Mines big source of mercury pollution, reports show

Thursday, March 2, 2000 | 10:44 a.m.

In July for the first time, the state's mines were required to submit toxic release inventory reports to the federal agency. Until they saw the mines' reports, EPA officials said they had no idea the sites emit thousands of pounds of mercury every year from their smokestacks.

The newspaper reviewed copies of the mines' reports on file at the Nevada Division of Environmental Protection. The EPA will make these reports, along with those submitted by thousands of other industrial firms, public some time this month.

Ellen Brown, an air analyst in the EPA Washington, D.C., office, said mining has never been on the agency's list of industries regulated for air pollution. "We're going to look into it for sure," she said.

Four mines, all in the Humboldt River watershed, reported releasing an estimated 13,560 pounds of mercury in 1998.

Mining-industry representatives point out the mines' mercury air emissions are not illegal and the mercury emitted is in tiny concentrations. Mercury is naturally present in the gold ore the mines process and refine. It gets released into the environment when mining companies heat the ore to separate out the precious metals.

"There isn't any indication whatsoever that there is harm to the environment," said John Hardaway, spokesman for Anglo Gold North America that owns the Jerritt Canyon Mine. "It's what is permitted, the state is well aware of it.

"The emission of that controlled amount is not a problem when you consider what the concentration is," he said. "It's not in one big puff."

Mercury affects the central nervous system of animals and humans and in severe cases irreversibly damages the brain. Children and fetuses are especially sensitive to mercury's effects.

Mining companies capture most of the mercury released during the milling and refining process and sell it to metals dealers, Hardaway said. Nevada is the nation's largest mercury producer. Every year, the state's mines supply 228,000 to 304,000 pounds of mercury to the nation's mercury market. From there it gets used in things like thermostats, thermometers and chlorine production.

State regulators say they cannot limit mine mercury emissions because the EPA has not adopted a mercury emission standard for mines.

Mercury in aquatic environments is particularly bad because bacteria convert mercury to methylmercury. Unlike elemental mercury, methylmercury is 100 percent absorbed by living tissues. And when methylmercury enters the food chain, it becomes progressively more concentrated with each step up the food chain.

Forty states, including Nevada, warn the public to limit their intake of sport fish caught in thousands of lakes and streams because of mercury pollution. The only Nevada body of water with a mercury warning is the Carson River below Dayton. During the late 1800s, gold mills dumped an estimated 7,500 tons of mercury into the river.

The state has monitored the Humboldt River for mercury since 1989 and has not detected any.

In a study conducted between 1986 and 1996, the U.S. Fish and Wildlife Service and the U.S. Geological Survey did find mercury in aquatic invertebrates and American coots in the Humboldt Sink. During that time, researchers saw a twofold increase in mercury levels in water boatmen, an invertebrate that's an important food source for migratory birds, and a fivefold mercury increase in coot liver tissues and eggs.

Peter Tuttle, an environmental contaminant specialist with the Fish and Wildlife Service, said he can't blame these rising mercury levels on the mining industry.

"There are a number of environmental variables," Tuttle said. "It may have been the drought conditions. We don't know. Certainly there are increases, and it does raise some concern."

Environmentalists say mines' mercury emissions are causing trouble somewhere, but nobody is looking for it.

Matt Holford, executive director of Nevada Trout Unlimited, said if mercury is being released in the Humboldt River watershed, it's washing into the streams somewhere.

"It would behoove the state to protect its people, especially if it's promoting recreation," said Holford, who lives in Elko. "This is a big hunting and fishing area."

Bill Denier, Pershing County commissioner, said the Humboldt River Basin Water Authority will scrutinize the reports and comment later on their mercury emissions. The water authority is a coalition of county government officials that looks out for their constituents' interests in the Humboldt River.

"The water authority will be really interested in this," said Denier, who belongs to the group. "The Humboldt Sink is the cesspool of the Humboldt River. Anything that's in the Humboldt River collects down there."