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Monday, September 10, 2012

Is fish good for us? The nasty toxin, mercury, makes that complicated

David Brooks

Want a poster child for the dilemma we all face when trying to eat healthy? Consider fish.

Fish provides protein with less fat and calories than meat or poultry. It is full of omega-3 fatty acids that seem to ward off heart attacks. Good!

But fish tends to be loaded with some of the nastier byproducts of human society, particularly heavy metals that accumulate in the aquatic food chain, and which can cause serious neurological problems. Even fish in remote, pristine New Hampshire lakes are contaminated. Bad!

That is why health officials have such long, complicated advice: Yes eat fish, but … never eat this species, it’s OK to eat that species (usually), smaller fish are better for you (probably), some people can eat this species but others can’t, sometimes you should eat wild fish but sometimes farm-raised, you can eat this species but only when packed in water rather than oil (or maybe the other way around), and so on.

It’s enough to baffle the most devoted piscophile.

Dartmouth Toxic Metals Superfund Research Program, of all groups, to the rescue!

This research group – scientists, grad students and technical staff associated with the Geisel School of Medicine in Hanover – has created a 10-minute film for the web, which will also be shown Thursday, Sept. 13, at Red River Theater in Concord. It’s called “Mercury: From Source to Seafood” and it condenses a ton of information about why mercury is bad for us, how it gets into the environment (burning coal is a main source but not the only one), and what consumers should do with that information. It builds on a lot of research done in the program, first with lake fish in New England more recently with fish caught in the oceans.

“We wanted to help people understand how mercury gets into aquatic systems, how it gets into the fish we eat, and why it’s important to still eat fish, but know which fish to eat,” said Laurie Rardin, a spokeswoman for the program.

I’m familiar with the research program because they participated in a Science Cafe NH discussion in June about arsenic, which is the other toxic metal they study.

They have found that short movies are a good way to get across complex topics. This one was created by a production firm in Boston.

Now, you might think – I certainly did – that the problem of mercury in fish is easing because the amount of coal being burned for electricity in New Hampshire and the country is declining, pushed out by cheaper natural gas power and environmental constraints. Public Service of New Hampshire, for example, has turned its coal-burning mainstay, Merrimack Station in Bow, from an always-on baseline power plant into one that’s only occasionally fired up to meet peak demand during hot summer days – which is kind of ironic, since it now has a $450 million scrubber which removes most of the mercury from its emissions.

But mercury is so bad for us, especially for fetuses and young children and the elderly, and can linger so long in the environment that we’re a long way from sighs of relief, I learned.

“When individual states have put in controls to reduce the amount of mercury emissions, we are seeing reductions of mercury in the environment,” said Rardin, but that’s not much, partly because the situation is so complicated. “One of the things we need is more monitoring.”

The film also makes it clear that even without specific information, it’s penny wise but pound foolish of us not to limit releases of mercury by industrial activity, even if it means difficult choices like cutting way back on coal-fired power. That’s an absolute step if we even want to fry up our catch from a fly-fishing session on the Souhegan River without any worry.

As for eating seafood or fresh-water fish, here’s the shorthand advice: Pregnant women and very small children should avoid it unless they’re very knowledgeable. The rest of us should follow Aristotle’s advice and seek moderation in all things. Eat fish or seafood a few times a week, but mix up the species and types (trout, scallops, tilapia, catfish, lobster, oysters, tuna), lean toward smaller fish like sardines because they’re not so far up the food chain, and don’t go too crazy over sushi.

For details, the Monterey Bay Aquarium’s Seafood Watch has long been the go-to source: www.montereybayaquarium.org

Granite Geek appears Mondays in the Telegraph, and online at www.granitegeek.org. David Brooks can be reached at 594-6531 or dbrooks@nashuatelegraph.com.