Laboratory and Human Studies on Polychlorinated Biphenyls (PCBs) and Related Compounds

Abstract

Similar qualitative toxic effects have been observed in animals for a class of halogenated aromatic compounds, which include the halogenated biphenyls, naphthalenes, dibenzodioxins, and dibenzofurans. All of these compounds are lipid soluble and persist in the environment and in mammals. The polybrominated biphenyls (PBBs) are the most persistent. They are predominantly stored in fatty tissue; they pass the placenta and are excreted in milk. Some isomers of the halogenated biphenyls are more toxic than others. With some exceptions, the more toxic isomers are retained longer in tissues and are also the carcinogenic components of the mixture. Most of these chemicals seem to be promoters of carcinogenesis in animals rather than initiators. An array of toxic effects in laboratory animals has been ascribed to these compounds and numerous reviews summarizing this information are available. Less information is available on the human health effects of environmental and occupational exposure. Results of recent studies in animals to further elucidate the effects of these chemicals are presented, and results from some human studies conducted in the United States are reviewed.

Yucheng: health effects of prenatal exposure to polychlorinated biphenyls and dibenzofurans

“…PCBs were manufactured for many purposes, including insulators, fire retardants, lubricants for heavy machinery and dielectric fluid in transformers. With long environmental half-lives (Kimbrough 1985), these POPs will remain in the environment for decades to come.…”

Polychlorinated Biphenyl Quinone Metabolites Poison Human Topoisomerase IIα: Altering Enzyme Function by Blocking the N-Terminal Protein Gate

“…Exposure to PCBs is associated with a broad spectrum of human health problems, including neurotoxicity, hepatotoxicity, hypothyroidism, and immunodeficiency (1,3,(6)(7)(8).…”

Subchronic Toxicity of 2,2',3,3',4,4'-Hexachlorobiphenyl in Rats

“…Commercial production of these compounds was banned in 1979; however, PCBs continue to be a health concern due to their persistence in the environment and demonstrated toxic effects. Numerous toxicity studies have been carried out on commercial PCBs and have demonstrated a broad range of toxic effects (Kimbrough, 1985;Safe, 1994). Recent advances in analytical chemistry have shown that not all congeners of PCBs are retained in biological systems (Duinker & Hillebrand, 1983;Williams & LeBel, 1990;Mes et al, 1993).…”

“…Polychlorinated biphenyl (PCBs) have been widely used since the 1930s as ingredients for dielectric fluids and lubricants (Kimbrough, 1985;Jensen, 1966). Commercial production of these compounds was banned in 1979; however, PCBs continue to be a health concern due to their persistence in the environment and demonstrated toxic effects.…”