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You need to be a subscriber to download it. It has been revised a couple of times since but the basics have remained pretty much the same. Polychlorinated biphenyls : Human health aspects.The standard which I think is most commonly used for symbols/reference designators is ANSI/IEEE Std 315 (1975). environmental samples, such as in air, drinking water, soil, sediment, and solid waste.biological samples, such as human blood, milk, and fatty tissue, as well as in some foods such as animal tissues, fish and dairy products.This solubility in fat explains why PCBs can build up in animal fat and along the food chain ( see question 2.2) The degree of solubility is largely dependent on the number and position of chlorine atoms in the PCB molecule.Īlthough in general PCBs do not easily evaporate, especially those with more chlorine atoms, PCB evaporation does occur, and can account for significant amounts of PCB transport ( see question 2.1) Generally, PCBs are not very soluble in water, but readily soluble in fats.PCBs persist in the environment because they are highly unreactive and are largely resistant to breakdown by acids, bases and heat.PCBs were manufactured and sold as mixtures of several congeners, with a variety of trade names, including Aroclor, Pyranol, Pyroclor (USA), Phenochlor, Pyralene (France), Clophen, Elaol (Germany), Kanechlor, Santotherm (Japan), Fenchlor, Apirolio (Italy), and Sovol (USSR). They are also referred to as " dioxin-like". Those PCBs which have both rings lying in the same plane are considered to be most toxic, based on combined health effects considerations. The shape of the molecule is further influenced by the repulsion between nearby chlorine atoms so that the rings of a specific PCB will either lie approximately in the same plane (called coplanar) or in different, more perpendicular planes (termed non-planar). Polychlorinated Biphenyls and Human Health. The two rings in a PCB molecule can rotate around the bond connecting them. For more information on PCB health effects, we recommend starting with these two papers: Carpenter, D. PCBs which have the same number of chlorine atoms attached but at different positions, are referred to as isomers. Another system assigns a separate number, from 1 to 209, to each of the 209 specific PCB congeners. In the IUPAC system used in the examples above, the numbers at the beginning of the name specify the sites where chlorines are attached to the phenyl rings. Two different systems are used for naming PCBs. The high price reflects that - tens of thousands of dollars, though the cost will depend on board and fixture size, among other factors. Section 1 Executive summary and Section 4, Sources of human and environmental exposure In-circuit testing (ICT) is the most robust type of PCB testing in existence. Concise international chemical assessment document 55 High-frequency PCB materials often include FR4-grade glass-reinforced epoxy laminate, polyphenylene oxide (PPO) resin and Teflon. High-frequency PCB is designed to transmit signals over one gigahertz. Polychlorinated biphenyls : Human health aspects. High-frequency PCB refers to a general PCB design element, rather than a type of PCB construction like the previous models. PCBs can also evaporate from contaminated water bodies, such as the North American Great Lakes.The incineration of municipal waste may lead to PCB pollution and produce dangerous by-products, such as hydrogen chloride (HCl) and dioxins ( PCDDs and PCDFs).
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This environmental contamination may continue to occur due to the disposal of old electrical equipment containing PCBs.
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