Thanks to coal-burning power plants, the fish on the left might be more dangerous than the fish on the right

The can of tuna might be more dangerous thanks to mercury, most of which is polluted by coal-burning power plants, like those on Jacksonville's Northside. And while tuna isn't the only fish that might come chock full of mercury (in fact, even shark has mercury in it), canned tuna is the most popular fish in the U.S. And, certainly, way more people eat tuna and are possibly exposed to this toxin than are ever bitten by a shark.

Self magazine recently published an excellent article about the dangers of mercury - "How safe is what's in this can?"

If you don't have time to read the full article, here's a look at some key takeaways and excepts:

Mercury's effects on your health...

"When a pregnant woman consumes mercury, it passes through the placenta into the brain of the fetus, where it can linger for years. In extreme amounts, more than 10 micrograms per gram as measured in hair (which scientists use to gauge the body's mercury levels), mercury can cause mental retardation, cerebral palsy, deafness and blindness. In the lower-level amounts typically found in Americans—fewer than 2 micrograms per gram in hair—risks to a newborn include a drop of a few IQ points, slow brain development and learning disabilities. Researchers at the U.S. Environmental Protection Agency estimate that more than 300,000 babies born each year in this country are at risk of having brain damage due to mercury exposure in utero."

"Women may also have to worry for their own health: A 2003 study by San Francisco internist Jane Hightower, M.D., published in the journal Environmental Health Perspectives, found that 89 percent of her female patients had mercury levels above what most scientists consider safe, and that high mercury levels in adults correlated with memory loss, fatigue and muscle aches. Another preliminary study this year found that mothers who delivered prematurely were more likely to have high mercury levels."

"The Faroes study, which also appeared in 1997 and was led by Philippe Grandjean, M.D., professor of environmental health at the Harvard School of Public Health in Boston, showed that children born to mothers with elevated mercury levels were slow to develop motor and speech skills. "Over an entire population, it can be significant," Dr. Grandjean says. "You will have fewer kids who are really bright and will have pushed a few [down so far] they can't compete in high school."

"Recent research on men in Finland found that mercury in fish increased their risk for heart disease, potentially counteracting the benefits hearts get from omega-3's. Dr. Grandjean, who led the Faroe Islands study, argues that although low-mercury fish is definitely a health food, the evidence linking mercury to heart disease is now strong enough that no one—man, woman or child—should eat fish with elevated mercury levels."

Where does the mercury in tuna and other fish come from?

"Mercury is a liquid metal found in rocks, including coal. When power plants burn coal, they release mercury, causing nearly half of U.S. man-made mercury pollution, according to the EPA."

"Every day in this country, coal-fired power plants in all 50 states spew out particles laced with mercury."

"... a 2002 study published in Environmental Science & Technology estimated that 70 percent of the mercury in our atmosphere was put there by humans."

And now a quick look at the power industry...

"But has women's health truly come first in the government's handling of the mercury issue? For the past decade, numerous scientists have accused the FDA of ignoring their advice and watering down its rules to suit the wishes of Big Tuna: the fisheries that catch and process tuna and the companies that sell it. "It's been complete and utter foot dragging by the FDA," says Deborah Rice, Ph.D., a former senior toxicologist at the EPA now working for the state of Maine. At the same time, Big Tuna—and the electrical-power industry that generates mercury emissions in the first place—have put money into scientific studies that found low threats from mercury and have used that research to argue against tighter rules. Leonardo Trasande, M.D., an expert on environmental toxins at the Mount Sinai School of Medicine in New York City, says the result of the country's lax methylmercury regulations will be felt for decades to come: 'Mercury is going to poison an entire generation of our nation's children.'"

"But the most reassuring mercury news that year came from an international team ... working in the Seychelles islands off the east coast of Africa. At the time the women studied gave birth, they had about 6 mcg per gram of mercury in their hair—an alarmingly high level. But at a year and a half, the women's babies showed no ill effects. The work...was funded by the governments of the United States and the Seychelles, not private industry. Big Tuna and the power industry chipped in the following year, giving some of the Seychelles researchers grants of half a million dollars to evaluate methods of testing children for cognitive defects resulting from environmental toxins, including mercury. In addition to money from an FDA program, the project attracted $5,000 from the fisheries institute, $10,000 from the U.S. Tuna Foundation and $486,000 from the Electric Power Research Institute in Palo Alto, California, a research group funded by electric power-plant companies. (Officials with the EPRI did not return calls for comment.)"

"Yet the fact remains, as Dr. Hightower puts it, that in contrast to studies connected to industry, "most independent studies have found that mercury has harmful health effects." A 2007 British study published in Lancet was the exception, suggesting that eating seafood while pregnant has net health benefits for children. But other independent studies in the United States, New Zealand and the Faroe Islands near Iceland have all shown danger to children due to mercury in seafood."

"The power industry helped underwrite a speech by University of Rochester researcher Philip Davidson, Ph.D., (from the Seychelles study) to a July 2003 conference co-hosted by the American Association on Mental Retardation."

"The San Francisco judge who ruled against consumer warnings relied heavily on the testimony of François Morel, Ph.D., professor of geosciences at Princeton University in New Jersey, whose findings indicate that very little of the mercury in tuna comes from man-made sources. The state countered in its appeal that Morel's claims are "not shared by any other scientists in the field." Morel's research had been aided by—surprise—the U.S. Tuna Foundation. He says that since 2003, he has also accepted roughly $150,000 a year in grants from the Electric Power Research Institute. The power industry has funded almost all of the research into the chemistry of mercury, he adds. "I've yet to see any problems. People are honest and EPRI realizes it would damage itself by trying to skew the results."

And mercury doesn't just damage health, but possibly the economy as well

"And then there's tuna. It has become a focus of mercury worries because we eat so much of it: Canned tuna is the most popular fish in the United States and the second most popular seafood after shrimp, generating close to $1.5 billion in sales annually. That means, as Dr. Jane Hightower notes, 'the issue of mercury in fish involves not only the health of the consumer, but the health of the economy.'"

What to do? What to do?

"The message she (Dr. Jane Hightower, who has treated nearly 100 women for mercury poisoning) gives patients: Use common sense. Fish such as salmon, flax-fed hens, grass-fed beef and fortified products are all good sources of healthy fats. "You can get omega 3's without significantly increasing your mercury level and at the same time have a very healthful diet," she says. "Poison is not a good thing to eat."

The tools at OceansAlive.org can help you sort out which fish have high levels of mercury, and which have low levels of mercury.

Write the city council and mayor. Tell them to require JEA to lower mercury emissions and fund the testing of Jacksonville's water for mercury.