Polychlorinated Terphenyls PCT

Historically, polychloriaated biphenyls (PCBs) and to a lesser extent polychlorinated terphenyls (PCTs) were the most important derivatives of the respective polyphenyls. When they came to be recognized as serious environmental contaminants, production ceased in the early 1970s. These products are now of significance primarily because of thek environmental aftereffects (62). Much environmental research and governmental regulations stem therefrom... 

Keywords. Polychlorinated terphenyls (PCTs), Production, Analysis, Environmental distribution, Toxicity... 

Fig. 4 Molecular structures of 1 - Polybrominated naphthalenes, PBNs, 2 -Tetrachlorobenzyltoluenes, TCBTs, 3 - Polybrominated diphenylethers, PBDEs, 4 - Polychlorinated terphenyls, PCTs, 5 - Polychlorinated triphenylmethanes, PCTPM, 6 - Polychlorinated dibenzothiophenes, PCDBT.

In accordance with annex II part B of Directive 76/769/EEC [4-5], Member States of the European Community can require that equipment and plant containing polychlorinated biphenyls (PCBs) or polychlorinated terphenyls (PCTs) should display instructions concerning the disposal of PCBs and PCTs and the maintenance and use of equipment and plant containing them. These instructions must be capable of being read horizontally when the object containing the PCBs or PCTs is installed in the normal way. The inscription must stand out clearly from its background. 

Polychlorinated (not mono- and dichlorinated) biphenyls (PCB), biphenyls, polychlorinated terphenyls (PCT), and preparations including waste oils with a PCB or PCT content higher than 0.005 % by weight may not be used. 

R 687 A. Pieper, R. Vogt, H. Wichmann and M. Bahadir, Synthesis and Levels of Polychlorinated Terphenyl (PCT) by Thermal Load , Mitteilungen der Fachgruppe Umweltchemie und Oekotoxikologie, 2003,9, 6... 

In addition to PCDFs and PCDDs mentioned above there are several classes of polychlorinated aromatic hydrocarbons which may be contained as impurities or degradation products of PCBs. These classes include polychlorinated terphenyls (PCTs), polychlorinated quaterphenyls (PCQs), polychlorinated quaterphenyl ethers (PCQEs), polychlorinated naphthalenes (PCNs), polychlorinated biphenylenes (PCPs), polychlorinated pyrenes (PCPYs) and polychlorinated chrysenes (PCCYs). 

In the last three decades, there has been considerable public concern about the presence of halogenated anthropogenic compounds in the environment because of their persistence, the bioaccumulation potential, and the health risks that they bring about [13]. Examples of members of this family of xenobiotics are polychlorinated biphenyls (PCBs), polychlorinated terphenyls (PCTs) and toxaphene. Polychlorinated biphenyls were described as ubiquitous, environmentally harmful substances more than 30 years ago [4j. In addition, the presence of PCBs and toxaphene in the environment has been extensively documented [5-7]. In contrast, litde attention has been paid to polychlorinated terphenyls, which are similar to PCBs in chemical characteristics and applications. In this chapter, we discuss different methods described in the literature for the analysis of PCTs and toxaphene using high resolution gas chromatography (HRGC) coupled to mass spectrometry (MS). 

PCBs and PCTs are particularly troublesome liquids because of their toxicity and persistence in the environment. They are defined as polychlorinated biphenyls, polychlorinated terphenyls, monomethyl-dibromo-diphenyl metliane, monomethyl-dichloro-diphenyl metliane or monomethyl-tetrachlorodiphenyl methane. With low electrical conductivity and heat resistance they found wide use as dielectric fluids and were formerly used as hydraulic fluids. PCBs have not been made in the UK since 1977 and whilst most new uses for the substance are banned in most countries, around two-thirds of the 1.5 million tonnes manufactured in Europe and the US prior to 1985 still remain in equipment such as transformers. PCTs have been used in the past in a restricted range of specialist industrial applications. 

EC Directive on the disposal of polychlorinated biphenyls and polychlorinated terphenyls (PCB/PCT)... 

Disposal of waste lubricant classified as a hazardous waste requires that it is burned in a suitably authorised incinerator at high temperatures to complete oxidation of the PAHs, PCBs and PCT (polychlorinated terphenyls). The expense of this disposal... 

PCDE PCDF PCN PCT PCTPM PER PMF POM POP PVC Polychlorinated diphenylethers Polychlorinated dibcnzofuranes Polychlorinated naphthalenes Polychlorinated terphenyls Polychlorinated triphenylmethanes T etrachloroethylene Polycyclic synthetic musk substitutes Particulate organic matter Persistent organic pollutant Polyvinyl chloride... 

For maximum sensitivity, the temperature of the ECD must be in the area of 300 C Inasmuch as the chromatographic column can withstand it. If the gas chromatograph is coupled with a mass spectrometer (GC-MS), the interface must be maintained at 250 C or higher. For analysis of PCTs (polychlorinated terphenyls), the above reference temperatures must be even higher. 

Polychlorinated terphenyls have been found (Allen et al. 1973) to have qualitatively similar enzyme inducing effects to those of PCBs but appear to be less potent (Goldstein 1980). Mixtures of PCBs and PCTs have been marketed but were not widely used. 

Polychlorinated terphenyls have been used extensively in sealants, hydraulic fluids, electrical equipment, plasticizers, and paints because of their desirable electrical and flame-retardant properties [8]. The Monsanto Chemical Co. started the production of both PCTs and PCBs in the United States in 1929. Since then, PCTs have also been produced in France, Italy, Germany, and Japan. Information about PCT production is incomplete, but during the period 1955 to 1980, approximately 60,000 metric tons were produced worldwide [8,9], which is 15 to 20... 

Polychlorinated terphenyls have been produced as technical mixtures under different commercial names such as Aroclor, Kanechlor C, Leromoll, Clophen, Cloresil, Electrophenyl T-60, Phenoclor, and Terphenyl Chlore T-60. These technical formulations consisted of mixtures of congeners with variable degrees of chlorination. Commercial formulation of PCTs could be expected to be much more complex than those of PCBs because of the presence of an additional aromatic ring, which increases the positions available for chlorination. The theoretical number of PCT congeners with Ci8Hi4 xClx (1 < X < 14) is 8557 [10,11], as shown in Table 1. 

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