Oceana Magazine Spring 2008: Tainted Tuna

Eating fish in a healthy way doesn't have to be as complex as an intricate sushi roll. A new Oceana report, Hold the Mercury: How to Avoid Mercury When Buying Fish, clears up the confusion.

Now, more than ever, consumers have a choice of seafood from around the globe: swordfish from South Africa, salmon from Alaska, tilapia from Honduras.

Rarely, however, can consumers find correct information about mercury in fish from in a grocery store, market or restaurant. The U.S. Food and Drug Administration recommends that women of childbearing age and young children do not eat four high-mercury species: swordfish, shark, tilefish and king mackerel. In addition, the FDA recommends limiting consumption of albacore tuna or tuna steaks to six ounces or less each week, and limiting low-mercury fish to 12 ounces or less per week.

Mercury contamination can damage critical organs of the central nervous and cardiovascular systems. The developing nervous system of infants and children are particularly sensitive to excessive mercury exposure and may lead to problems with attention span, language, visual-spatial skills, memory and coordination.

Now, thanks to Oceana's campaign, nearly 30 percent of grocery stores nationwide are voluntarily posting the FDA's advice on signs at seafood counters. These stores have become part of Oceana's Green List; those that haven't are on the Red List. An interactive version of both lists is available here.

Still, a majority of groceries do not post the mercury advisory. So how can consumers find out about mercury in seafood? 

In Hold the Mercury: How to Avoid Mercury While Buying Fish, Oceana sent staff and volunteers to 40 seafood counters across the United States to ask one question: "What is the government advice on mercury in seafood for women who are thinking about having kids?" Only 13 percent of the responses correctly explained the FDA health warning. The other responses were all over the map: from ignorance of the mercury issue entirely to advice to eat large cherrystone clams if the woman in question wanted a baby boy, and smaller clams for a girl.

In addition to asking questions, Oceana staff and volunteers collected fish samples from 26 U.S. cities and analyzed them for mercury. Average mercury concentration in the tested grocery store tuna was .68 parts per million (ppm), nearly double the level in FDA data, which showed average concentration at .38 ppm for fresh or frozen tuna. Oceana found sushi tuna to be even higher, with an average value of .86 ppm.

In a separate study commissioned by The New York Times and released the same week as Hold the Mercury, mercury in sushi from upscale restaurants in New York was well above the FDA's average. Sushi from Nobu Next Door tested at 1 ppm for mercury, and Blue Ribbon Sushi featured the highest level tested at 1.4 ppm. 

The confluence of the study from The Times with Oceana's led to renewed nationwide interest in the mercury issue. Oceana's study was featured in a follow-up story in The Times, as well as other national newspapers, The Today Show and on National Public Radio.

The FDA can remove fish with mercury contamination above 1 ppm from market, but it never does, even though the prevalence of highly contaminated fish seems to be increasing. One in three of the sushi tuna samples tested by Oceana exceeded the FDA action level. Despite these findings, however, fresh tuna, like that found in sushi, is not included in the FDA's "Do Not Eat" advice. 
"Shoppers have a right to know about the government mercury warning, and it's up to grocers to make it available," said Jackie Savitz, director of Oceana's campaign to end seafood contamination. "While we now have 28 grocery store chains posting signs, many people are still getting the wrong message about mercury versus the health benefits of eating fish because they shop at Red List stores like Costco, Publix and A&P."

Two years after the FDA announced the consumer advisory, the Center for Science in the Public Interest found that 31 percent of pregnant women, women planning to become pregnant and nursing mothers were unaware that high-mercury seafood could be harmful. At the same time, another 18 percent of fish consumers may have misunderstood the advice and unnecessarily reduced their fish intake. Fish is an excellent source of low-fat protein and the omega-3 fatty acids found in fish have been associated with improved cardiovascular health.

"Oceana's new report aims to simplify the issue," Savitz said. "We want people to continue to enjoy low-mercury fish, which they can easily do if they're aware of the fish most affected by mercury contamination."

The report is part of Oceana's larger campaign to educate consumers and end mercury pollution. A major source of mercury is outdated technology in chlorine plants, which emit mercury into the air and waterways. In three years, Oceana has convinced five of the remaining nine chlorine plants in the United States to stop using mercury technology, since mercury-free technology is available and is already in use by more than ninety percent of the industry.