"We have just reached the crisis level on mercury," Steinwachs, the environmental quality specialist with the University of Missouri Extension, says. She has spent years trying to reduce and recycle hazardous waste. "Now, we're finding it in our food, our water, our soil, our babies, everywhere."

Carroll's character of the Mad Hatter in "Alice in Wonderland" was based on hat makers of the 1800s, who frequently showed signs of nervous system degeneration due to the use of the element in the process of making felt hats.

In recent years, concern has arisen regarding dental fillings made with amalgams containing mercury, the use of mercury-based thimerosal as a preservative in vaccines for children, and mercury emissions from coal-fired powerplants.

And this summer, advisories were issued regarding fish — eating the animals, the U.S. Environmental Protection Agency feared, could lead to ingestion of methylmercury. Methylmercury is an organic compound created when pure mercury enters the air, then gets into a water supply. Bacteria in the water cause chemical changes that transform the mercury into methylmercury. It is this type of mercury that can be harmful to unborn babies and young children. Fish absorb the methylmercury as they feed, then the substance builds up in their tissues.

In a report on methylmercury contamination in freshwater lakes and streams, the EPA estimated one of every three lakes and one quarter of the nation's rivers are contaminated enough that some fish taken from them shouldn't be eaten by pregnant women, women who are nursing, women considering pregnancy or children under 12 years of age.

Missouri had a jump on the EPA: It has issued advisories on fish contaminated by methylmercury for several years. Gale Carlson, whose job with the Missouri Department of Health and Human Services includes supervising the department's mercury advisory program, said the state's Department of Health issued its 2004 advisory just for largemouth bass that are more than 12 inches long. Big largemouth bass are the focus of concern because they have the highest concentrations of mercury, he said.

Other fish in this state aren't included in the mercury advisory.

Missourians can expect changes in the advisory system because it's being refined to determine whether other fish should be included and to define areas of concern, he said.

"Hopefully, we can get a regional advisory rather than a statewide advisory," he said.

Currently, the state is trying to reassure people that fish not included in the advisory are a good source of protein and can be eaten without concern, Carlson said.

Why single out large fish?

Mercury enters the environment from coal-fired power plants in Missouri (or even from plants in other states, hundreds of miles away), chlorine plants using mercury as part of the production process, and from products such as mercury switches that aren't removed from junked cars before they're smelted to make new steel products, Carlson said.

And there are other, more unusual sources, he said. One is cultural, with the area's increasing number of Hispanic residents continuing a tradition of burning candles with mercury-soaked wicks or sprinkling mercury on floors beneath beds, he said.

Once it's in vapor form, mercury can become part of a raindrop — and fall into lakes and rivers, turning into a food source for plants and tiny critters that make up the base of the aquatic food chain.

"All that stuff, no matter what form it's in, when it gets into water ... small organisms actually use that chemical to make energy," he said.

And that mercury persists up the food chain, ending in big predator fish such as largemouth bass. As the fish grow larger, they concentrate higher levels of mercury in their flesh — and the methylmercury can't be removed by cutting away fat or by cooking, Carlson said.

Although older children and adults can eat those fish on an occasional basis, the threat is highest for fetuses because mercury can interrupt the formation of the nervous system, he said.

Determining whether a fetus has had too much exposure involves trying to detect mercury levels in a baby's or small child's system, he said. But he's never seen a physician report that mercury caused a child's developmental problems, Carlson said.

"We'll never see that happen," he said. "Those levels are so low we're not going to be able to determine the number of people harmed. ... Even if in fact you had a young baby who had some kind of developmental delay, you can't point to mercury and say because the child was this way, it was caused by mercury."

Symptoms of poisoning

The situation is different when exposure to elemental mercury, the substance in its purest form, is involved. Because long-term exposure to vapors from the silver element is readily apparent, deciding that a person suffers from mercury poisoning isn't difficult, Carlson said.

But just how mercury in levels high enough to require hospitalization affects the body — and why some people are more susceptible to mercury contamination — isn't known, said Dr. Stephen Adams, medical director of Cox Walnut Lawn Urgent Care Center.

"Once that mercury molecule gets turned into something that's fat-soluble, it can enter cells and start doing damage," he said. "The way mercury does its damage is unclear at this point."

Some researchers contend that mercury blocks the neural transmitters that send signals from the brain, while other researchers speculate that mercury changes how the body uses proteins, he said.

Symptoms of poisoning run a wide gamut, Adams said. They range from diarrhea and stomach cramping to chronic fatigue, tremors, irritability, agitation or shyness and memory loss.

Treatment involves chelation therapy, which is also used to treat people who have been exposed to lead and arsenic, Adams said. In the therapy, chemicals attach to mercury molecules to draw them out of the body's cells and into the bloodstream. The mercury returns to its elemental form and is eliminated in urine, he said. The procedure can take weeks or months.

Cleaning it up

Springfield-Greene County Health Department environmental health services administrator Ron Boyer said he's familiar with one case in Springfield in which exposure led to chelation treatment. The exposure occurred when acquaintances of a woman living in a Springfield apartment scattered elemental mercury around without her knowledge, he said.

"She breathed enough mercury fumes (that) she ended up in the hospital and was quite ill," he said."She had acute poisoning. You have to have a pretty big dose for that."

The woman received medical treatment and her apartment had to undergo cleanup, Boyer said.

Mercury cleanups happen more often than people might think, said two Environmental Protection Agency representatives from Region 7, which covers Iowa, Kansas, Missouri, Nebraska, and 9 Tribal Nations. Their office currently is working on two spills in Iowa and Nebraska, Eric Nold and Ken Rapplean said.

One incident in Council Bluff, Iowa, started when a man mailed three vials of mercury to the apartment where he was moving, Rapplean said.

"For some reason or other he had three small vials of mercury, and ... a cap got loose," he said. "When the box was delivered, the (apartment) owner recognized it was elemental mercury. It sort of mushroomed from there."

The spill resulted in cleanups not only at the apartment, but also at the local post office and in the vehicle carrying the mail.

The process of cleaning up after mercury can vary according to the amount of the substance involved, how long it has been present and whether it has been tracked into other areas, Nold said.

"In general, the first thing we always do is go for the elemental mercury, pick up the source," he said. "Once we pick up all the elemental mercury, we do field monitoring."

That determines whether mercury has vaporized and if ventilating a structure is necessary.

Sometimes, the contamination is so serious that further work has to be done, ranging from removing carpeting and stripping walls to using special materials to absorb mercury. And when even that isn't enough, sometimes buildings must be torn down.

Local recycling efforts

Since mercury exposure can result in a hospital visit, the public needs to be educated about hazards posed by the substance and how to reduce its use, Steinwachs said.

She wants to convince legislators that Missouri should join states that require removal of mercury switches from scrapped automobiles, and that the state should provide more recycling options for products such as thermometers, microwave ovens, televisions and over-the-counter drugs that contain mercury.

Raising awareness, she said, requires more public education and government action — and it could lead to results similar to the removal of lead from gasoline after it was discovered to pose a health hazard, she said.

"People are still catching on," she said. "It's in the news right now. People are beginning to understand mercury is dangerous. There's a lot of headshaking; (people are saying) 'I used to play with it as a kid.' But there's also awareness it's not good stuff, it's not good to have it in the environment."

Although the Household Chemical Collection Center in Springfield accepts household items containing mercury such as light switches and batteries, it can't take anything from businesses, Springfield Public Works recycling coordinator Barbara Lucks said.

That's why she and others are working with Steinwachs to win grant money to start a mercury recycling program in the Springfield area.

Whether that happens depends on how a grant application fares, but Steinwachs said if it becomes reality, the program could be groundbreaking.

"It would be looking at best management practices for a number of sources; small businesses, homes, schools," she said.

"It would be a good test market here because people are environmentally aware and conscious and we have a good response from the business community and government."