Something's Fishy: Toxins in Fish

Mercury, a toxic metal released into the environment from coal-burning power plants and incineration of medical waste, can permanently damage developing brains and nervous systems, particularly of fetuses and young children.

Polychlorinated biphenyls (PCBs) are chemicals used in electrical equipment before 1978. Now banned, they persist in air and water. PCBs in fish eaten by women before or during pregnancy can cause impaired learning and memory and lower I.Q. scores in their children. Adults exposed to PCBs also show learning deficits and memory loss.

Chlordane and DDT, banned insecticides, are "probable" carcinogens and suspected hormone disrupters that continue to contaminate the environment.

Dioxins are produced during manufacture and incineration of PVC plastic and chlorine bleaching of paper. Potent carcinogens, they can also harm reproductive organs.