The levels of mercury in 11 samples of albacore canned tuna averaged 0.560 micrograms of mercury per gram of tuna. The average reported by FDA this year is 0.350 micrograms per gram. The sample size is small, but three out of the 11 cans had mercury levels more than twice the average values reported by the FDA.
The average mercury level in 48 samples of “light” tuna was roughly one-third the amount found in the white tuna.
The report adds to other research showing that albacore has more mercury than FDA tests have revealed.
“The main value of this study is that it points out that because tuna, especially white, or albacore, can be moderate-to-high in mercury – and because canned tuna is so popular in our diets – that mercury exposure from canned tuna is of concern,” said Roxanne Karimi, a marine scientist at Stony Brook University who was not involved with the study. Karimi’s research also has shown that mercury levels in fish vary widely from what the FDA reports.
The new study examined the mercury concentrations in 35 large (66.5 oz) cans and 24 large (43 oz) foil pouches from brand lines and products sold specifically to schools. The tuna was from six brands of “light” tuna and two brands of albacore tuna, including Sunkist and Chicken of the Sea, which made up 60 percent of the light tuna studied.
Fifty of the 59 tuna samples were imported to the United States. The nine samples of U.S.-caught tuna had the lowest average mercury concentration. “Light” tuna from Ecuador had the highest.
In the study, tuna mercury levels were highly variable between samples, which means parents or schools can’t easily judge its safety, Groth said. The report suggests that schools should avoid buying tuna from Ecuador and other Latin American countries, instead buying U.S. or Asian tuna.
Groth said the take-home message for parents isn’t that their kids should stop eating fish. “Focus on kids who eat too much tuna and give them other kinds of nutritious seafood,” he said. “Don’t stop eating tuna. It’s OK for most kids.”
The report was co-sponsored by nine other advocacy groups, including Physicians for Social Responsibility and the Center for Science in the Public Interest.
This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.