Polychlorinated terphenyls (PCTs) have been produced over the same period as polychlorinated biphenyls (PCBs), but in 15-20-fold lower quantities (ca. 60,000 tons in total). The production of PCTs has been terminated in most countries in the mid-1970s. PCTs have similar properties to PCBs and have been used for the same purposes such as in electronic equipment, lubricants, sealants, etc. They are also found as global contaminants and the ratios of environmental levels of PCBs and PCTs approximately reflect the production figures. Because of the complexity of PCTs the analysis is difficult. Gas chromatography (GC) with electron capture detection or mass spectrometric detection has been applied, but the best possible quantification at the moment is still a semi-quantitative total PCT analysis. More advanced techniques, such as comprehensive multi-dimensional GC, are required to enable a congener-specific PCT analysis. The lack of commercially available PCT congeners has also hindered a congener-specific analysis. Relatively high PCT concentrations, more than 10 mg/kg on a lipid weight basis in marine mammals and birds, show the bioaccumulative properties of PCTs. The persistent character of PCTs was confirmed in an in vitro study in hepatic microsomes of marine mammals. The toxicity of PCTs is generally considered to be equivalent to that of PCBs. A difficulty in toxicological studies of PCTs is the contamination of PCT mixtures with PCBs.
|Title of host publication||The Handbook of Environmental Chemistry|
|Subtitle of host publication||Volume 3 Anthropogenic Compounds Part K|
|Editors||O. Hutzinger, J. Paasivirta|
|Publication status||Published - 2000|