Mercury rising

Published in The Post-Star (A1)
April 8, 2007

A recent study warns of widespread mercury contamination in the Adirondacks after scientists found high levels of the dangerous element in the picturesque wilderness and wildlife that personify the region.

"I do a lot of work in the Adirondacks, so I knew the concentrations were high. But to put all this together, and learn that 10 of the top 13 species of fish had average concentrations above the EPA guidance value — to me, that’s unbelievable!" said Charles Driscoll, a professor of civil and environmental engineering at Syracuse University. He led the mercury study, which includes the central Adirondacks on a list of five confirmed biological mercury hot spots in the Northeast.

Driscoll worked with scientists from Clarkson University and the Hubbard Brook Research Foundation, a New Hampshire-based nonprofit group that studies forest ecosystems. The team spent three years analyzing data from more than 6,800 observations of seven wildlife species in the Adirondacks and New England. The results, which were published in a January 2007 study called "Mercury Matters," shocked him.

Mercury is fairly harmless in its elemental form, but when it enters watersheds and lakes, it gets transformed into a much more mobile and toxic form called methyl mercury. Then it bioaccumulates, becoming more concentrated at higher levels of the food chain. As it moves from water, to plankton, to fish, to birds, methyl mercury can increase in concentration by a factor of up to 10 million, Driscoll said.

And when it gets into people’s bodies, mercury contamination has been linked to heart disease and reduced brain function.

Stressed species

In the central Adirondacks, researchers found that 25 percent of common loons have blood mercury levels that exceed the wildlife health threshold of 3.0 parts per million, putting the already fragile population at risk of further decline. Mercury accumulates in loons’ bodies from eating contaminated fish, and can cause brain lesions, spinal cord degeneration, difficulty flying and swimming and lowered reproductive success, according to the study.

"The loon already has a variety of stresses on it ... it doesn’t need this one," said John Sheehan, spokesman for the environmental group the Adirondack Council. He said New York state considers the loon "a species of concern," which is one step down from the endangered species list.

"It’s one of the signature species in the park. I can’t tell you how many tourists come back just for the opportunity to hear them at night," Sheehan said.

High mercury levels were also found in the flesh of yellow perch sampled from both the west and central Adirondacks, with concentrations averaging twice the health threshold. In addition to contaminating wildlife above it on the food chain, like loons, this poses a human health risk to anyone who eats fish from the region.

In humans, mercury is a powerful neurotoxin that can interfere with brain development, leading to learning disabilities and reduced cognitive function in children of women who eat large amounts of fish during pregnancy. One recent study estimated that prenatal mercury exposure affects between 200,000 and 400,000 children born in the U.S. each year. In adults, mercury exposure has been linked to higher risk of heart attacks.

A double whammy

Nearly every U.S. state has issued one or more fish-consumption advisories related to mercury in the last several years, indicating that the problem is widespread. But the Adirondacks are especially susceptible after experiencing decades of acid rain, Driscoll said.

Sulfur and nitrogen emissions from Western power plants tend to blow East and get "wrung out" over the Adirondacks, changing the pH balance of the soil and water.

"It’s naturally sensitive, but you have a sort of double whammy with the acid rain," he said.

Scientists have found that adding sulfuric acid to a lake or wetland causes a bacterial interaction that leads to increased production of methyl mercury.

It could also mean mercury has less opportunity for "biodilution," Driscoll said.

"One idea is that the acid rain has affected the number and productivity of organisms in lake, so the mercury gets distributed at a very high level among the fish that are left," he explained.

A third factor is that acidified lakes inhibit a natural process that removes mercury from water by transforming it into a gas, he added.

Mercury contamination is often strongest in shallows and wetlands, which Sheehan noted are "cradles of aquatic life — exactly where you don’t want to have it."

Controlling coal

Coal-fired power plants are currently the largest source of mercury emissions in the U.S., the study found. Although total mercury emissions in the U.S. were cut in half from 1990 to 2002, that reduction was mostly due to stricter pollution controls for waste incinerators.

The amount of mercury emitted by coal-fired power plants declined only 13.7 percent over the same time period, from 116,000 pounds to 100,000 pounds.

The HRBF study suggests that the U.S. Environmental Protection Agency’s national models have underestimated the extent of mercury deposition in areas near coal-fired utilities and other large emission sources.

"The EPA had suggested that local sources probably weren’t that significant," Driscoll said. "But we applied a local-scale model."

Looking specifically at an area near a coal-fired power plant in southern New Hampshire, the HBRF team found levels of mercury deposition that were four to five times higher than levels estimated by the EPA’s model.

Their study noted that the bulk of emissions from coal-fired power plants in the Northeast are in the form of reactive gaseous mercury, which generally travels no more than 150 miles from its source.

Sheehan and other environmentalists think that should raise a red flag about emissions trading, a policy that allows facilities emitting less than the maximum pollution allowance to sell "credits" to facilities that exceed the allowance.

"Trading is not a bad way of going about controlling nitrogen and sulfur pollution, but those are pollutants where a temporary shift of the geographic source doesn’t have a real profound effect on the community," Sheehan said. "But with mercury ... it really takes very little to make people sick. A slight increase here or there could cause damage to public health."

The EPA’s 2005 Clean Air Mercury Rule established a cap-and-trade system for mercury emissions and decided that coal-fired power plants no longer qualified for regulation under the Clean Air Act, a move that New Jersey and other states recently challenged in court. That case is now in the U.S. Court of Appeals for the District of Columbia.

The Adirondack Mountain Club filed a brief in the appeal in January 2007, arguing that the CAMR "is an illegal attempt to weaken the strict mercury controls set forth in the Clean Air Act" and would perpetuate mercury hot spots in the Northeast.

The good news

The HBRF team’s case study of New Hampshire, a state that implemented strict mercury emissions controls in the mid-1990s, found that mercury levels in loons decreased rapidly in response to decreased local pollution.

"It was amazing, almost instantaneous!" Driscoll said. "We don’t know if it is a one-shot deal or if it can apply to other areas, but it’s encouraging."

Sheehan said he’s looking forward to 2010, when the Clean Air Interstate Rule goes into effect to reduce sulfur and nitrogen pollution in the eastern U.S. That will mean less acid rain for the Adirondacks, and could have other benefits.

"The good news is that reductions in those things are hard to make without making cuts in mercury, too, so the people who live around the plants should be getting healthier, too," he said.

Driscoll hopes the HBRF study will encourage policymakers to implement a comprehensive mercury emissions monitoring program, such as the one proposed in March by Sen. Hillary Clinton and others.

"These types of monitoring programs are not in place for mercury, so we have no idea how emissions control programs are working," Driscoll said. "I’m just a lowly researcher ... but if you’re talking about a multibillion dollar program that involves a significant health component ... it seems to me it’s a no-brainer that you want to know if it works."

LOGGING ON
EPA mercury information: www.epa.gov/mercury/
Current fish consumption advisories in New York state: www.health.state.ny.us/environmental/outdoors/fish/fish.htm
Mercury Matters study: www.hubbardbrookfoundation.org
Adirondack Mountain Club brief: www.adk.org/issues/Mercury.aspx
Adirondack Cooperative Loon Program: www.adkscience.org/loons/