Undercover Fish Testing Reveals Mercury at Three Times Federal Limits

California sushi eaters, watch out: San Francisco-based public awareness campaign Got Mercury? released the results from its most recent undercover fish testing operation earlier today. The data are pretty scary, and they're making news. But it's a little unclear whether the alarm is totally warranted, and—more importantly—what we should be doing about it.

The campaign explains that they "randomly selected 41 grocery stores in California to purchase fresh and frozen samples of swordfish, ahi tuna or yellowfin tuna, and salmon," which they then submitted to laboratory analysis. Their findings include the startling fact that more than a third of the grocery store fish studied had levels of methylmercury in excess of the the FDA do-not-sell limit of 1 part per million, with swordfish being by far the worst offender. In fact, only 6 of the 32 swordfish samples analyzed came in below 1 part per million, and one fish, purchased at a Ralph's in Los Angeles, had 3 parts per million.

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Full details on where each sample was purchased and how it fared during testing are available in Got Mercury?'s "Operation Safe Seafood" report [PDF], which also includes a list of recommended next steps for both legislators and individual consumers, as well as the link for a handy app that helps you calculate your mercury exposure.

Many of Got Mercury?'s suggestions make a lot of sense—for example, the FDA and EPA already advise that pregnant women and children should avoid swordfish altogether, and it is hard to argue against a call for restaurants, chefs, and consumers to "stop serving, buying, selling and eating endangered bluefin tuna."

Other action items are more controversial, and a handful of experts have told the San Francisco Chronicle that they found the alarm "overblown:"

The FDA's benchmark [...] was calculated with a significant buffer zone. That is, mercury levels are not harmful until they reach 10 parts per million—10 times the 1 part per million guideline.

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To further muddy the waters (no pun intended), both sides in the debate are not being particularly transparent about their own agenda. The experts quoted in the Chronicle—Gavin Gibbons, spokesman for the National Fisheries Institute, and Pamela Tom, manager of the seafood extension program at UC Davis—are hardly unbiased, as both come from firmly within the ranks of the seafood trade. Meanwhile, Got Mercury? itself is a project of the Turtle Island Restoration Network, which means that their motivation is also subject to question. As Gibbons told the Chronicle: "They want to cut down on seafood consumption so the sea turtles don't end up as bycatch. It's detrimental to public health and it's cloaked as helping the public."

Mixed motivations aside, however, the fact remains that mercury levels in large fish, and swordfish in particular, are unacceptably high. Scientists are pretty much agreed on both the health benefits of eating fish and the health risks—especially to young and unborn children—of mercury exposure.

So, what to do? It seems pretty clear to me that in an ideal world, state and federal representatives would push for tighter controls on mercury use and emissions, fish with mercury levels above FDA limits would be removed from the market, and individuals would be adequately informed of the trade-off between health benefits and risks in seafood consumption. The difficulty comes in finding a budget to enforce regulations—especially in California, a state that is currently considering cutting off funding to all public libraries in order to fix its budget deficit—and also in deciding whether point-of-sale warnings are an effective way to inform consumers about risk or instead add up to little more than a gift to the signage industry.

What do you think? Is this issue overblown or deadly serious? And how should we respond?

Photo (cc) by Flickr user yummyporky