Polychlorinated biphenyls are a class of manufactured chemicals which are no longer produced in the United States, but are still found in the environment. In the Mount Sinai test group, Bill Moyers had the highest levels of heavily chlorinated PCBs.

Because PCBs do not burn, electric utilities used them as insulators in transformers (those ubiquitous metal cans attached to electrical poles). PCBs also went into plasticizers, lubricants, inks, adhesives, pesticides, carbonless copy paper, paints, varnishes, water proofing compounds, and air compressors. In the 47 years PCBs were on the market, industries sold an estimated 3.4 billion pounds worldwide.

The US banned the manufacture of PCBs in 1976 because they are likely to cause cancer in humans. Today, they are still released from hazardous waste sites that contain PCBs, from illegal or improper dumping of PCB wastes, and through leakage from the millions of pounds which remain in electrical transformers around the country. According to the EPA, industries and waste handlers disposed of 3,747,166 pounds of PCBs on land and, to a lesser extent, in water in 1998.

Exposures for most people come through fatty foods and drinking water. As with dioxin and other persistent pollutants, PCBs do not readily break down in the environment. Their disposal has led to the concentration of these compounds in sewage, vegetation, marine life and eventually humans. PCBs also "bio-accumulate" – building up as they move up the food chain to levels of concentration in fish and mammals millions of times higher than the levels in water or soil. They travel so efficiently, scientists have found them thousands of miles from their origin. Both humans and wildlife north of the Arctic Circle now carry heavy body burdens of PCBs. (Please see A Toxic Journey)

In 1999, 38 states warned people to limit or avoid eating certain types of fish because of PCB contamination. As of February 2001, EPA reported finding a variety of PCB mixtures in four public water systems in Massachusetts. According to EPA’s Safe Drinking Water fact sheets, if people consistently drink water that contains more than the maximum contaminant level (MCL) of PCBs set by the agency, they “could experience changes in their skin, problems with their thymus gland, immune deficiencies, or reproductive or nervous system difficulties and may have an increased risk of getting cancer.”

In June 2000, scientists at the National Center for Environmental Assessment raised the possibility that neurotoxic chemicals such as PCBs may be a factor in attention deficit hyperactivity disorder (ADHD). The researchers outlined similarities between the behavior of ADHD children and monkeys exposed to PCBs during early developmental stages. Scientists have also documented severe neurodevelopmental problems and hyperactivity among the children of PCB-poisoned mothers in Japan and Taiwan. In both of those cases, PCBs had leaked from processing equipment into rice oil. Many of the children born soon after the poisoning episode died within their first few years of life. Other children suffered a range of problems, including lowered IQs, smaller than normal body size and shorter penile length in boys at ages 11 to 14, and discolored, fragile teeth and nails.

Another study, sponsored by Health Canada, reported that PCB levels in the general population are about the same as those that produce permanent immunosuppression in rhesus monkeys; PCB-exposed mothers passed the chemical to their offspring – with resulting immune system damage in the young monkeys. Furthermore, the Health Canada report notes a higher incidence of bacterial infections in breast-fed human infants born to mothers who consumed large amounts of PCB-tainted Great Lakes fish. Other researchers have documented lowered IQs in children exposed to PCBs in the womb.

For more information on the health effects of PCBs:

National Institutes of Health website

http://ehis.niehs.nih.gov/roc/ninth/rahc/pcbs.pdf

Environmental Health Perspectives Focus, Poisoning Young Minds

http://ehpnet1.niehs.nih.gov/docs/1999/

New Jersey Department of Health fact sheet

pdf - http://www.state.nj.us/health/eoh/rtkweb/1554.pdf

References from the National Institute of Environmental Health Sciences:

Environmental Health Perspectives Volume 108, Supplement 3, June 2000; Rice, D., Parallels between Attention Deficit Hyperactivity Disorder and Behavior Deficits Produced by Neurotoxic Exposure in Monkeys

Environmental Health Perspectives Volume 108, Supplement 3, June 2000; Porterfield, S., Thyroidal Dysfunction and Environmental Chemicals—Potential Impact on Brain

Development Environmental Health Perspectives Volume 107, Supplement 4, August 1999; Characterization of Potential Endocrine-Related Health Effects at Low-Dose Levels of Exposure to PCBs

Environmental Health Perspectives Volume 103, Supplement 9, December 1995; Tryphonas, H., Immunotoxicity of PCBs (Aroclors) in Relation to Great Lakes

Full list of sources available via e-mail