Are PCBs Really Dangerous?

Here's what the studies say

by Mitch Rice
Feb 6, 1997
from the Bloomington Voice

Everyone in the Bloomington community knows that we have a PCB problem, but how many of us know about the dangers of exposure to PCBs? Here's a summary of the health effects of PCBs as published by the EPA on their website at http://www.epa.gov/.

Hazard Summary

• Polychlorinated Biphenyls can affect you when breathed in and by passing through your skin.
• Polychlorinated Biphenyls are CARCINOGENS - HANDLE WITH EXTREME CAUTION.
• They may be teratogens [causing birth defects] and may damage the adult reproductive system.
• Exposure can cause an acne like skin rash (called chloracne).
• They can damage the liver.
• High exposure can damage the nervous system, causing numbness, weakness and tingling ("pins and needles") in the arms and legs

From this summary, it is easy to see that PCBs are harmful to human health. In the years since this Hazard Summary was published, we have learned more about the health effects of PCBs, both as a carcinogen and a teratogen.

Cancer and PCBs

PCBs have been shown to cause cancer in animals, this is undisputed. The EPA has just released a document called "Cancer Dose-Response Assessment" and it gives all the parameters for the risk of cancer due to exposure to PCBs for humans. Liver cancer is often associated in the literature with PCB exposure, and The Indiana Dept of Public Health did a study of Westinghouse workers which found a statistically signifigant rise in brain cancer rates in the exposed workers.

Reproductive Effects

Research has illuminated many of the effects of the endocrine disrupting chemicals, the organo-chlorines: PCBs, dibenzofurans, dioxin, and DDT. These chemicals mimic estrogen in the human body. and subsequently effect the development of the human reproductive and nervous systems.

In a Scientific American article from January of 1994, researchers revealed that PCBs reduce penis size in boys whose mothers were exposed to PCBs while pregnant.The boys in Taiwan were born to mothers who unwittingly consumed PCB-contaminated rice oil during a 10-month period in 1979. As many as 2000 people consumed the contaminated oil. The children consumed no contaminated oil themselves; they were exposed before birth to PCBs that were carried by their mothers' blood and crossed the placenta; they may have also been exposed shortly after birth by drinking their mothers' milk. The rice oil contained 100 parts per million (ppm) PCBs and 0.1 ppm PCDFs [polychlorinated dibenzofurans, a potent dioxin-like poison].[4] A new mother in the U.S. today has an average of one ppm PCBs in her breast milk.

The children in Taiwan have been observed medically for many years. They are known as the "yucheng" (or "oil disease") children. A similar PCB contamination event ("yusho") occurred in Japan in 1968.

When 115 yucheng children were examined in 1985 they were less developed than a control group of children on 32 of 33 different measures. They were delayed, compared to controls, in the age at which they performed tasks such as saying phrases and sentences, turning pages, carrying out requests, pointing to body parts, holding pencils, and catching a ball.

The yucheng children also had a variety of physical defects at birth, including dark colored heads, faces and genitals, and abnormal nails that were often dark and ridged, split, or folded.

These children provided the first direct evidence that PCBs are teratogenic [birth-defect-producing] in humans. Since then, other studies have shown that American children with "normal" levels of PCBs in their blood show slight physical, mental and emotional retardation.

In an article in the N.Y. Times of Sept 12, 1996, reporter Jane Brody wrote concerning a study done at Wanye State University in Detroit. The researchers, Dr. Joseph L. Jacobson and his wife, Dr. Sandra W. Jacobson, psychologists at Wayne State University in Detroit, concluded that the fetal brain damage caused by environmental exposure to PCBs was comparable to the damage found in children exposed to low levels of lead [which are a well documented health hazard]..

The Jacobsons had previously linked prenatal PCB exposure to poor short-term memory in infants and young children. The new findings, in older children, are consistent with reports of reduced IQ scores among more heavily contaminated children in Taiwan whose mothers, while pregnant with them, ingested rice oil accidentally laced with PCBs and other chemicals.

PCBs enter the body through contaminated food and air and through skin contact. The most common route of exposure is by eating fish and shellfish from PCB-contaminated water. Exposure from drinking water is minimal. It is known that nearly everyone has PCBs in their bodies, including infants who drink breast milk containing PCBs. Each time it rains hard in Bloomington, PCBs are washed out of the Lemon Lane karst, and emerge at the Illinois Central Springs, which with the Jordan, forms the headwaters of Clear Creek. The water is turbulent, causing the PCBs to volitalize, thus entering the atmosphere, the air we breath. More on this and other topics will appear in upcoming articles. In the meantime, for more information, stop by the COPA PCB Web at http://copa.org/, or email to: info@copa.org.