Debate rages over mercury pollution

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This summer, a Division of Wildlife biologist and a state health department researcher will go fishing at McPhee and Narraguinnep reservoirs. Their excursions won’t be recreational. Instead, they will be acquiring samples of fish to test for mercury.

The data should provide a few more pieces to a puzzle that has troubled area biologists, anglers, and local citizens for more than a decade: Why are mercury levels high in certain fish species in those particular lakes, and what can be done to bring the levels down?

Many citizens point a finger at nearby coal-burning power plants, saying they need to reduce the amount of mercury they disgorge into the atmosphere. But local power plants are only part of a larger, complex picture, researchers say. And mercury is not just a regional concern, it’s a problem of global proportions.

The new testing at local reservoirs comes as a furor rages nationwide over mercury pollution.

On April 29, the Environmental Protection Agency, deluged by hundreds of thousands of responses, extended by 60 days the public-comment period on the Bush administration’s controversial proposed mercury standards for power plants. The comment period now ends June 29, and final action on the proposed rule has been pushed back from December 2004 to March 2005.

Adding urgency to the debate, the EPA in January doubled its estimate of how many infants in the United States are born with blood mercury levels higher than its “level of concern,” 5.8 parts per billion. The agency now says more than 630,000 babies each year are born with elevated mercury levels, and more than 1 in 12 women of reproductive age may have enough mercury in their bodies to put fetuses at risk.

Don’t eat too much fish

Mercury is familiar to anyone who has ever seen a thermometer containing the liquid metal. Many children, unaware of the substance’s toxicity, played with blobs of “quicksilver” from broken thermometers before the old-fashioned instruments were phased out in favor of digital ones.

Those children probably did themselves no lasting harm, but children and pregnant women are particularly vulnerable to mercury. The chemical especially affects the central nervous system and kidneys, and at high levels can cause kidney failure, memory problems, tremors, personality changes and death.

Acute cases of mercury poisoning are rare, but chronic exposure in infants or children can cause learning deficits, developmental disorders and neurological or heart damage.

For most people, the only danger of mercury exposure comes from eating fish. Certain saltwater fish such as shark, swordfish and tuna are often contaminated with mercury, and fish in freshwater lakes can harbor high levels of the substance as well.

Eight lakes in Colorado carry mercury advisories warning anglers not to eat too much of certain types of fish. In addition to McPhee and Narraguinnep, they are Navajo, Sanchez, Teller, Ladora, Mary and Lower Derby reservoirs.

Portions of the San Juan River from the Hammond Diversion to the mouth of the Mancos River are also under mercury advisory, as is Lake Farmington in San Juan County, N.M.

In northern Arizona, fish-consumption advisories due to mercury are in effect for Lower and Upper Lake Mary, Long Lake, and Soldier Lake near Flagstaff, as well as Lyman Lake 20 miles west of the New Mexico border.

As of 2000, more than 52,000 lakes in 40 states nationwide had mercury advisories, according to the EPA, as well as 238,000 miles of rivers.

A complex process

Mike Japhet, aquatic biologist with the DOW in Durango, said it’s difficult to tell whether mercury levels in local fish are showing a trend, because they have been tested only twice in the last 12 years or so.

In June and July, he will be working with Lucia Machado, physical-research scientist with the Colorado Department of Public Health and Environment, to conduct testing at McPhee and Narraguinnep, as well as Navajo Reservoir on the New Mexico border.

“We need to have updated data,” Machado said.

Why one lake’s fish show high concentrations and not another’s is unclear, she said.

“There are different patterns,” she said. “It depends on weather, wind and all of that, what is deposited on land around the lake and when erosion brings it into the lake. Some lakes are more prone to making mercury available to the food chain. It’s a very complex process, taking the mercury from an inorganic form and making it available biologically.”

River fish are rarely affected, she said, because swift-flowing water doesn’t lend itself to mercury accumulations.

“In a lake, the opportunity to bioconcentrate is greater, as opposed to a traveling system where the fish are moving,” she said.

Machado said the sampling will involve collecting about 120 fish from each lake. For each body of water, two main species of concern are selected and two different size groups within each species. Ideally, 30 fish from each of the four groups will be collected, either through electric shocking or gill nets.

The fish tissue will then be analyzed for mercury content. Results should be available in about two months.

Airborne pollution

Mercury is not being created or destroyed, but human activities are helping to release more of it into the environment. According to the EPA, most mercury sent into the atmosphere comes from municipal-waste, hazardous-waste, and medical-waste incinerators, and coal-fired power plants. But the former three sources were regulated in the 1990s and have greatly reduced their emissions. For the moment, power plants’ mercury emissions remain unregulated.

There are approximately 1,200 coal-burning power plants in the United States, according to the Washington Post. They emit several major pollutants: sulfur dioxide, nitrogen oxides, particulates, carbon dioxide and mercury. Older plants are the worst offenders.

When coal or hazardous wastes are burned, the mercury they contain is released. It can be carried thousands of miles before being deposited on ground or water.

Mercury is also present in some ores and soils, and can leach into bodies of water from mining sites.

But airborne pollution is the main problem. According to the EPA, roughly 60 percent of the mercury deposition occurring in the U.S. comes from domestic, human-caused pollution. The U.S. contributes only about 3 percent of the total global atmospheric mercury, but it still exports more than it imports, according to the EPA.

Coal-fired plants released more than 45 tons of mercury and mercury compounds into the air in 2001 and were the largest industrial source of mercury emissions, according to EPA’s 2001 Toxic Release Inventory. That makes up about 30 percent of the human-caused mercury emissions in the U.S. and 1 percent of them worldwide, according to industry sources.

In December 2000, under the Clinton administration, the EPA found that mercury from power plants is a hazardous air pollutant and should be regulated under the Clean Air Act. Power plants thus would have to slash mercury emissions by 90 to 95 percent by 2007.

But the Bush administration decided that goal wasn’t feasible with existing technology and has sought to revoke the finding. It is proposing instead a 29 percent reduction by 2007 and an industry-wide reduction of 70 percent by 2018, according to the Washington Post.

Under the new proposal, mercury would be regulated under a different section of the Clean Air Act and emissions could be “traded.” Companies that failed to meet standards could buy credits from other power plants anywhere in the U.S. that were less-polluting.

The most harmful form

Mercury exists in different forms, including elemental mercury vapor and mercury salts. Such inorganic types of mercury are not well absorbed by living organisms and hence aren’t very harmful.

But inorganic mercury can be converted by bacteria to an organic form called methylmercury, which is much more easily absorbed and more dangerous.

Such a process often occurs in bodies of water, when inorganic mercury is deposited, exposed to sunlight, ionized and oxidized, consumed by micro-organisms and turned into methylmercury. The micro-organisms are eaten by fish that are in turn eaten by other fish.

Gradually, the element accumulates in older fish and those higher on the food chain. This occurs even though mercury levels in the water itself may be acceptable, as is the case at McPhee and Narraguinnep.

If humans eat enough contaminated fish, over time they can develop elevated mercury levels. Likewise, wild animals that consume lots of fish – such as mink, otters and eagles – can be harmed.

Pinpointing the direct sources of the mercury is almost impossible, but educated guesses and modeling can suggest answers.

A 2003 TMDL (Total Maximum Daily Load) report by the state health department and EPA estimated that in McPhee, just 10 percent of the mercury came from airborne sources and 90 percent from other sources, particularly the Rico/Silver Creek, Dunton, and La Plata mining districts in the Dolores River watershed.

On the other hand, nearly half of the mercury in Narraguinnep was estimated to have come from airborne sources.

Whether those airborne sources are mainly local is open for debate.

The Four Corners is home to a number of coal-fired power plants. The Grand Canyon Trust, an environmental group, estimates some 3,000 pounds of mercury is belched into the air annually by facilities in the region.

Two of the largest are the San Juan Generating Station in Waterflow, N.M., and the Four Corners Power Plant near Fruitland, N.M.

According to 2000 EPA data, the San Juan facility then spewed 751 pounds of mercury annually, while the Four Corners plant released 621 pounds. The Navajo power plant in Page, Ariz., added 341 pounds.

Also affecting the region’s air were the Mohave Generating Station with 399 pounds a year, and the Springerville and Coronado plants in eastern Arizona, which released a combined total of 640 pounds of mercury.

By contrast, the most-polluting Colorado plant in 1999 was the Craig plant in Moffat County, which emitted 128 pounds, according to EPA data.

“A global problem”

But industry officials say local plants are unfairly blamed.

Amy Miller, spokesperson for Public Service Company of New Mexico, which owns and operates the San Juan Generating Station, said research by the Electric Power Research Institute, an industry non-profit, shows that most mercury deposition in the U.S. originates from outside the country.

She said atmospheric modeling shows the majority of mercury in the area comes from Asia, particularly China, where there are few environmental controls. “It’s a global problem and an international challenge,” she said.

She said Western power plants emit mainly elemental mercury, not methylmercury.

Miller said PNM is working to reduce pollution. In 1998, it installed an $80 million limestone scrubbing system at the San Juan station that cut sulfur-dioxide emissions by 64 percent, she said. The system also removes some mercury, but not enough to meet the stricter proposed standards.

“The challenge for Western plants is that we burn sub-bituminous coal, and pollution-control systems are not as good at removing mercury from it as in Eastern states where they burn bituminous coal,” she said.

“Everyone in our industry is going to have to look at mercury emissions and improve our reductions. The challenge is finding technology that can do that.”

U.S. mercury levels peaked in 1960, she said, and have declined since.

Miller said achieving the Clinton administration’s target reductions is not feasible, given today’s technology.

“Too weak and too slow”

But Jon Devine, an attorney for the Natural Resources Defense Council in Washington, D.C., said new emissions-cleaning methods are in the works that could make those goals feasible in the near future.

“Two makers of pollution-control equipment have said there is technology available now or which will be available soon that will achieve 80 to 90 percent reductions from all coal types,” Devine said.

He called the Bush administration proposal “far too weak and far too slow.”

“The proposed cap-and-trade program first calls for no near-term reductions except for those occurring from other pollution-controls,” he said, “and then gives sources an extended time line to reduce their mercury emissions.”

The EPA proposal established a second cap in 2018 designed to achieve a 69 percent cut from present levels, he said, “ but because of the cap-and-trade program, facilities will be allowed to bank emissions reductions they make earlier and use those when the second cap becomes effective.”

The EPA’s own modeling anticipates only a 50 percent cut in emissions by 2022, he said.

“It’s hard to say which individual plants will pollute more or will fail to reduce, but for those folks who live near the ones that do, it certainly raises the possibility that they will be part of a hot spot where mercury levels will continue to be high,” Devine said.

More fumes for the Four Corners?

That’s exactly the fear of the Durango-based San Juan Citizens Alliance, an environmental group.

“Those regulations will directly influence us in the Four Corners,” said Dan Randolph, oil and gas organizer for the alliance. “The mercury cap-and-trade system favors those areas which have both the political and economic ability to demand clean air. What that means is the power plants back East which affect larger populations will trade with people here so they can continue to pollute more.”

Complicating the picture, he said, is that there are two proposals for a new power plants on the Navajo reservation.

German-based Steag has proposed a 1,500-megawatt plant due south of the Four Corners plant and similar in scale to the San Juan station, Randolph said. Steag has submitted a permit application to the EPA and hopes to start construction in 2005.

BHP Billiton of Australia has proposed a 500-megawatt plant for the same site if the first proposal is rejected.

The newer plant would be less-polluting than existing ones, Randolph said, “but until the older plants are cleaned up, the question is, can our air quality really stand another big hit?”

Besides, he said, every time another coal-fired plant is built, there is less reason to look for new power sources.

“To the extent that we build more capacity in fossil-fuel energy sources, we are creating a disincentive for moving beyond fossil fuels.

“And as the Four Corners continues to be a massive cheap energy source, we will continue to have questionable air.”

The NRDC’s Devine agreed. “Power plants are the single largest unregulated source of mercury in the U.S.,” Devine said. “All but a handful of states have fish advisories for some of their water bodies. It’s high time to get about the job of controlling these plants.”


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From June 2004.