Why Worry About Toxics in Fish?

Pollution from factories and power plants ends up in lakes, rivers, and the ocean—which in turn pollutes the fish we eat. Almost all fish contain at least low levels of toxic pollutants.

Where children’s health is concerned, it pays to be cautious. With their small bodies and rapidly developing brains, exposure to certain contaminants can cause harm. Many studies have shown that the contaminants found in seafood can be particularly harmful to children by increasing the risk of learning disorders (1), behavioral problems (2), and memory loss (3).

To know if a fish is safe involves making calculations based on your child’s body weight, age, gender, portion size, and other risk factors—and tracking how much they eat on a monthly basis—a complicated process for busy parents. For a list of recommended meals per month by fish, click here.

Learn more about toxics in fish:

• Mercury >>
• PCBs >>
• Other Contaminants >>

Mercury

Mercury is an environmental toxin that causes a wide range of harmful health effects in humans. It can impact the central nervous system, kidneys, and immune system, and, in particular, brain development.

According to the American Academy of Pediatrics, “Mercury in all of its forms is toxic to the fetus and children, and efforts should be made to reduce exposure to the extent possible to pregnant women and children as well as the general population.” (4)

While naturally occurring in the environment, mercury is also released through industrial pollution, such as from coal-fired power plants. It falls from the air in rain and other forms of precipitation, getting into surface water and working its way into streams, lakes, and the ocean. Then bacteria cause chemical changes that transform mercury into its toxic form, methyl mercury. Fish absorb methyl mercury as they feed on aquatic organisms and other fish.

Although dangerous, mercury can be eliminated from our bodies over time. For a person with long-term regular exposure, it can take up to a year to fully eliminate methyl mercury from the body. (5)

PCBs

Polychlorinated biphenyls (PCBs) are a group of chemicals that were produced as lubricants and insulators for electrical equipment. The US Environmental Protection Agency has classified them as carcinogens (6) —that is, substances that can cause cancer. While their production was banned in the US in 1977, PCBs are persistent, meaning that they do not degrade over time.

PCBs are highly toxic. Early life exposure to PCBs can cause harmful neurological effects, leading to learning deficits, poor memory, and behavioral problems. (7)

Because they are fat soluble, PCBs accumulate in the fatty tissues of animals. Animals at the top of the food chain have the most, including fatty fish, beef, dairy products, and, ultimately, the humans who eat them. (8)

Based on state and academic studies, the highest known levels of PCBs are found in bluefish, wild striped bass, and Atlantic salmon. (9) Yet, as seafood is not comprehensively tested for PCBs by the US Food & Drug Administration (FDA), many types of fish and shellfish have never been tested.

You can reduce (but not eliminate) the amount of PCBs in fish by properly trimming, skinning, and cooking it to remove fat. Cooking does not destroy PCBs, but heat allows some of the contaminated fat to melt off. In order to reduce the amount of PCB contaminants, you can broil, grill, or bake the trimmed, skinned fish on a rack so the fat drips away. (10) Nutritionists recommend that you do not use the drippings to prepare sauce or gravies. (11)

Other Contaminants

Other contaminants are also found in fish: dioxins, antibiotics (primarily through fish farming), pesticides from agricultural runoff, and flame retardants (called PBDEs). KidSafe Seafood will not endorse any fish known to contain these substances, but much more testing and research is needed to understand the impact and extent of these contaminants in fish.

More information about mercury, PCBs and other toxic chemicals; and research into developmental, learning, and behavioral disabilities in children can be found in Physicians for Social Responsibility’s report, In Harms Way: Toxic Threats to Child Development.

1. Patandin S, et al, 1999. "Effects of environmental exposure to polychlorinated biphenyls and dioxins on cognitive abilities in Dutch children at 42 months of age." Journal of Pediatrics 134: 33-41. See also US EPA, 1999. "Public health implications of exposure to polychlorinated biphenyls (PCBs)."
2. Physicians for Social Responsibility and the Association of Reproductive Health Professionals, 2004. "Fish consumption to promote good health and minimize containments: A quick reference guide for clinicians." p. 7.
3. Schantz, S et al, 2001. "Impairments of memory and learning in older adults exposed to polychlorinated biphenyls via consumption of great lakes fish." Environmental Health Perspectives 109: 605-611.
4. Goldman, L, Shannon, M, and the Committee on Environmental Health, 2001. "Technical Report: Mercury in the Environment: Implications Pediatricians." Pediatrics 108: 197-205, p. 203.
5. Clarkson, T, 2002. "The three modern faces of mercury." Environmental Health Perspectives 110 (Suppl 1): 11-23, p. 13.
6. US EPA. "Health Effects of PCBs."
7. Physicians for Social Responsibility and the Association of Reproductive Health Professionals, 2004. "Fish consumption to promote good health and minimize containments: A quick reference guide for clinicians." p. 7.
8. US EPA, 1999. "Public health implications of exposure to polychlorinated biphenyls (PCBs)."
9. Environmental Defense, 2006.
10. Armbruster, G, Gerow, KG, Gutenmann, WH, Littman CB, and Lisk, DJ, 1987. "The effect of several methods of fish preparation on residues of polychlorinated biphenyls and sensory characteristics of striped bass." Journal of Food Safety 8: 235-243.
11. Kannan, N. 2000. "Non- and mono-ortho chlorinated biphenyls." From The Handbook of Environmental Chemistry 3 (Part K): New Types of Persistent Halogenated Compounds (J. Paasivirta, ed.), Springer-Verlag, Berlin Heidelberg. P. 127-156.