Polychlorinated dibenzofUrans levels

Schecter A, Ryan JJ, Constable JD. 1987b. Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran levels in human breast milk from Vietnam compared with cow s milk and human breast milk from the North American continent. Chemosphere 16 2003-2016. 

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and ortho-unsubstituted polychlorinated biphenyls (non-ortho polychlorobiphenyls) are three structurally and toxicologically related families of anthropogenic chemical compounds that have in recent years been shown to have the potential to cause serious environmental contamination due to their extreme toxicity [77-82], These substances are trace-level components or byproducts in several large-volume and widely used synthetic chemicals, principally polychlorobiphenyls and... 

For the quantitative determination of polychlorinated diben-zodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), sample treatment and conservation play crucial roles, too. Only some of the 75 PCDD isomers and 135 PCDF isomers are highly toxic. The collection and analysis of the hazardous compounds present at ultratrace levels in environmental samples must preferably be isomer-specific. The exposure routes for these compounds originate from combustion processes (18-19). 

Dioxins in food and the environment have been intensively studied over the past twenty years (see for example Steering Group on Chemical Aspects of Food Surveillance, 1992a). The term dioxins has come to be used for polychlorinated dibenzo-p-dioxins and in some cases also polychlorinated dibenzofurans. Both of these are ubiquitous environmental contaminants. They are highly resistant to breakdown in the environment. They are particularly difficult to study because of the large number of substances involved and the very low levels of detection needed. Nevertheless, much surveillance work has been done on polychlorinated dibenzo-p-dioxins, particularly 2,3,7,8-tetrachlorodibenzo-p-... 

Knutzen, J., Bjerkeng, B., Naes, K., Schlabach, M., 2003. Polychlorinated dibenzofurans/ dibenzo-p-dioxins (PCDF/PCDDs) and other dioxin-like substances in marine organisms from the Greenland fjords, S. Norway, 1975-2001 Present contamination levels, trends and species specific accumulation of PCDF/PCDD congeners. Chemosphere 52, 745-760. 

Taucher, J.A., Buckland, S.J., Lister, A.R., Porter, L.J., 1992. Levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in ambient urban air in Sydney, Australia. Chemosphere 25, 1361-1365. 

Schecter, A., Furst, P., Furst, C., Meemken, H.A., Groebel, W., Constable, D., 1989a. Levels of polychlorinated dibenzofurans, dibenzodioxins, PCBs, DDT and DDE, hexachloro-benzene, dieldrin, hexachlorocyclohexanes and oxychlordane in human breast milk from the United States, Thailand, Vietnam, and Germany. Chemosphere 18, 445-454. 

Needham LL, Patterson DG, Alley CC, et al. 1987. Polychlorinated dibenzo-p-dioxins and dibenzofurans levels in persons with high and normal levels of 2,3,7,8-tetrachlorodibenzo-p-dioxins. Chemosphere 16 2027-2031. 

Schecter A, Furst P, Ryan JJ, et al. 1989e. Polychlorinated dioxins and dibenzofurans levels from human milk from several locations in the United States, Germany, and Vietnam. Chemosphere 19 979-984. 

Schecter A, Ryan JJ. 1988. Polychlorinated dibenzo-p-dioxin and dibenzofuran levels in human adipose tissues from workers 32 years after occupational exposure to 2,3,7,8-TCDD. Chemosphere 17 915-920. 

Smith LM, Stalling DL, Johnson JL. 1984b. Determination of part-per-trillion levels of polychlorinated dibenzofurans and dioxins in environmental samples. Anal Chem 56 1830-1842. 

Another major exposure route for humans is via contaminated food. For example, North America s Great Lakes, which are the largest body of freshwater in the world, are polluted with about 362 contaminants that were found in quantifiable amounts in the water, sediment, and biota (IJC 1983 USEPA 1994). The critical pollutants were identified as PCBs, DDT, dieldrin, toxaphene, mirex, methyl mercury, benzofa) pyrene, hexachlorobenzene, polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and alkylated lead. Some of these pollutants biomagnify in the aquatic food chain and can be detected in increased levels in cooked Great Lakes fish. Consequently, the blood serum levels of these chemicals are significantly increased in consumers of contaminated Great Lakes sport fish compared to people who do not eat such fish (Flumphrey 1983 Fiore et al. 1989 Sonzogni et al. 1991). 

Lexdn K, de Wit C, Jansson B, Kjeller LO, Kulp SE, Ljung K, Sdderstrom G, Rappe C (1993), Chemosphere 27 163-170. Polychlorinated dibenzo-p-dioxin and dibenzofuran levels and patterns in samples from different Swedish industries analyzed within the Swedish dioxin survey"... 

Yao, Y., Takasuga, T., Masunaga, S., Nakanishi, J. (2002). Detailed study on the levels of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in Yusho rice oil. Chemosphere 46 1461-9. 

A further example for the analysis of trace levels of pollutants is the determination of polychlorinated diben-zodioxins and polychlorinated dibenzofurans in milk. The method includes gel permeation chromatography, alumina cleanup, and porous graphitized carbon chromatography, followed by analysis by gas chromatography-... 

During production, Aroclor mixtures were contaminated by small amounts of polychlorinated dibenzofurans (PCDFs) as impurities. Although PCDFs are formed during the pyrolysis of PCBs, in the absence of fire, PCDF levels do not appear to increase during the normal use of PCBs in electrical equipment. PCDFs have their own toxicological properties, which have been summarized in ATSDR (1994). The concentration levels for tetra-, penta-, hexa-, and total PCDFs found in commercial PCB mixtures are shown in Table 4-6 (de Voogt and Brinkman 1989). 

Omara FO, Flipo D, Brochu C, et al. 1998. Lack of suppressive effects of mixtures containing low levels of methylmercury (MeHg), polychlorinated dibenzo-p-dioxins (PCDDS), polychlorinated dibenzofurans (PCDFS),and aroclor biphenyls (PCBS) on mixed lymphocyte reaction, phagocytic, and natural killer cell activities of rat leukocytes in vitro. J Toxicol Environ Health A54 561-577. 

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