PCBs

Topic summary contributed by volunteer(s): Claire

Polychlorinated biphenyls, also known as PCBs, are industrial chemicals considered to be carcinogens. PCBs may adversely affect male sperm counts and may be responsible for early onset puberty.  Exposure to organic pollutants including PCBs, dioxins, and certain chlorine-containing pesticides may be a risk factor for metabolic diseases like diabetes.  

The U.S. Congress banned PCB production in 1979, leading to a decline in contamination levels. However, most U.S. women today are contaminated with heavy metals, toxic solvents, endocrine disrupters, fire retardant chemicals, pesticides, and PCBs. Except for people living or working around industrial sites, the most common source of exposure to PCBs may be from eating animal foods, especially seafood, but also meat, cheese, eggs, dairy, and poultry.

PCBs can build up in animal fat and cannot be fully removed by washing or cooking.  Once in the body, organic pollutants including PCBs and dioxin can persist for years.  Pregnant mothers may pass on some of their accumulated PCBs to their children through the pregnancy itself and later through breastfeeding.  A study showed that the children exposed at birth to PCBs from their mothers needed four to nine years to rid their bodies of about one-half of their PCB amounts.

Research indicates the top three sources to be fish oil, fish, and eggs.  Fish are a key source of PCBs, dioxins, and other pollutants likely because of what washes into the sea. Farmed salmon averages almost ten times the PCB load of wild-caught salmon.  Use of fish oil supplements, even those marketed as being distilled, can also expose people to PCBs and other pollutants. A study of 13 over-the-counter children’s fish oil supplements found that all were contaminated with PCB pollutants.

Eating a plant-based diet appears to help lower PCB levels in the body.