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PCB warning label on a power transformer known to contain PCBs. Polychlorinated biphenyls (PCBs) are organochlorine compounds with the formula C 12 H 10−x Cl x; they were once widely used in the manufacture of carbonless copy paper, as heat transfer fluids, and as dielectric and coolant fluids for electrical equipment. [2]
Ortho-PCBs may alter hormone regulation through disruption of the thyroid hormone transport by binding to transthyretin. [8] Coplanar PCBs are similar to dioxins and furans, both bind to the aryl hydrocarbon receptor (AhR) in organisms and may exert dioxin-like effects, in addition to the effects shared with non-coplanar PCBs.
PCB-compounds, always containing low concentrations of dioxin-like PCBs and PCDFs, were synthesized for various technical purposes (see Polychlorinated biphenyls). They have entered the environment through accidents such as fires or leaks from transformers or heat exchangers, or from PCB-containing products in landfills or during incineration.
Not to be confused with Printed electronics. "PCB" redirects here. For other uses, see PCB (disambiguation). "PC board" redirects here. For the mainboard of personal computers, see Motherboard. "Panelization" redirects here. For the page layout strategy, see N-up. Printed circuit board of a DVD player Part of a 1984 Sinclair ZX Spectrum computer board, a printed circuit board, showing the ...
Polychlorinated biphenyls (PCBs) were once commonly used electrical insulators and heat transfer agents. Their use has generally been phased out due to health concerns. PCBs were replaced by polybrominated diphenyl ethers (PBDEs), which bring similar toxicity and bioaccumulation concerns. [citation needed]
Congener descriptors give a shorthand notation for geometry and substituent positions. The twelve congeners that display all four of the descriptors are referred to as being "dioxin-like", referring both to their toxicity and structural features which make them similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD). [1]
No harmful levels of carcinogenic PCBs were found inside the missile launch facilities at F.E. Warren Air Force base in Wyoming, the service said Tuesday, as it looks for possible causes for ...
Exposure to the coplanar stereoisomer 3,3',4,4',5,5'-hexabromobiphenyl (but not the non-coplanar stereoisomer) in genetically susceptible mice is known to cause immunotoxicity and disorders related to the central nervous system, and even at doses as low as 2.5 mg/kg, excess neonatal fatalities are observed (LD 50 is from 5–10 mg/kg). [1]