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Public Radio's Environmental News Magazine (follow us on Google News)

Mercury in Fish: Casting Caution to the Wind?

Air Date: Week of

An ad campaign called FishScam.com says government mercury advisories are inaccurate and meant to scare consumers. Host Bruce Gellerman talks to David Martosko of the Campaign for Consumer Freedom about the campaign. He also speaks with Dr. Leo Trasande of Mount Sinai Medical School who says studies show that, in fact, the government safety threshold for mercury should be even stricter. We also speak with reporter Sam Roe of the Chicago Tribune. His recent series "The Mercury Menace" revealed many fish deemed safe by the government contain high levels of mercury.


GELLERMAN: From the Jennifer and Ted Stanley Studios in Somerville, Massachusetts, this is Living on Earth. I'm Bruce Gellerman, sitting in for Steve Curwood.

Scientists agree, fish is good for you. High in protein and rich in omega 3 fatty acids, it's healthy for your heart and your brain.

Tuna in net. (courtesy of NOAA)

But you can also have too much of a good thing. Virtually every fish in the world, especially large predator fish at the top of the food chain, like shark, tuna and king mackerel, contain minute amounts of methyl mercury, a potent neurotoxin that can harm the developing nervous system of a young child or fetus.

Methyl mercury comes from natural sources and the burning of fossil fuels in power plants. And while there is general consensus on the benefits of consuming fish, just how much mercury is in our fish, and how much is safe to eat, is at the heart of an intense public debate.

This ad is part of a public service campaign produced for Earthshare, a coalition of environmental groups.

WOMAN: Mercury poisoning may cause neurological damage that impairs learning, language development, vision and memory.

MAN: According to the latest study, you shouldn't eat any fish.

GELLERMAN: This radio spot, produced for the Center for Consumer Freedom, says don't get hooked on mercury hype:

MAN: If you do eat fish, the latest study claims you could grow gills or start responding to the name “Flipper.”

FishScam.com billboard ad

GELLERMAN: David Martosko is director of research at the Center for Consumer Freedom.

MARTOSKO: The public is hearing so much, I think, in terms of scare tactics, this fear factor approach to fish, that, it’s unfortunate, but we thought we had to be a little bit irreverent, a little bit over the top, in order to get people’s attention.

GELLERMAN: Martosko believes government and advocacy group warnings about the dangers of mercury in fish are overblown, and potentially harmful. On the group's website, FishScam dot com, you can calculate how much fish you can eat before, his group says, you'd get a dangerous dose of mercury. For example, according to the FishScam calculator, an average woman of child bearing age weighing 161 pounds would have to eat 3.2 pounds of albacore tuna to put herself and her baby at risk.

MARTOSKO: Yeah, that’s true. According to the best science, and according to the science that the EPA uses to figure out where that line in the sand is where you might hurt yourself from eating food, if you’re 161 pounds you’d have to eat over three pounds of tuna every week for life before you should worry about it.

GELLERMAN: But I’m looking at the FDA/EPA advisory from 2004, and it says it’s six ounces per week.

MARTOSKO: Well, what they do is they divide everything by ten. This is a very standard practice in epidemiology and toxicology research. They find the level that actually might harm you and they apply some sort of a safety factor to it. That doesn’t mean that that safety-adjusted number is the magic, you know, harm threshold. And it simply isn’t. The truth is, when you hear a number from the EPA or the FDA about mercury in fish, you should mentally multiply by ten in order to find where the actual danger line might be.

Now look, there’s nothing wrong with being extra safe. That’s fine. If you want to follow that advisory, that’s a perfectly fine thing to do. But you shouldn’t be bamboozled into thinking that you’re putting your health at risk by eating, you know, six ounces of tuna a week. It simply isn’t true.

GELLERMAN: Now, you have studies that back this up?

MARTOSKO: Oh, yeah. Not only do I have studies that back this up, the EPA has them. I mean, the EPA knows the level of exposure that represents a hypothetical risk, but it adjusts that by a factor of ten to get what it calls a “reference dose.” And it’s this smaller number, this sort of hyper-cautionary number, that environmental advocacy groups often use in order to scare some Americans into believing that these tiny amounts of mercury in fish represent a health hazard.

GELLERMAN: I was looking at studies from the Faroe Islands, which is off Iceland, and another one from New Zealand. They suggest there is a health hazard, and at low doses.

MARTOSKO: Well, you know, there’s sort of a dueling studies mentality in the scientific world right now about mercury. There are two very well-regarded studies, one from the Faroe Islands and one from the Seychelles Islands. Both populations of these people eat a lot of fish. The Seychelles Islands study has come to the general conclusion that the mercury in the fish these people eat is not harming them at all. The Faroe Islands study found a very, very small health effect in some children on the order of a, say, an IQ shift of, you know, a tenth of a point. On a test, by the way, that’s got a margin of error of three to five points so it’s statistically insignificant. But they found something.

Our EPA says, ‘well goodness, these people found something and those people didn’t, we better just be careful and, you know, pay attention to the people who found something.’ I think you ought to pay a little more attention right now, at least while the science is evolving, to actual real-life people. Look at the population of Japan, for instance, that eats, you know, five to ten times as much ocean fish as we do – 74 percent of the women of childbearing age in Japan right now are above the U.S. reference dose for mercury. Now I ask you, are their kids, you know, woefully inadequate in math and science and cognitive abilities? Or are their children out-performing ours in math and science? You know, it seems to me that if there’s any real damage from the mercury, all these fish that the Japanese people eat, we ought to be able to see it in their kids.

GELLERMAN: Mr. Martosko, do you or does the Center for Consumer Freedom get money from the seafood industry, from coal companies, utilities?

MARTOSKO: Well, I know that we never accepted money from utilities or coal companies. I don’t know exactly which companies in the food sector support us. You know, it’s not my job to know. I really don’t pay attention. I do know that the vast majority of our, say, institutional funding, comes from the food sector. Beyond that, I just don’t know.

GELLERMAN: You were involved in the cigarette controversy, about having Americans be able to smoke cigarettes in public places.

MARTOSKO: Way back, and I think this is going back eight or nine years, long before I was there, I believe that my organization weighed in some on the rights of individual restaurant owners to allow their patrons to smoke in, you know, restaurants and bars. You know, it was more of a consumer-choice thing. We believed at the time, and we believe now, that consumers ought to be able to do what they want, free from whatever interference isn’t justified.

GELLERMAN: I was reading research by Dr. Leo Trasande, and he says, quote, “there’s a significant threat to the economic health and security of the United States posed by mercury poisoning and mercury in fish.”

MARTOSKO: Well, Dr. Trasande would have to actually produce a case of mercury poisoning from fish. There has been none actually documented in the United States, pretty much ever.

GELLERMAN: David Martosko of the Center for Consumer Freedom has a point: massive mercury poisoning is a rare occurrence. But scientists measure methyl mercury in fish in parts per millions, and Dr. Leo Trasande says the effects are subtle. Trasande is assistant director for the Center for Children's Health and the Environment at Mt. Sinai School of Medicine in New York.

TRASANDE: The science on methyl mercury toxicity is very strong. The National Academy of Sciences, in 2000, found effects even at very low levels as a result of methyl mercury toxicity.

GELLERMAN: So, what do you think of Mr. Martosko’s statement about your work, and not being any recent cases of mercury poisoning?

TRASANDE: Well, unfortunately we have between 300,000 and 600,000 silent cases of methyl mercury toxicity each year that have profound implications for the learning and development of our nation’s children. Because these children suffer loss in IQ, they are less well able to perform well in school, and, therefore, less well able to perform in the economy. Unfortunately, methyl mercury toxicity costs our nation $8.7 billion each year in lost economic productivity.

GELLERMAN: David Martosko, the research director of the Center for Consumer Freedom, says that the government’s reference dose is hyper-cautionary. That is, it took a factor, divided it by ten, and said that’s safe.

TRASANDE: Well, two major epidemiologic studies prove otherwise: one in the Faroe Islands and one in New Zealand. They both found consistent effects on learning and development in children at right around, and possibly below, the current EPA and FDA safety threshold. In fact, they suggest that the safety thresholds might have to be lowered further.

It’s important not to stop the general public from eating fish that are high in omega-3 fatty acids. They’re terrific for brain development, they’re terrific for preventing heart disease and stroke. But it’s unconscionable not to focus the attention on getting the mercury out of fish.

GELLERMAN: Leo Trasande is a pediatrician and author of numerous articles about the effects of mercury on children.

It's supposed to be the job of federal regulators to measure and monitor the amount of methyl mercury in the fish we eat. But a recent investigative series in the Chicago Tribune found that, for decades, the U.S. government knowingly allowed millions of Americans to eat seafood with levels of mercury exceeding it's own safety standards. Reporter Sam Roe co-authored the Tribune's series, “The Mercury Menace.”

ROE: First of all, we went out and we did a random sample of supermarkets in the greater Chicago area, and we bought popular fish, at each of these supermarkets, and we had them tested. Sent them out to a laboratory out at Rutgers University and had them tested for mercury, and found that there were incredibly high levels of mercury in a variety of popular seafood. And, in some cases, the levels were high enough where the government could seize the fish.

We also took a very hard look at canned tuna, especially light tuna. This is a very popular food in America, and one that the government specifically recommends for at-risk groups to choose if they’re concerned about mercury. And what we found is that there is a significant portion of this canned light tuna that is made with a high-mercury species, called Yellowfin, and often times the labels don’t suggest that. And so consumers going into the store buying canned light tuna, thinking they’re going to get low-mercury fish, can often get a high-mercury can and they have no way of knowing which can may be higher than the next can.

GELLERMAN: Isn’t there a federal testing program for mercury and canned tuna?

ROE: No, not really. In fact, there’s not really a testing program for any fish. They used to routinely test them years ago, but that stopped. They claim that, you know, finances is a problem. And it is sort of remarkable, it’s the one thing that sort of kept us going when we first got into this, knowing that the government is really not taking basic steps to determine which species are more harmful than others.

GELLERMAN: Now, you tested Walleye fish. Eighteen fish you tested, I guess, in your laboratory.

ROE: Yes, 18, and actually it may sound like a small amount but it’s actually many more numbers than the government has actually tested. The government has only tested four Walleye in the last 25 years, and it’s a very popular fish out here in the Midwest. And we found in the case of Walleye numerous samples were over the legal limit. And Walleye averaged over Canada’s limit, which is really interesting because all of the Walleye we’re getting in this country comes from Canada; and it averages over their safety limit in Canada and they’re shipping it down here.

GELLERMAN: So it’s safe to ship fish that would be banned in Canada and sell it in the United States?

ROE: That’s right. Canada’s mercury limit is much tighter than the U.S.; it’s half as much as what the U.S. is.

GELLERMAN: What’s been the effect of your investigation?

ROE: As far as official response, the FDA has opened an investigation into the canned tuna issue to see, you know, why there’s high-mercury tuna being put into a low-mercury choice. There’s been calls in Congress for some action on the FDA. And recently, here in Illinois, the governor proposed reducing mercury emissions at coal-fired power plants, a major emitter of mercury, to reduce those emissions by 90 percent over the next few years.

GELLERMAN: Chicago Tribune reporter Sam Roe. For more information on mercury in fish, check out our web site www.loe.org.




EPA/FDA 2004 Mercury and Fish Advisory

Environmental Working Group on Mercury and Seafood

Got Mercury? Turtle Island Restoration Network Project

Environmental Health Perspectives May 2005 article by Leo Trasande – “Public Health and Economic Consequences of Methyl Mercury Toxicity to the Developing Brain”

Chicago Tribune series “The Mercury Menace”


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