Commercial limitations polychlorinated biphenyl

Polychlorinated biphenyls ( PCBs ) have been manufactured and used commercially for 50 years because of their chemical stability, fire resistance, and electrical resistance properties. PCBs are frequently used in electrical transformers and capacitors. However, concern has been expressed that PCBs may be toxic to humans and to wildlife. Because of these concerns, the major American manufacturer of PCBs limited its sales of PCBs after 1972 to manufacturers of transformers and capacitors and then in 1977 ceased all manufacture of PCBs and shipped the last of its inventory. Today, PCBs are produced in this country only as incidental byproducts of industrial chemical processes. There are known natural sources of PCBs. 

DDT (trace A) and its metabolites DDE and DDD (trace B), and traces F and G are the commercial polychlorinated biphenyl (PCB) mixtures Arochlor 1242 (trace F) and Arochlor 1254 (trace G). As is illustrated, extracts of local Laurencia species (traces C and D), and the extract of a halogenating bacterium Chromobacterium sp. (trace E), contain compounds of similar retention time to DDT and its metabolites. Traces H and J were produced from extracts of Plocamium cartilagineum and Chondria californica, two locally abundant red algae, and trace I was produced from a species unidentified sponge of the genus Verongia. In this case mixtures of halogenated natural compounds fall within the limits of detectability of the PCBs. 

Finally, even if most of the pesticides worldwide are used in fruit and vegetable crops, data on pesticide residues in animal products are also essential, taking into account that livestock can be easily exposed to pesticides directly or through residues in their feed. For instance, the 2009 European Union Report revealed the presence of 34 different pesticides in animal products [115]. Garcfa de Llasera et al. [128] revealed the presence of chlofenvinphos and chlorpyrifos in liver samples, whereas a-endosnlfan, endosulfan sulfate, and dichloran have been reported in pork and lamb samples (<10 pg/kg) [129]. Bolafios et al. [130] studied the occurrence of organochlorine pesticides and polychlorinated biphenyls in chicken eggs. Benzene hexachloride and 28 polychlorinated biphenyl were detected in only one of the 30 samples at concentrations of 15 and 10 ng/g, respectively. However, five samples also contained traces of OC and PCB residues, even if at concentration levels below the limit of quantification. Einally, a-endosulfan and P-endosulfan were found in commercial milk-based infant formulas at concentration levels from 1.18 to 5.03 pg/kg [35]. The same study also showed the presence of fenitrothion, chlorpyrifos ethyl, and bifenthrin at maximum concentrations of 0.23,1.30, and 0.68 pg/kg, respectively. 

Gas Chromatography with Mass Spectrometry (GC/MS) has been used for the determination of polychlorinated biphenyls (PCBs) as impurities in copper phthalocyanine blue and green, as well as in PR 144. PCBs are suspected carcinogens, and their concentration in commercial products is limited in the United States to a max-... 

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