that links the dedicated efforts of a diverse staff, including more than 500 scientists located across the U.S. and in more than 30 countries around the world with many partners, including individuals, academic institutions, non-profit organizations, governments, and corporations. For more information, visit www.nature.org.
Contact Name: Deborah McKew
Telephone Number: (207)839-7600