Polychlorinated Biphenyls (PCBs): Exposure and Health Effects

• December 2, 2020

As one of the most extensively researched types of environmental contaminants, polychlorinated biphenyls (PCBs) are a topic of ongoing scientific focus. These environmentally persistent chemical substances have been shown to yield adverse health effects, both in animals and humans. In this blog post, we discuss PCBs and take a look at some of the harmful health effects associated with them.

A Look at PCBs

PCBs are a group of synthetic organic chlorinated hydrocarbons with the chemical formula C12H10-xClx. While PCBs typically maintain a biphenyl core structure, hydrogen atoms may be substituted with chlorine atoms in various configurations. As a result, 209 different PCB chemical compounds (congeners) can exist.

First synthesized domestically more than 90 years ago, PCBs were used for decades in a wide range of industrial products and processes, including electrical product and appliance development, rubber and plastic manufacturing, use in paints and pigments, and many others. Because of the risks associated with them, the production of PCBs was banned by the U.S. Environmental Protection Agency (EPA) in 1979.

Health Effects

A wide range of harmful health effects can result from PCB exposure. Among these are carcinogenesis, as well as effects on multiple bodily systems. As is the case with any chemical substance, these effects may be impacted by factors such as amount, duration, and conditions of exposure.

• • Carcinogenic Effects

    • The potential carcinogenicity of PCBs has been a topic of scientific investigation for years. First evaluated by the EPA in 1987, the carcinogenic potential of PCBs has been reviewed in studies of animal and human populations. The International Agency for Research on Cancer (IARC) and the EPA have concluded that PCBs are probable human carcinogens.

• • Endocrine Effects

    • Research conducted on the endocrine disrupting effects of PCBs has established they can cause alterations in hormone levels. Examples include thyroid hormone and estrogen.

• • Immune Effects

    • Research has shown that PCB exposure can exert significant immunological effects within the body. Decreased immune system function, in turn, may result in a greater likelihood of disease development.

• • Neurological Effects

    • The impact of PCBs on the nervous system has been evaluated in research on both animals and humans. Several animal studies have demonstrated that PCB exposure may be linked to learning deficits, visual impairment, and a diversity of other effects. Similar effects have been shown in human studies.

• • Reproductive Effects

    • PCB exposure has been shown to yield a variety of reproductive effects. These range from a marked reduction in gestational age to decreased birth weight.

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