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Uncertain future of anti-pollution laws could invite rise in mercury-poisoned seafood

Uncertain future of anti-pollution laws could invite rise in mercury-poisoned seafood

Picture of Kathy Jean Schultz
2014 File photo of plant by U.S. Los Alamos National Laboratory
2014 File photo of plant by U.S. Los Alamos National Laboratory

One woman’s wrong diagnosis spotlights the severity of health threats

Sapphire waters frame lush forests, volcano sunsets and other scenic glories. Beneath the waters, it’s a different story, as Nancy Seagal found out while living in Hawaii in the 1990s. She began to experience dizziness and nausea, and over time, her hair fell out, she was vomiting and had hearing loss. For 12 years Seagal’s symptoms worsened. Her muscles were sometimes paralyzed, leaving her unable to move. Despite multiple tests and exams, doctors could find nothing wrong with her, and told her it was all in her head. Hospitalized numerous times for neurological symptoms, even a spinal tap procedure showed no reason for her illness.

Life was steeped in exhaustion for the 26-year-old massage therapist and licensed hypnotist. “I had a massage therapy business as my health was declining,” she said in a recent phone interview. “I could not get out of bed all day. I could get up for one massage customer or one hypnotherapy session, and then went back to bed. Eventually I could not work at all – I had to close my business and get food stamps. It was terrifying.”

Her odyssey took her from doctor to hospital to psychiatrist and psychologist, none of whom could detect that she had mercury poisoning. She’d been eating a moderate amount of fish, but it was not suspected by any practitioners who tested her.

 Seagal had at first been given a urine test to detect mercury poisoning, but the result was negative. Twelve years later she would learn it was the wrong test, and that it had not actually assessed mercury levels in her body. She had no way of knowing that at the time, so she believed the original test results.

 While on the U.S. mainland in 1998, she braved the first of many hospitalizations with no diagnosis. Her legs stiffened into paralysis: “They did lots of testing, including a spinal tap. Nothing showed up.” The problems that began at age 26 left her unable to function by 32.

 One day, Seagal accidentally broke a mercury-filled thermometer and didn’t clean it up quickly, but instead touched some of the spilled mercury. “My symptoms got much worse right after that,” she recalls. Yet it was hard to cement any connection between mercury and symptoms, given that neurologists did not suspect mercury. And there was the negative result of a mercury test.

 “There were times I wanted to end my life. I didn’t want to give up, but I could not function or be productive,” she said. Friends and family took her in, but living with pain and no clue to its source became harrowing. She used a walker and a wheelchair when she could not stand. “I know the power of the mind, because I’m a hypnotherapist,” she says. “I took proactive action to heal myself, with hypnotherapy techniques,” she says.

“I was in and out of emergency rooms so many times I don’t remember how many. My body would freeze up. One night I could not move at all and I begged the nurse, ‘Please, all you have to do is pull my arms down, and that releases the spasm.’” But the nurse had doctors’ orders not to do that. The nurse did eventually pull Seagal’s arms down, and that did break the spasm. “The next day, I asked the doctor, don’t ever give this order again. By that time, I knew it was me against the whole medical industry. I had no one to advocate for me. I was doing anything possible to help myself.”

In 2003, Seagal met with a physician who practices complementary medicine, combining conventional medicine with alternative therapies. He reviewed all her previous exam results and immediately blood-tested her for mercury poisoning. “He told me my mercury level was 17, whereas the safe level is less than 3,” she says.

“I felt so happy, and justified that I’d been right,” she says of her reaction. “I felt angry at all the medical professionals I’d seen, as well as the people in my life who had suspected all kinds of crazy things about me.”

(Safe levels of mercury in the bloodstream are an ongoing area of research but in general, less than 3 micrograms/liter is considered safe, 3-10 mcg. are acceptable but less safe, and higher than 10 mcg. is dangerous. Seagal tested at 17 mcg/L.)

Chelation therapy is a common treatment and Seagal began it right away. She was so weak by that point that she could only tolerate low doses of medicine, so two years’ painful treatment was needed to finally rid her body of mercury. “About 3 months into treatment I felt energy I hadn’t had in years. But after 5 months, the level was still only down to 12, and it needed to be 3. I was devastated. It was going so slowly. I had a long ways to go.”

“Chelation” means to grab, and comes from the Latin word for “claw.” A synthetic chemical solution is injected into a patient, or taken by mouth. The solution "grabs” onto mercury atoms in the blood. Just as certain metals are drawn toward a magnet, mercury is pulled to these chemicals.

After grabbing the mercury, the solution moves it through the kidneys and out with urine, as in normal digestion. The effect is to grab and then push mercury out of a patient’s system. Without it, the mercury remains stuck. In addition to sticking to human tissue, it also does not move out of fish or wildlife that eat fish. This is why mercury accumulation can build up in frequent consumers of seafood. Once inside, it does not move out of either fish or humans, and then, “The central nervous system is the most susceptible target organ for mercury,” according to a 2016 study in the journal Medicine. 

Seagal believes that her original urine test was meant to assess occupational exposure to metals, but not blood mercury level specifically. “They didn’t find it because they did not test properly,” she says. “This is why I was not diagnosed correctly.”

Sushi is trending

When her symptoms surfaced in 1991-92, Seagal had been eating a moderate amount of seafood, including sushi usually made from tuna, but not every day. The U.S. Food and Drug Administration’s recommended list of seafood to avoid includes tilefish, shark, swordfish and king mackerel. Seafood with generally low and safe levels of mercury include salmon, canned light tuna, catfish and cod. The FDA suggests weekly intake of albacore tuna should be limited to six ounces to avoid mercury’s neurotoxic effect.

Sushi is a type of recipe, not a type of fish, so the word “sushi” does not appear on most lists of seafood to avoid. Eating tuna-based sushi every day, which many city residents do because of the convenience of sushi cafes in big-city centers, risks mercury toxicity. One study found sushi tuna had high mercury levels regardless of whether it was called albacore, bigeye, bluefin, yellowfin, chunk light, chunk white, canned light, ahi or something else.

The origin of Seagal’s poisoning will never be known, although her seafood was often sushi. The key fact about mercury is that it accumulates. Accumulation over a long time, in the water, in fish and in the human body, is critical.

Healthy today and living in Santa Barbara, Seagal works as a corporate wellness speaker and author. Her books include “Rising Above Mercury: My Story of Poisoning and Recovery.” The fact that mercury accumulates inside the body is what makes it so dangerous, and she calls herself a mercury-poisoning survivor. “In my opinion there are a lot of people walking around who have mercury poisoning they don’t know about,” she says.

The Way Forward: Uncharted Waters

Reasonable sushi consumption is not dangerous. Eating tuna steaks and tuna salad is not always risky. But if water pollution from mercury increases, that could change.

The biggest source of mercury pollution is burning coal at coal-fired energy and electricity plants. Billowing from plant chimneys and then drifting into the air, mercury emissions eventually float down into water, where fish absorb them.

If fish did not absorb mercury, seafood consumers would not get mercury poisoning. The need for any kind of treatment would diminish. Mercury in small doses is a natural earth chemical, but large, man-made mercury vapors pollute the air, the water and then the fish in that water.

The U.S. Geological Survey’s National Water-Quality Assessment program, or NAWQA, reported that in 2005, coal-burning was the single largest source of mercury emissions. In 2008, NAWQA listed mercury as the second-leading cause of impairment in streams throughout the country. When both rivers and streams are assessed, mercury is the cause of more than 100,000 impairments, according a 2014 report.

All 50 states publish “Fish Advisory Lists” for local regions, to warn consumers, particularly children and pregnant women, not to eat local fish that might contain mercury. One Environmental Protection Agency assessment found almost 4,500 occurrences of mercury in bodies of water in the U.S. between 2008 and 2014, as well as more than 3,000 instances of mercury found in fish.

Mercury is unlike other kinds of pollution, and significant technical innovation will likely be needed to decrease it to healthy levels. Unlike most other chemicals, mercury at certain temperatures is a gas — not a liquid or a solid. Thus it can drift into and pollute waters. Moreover, it does not degrade, but instead continues to poison water long after it first sinks in.

Sometimes mercury turns into methylmercury, a highly toxic poison that if swallowed fuels brain damage, nervous system problems, spinal cord damage, blindness, hearing loss, heart disease, lung disease and endocrine disruption. The extremely toxic methylmercury threatens fish-eating birds, fish and humans.

Air pollution from mercury has decreased steadily since 2004. Globally, mercury emissions decreased 30 percent between 1990 and 2010. But 30 percent is not 90-100 percent. Although air pollution has lessened, water pollution is more persistent, as a 2015 excerpt from the New England Journal for Investigative Reporting highlights:

“Mercury emissions from major Massachusetts sources have declined by 90 percent over the past two decades, but mercury levels in the state’s freshwater fish hold stubbornly high, with many species too contaminated for pregnant women and children to eat.”

According to the 2014 U.S.G.S. report “Mercury in the Nation’s Streams – Levels, Trends and Implications,” reduction of brain function in children linked to methylmercury exposure has been reported in studies worldwide, as have neurological impacts on fetuses of pregnant women. Other report conclusions are:

  • Obsolete tools cannot match the pace of contemporary pollution. Measurement tools designed long ago do not track fish-borne methylmercury in ways that yield consistent trend assessment. Technological innovation and novel approaches are needed to track mercury in fish accurately.
  • Emission controls work. Downward trends of mercury contamination followed the Clean Air Act of 1970, the Clean Water Act in 1972, and other legislation designed to limit pollutants. Mercury emissions from coal-fired utility plants have decreased during the last two decades.
  • Decreasing emissions in further compliance with the Clean Air Act would drive down persisting levels of toxins in seafood.
  • In about 25 percent of U.S. stream fish, methylmercury concentrations exceed EPA criterions.
  • Climate change is likely to increase the water conditions that fuel methylmercury concentration in fish.
  • Air knows no borders, and therefore global cooperation is necessary. Mercury pollution from Asia has sometimes impacted fish caught and consumed on the West Coast, blunting legislative efforts to cut international pollution.
  • The large amounts of mercury in rivers near old mines, including gold, copper and mercury mines, still contaminate fish decades after mining activity has ceased and, without costly remediation, will continue to contaminate seafood.
  • Methylmercury poisoning in wildlife and birds that consume fish is currently severe.
  • The elimination of national, coordinated fish contaminant monitoring after 1987 has left insufficient data to thoroughly analyze national trends since that time.

Although methylmercury is the focus of intense research, its presence is still inadequately surveyed, according to the U.S.G.S.’ Dr. David Krabbenhoft’s 2016 measure of its “existing inventories”:

“The challenge currently confronting resource managers, lawmakers, and the scientific community at large is to bring this complex problem into a more complete understanding that will allow for the proper and responsible actions to not only reduce new releases to the environment, but also prescribe effective land management strategies to deal with existing inventories.”

The EPA has proposed a new Clean Power Plan that would require emissions-cutting strategies — not just power-plant by power-plant, and state by state, as previous legislation has done — but across the whole electricity grid. The legality of the Clean Power Plan has been challenged and it’s now winding its way through the legal system. The Plan may not be implemented if a court finds it unconstitutional.


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This is a sobering but ultimately a positive outlook on the effects of mercury poisoning on humans. Our government's efforts to alleviate this problem must be continued to remove this silent killer from our food source.

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Thank you for this article. It is well researched and fascinating. Not only that, but it is timely for us.

I have been wondering if my husband was eating too much tuna fish and this could explain a lot. I'm going to see if he will get tested.

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Thanks for this well researched and well written article. It is timely because my husband is having some mysterious ailments and I was wondering about his tuna sandwich habit. I will try to persuade him to get tested. So thank you.

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