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Agency for Toxic Substances & Disease Registry
Polychlorinated biphenyls
Polychlorinated biphenyls are mixtures of up to 209 individual compounds known as congeners. PCBs have been used as coolants and lubricants in transformers, capacitors and other electrical equipment because they don't burn easily and are good insulators. The manufacture of PCBs was stopped in the U.S. in 1977 because of evidence they build up in the environment and can cause harmful health effects. Products made before 1977 that may contain PCBs include old fluorescent lighting fixtures and electrical devices containing PCB capacitors, and old microscope and hydraulic oils. PCBs were manufactured and sold under many names, the most common being the Aroclor series. (Refer to the Environmental Protection Agency's website for a list of PCB trade names. 
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PCBs can still be released to the environment from hazardous waste sites; illegal or improper disposal of industrial wastes and consumer products; leaks from old electrical transformers containing PCBs; and burning of some wastes in incinerators. PCBs do not readily break down in the environment and thus may remain there for very long periods of time. In water, a small amount of PCBs may remain dissolved, but most stick to organic particles and bottom sediments. PCBs also bind strongly to soil. PCBs are taken up by small organisms and fish in water. They are also taken up by other animals that eat these aquatic animals as food. PCBs accumulate in fish and marine mammals, reaching levels that may be many thousands of times higher than in water.
Studies of people exposed to PCBs in the workplace suggest that some people may experience irritation of the nose and lungs, gastrointestinal discomfort, changes in the blood and liver, and depression and fatigue. Persons exposed to high levels of PCBs may develop an acne-like rash on their skin (chloracne). In some studies women who ate large amounts of fish contaminated with PCBs had babies that weighed slightly less than babies from women who did not have these exposures. Babies born to women who ate PCB-contaminated fish also showed abnormal responses in tests of infant behavior. Some of these behaviors, such as problems with motor skills and a decrease in short-term memory, lasted for several years. Other studies suggest that the immune system was affected in children born to and nursed by mothers exposed to increased levels of PCBs. Some studies of workers indicate that PCBs were associated with certain kinds of cancer in humans, such as cancer of the liver and biliary tract. In animal studies rats that ate food containing high levels of PCBs for two years developed liver cancer. The EPA and the International Agency for Research on Cancer (IARC) both identify PCBs as carcinogenic to humans.
The N.C. Department of Environmental Quality (DEQ) routinely monitors water quality and fish tissue for potential problems (Learn more about the DEQ Water Sciences Section). In the event that potentially hazardous levels of chemicals are detected in fish, the N.C. Department of Health and Human Services (DHHS) issues public advisories telling people to either limit consumption or, if necessary, avoid eating those kinds of fish entirely.
Current PCB-related fish advisories in effect for North Carolina are available on the Occupational and Environmental Epidemiology Current Fish Advisories page as well as through the U.S. Environmental Protection Agency.
See also: Badin Lake public health consultation and fish tissue study and Yadkin-Pee Dee River fish and sediment health risk evaluation.
