Her paintings are abstract. Right now she's in the middle of a huge acrylic with big sweeps of red, yellow ocher and burnt umber. Just a few months ago, Beth Kokol's brushes stood idle.

An artist and private art instructor in Tampa, Fla., Kokol, 46, underwent a medical screening for heavy metals in early December. Her mercury count was twice the normal level. The culprit? A diet heavy in high methylmercury fish.

In light of recent news articles about methylmercury, Kokol's husband, Bob, contacted the St. Petersburg Times. He thought it was important that those at risk hear her story.

"I would have a can of tuna fish for lunch once a week," Beth Kokol recounted, "and two or three nights a week we'd go out for sushi ahi tuna sashimi, along with some kind of tuna roll. I thought I was eating healthfully."

Two and half years ago, she said, she began experiencing numbness and tingling in her feet and legs. She went to see a doctor, who referred her to a neurologist. She put it off.

"I was very busy. I just figured I was getting older," she said. "I'm from a family of doctors. My father always raised us to think if you wait long enough, most things go away."

But this didn't. Over the next year, she began to lose function in her hands and feet. She would drop things; she would fall. She began having speech problems and noticing mental slowness.

"It got to the point where I couldn't write a check. I was unable to sit still and relax, and I was incredibly tired all the time."

Dr. Steven Masley, a physician and nutritionist at University of South Florida, conducts health assessments that routinely test mercury levels in patients. He said this type of mercury toxicity, meaning high levels of mercury, in patients who are symptomatic is rare. He sees it in, at most, 5 percent of his patients.

The Centers for Disease Control and Prevention and the Food and Drug Administration (FDA) keep no records on mercury toxicity.

"This kind of toxicity is often confused with other neurological problems such as complications from diabetes. Symptoms include tingling and burning in the nerves, high blood pressure, and a metabolism that is out of whack.

"But a very small percentage of doctors test for mercury."

Kokol's experience bears this out.

In addition to her primary-care doctor and neurologist, she also saw a rheumatologist and other doctors. They conducted MRIs and electromyograms, which record the electrical activity of muscles.

"Nobody said, 'This is mercury,' " Kokol said.

"I said, 'You know, I eat a lot of seafood.' And my doctor said we don't see a lot of mercury toxicity here."

In 2004 the Environmental Protection Agency and the FDA advised women of childbearing age and young children that they could safely eat up to 12 ounces of low-mercury seafood per week. Those women and children also were told to limit consumption of canned albacore tuna and tuna steaks to 6 ounces a week.

Swordfish, tilefish, king mackerel and shark were put on the "Do Not Eat" list.

Dr. Rashid Buttar, chairman of the American Board of Clinical Metal Toxicology, and Masley both said these limits are too liberal.

"There are now clinical standards for what's a normal mercury level. It's 5 micrograms per liter of blood. I see elevated levels in a third of my patients. These are people with no symptoms, but elevated levels turn up in routine screening," explained Masley.

"These are people who eat tuna, swordfish, grouper, snapper or bass at least once a week. To test normal for mercury, people should eat these fish less than once a week.

"Pregnant women and children shouldn't eat any tuna at all."

For Kokol, once her elevated mercury was detected, a first step was obvious: limit her consumption of high-mercury fish. Beyond that, she has opted against potentially dangerous chelation therapy to eliminate mercury from her body.

Instead, she has been using a wheat grass drink, which contains oxalic acid, a natural chelator that binds to heavy metals and flushes them from the body. She's doing better.

"In two weeks I noticed a dramatic change. I'm 80 percent back to what I was three years ago. I did a painting this weekend. I worked on it for six hours."