A polychlorinated biphenyl (PCB; CAS number 1336-36-3 ) is any of the 209 configurations of organochlorides with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for a PCB is C12H10-xClx. 130 of the 209 different PCB arrangements and orientations are used commercially.
PCBs were widely used as dielectric and coolant fluids, for example in transformers, capacitors, and electric motors. Due to PCBs' environmental toxicity and classification as a persistent organic pollutant, PCB production was banned by the United States Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. According to the U.S. Environmental Protection Agency (EPA), PCBs have been shown to cause cancer in animals, and there is also evidence that they can cause cancer in humans. A number of peer-reviewed health studies have also shown a causal link between exposure to PCBs and non-Hodgkin Lymphoma, a frequently fatal form of cancer.
Concerns about the toxicity of PCBs are largely based on compounds within this group that share a structural similarity and toxic mode of action with dioxin. Toxic effects such as endocrine disruption and neurotoxicity are also associated with other compounds within the group. Therefore, the current maximum contaminant level as stated by the EPA for PCBs in drinking water systems is 0.5 ppb.
According to the Agency for Toxic Substances and Disease Registry (ATSDR), approximately 99 percent of the PCBs used by U.S. industry were produced by the Monsanto Chemical Company.
Read more about Polychlorinated Biphenyl: Physical and Chemical Properties, Alternative Names, Applications, History, Environmental Transport and Transformations, Health Effects, Containment, Methods of Destruction, PCB Data
Other articles related to "polychlorinated biphenyl, biphenyl":
... Note that biphenyl, while not technically a PCB congener due to its lack of chlorine substituents, is still typically included in the literature ... PCB Homolog CASRN Cl Substituents Number of Congeners Biphenyl 92-52-4 1 ... Monochlorobiphenyl 27323-18-8 3 ... Dichlorobiphenyl 25512-42-9 12 ... Trichlorobiphenyl 25323-68-6 3 ...