Which Fish Are Safe To Eat To Avoid Mercury?

July 4, 2010

Dear EarthTalk: I always thought eating fish was healthy, but now I’m concerned about mercury in tuna and other fish. Are there any fish that are still safe to eat?

You should be concerned about contaminants in certain fish, including some kinds of tuna. The non-profit Environmental Defense Fund (EDF) recommends minimizing consumption of albacore (white) tuna, a large fish that accumulates moderate amounts of mercury in its fatty tissue. But other kinds of (smaller) tuna, such as skipjack (usually canned as light), which accumulates a third the amount of mercury as albacore, are OK to eat in moderation, though consumption by those under age seven should be limited.

To further complicate the issue, some canned light tuna may contain yellowfin tuna, which has mercury levels similar to those of albacore; these products are sometimes but not always labeled as gourmet or tonno and their consumption should be limited, even by adults. Mercury, a known neurotoxin (a poison that affects the nervous system), is particularly insidious because it is widespread in our oceans, primarily due to emissions from coal-burning power plants. These smokestacks deposit mercury into waterways, which carry it to the ocean where bacteria convert it into methylmercury. Fish then ingest it with their food and from water passing over their gills. Generally speaking, bigger, older and large predatory fish (such as sharks, swordfish, tilefish, king mackerel and some tuna) near the top of marine food chains are more likely to have high levels of mercury than fish lower in the marine food chain.

People exposed to high levels or frequent doses of mercury can suffer nervous system disorders, impaired mental development and other health problems. An April 2003 study, published in Environmental Health Perspectives, found that 89 percent of study subjects, chosen because they ate a significant amount of fish, had blood mercury levels above the U.S. Environmental Protection Agency’s (EPA’s) safety threshold of five micrograms per liter. Even though there are health benefits to eating fish (including the intake of healthy omega-3 fatty acids), the EPA advises that young children, pregnant women, nursing mothers and women of childbearing age limit their intake of high-mercury fish to one serving per week at most, while limiting their overall intake of any fish or shellfish to no more than two to three servings, or 12 ounces total, per week.

Mercury isn’t the only harsh pollutant lurking in the ocean. Industrial chemicals like PCBs and pesticides like DDT are awash in marine food chains around the world. According to EDF, it can take five years or more for women of childbearing age to rid their bodies of PCBs, and 12-18 months to appreciably reduce their mercury levels. EDF adds that moms who eat toxic fish before becoming pregnant may have children who are slower to develop and learn because fetuses are exposed to stored toxins through the placenta.

To learn more, visit the EPA’s Fish Advisories website. It includes links to individual state advisories, which have details on what fish should or shouldn’t be eaten from nearby lakes or coastal areas. Catfish, Pollock, salmon, shrimp and canned light tuna are currently on the EPA’s safe list, as they feed toward the bottom of the food chain and thus have less opportunity to accumulate mercury and other contaminants.

CONTACTS: EDF, www.edf.org; EPA Fish Advisories, www.epa.gov/waterscience/fish.

SEND YOUR ENVIRONMENTAL QUESTIONS TO: EarthTalk, c/o E The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; earthtalk@emagazine.com. E is a nonprofit publication. Subscribe: www.emagazine.com/subscribe; Request a Free Trial Issue: www.emagazine.com/trial.

Photo by Augapfel

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About the Author:

After a varied past of being a test driver for automotive television programs, a Hollywood studio lackey, and an online media sales director, David is now the publisher and editor of The Good Human. In his spare time he rides motorcycles, drinks good beer, and builds stuff in the garage. You can follow him on Twitter at @thegoodhuman or G+ at Google
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Comments (6)

  1. Noah says:

    There is an app for the iPhone that keeps current on various levels of mercury, other pollutants, and the environmental repercussions of many, many types of fish. It’s called Seafood and is incredibly useful and well thought out. I think it’s free, too.

    I use it all of the time, and the results are often me not ordering much fish anymore. :-(

  2. Dan says:

    Fish is one of the most unsustainable “foods” you can eat. There are more risks than benefits and you can get all your nutrients from more sustainable alternatives.

    Why even worry about mercury? Don’t eat fish.

  3. Michael Jones says:

    Unfortunately for me I’m crazy about Albacore tuna. What other fish might I eat that doesn’t have great amounts of mercury, other than ‘light’ tuna which isn’t that good quality wise?

    • david says:

      These fish have the lowest amounts of mercury in them:

      Anchovies
      Catfish
      Clam
      Crab
      Flounder
      Herring
      Mackerel
      Oyster
      Perch (Ocean)
      Salmon (Fresh)
      Sardine
      Sole (Pacific)
      Tilapia
      Trout (Freshwater)
      Whitefish

  4. Michael Jones says:

    Thankyou David…I’m liking this site more and more (-”

  5. Trevor says:

    I have been eating 125 gram John West tuna on toast for lunch every day for ages. I don’t know what kind of tuna it is and just today the mercury issue dawned. After reading some of the information and comments I better go back to sardines. I’m looking for a good source of omega 3. I don’t like too much animal meat; chicken is bland and meats such as samami etc. have nitrates used as preservatives.