Dangerous levels of mercury have been discovered in fish jerky sold in Hawaii stores, according to a study published last week in the Journal of Environmental Health.

The study found that mercury levels in marlin jerky were five to 28 times federal recommended limits. Such levels are believed to pose a particular danger for brain development in fetuses and young children. High mercury levels have also been tied to memory and vision loss and heart disease.

State health officials urged people to be cautious about the study, which only tested jerky, not fresh marlin. Peter Oshiro, environmental health program manager at the Hawaii Department of Health, said the agency is reviewing the study, which was published in a respected health journal and reviewed by other scientists before publication.

“Once people hear the word mercury or radiation a lot of people panic and it’s not needed,” he said.

But one national health expert said the Hawaii numbers are reason to be concerned. The risks to fetuses and children are those that are best understood, according to Dr. Philippe Grandjean, adjunct professor of environmental health at the Harvard School of Public Health and chairman of the department of environmental medicine at the University of Southern Denmark. He said that the amount of mercury adults can tolerate is much less clear.

“I think the numbers that were produced by those analyses, those numbers are very high, and I think there is a good reason to worry about it because the consumers are not warned about the high mercury content,” said Grandjean, adding that the FDA needed to provide better guidance on the issue.

Eighty-nine percent of the 75 samples of marlin tested exceeded recommended safety levels of the U.S. Environmental Protection Agency. Seventy-five percent of samples exceeded the maximum level of safety set by the U.S. Food and Drug Administration – the agency’s threshold is twice that of the EPA.

“There are certain fish that humans just should not consume and this may be one of them,” said Jane Hightower, the study’s author. She is a California physician who has garnered national attention for her work on the health threats of mercury levels in fish.

Samples of ahi tuna and salmon jerky were also tested, most measuring below FDA levels.

Large fish that have long lifespans, such as marlin, carry a higher risk for mercury because they eat smaller fish, absorbing their mercury content. The mercury accumulates in the flesh of the fish as well as its organs. When dried for jerky, mercury levels can become more concentrated.

John Kaneko, of the Hawaii Seafood Council, disputed the findings and said that deterring people from eating fish deprived them of substantial health benefits.

“If you scare women off eating fish then you are pushing people off the deep end,” he said. “You need to be very careful about how people respond to news reports, but also to these federal guidelines.”

Kaneko also argued that it was important to test levels of selenium in fish that counteract negative effects of mercury, and that it was important to differentiate between non-toxic mercury and methylmercury, which is dangerous.

“I don’t believe that the levels we find naturally in open ocean fish like marlin, sharks or swordfish have a public health significance,” said Kaneko.

He said that the study was deficient in not testing specifically for the methylmercury.

But Grandjean said that that most mercury found in fish is the toxic kind. “It would be a very serious mistake to think that any substantial part of mercury in fish is anything but methylmercury,” he said.

Hightower criticized the FDA for failing to warn the public about fish jerky. She also faulted the fishing industry for not doing more to protect its consumers.

Government agencies that are expected to provide people with information about public health risks should be stepping up their efforts, she said.

“I’ve done my job, now let’s see if they do their job,” she said.

DISCUSSION: Do you think there should be more federal and state oversight of mercury levels in fish?*

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