Polychlorinated biphenyls . See

In earlier editions of the Eniyclopedia there have been articles covering the properties, manufacture, capacities, etc, of polychlorinated biphenyls (PCBs), chlorinated naphthalenes, benzene hexachloride, and chlorinated derivatives of cyclopentadiene. These materials are no longer in commercial use because of their toxicity. However, they stiU impact on the chemical industry because of residual environmental problems. Their toxicity and environmental impact are discussed (see Cm.OROCARBONSANDCm.OROHYDROCARBONS, TOXIC aromatics). 

CRMs for Contaminants in Environmental Matrices For nearly two decades NIST has been involved in the development of SRMs for the determination of organic contaminants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated pesticides in natural environmental matrices such as fossil fuels (Hertz et al.1980 Kline et al. 1985), air and diesel particulate material (May and Wise 1984 Wise et al. 2000), coal tar (Wise et al. 1988a), sediment (Schantz et al. 1990, 1995a Wise et al. 1995), mussel tissue (Wise et al. 1991 Schantz et al. 1997a), fish oil, and whale blubber (Schantz et al. 1995b). Several papers have reviewed and summarized the development of these environmental matrix SRMs (Wise et al. 1988b Wise 1993 Wise and Schantz 1997 Wise et al. 2000). Seventeen natural matrix SRMs for the determination of organic contaminants are currently available from NIST with certified and reference concentrations primarily for PAHs, PCBs, chlorinated pesticides, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofiirans (PCDFs) see Table 3.11. 

CDP A process for destroying dioxins and polychlorinated biphenyls by treatment with a polyethylene glycol and sodium peroxide in a fixed catalyst bed. Developed by Sea Marconi Technologies, Turin, Italy. See also KPEG. 

Chloroff A process for removing chlorine from organic chlorides such as polychlorinated biphenyls by reaction with hydrogen under pressure, over a proprietary catalyst. Developed by Kinetics Technology International. See also Hi-ChlorofiF. 

Human health effects, of polychlorinated biphenyls, 13 140-142 Human IgG (hlgG), detection of, 14 155, 156. See also Immunoglobulin G (IgG) Human immunodeficiency virus (HIV). See also HIV entries Nevirapine entries inactivation of, 12 139 lactoferricins and, 18 258... 

The quantitative environmental analysis of surfactants, such as alcohol ethoxylates, alkylphenol ethoxylates (APEOs) and linear alkylbenzene sulfonates (LASs), is complicated by the presence of a multitude of isomers and oligomers in the source mixtures (see Chapter 2). This issue bears many similarities to the quantitation problems that have occurred with halogenated aromatic compound mixtures, e.g. polychlorinated biphenyls (PCBs) [1]. 

Polychlorinated biphenyls (PCBs) are a family of compounds, manufactured in the United States from 1930-1975, which were used in a number of discard applications and extensively as an electrical insulating fluid (see Chap. 1). Environmental concerns have led to strict controls on the use of PCBs and standards for cleanup of PCB discharges. One of the purposes of this section is to present information on the chemical and physical characteristics of these compounds. Based on this, the mechanisms of their movement in the surface/subsurface environment can be explained. 

Polychlorinated biphenyls (PCBs) were manufactured by catalytic chlorination of biphenyl to produce complex mixtures, each containing 60-90 different PCB molecular species or congeners (see Chaps. 1 and 4). In the United States, PCB mixtures were manufactured by Monsanto under the trade name Aroclor and were widely used as dielectric fluids in capacitors and transformers from 1929 to 1978. PCBs are widespread contaminants of aquatic sediments and continue to be a focus of environmental concern because they tend to accumulate in biota and are potentially toxic. The following sections show the most effective bioremediation techniques applied to various PCB contaminated environments ... 

P-branch (spect) A series of lines in molecular spectra that correspond, in the case of absorption, to a unit decrease in the rotational quantum number). pe. branch ) PCB See polychlorinated biphenyl. 

It should be realized that with the exception of a few groups of chemicals (such as some organophosphorous and carbamate pesticides as well as some polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs), precise mechanistic information on their toxic effects are scarce. In realizing that the exact molecular mechanism is not known for most chemicals the term mode of action is used to describe toxicides that appear to be similar albeit the mechanism is not known in detail, see also Section 4.2.6. For several groups of endocrine disrupters this terminology seems appropriate. 

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