Mercury and coal: a threat to wildlife and humans in US parks

Mercury and coal: a threat to wildlife and humans in US parks

28th February 2008

A six-year study of the impacts of airborne contaminants in twenty US national parks and wildlife areas has discovered alarming levels of toxics which endanger wildlife and humans.

At the head of this list is mercury spewed from coal-fired power plants. Authors of the study concede that identifying the point sources of pollution is problematic - some of it may come from as far afield as China. Nonetheless, mercury was found to be "more prevalent in parks that were downwind from coal-burning plants."

Parks less than pristine: Dangerous levels of toxics imperil humans, wildlife

Peter Fimrite, San Francisco Chronicle Staff Writer

28th February 2008

The fallout of industrialization has been detected in the forests of the western United States, where some of the country's most pristine sanctuaries are apparently coated with dangerous levels of toxic chemicals.

A federal study released this week found surprisingly high concentrations of 70 contaminants, including mercury and a wide variety of pesticides. The pollution was found in the air, snow, lakes, on plants and in the fish at 20 national parks and monuments, including Yosemite.

The six-year, $6 million study by the National Park Service, the U.S. Environmental Protection Agency and several other federal agencies was the first attempt to measure the affect of airborne contaminants on the ecosystem of national forests.

The mostly man-made toxic substances were apparently spewed into the atmosphere and wafted down like gas into the wild forests of Alaska, remote portions of the Rockies and the redwoods of California.

"It's a fundamental law of nature that what goes up comes down," said Colleen Flanagan, an ecologist for the National Park Service Air resources Division, who admitted that she and the other scientists did not expect to find the amount of contaminants they found.

"The sky isn't falling, but it's a wake-up call."

Three California parks were included in the study - Yosemite, Sequoia and Kings Canyon and Mount Lassen Volcanic national parks.

Of the eight key parks that were the primary focus of the study, Sequoia and Kings Canyon was one of the three worst in terms of the amount of toxic chemicals found within its boundaries. Contaminants were also found in lichens and conifer needles at Yosemite and Lassen, which were among 12 secondary parks that underwent a less-rigorous review.

The most disturbing part of the study, known as the Western Airborne Contaminants Assessment Project, was the discovery of mercury, apparently from coal-fired power plants, PCBs from industrial plants and the banned insecticides dieldrin and DDT, according to Flanagan.

All of those substances have been linked to health problems in humans, including nervous, immune system and reproductive failures. Flanagan said the chemicals also have the ability to bio-accumulate, meaning their health effects intensify as they move up the food chain.

Fish at Sequoia and Kings Canyon, Mount Rainier, Olympic, Glacier, Rocky Mountain, Gates of the Arctic and Denali national parks and Alaska's Noatak National Preserve exceeded human-consumption thresholds set by the EPA for the various contaminants, which are described in the report as "semi-volatile organic compounds," or SOCs.

Mercury levels in fish at all eight parks and DDT levels at Glacier and Sequoia and Kings Canyon exceeded health thresholds set for wildlife that eat the fish.

"We found some of the highest concentrations of mercury in the Alaska fish," said Dixon Landers, a U.S. Environmental Protection Agency specialist who was the project's scientific director.

Landers explained that the large watershed lands in Alaska actually assist the dispersal of mercury. But, he said, the most polluted sites were in the contiguous United States.

"Sequoia and Kings Canyon, Glacier and Rocky Mountain tended to have the highest overall concentrations of SOCs," he said.

The contaminants actually caused some male trout to develop female organs in Rocky Mountain and Glacier national parks, according to the report. And, said Landers, the study tended to show that cold, remote, high-elevation sites were at higher risk of being sprinkled with toxic chemicals.

There is no way of knowing exactly where the contaminants came from, but the highest concentrations of pesticides were found in parks closest to agriculture. Conversely, contaminants like mercury were more prevalent in parks that were downwind from coal-burning plants.

"What we found was that contaminants tended to come from local or regional sources rather than transpacific sources, like Asia," Flanagan said.

The obvious solution, according to the researchers, is to curb emissions from coal-burning plants, tighten regulations on pesticide use and reduce greenhouse gas emissions. That may be easier said than done, especially when some of the pollution is coming from overseas.

Landers said the contaminants in Alaska probably came from Asia and Europe, where they mingled with the clouds, traveled across the ocean and dropped down with the rain and snow.

"It can stay in the air for a year or two," Landers said. "You can't point to one particular source as being the major contributor, although we do know that China has become the number one user of coal in the world."

Ultimately, he said, it means that even the Earth's most pristine wilderness is not safe from the bombardment of pollution caused by man.

"The most stunning thing about the report is that there are just so many chemicals in some of the most pristine places we have in the United States," said Mark Wenzler, the director of clean air and climate programs for the National Parks Conservation Association.

"This reports conclusively shows that activities many miles away can have major impacts and that what we put up today will continue to fall in our national parks decades into the future. If we truly value our national parks, we have to protect beyond their borders."

Online resource To view the Western Airborne Contaminants Assessment Project report go to: http://www.nature.nps.gov/air/Studies/air_toxics/wacap.cfm

E-mail Peter Fimrite at pfimrite@sfchronicle.com

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