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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]
PCBs share the basic chemical structure of biphenyl and one or more of the hydrogen atoms on the aromatic rings are replaced by chlorine atoms. [1] PCBs is in viscous liquid form at normal temperature and has a poor solubility in water. The aromatic hydrocarbon structure gives PCBs relatively high molecular stability.
The inclusion of PCBs as a PBT may be attributed to their low water solubility, high stability, and semi-volatility facilitating their long range transport and accumulation in organisms. [5] The persistence of these compounds is due to the high resistance to oxidation, reduction, addition, elimination and electrophilic substitution. [ 6 ]
Test results conducted in the fall showed the presence of PCBs, or polychlorinated biphenyls — toxic, man-made chemicals that were banned from being produced in the United States in 1979.
Pentachlorobenzene (PeCB), is a pesticide and unintentional byproduct. PeCB has also been used in PCB products, dyestuff carriers, as a fungicide, a flame retardant, and a chemical intermediate. This compound is moderately toxic to humans, whilst being highly toxic to aquatic organisms.
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 ...
Polychlorinated biphenyls (PCBs), derived from biphenyl, of which 12 are "dioxin-like". Under certain conditions PCBs may form dibenzofurans through partial oxidation. Polybrominated analogs of the above classes may have similar effects. "Dioxin" can also refer to 1,4-dioxin or p-dioxin, the basic chemical unit of the more complex dioxins. This ...
Michigan Chemical Corporation (MCC) in St. Louis, Michigan, which was then owned by Velsicol Chemical Corporation, was a major producer of the FireMaster range of PBB-based flame retardants. FireMaster BP-6 (a yellow-brown powder) is a mixture of many different PBB congeners with 2,2',4,4',5,5'-hexabromobiphenyl and 2,2',3,4,4',5,5 ...