A coal-burning power plant emits mercury pollutants which can contaminate fish we eat.

Seafood contamination usually is not easy to observe. It takes a wise consumer to decrease their health risks by avoiding contaminated fish while choosing to eat and properly cook those that are safe.

The main chemicals of concern that contaminate fish humans eat are Mercury, Pesticides and PCBs.

The mercury cycle

The EPA has developed a “virtual safe limit” based on body weight and mercury content of the fish. By adhering to the following general recommendations, you can stay with this "safe limit" and enjoy the health benefits of fish while lowering your mercury exposure.

Recommendations

• Avoid fish with high levels of mercury. In general do not eat shark, swordfish, king mackerel, or tilefish.
• Calculate your mercury exposure. In general, eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury such as shrimp, canned light tuna, salmon, pollock, and catfish. Albacore ("white") tuna has more mercury than canned light tuna. When choosing your two meals of fish and shellfish, eat up to only 6 ounces (one average meal) of albacore tuna per week.
• Check local advisories about the safety of fish caught by family and friends in nearby lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.
• Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions.

More Information

• Mercury Contamination in Fish - A Consumer Guide
  NRDC
• Got Mercury? - Mercury Calculator
  Turtle Island Restoration Network
• Mercury in Fish and Shellfish
  Oceans Alive
• Seafood Contamination
  Oceana
• Mercury Contamination of Seafood
  CA Academy of Sciences
• EPA: Mercury
  EPA
• What You Need to Know about Mercury in Fish and Shellfish
  EPA & FDA

Fish for sale at a local market. Photo: Fish Contamination Education Collaborative

Agricultural pesticides that are found in fish include Chlordane, Dieldrin/Aldrin, Mirex, Toxaphene, and DDT. Although these pesticides have been banned from use for many years (except Chlordane which is restricted to termite control only), the chemicals are slow to degrade, persisting in the environment for long periods of time and bioaccumulating in human food sources. The EPA classifies these pesticides as "probable human carcinogens" and people who eat fish containing elevated levels of these chemicals can be harmed (see top-right sidebar "Human Health Risks").

PCBs, or polychlorinated biphenyls, are highly toxic industrial compounds which were used a variety of industrial applications, including use in electrical transformers, hydraulic fluids, lubricants and carbonless paper. Although they were banned from manufacture in the United States in 1977, PCBs are slow to break down and can persist in the environment at dangerous levels, often bioaccumulating in human food sources. According to EPA, contaminated fish are a persistent source of PCBs in the human diet and eating contaminated fish over an extended period of time may be harmful (see top-right sidebar "Human Health Risks").

Recommendations

• Avoid fish with high levels of pesticides and PCBs.
• Before cooking, remove the skin, fat (found along the back, sides and belly), internal organs, tomalley of lobster and the mustard of crabs, where toxins are likely to accumulate.
• When cooking, be sure to let the fat drain away and avoid or reduce fish drippings.
• Serve less fried fish; frying seals in chemical pollutants that might be in the fish's fat, while grilling or broiling allows fat to drain away.
• For smoked fish, it is best to fillet the fish and remove the skin before the fish is smoked.

More Information

• Pesticides in Fish and Shellfish
  Oceans Alive
• PCBs in Fish and Shellfish
  Oceans Alive