The Mercury Morass
By the University of Wisconsin
Coal-fired electric utilities are the largest single source of mercury in the atmosphere. Photo: USGS
Burning makes 86 percent of total U.S. mercury emissions. Coal-fired utility boilers account for 34 percent; other big sources include coal-fired industrial boilers, burning of municipal, medical, and hazardous waste, and manufacturing. Graph: Environmental Protection Ag
Mercury from power plants and other pollution sources is converted by bacteria into methylmercury, which gets bio-accumulated in the food chain. Top predators have far higher concentrations of methylmercury than the animals they eat. Image: USG
Just before leaving office, the Clinton Administration wrote regulations to reduce mercury air pollution. Nobody argues that high levels of mercury contamination can cause birth defects and brain damage.
Although cases of obvious mercury poisoning are rare, levels in rain and surface waters have risen over the decades, and coal-burning power plants are the largest single source of mercury in the air. Pres. Clinton's Environmental Protection Agency (EPA) proposed a 90 percent reduction in electric-utility emissions by the end of 2007.
Industry objected. Too expensive, it said. "...there is no existing technology that can control mercury emissions across the entire utility industry," it wrote.
The new administration deep-sixed the Clinton cuts and called for a regulatory system to reduce utility mercury by 70 percent -- in 2018.
Like the Administration's earlier proposal to ease regulation on arsenic in drinking water, the back-tracking alarmed physicians, public-health types and environmental activists. The EPA itself had said that each year, mothers' mercury threatened 300,000 American children with brain defects (see "Blood Organic Mercury").
"The fundamental question is, does this protect children as soon as technologically possible? Everything indicates that it doesn't," says Susan West Marmagas, director of environment and health programs at the non-profit Physicians for Social Responsibility. Charging that two EPA reviews had already agreed that power plant controls were feasible, she adds, "We have the technology to produce the 90 percent reduction by 2007, and this proposal does not do it soon enough."
The revised mercury rule also sparked protests from eastern-state senators. The March of Dimes, an organization that fights birth defects, asked the EPA to "withdraw its current proposal on mercury emissions from coal-powered utility units and replace it with a more stringent set of guidelines to be implemented as soon as possible." Industrial mercury, the normally non-political group said, "seriously threatens the health of America's mothers and babies."
The mercury rule and other changes caused upheaval at the EPA, and some air-pollution staffers quit in disgust (see "Changing All the Rules..." in the bibliography).
Over a decade, mercury pollution has ballooned from an obscure concern into a pressing environmental problem. Almost every list of dangerous air pollutants now mentions the silvery, liquid metal that, like uranium, plutonium and neptunium, shares its name with a planet.
Mercury has been used in patent medicine, thermometers, vaccines, paints, light switches, and is still used in fluorescent light bulbs. Once released into the atmosphere, usually by burning, some mercury compounds can be converted by bacteria into methylmercury, which is taken up in plants and the animals that eat them.
Biological accumulation sounds like a nightmare invented by radical greenies, but it's a reality with decay-resistant chemicals like PCBs and mercury. In water that contains 1 to 10 parts of mercury per trillion parts of water, methylmercury can bio-accumulate to 1 part per million, a level found in some top predators like tuna, swordfish and shark.
That's a million-fold increase.
Don't drink the water. Don't breathe the air. And DON'T eat the fish
One result of bio-accumulation is a profusion of warning signs at America's waterways. Indeed, mercury pollution is "extraordinarily widespread," says Charles Driscoll, a professor of civil and environmental engineering at Syracuse University, who studies mercury levels in the environment. "There are 45 states with fish advisories, 19 with blanket advisories [covering all surface waters], 12 million acres of lakes and 473,000 river miles where there are advisories. It's a large proportion of our aquatic resources."
Nonetheless, the Edison Electric Institute, a utility-industry group that failed to respond to our request for comment, answered "Is it safe for me to eat fish" with a bold-faced, one-word sentence: "Yes" in its publication, "Straight Answers about Mercury".)
Industrial dumping of mercury in Japan during the 1950s caused horrific birth defects and proved the danger of high-level mercury poisoning.
The health worries about mercury date to the mid-1950s, when villagers in Minamata, Japan, began complaining of numbness, dizziness, and other nerve symptoms. Cats were said to be "committing suicide," and birds were falling from the sky.
It turned out that a local chemical factory had dumped about 27 tons of mercury into nearby waters over the decades, and the mercury was concentrated -- bio-accumulated -- in fish eaten by all the injured parties. "Minamata disease" proved that high concentrations of mercury could kill and cause grievous injury.
Just how much of a health threat is low-level mercury contamination?
The Minamata disaster in Japan put mercury's health effects in the headlines. But was this massive exposure relevant to the tiny exposures of day-to-day life?
After all, toxicology lives by the maxim, "The dose makes the poison."
Is eating a lot of fish hazardous to your health? Perhaps, especially if you eat predators, where mercury tends to concentrate. Photo: William B. Folsom, NOAA
You can safely down an aspirin every day to keep your blood moving. But gobble the whole bottle, and you will rot your digestive pipes. At the recommended dose, aspirin is medicine. At the 81132582">whole-bottle overdose, it's poison.
But if the mercury poisoning in Minamata does not prove the danger of low doses, nor does it prove their safety, either.
The next mercury disaster struck in Iraq in 1961, where villagers ate donated grain seeds that had been treated with mercury fungicide (the seed bags bore a warning label -- in English). Again, the symptoms included nerve problems -- mercury, like lead and many other heavy metals, is toxic to nerve cells. But again, the doses were higher than those you can get from eating fish, and while 35 people died, the low-dose question remained unanswered.
Mercury: Thermometer rising
In the 1980s, using ever-more accurate chemical detectors, scientists found widespread, low-level mercury contamination, even in "pristine" places like the Wisconsin northwoods, miles from sources of industrial pollution. In the open ocean, tuna and other predators were also carrying a burden of mercury.
Tests for mercury in blood and hair showed that mercury, AKA "quicksilver," was also finding its way into another top predator, Homo sapiens. How did mercury get there, and what was it doing?
The answer to the first question came quickly: Almost all human exposure to methylmercury, which is apparently the most dangerous form, came from eating fish and shellfish.
Here's a historical irony for you. During the 1980s and '90s, a long campaign to restrict use and dumping of PCBs was starting to bear fruit. And so as public workers started taking down some of the "Caution: Fish polluted with PCB" signs, others began nailing up placards with a different warning: "Caution: Fish contain mercury. Don't eat if you're pregnant, thinking about getting pregnant, or a young child."
Today, as we've mentioned, 45 states warn about mercury pollution in some lakes or rivers. In 19 states, these "advisories" apply to all freshwaters.
Although even people who eat some fish usually have low levels of contamination, Michael Gochfeld, of the Environmental and Occupational Health Sciences Institute in New Jersey, says clinics do see poisoning in the mercury-rich Eastern United States. Gochfeld, who chaired the New Jersey Mercury Pollution Task Force, says, "Periodically we see people who have eaten a lot of fish, and actually have some evidence of mercury impairment," such as difficulty with memory or muscle control. After they slack off on the fishwiches, he adds, "their blood mercury has gone down, their symptoms have gone down."
In the late 1980s, to probe the health effects of the chronic, low-level exposures that could be affecting hundreds of millions around the world, three major studies began looking at diet, mothers' mercury levels, and child health.
Results interesting, but confusing?
University of Wisconsin with grants by the National Science Foundation credits.
Twenty-One Percent of Women Tested Nationwide Have Mercury Levels Higher Than EPA Limit
Interim Results of Mercury Hair Sampling Project Highlight Negative Impact of Dirty Power
Wed October 20, 2004, Washington DC, UNITED STATES
Interim results of Greenpeace's Mercury Hair Sampling Project were released today by the Environmental Quality Institute (EQI) at the University of North Carolina-Asheville. The survey found mercury levels exceeding the EPA's recommended limit of 1 microgram of mercury per gram of hair in 21 percent (126 out of 597) of women of childbearing age tested.
So far, hair tests have been analyzed for 1,449 people of all ages around the country. Mercury contamination is a particular concern for women of childbearing years (16 to 49 years old) because mercury exposure in the womb can cause neurological damage and other health problems in children. The EPA has not established mercury exposure health standards for older children, men, or women older than 49.
"I have an obligation to protect the health of my children as well as my own health," said Leila Varella, a 29-year-old mother from Philadelphia who got herself and her 6-year-old son tested. "Knowledge is power and getting tested is a first step toward protecting my family and community from mercury pollution. "
Coal burning power plants are the nation's biggest mercury polluter, releasing 41 percent of the country's industrial mercury pollution. Mercury from these dirty power plants and other sources falls into lakes, streams and oceans, concentrating in fish and shellfish, which are then consumed by people.
"In the samples we analyzed, the greatest single factor influencing mercury exposure was the frequency of fish consumption," said Dr. Richard Maas, Co-director of EQI and author of the report. "We saw a direct relationship between people's mercury levels and the amount of store-bought fish, canned tuna fish or locally caught fish people consumed."
"People should not have to stop eating fish because they're afraid they'll get poisoned by mercury," said Greenpeace Energy Campaigner Casey Harrell. "We need a President who will cut mercury pollution and move us away from dirty fossil fuels by investing in clean, renewable energy."
Greenpeace started the Mercury Hair Sampling Project as a response to President Bush's failure to clean up power plant mercury pollution. Switching from coal and oil to wind and solar energy would reduce pollution and its negative health impacts, help solve global warming and create jobs.
EQI will continue testing into 2005 and issue the final report in the spring. Click here to get a Mercury Test Kit