Few traces remain of the Gold Rush prospectors who built this tiny Sierra outpost. A couple of fading storefronts. Some dusty folk tales. The yawning chasm of the old Polar Star Mine.
And one piece of a toxic puzzle.
Rick Humphreys and a band of environmental scientists ran across it on a recent visit. Humphreys, a state geologist, clambered into a sloping mine tunnel on the back side of Dutch Flat. Armed with a prospector’s pan, he scooped up watery gravel and began swirling. From the curtain of muck emerged several bright specks, glistening in the beam of a flashlight.
Gold? Silver? No. This was mercury, probably California’s most historic pollutant.
Generations before any environmental law, Mother Lode prospectors coated wooden sluice boxes with mercury to help coax gold from raw ore. Much of the mercury--by some estimates more than 7 million pounds--slopped out into Sierra streams. Even more trickled out of the state’s coastal mountains, where a rich mercury belt was first mined 150 years ago to feed the gold frenzy of the ‘49ers.
Today, the toxic substance continues to seep from old mines ringing California’s Central Valley. It cascades down creeks into foothill reservoirs and ultimately San Francisco Bay. The metal has spiraled up the aquatic food chain, prompting health warnings about mercury-laced fish from Clear Lake to San Luis Obispo County.
California is hardly alone. Belched into the air for eons by volcanoes and more recently by smokestacks, mercury has spread around the globe on the winds, prompting worries from Siberia to the Great Lakes and Florida’s Everglades. Nationwide, concerns about mercury have sparked fish warnings at more than 1,700 lakes and estuaries, three times as many as any other pollutant.
But mercury remains something of a mystery, elusive in the way it behaves in the human body as well as in nature. Although state and federal regulators have launched a massive war on the heavy metal, even the most devout environmental soldiers concede that there are no guarantees of success. Federal agencies cannot even agree what mercury levels pose a long-term health risk.
Given such uncertainties, some skeptics in academia and the smokestack industries have cautioned against pressing forward with an expensive assault on a pollutant that may present less of a threat to the average American than a drive on the freeway.
No one disputes that mercury is a nasty poison that in large concentrations can savage the brain and nervous system. But the worst levels of mercury in California and elsewhere, critics say, are typically a fraction of the amounts that caused history’s most notorious poisoning, in Japan’s Minamata Bay during the 1950s and ‘60s, which killed hundreds of people. The benefits of a vigorous cleanup, they contend, may be outweighed by the staggering costs.
“In the United States, even the most rabid environmentalist cannot point to one sickened child or doddering old fool made ill from mercury,” said Michael Gough, an environmental consultant at the Competitive Enterprise Institute, a Washington-based think tank. “This is as much about politics as it is health. It’s a huge public works project.”
Hazard Was Known in Roman Times
Government advocates of an aggressive attack, however, say the potential risks are simply too great to shrug off.
“No, there aren’t people dying in California; we’re not looking at levels of that magnitude,” said Tom Suchanek, a UC Davis research ecologist. “But we need to understand mercury and minimize it in the environment so we don’t see even low-level health effects.”
Man has pegged mercury as a hazard since the days of the Roman cinnabar mines. In 19th century England, mercury poisoning was common enough in the hat industry that it was nicknamed mad hatters’ disease.
Depending on the exposure, neurological effects can range from tingling in the extremities to coma and death, scientists say. It can be especially hazardous for children under 6 and those in the womb.
Researchers worldwide are studying health hazards. In California, state and federal officials trying to restore mercury-tainted fisheries in San Francisco Bay and delta--and ensure a consistent water supply to Southern California--have committed nearly $4 million for research.
Few communities have struggled as mightily as Clear Lake.
Sitting in a shallow bowl in the coastal mountains 90 miles north of San Francisco, the lake swirls with mercury. The source is Sulfur Bank Mine, a federal Superfund site that has been flushing pollutants into the lake for a century.
In water, mercury is absorbed by microscopic bacteria and transformed into an organic form, known as methylmercury. It climbs the aquatic food chain, from microbe to minnow, finally concentrating in the biggest fish.
Big fish are what Clear Lake is about--locals call it the bass fishing capital of the Western United States. A decade ago, the state issued fish advisories for Clear Lake, warning adults to eat no more than a pound of bass or catfish each month.
“It sort of put the fear of God in some folks,” said Kim Freitas, a fishing guide. “They figured if they ate the fish they’d fall over dead.”
Such worries have ebbed. Some locals fish 300 days a year and eat what they catch, Freitas said. Most stick to the smaller fish, which scientists say have less chance to accumulate mercury. “For the average recreational fisherman,” Freitas said, “it just doesn’t make a difference.”
Jim Brown, tribal chairman of the Elem Indian Colony, still has his fears.
The colony sits over a ridge from the mine, which opened during the Gold Rush, flourished during World War I when mercury was used in bomb fuses, and closed in 1957.
For years, the Elem saw no danger. Children caught the school bus on a mine road that was dusty with the toxic substance. Homes were built on waste rock laced with mercury. Each day, the tribe put fish caught from Clear Lake on the table.
“All those years,” Brown said, “none of us knew.”
Brown’s father, a fisherman, worked at the mine and died at the age of 59. Toward the end, he suffered slurred speech, nervousness and the shakes--what Brown now suspects were symptoms of mercury poisoning.
In the early 1990s, tests conducted on a few dozen Elem by the state Health Department found slightly elevated mercury levels, but not enough to pose a danger. Brown says the results are suspect because many tribe members, wary of outsiders, didn’t take part.
The U.S. Environmental Protection Agency has spent a decade at the mine, trying to figure out how to stem the flow of mercury.
The EPA brought in bulldozers in 1992 and sculpted the site to halt the erosion of waste piles into Clear Lake. It helped, but ground water has continued to carry pollutants into the lake. Authorities now talk of spending $15 million to fill the mine pit with dirt, creating a subterranean barrier.
“It’s a very complex site and it won’t be a simple fix,” said Ellen Manges, the EPA’s project manager.
From the mine, the trail of mercury follows the water. Clear Lake feeds Cache Creek, a major tributary of San Francisco Bay. Crashing down a scenic, boulder-strewn gorge, the creek links with other streams tainted by mercury oozing from more than two dozen other abandoned quicksilver mines.
Cache Creek then flows into the Sacramento-San Joaquin Delta, where biological concerns are greatest.
State and federal officials want to re-create 20,000 acres of wetlands in the delta, which for generations has been heavily diked and drained by farmers. The wetlands would act as nurseries for the state’s sagging fish population. But it’s a delicate balance; research has shown that the brackish estuaries also could serve as a breeding ground for methylmercury.
San Francisco Bay poses additional worries. Although the bay’s commercial fisheries have been on the skids for decades, hundreds of recreational anglers still hit the docks and shorelines each day.
“It’s almost impossible to catch a clean fish here,” said Lee Tyndell, 63, a retired taxi driver who has fished the bay for 50 years.
For some, particularly immigrants raised on a diet of fish, San Francisco Bay is a regular food source. A 1997 survey found that Asian and Latino anglers were consuming three times more fish from the bay than was recommended. So far, no research has been done on their health.
The answer to fixing the fish population, scientists say, rests in places like Clear Lake and Dutch Flat. Experts hope they can determine whether mopping up the worst mines will help. Even then, some experts concede, enough mercury might be left in streams and bay sediments that little improvement would be seen in decades.
“We’re trying to determine if pouring money into trying to fix this will give us a benefit that is worth the cost,” said Charles Alpers, a research chemist with the U.S. Geological Survey, which is studying mercury in Cache Creek and several Sierra streams.
“The more we get into this,” said Humphreys of the State Water Resources Control Board, “the more questions we have about mercury.”
Humphreys and others also worry about the more immediate health effects on amateur gold miners in Sierra streams. Weekend prospectors using suction dredges end up collecting a mix of mercury and gold. Back home, some boil the quicksilver on a stove. Last year, a Fresno woman and her baby died in a toxic cloud after she vaporized mercury at her apartment.
The mercury debate has large economic consequences. In California, where 40 bodies of water are impaired, sewage treatment plants could face expensive upgrades. Nationally, the spread of mercury through the air has regulators eyeing emission rules that could add $5 billion to yearly operating costs at coal-fired power plants.
But Is Cleanup Worth the Cost?
Remedies at the mines can be costly, too. Terry Brubaker, chief of the EPA’s western emergency response office, has a $10-million annual budget, but said he could spend $50 million “in a flash” cleaning up mercury and other toxic substances. Even then, hundreds of old gold and mercury mines in California would remain untouched. “We’re just trying to take the edge off,” Brubaker said.
Some fiscal hawks in Sacramento and Washington say that’s a Band-Aid not worth funding.
“Mercury is one of those things people love to hate,” said Richard Belzer, a public policy professor for Washington University in St. Louis. “But the horror stories we’ve heard through the years are based on levels of contamination that are astronomical compared to anything you’ll see in California.” Mercury levels in the vast majority of freshwater fish tested by the state are less than 1 part per million, the Food and Drug Administration’s limit for commercial seafood. Levels in fish in Japan’s Minamata Bay were as high as 30 parts per million.
Scientists have yet to agree on whether chronic exposure to lower levels of mercury is a hazard.
Long-term studies of fish-eating populations in isolated spots such as the Seychelles off Africa and the Faroe Islands in the North Atlantic have produced conflicting results.
Concerns remain that exposure of the unborn and young children to even low levels can cause subtle neurological changes that aren’t fully understood, perhaps delaying walking or language skills. The EPA estimates that 3% of U.S. women of childbearing age eat enough fish to be at risk.
“We’re talking about one kid developing a little slower than another kid,” said Jerry Pollack of the state Office of Environmental Health Hazard Assessment.
“That’s the controversy--what’s the safe level? The jury is out.”
Times correspondent Sam Bruchey contributed to this story.
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It is California’s most historic pollutant. During the Gold Rush, mercury was mined in the coastal range and carted to the Mother Lode for gold extraction. Today, it seeps from abandoned mercury mines and the Sierra gold country, flowing into streams and to the San Francisco Bay and Delta. Mercury spirals up the aquatic food chain, concentrating in the biggest sport fish and prompting many consumption warnings.
Sources: U.S.Geological Survey; Environmental Protection Agency