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Polychlorinated biphenyls, polybrominated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans.
Citation:
Kodavanti, P., J. Valdez, J. Yang, M. Curras-Collazo, AND B. Loganathan. Polychlorinated biphenyls, polybrominated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. Edition 2, Chapter 39, Ramesh Gupta (ed.), Reproductive and Developmental Toxicology, 2nd edition. Academic Press Incorporated, Orlando, FL, , 711-743, (2017).
Impact/Purpose:
This is a book chapter for the second edition describing PCBs, PBBs, PCDDs and PCDFs in terms source, environmental fate, potential human exposure and their health effects in humans and animal models. Potential mode(s) of action were also described.
Description:
Polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) belong to a group of compounds that are structurally related and are environmentally and biologically persistent. These chemicals have a tendency to bioaccumulate and biomagnify in the food chain. Residues of these chemicals have been detected in remote areas of the world and in a variety of animal species, including humans. Exposure to these chemicals has been linked to a broad spectrum of effects. Fetal and early developmental exposures are particularly sensitive, and can have different outcomes from adult exposure. Latent effects of early exposures include, but are not limited to, depressed circulating thyroid hormone levels and abnormal thyroid cytology; developmental effects of the heart, palate and kidney; delayed cognitive development; altered sensory and motor abilities; and reproductive impairment and compromised neuronal function. Although AhR activation has been attributed to several dioxin like coplanar compounds, some PCBs that are noncoplanar in nature seem to exert their toxic effects through different mechanisms including calcium signaling, oxidative stress, thyroid hormone perturbations, and neurotransmitter imbalance. While certain congeners and isomers can pose a very serious threat to the health of animals and humans, environmental exposure situations are generally such that risks of health effects are generally low. The most significant problem by these compounds involved in accidental poisoning via food supply or consumption of contaminated food from contaminated areas. Additionally, there are areas of the environment that are heavily contaminated by these chemicals because of past industrial activities. Animals and humans residing in or near contaminated locations certainly are at risk of serious health effects. Efforts must continue to reduce exposure to protect wildlife and humans. The best way to accomplish is to modernize technological processes to prevent the release of these chemicals in to the environment.
