NY Times op-ed

[Guest guest]

April 26, 2007

Op-Ed Contributors

The Danger Downwind

By DAVID C. EVERS and CHARLES T. DRISCOLL Jr.

IN 2005, the Environmental Protection Agency took its first

important step toward reducing mercury pollution from coal-fired

power plants. Its Clear Air Mercury Rule is intended to bring about

a 70 percent reduction in mercury emissions over the next 20 years.

But the new rule does not require all plants to reduce emissions by

the same amount. Some may be allowed to pollute more than others by

buying pollution credits from other plants.

The E.P.A.'s faith in this " cap and trade " approach is based on the

assumption that mercury pollution disperses evenly in the

environment. This strategy has worked well in reducing emissions of

sulfur dioxide, a component of acid rain. But mercury does not

behave in the same way as acid rain. In fact, much of the mercury

emitted by coal-fired power plants remains near those plants.

In a just completed 10-year study of birds, fish and mammals in the

northeastern United States and southeastern Canada, we found five

places where fish and wildlife have exceptionally high

concentrations of mercury in their blood. Under the E.P.A.'s new

rule, these biological mercury " hot spots " could persist, with

dangerous consequences for the health of people and wildlife.

For more than a century, mercury pollution has blanketed much of the

United States. Coal-fired power plants and other sources emit

mercury into the atmosphere, where it is carried with the wind and

deposited onto the ground. On land, particularly in wetlands,

mercury can change to a form known as methyl mercury, which readily

accumulates in organisms.

Methyl mercury is taken up by microscopic plants and animals, which

are then consumed by fish and other animals. As it moves up the food

chain, methyl mercury increases in concentration as much as 10

million times. Animals at the top of the chain that consume lots of

tainted fish — common loons, bald eagles, river otters and some

humans — are exposed to methyl mercury in amounts high enough to

cause neurological damage, behavioral abnormalities and reproductive

problems.

Children are particularly at risk for mercury poisoning. Some

200,000 to 400,000 children born in the United States each year have

been exposed to mercury levels in their mothers' wombs high enough

to impair neurological development, according to an analysis of data

gathered from 1999-2002 by the National Health and Nutrition

Examination Survey.

To reduce this exposure, the E.P.A. must monitor, and work to

eliminate, mercury hot spots.

Within one hot spot we found in western Maine, 43 percent of the

adult loons had blood mercury levels higher than 3.0 parts per

million — three times as much as loons tested from remote Alaskan

lakes, and high enough to be poisonous. One loon had a blood mercury

level of 14.2 parts per million and showed visible signs of

poisoning, including an inability to dive and evade approaching

boats. In southern New Hampshire, in an area downwind of several

coal-fired power plants, mercury deposition is nearly five times

higher than E.P.A. estimates.

Environmental protection officials in New York, New Jersey,

Pennsylvania and several other states have adopted state emissions

plans that prohibit trading of mercury pollution credits. The E.P.A.

should likewise consider the real danger of biological mercury hot

spots. At the same time, the agency should create a national mercury

monitoring network to track how well its emissions limits are

working. (A bill that would establish such a network is before

Congress now.) This approach is the only way the agency can evaluate

the need for steeper and faster reductions in mercury emissions,

track how well its emissions limits alleviate hot spots and

ultimately protect the environment and human health.

C. Evers is the executive director of the BioDiversity

Research Institute, in Gorham, Me., and T. Driscoll Jr. is a

professor of environmental systems engineering at Syracuse

University.