Mercury Contamination 'Hotspots' in the US Identified

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Hotspots of mercury contamination identified in eastern North America

Harmful levels of neurotoxin are detected in fish and birds

A US and Canadian research team surveying mercury contamination in

fish and birds in the northeastern United States and southeastern

Canada has identified five " hotspots " where concentrations of the

element exceed those established for human or wildlife health. The

team focused on levels of the potent neurotoxin in yellow perch and

common loons, but it also took into account contamination in other

fish, birds, and mammals. In addition to these hotspots in New

England, New York, and Nova Scotia, the researchers found

nine " areas of concern " in these regions and in Quebec and New

Brunswick. Findings from the team's analysis are summarized in the

January 2007 issue of BioScience.

The hotspots are believed to result from complex processes that move

atmospherically released mercury through the environment, and from

site-specific characteristics such as the high sensitivity of

wetlands and forested areas to mercury inputs. Local sources of

mercury are also significant. Although mercury is not directly

harmful at ambient levels, it is concentrated up to a millionfold

and chemically modified in aquatic food chains, resulting in

dangerous levels of methylmercury in some wildlife species. Fish

consumption advisories responding to mercury contamination exist in

all the states and provinces included in the study, and loons are

adversely affected by mercury levels they experience.

The hotspots have implications for " cap and trade " approaches being

implemented for regulation of emissions from coal-fired electric

power stations, which, along with municipal waste incinerators, are

major sources of mercury pollution. Cap and trade approaches seek to

reduce the total release of mercury but could lead to static or

increased emissions in some areas. Greater deposition of mercury

near areas that are highly sensitive to the element or that are

already affected by it could raise the risk to people and wildlife

that consume fish. There is reason to believe, however, that

lowering emissions can reduce risk: an analysis of levels of mercury

contamination over time in the Merrimack River watershed suggests

that lowered emissions reduced mercury levels in biota within a few

years.

The 10-member research team was led by C. Evers of the

BioDiversity Research Institute in Gorham, Maine. The study was

based on samples collected over four years by the Northeastern

Ecosystem Research ative and made use of 7311 observations for

seven species. The study report in BioScience is accompanied by an

overview article, written by T. Driscoll of Syracuse

University and colleagues, that summarizes current knowledge about

mercury contamination in the region; the authors conclude that

reductions in mercury emissions beyond those currently under way

will be needed to eliminate the element as a health risk to humans

or to populations of loons.

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BioScience publishes commentary and peer-reviewed articles covering

a wide range of biological fields, with a focus on " Organisms from

Molecules to the Environment. " The journal has been published since

1964. AIBS is an umbrella organization for professional scientific

societies and organizations that are involved with biology. It

represents some 200 member societies and organizations with a

combined membership of about 250,000.

The research articles in the January 2007 issue of BioScience are as

follows:

Mercury Contamination in Forest and Freshwater Ecosystems in the

Northeastern United States

T. Driscoll, Young-Ji Han, Celia Y. Chen, C. Evers,

Kathleen Fallon Lambert, M. Holsen, Neil

Biological Mercury Hotspots in the Northeastern United States and

Southeastern Canada

C. Evers, Young-Ji Han, T. Driscoll, Neil C. Kamman,

M. Wing Goodale, Kathleen Fallon Lambert, M. Holsen, Celia Y.

Chen, A. Clair, and