Polychlorinated dibenzodioxines/furanes

Table 23-9 Li mils for polychlorinated dibenzodioxins / furans underthe German Chemicals Prohibition Ordinance, 1996.

Chlorinated micropoUutants are harmful for man and environment due to their toxicity, persistence, and bioaccumulation. Persistent compounds are very stable and difficult to get metabolized and mineralized by biological and chemical processes in the environment, and as a result, they have become ubiquitous in water, sediments, and the atmosphere bioaccumulation is the result of the lipophilicity of these compounds. Polychlorinated dibenzodioxins and -furans (PCDD/F) are not produced purposely like many of other chlorinated technical products, such as chlorinated biocides DDT, lindane, and toxaphene. The production and use of persistent organic pollutants (POPs), the dirty dozen has now been banned worldwide by the Stockholm protocol. It should be mentioned that about 3000 halogenated products have now been isolated as natural products in plants, microorganisms, and animals," but the total amount of these products is much smaller compared to xenobiotics. 

POLYCHLORINATED DIBENZODIOXINS AND FURANS AS POLLUTANTS FORMED IN INCINERATIONS... 

WHO has conducted three international studies of PCBs, polychlorinated dibenzodioxins, and polychlorinated dibenzo-furans in human milk during 1987-2003 (WHO 2000). The first two surveys were conducted in 1987-1988 and 1992-1993 in a number of European countries. The third, conducted in 2000-2003, included additional countries. A fourth survey has been developed with the intent to assess the persistent organic pollutants (POPs) found in human milk so that each country can better identify and set priorities among POPs for remedial action (WHO 2000). The sample population will include at least 50 mothers from each country who are planning to breastfeed (WHO 2005). Two sampling periods have been proposed, the first to obtain a baseline sample of POPs in representative... 

Consequently, they are able to integrate pollutant levels over a broad area by bioaccumulation (Furness, 1993). A bird egg, unlike a mammalian fetus, is an isolated and independent metabolic system. In addition, persistent, bioaccumulative and lipophilic pollutants (e.g. PCBs, polychlorinated dibenzodioxins and furans) are known to biomagnify in the egg yolk and result in concentrations of orders of magnitude higher than the ambient concentrations in the diet of the female bird (Kleinow et al., 1999). The contaminant levels in waterbird eggs, therefore, provide important and useful information for monitoring changes in environmental quality. 

Dioxin A family of chemicals with related properties and toxicity. There are 75 different dioxins, or polychlorinated dibenzodioxins (PCDDs) 135 different furans, or polychlorinated dibenzofurans (PCDFs) and 209 different polychlorinated biphenyls (PCBs). Each different form is called a congener, a member of a family of compounds known chemically as dibenzo-p-dioxins. Concern about them arises from their potential toxicity as contaminants in commercial products. Tests on laboratory animals indicate that it is one of the more toxic anthropogenic (man-made) compounds a term used interchangeably with 2,3,7,8-tetrachlorodibenzo-p-dioxin or TCDD Disease prevention Measures used to prevent a disease or reduce its severity Dispersoids The particles of a dispersion... 

Butt, C. M., Diamond, M. L., Tmong, J., Ikonomou, M. G., Mortimer, W. (2009) Polychlorinated dibenzodioxins and furans from uncontrolled burning of garbage in a remote community and comparison with urban-rural locations in Toronto, Canada. EwvironTOcnto/JicotoxSa/cty, (submitted). 

In response to the continuing discovery of the persistence, bioaccumulative properties, and toxicity of POPs, regional, national and international policies ban the intentional production of compounds, such as polychlorinated biphenyls (PCBs), several organochlo-rine pesticides, such as mirex and dieldrin, and the brominated flame retardants poly-brominated diphenyl ethers (penta-BDE and octa-BDE, and most recently, deca-BDE). Policies and programs have also targeted the unintentional production and release of POPs such as polychlorinated dibenzodioxins and furans (PCDD/Fs). Evidence of the success of these policies has been seen in immediate reductions of air concentrations, followed by declining concentrations in water bodies, soils, biota and our food supplies... 

PAG PAH PBDE PCB PCDD/F PCR PM PM2.5 PNNL ppm ppt psi photoacid generator polycyclic aromatic hydrocarbon polybrominated diphenyl ether polychlorinated biphenyl polychlorinated dibenzodioxins and furans polymerase chain reaction particulate matter fine particulate matter (smaller than 2.5 microns in diameter) Pacific Northwest National Laboratory parts per million parts per trillion pounds per square inch... 

Because PCB molecules have two benzene rings or 12 carbon atoms as well as some chlorine atoms, they wUl bum at high temperatures when ignited. The main danger from a PCB fire is not the PCB itself, but the formation of extremely toxic byproducts of combustion, such as polychlorinated dibenzodioxins, polychlorinated dibenzofurans, and hydrogen chloride gas, which often produce immediate respiratory effect. The formation of dioxins and furans... 

Polychlorinated dibenzodioxins (PDDs) and furans PGDFs) are also analyzed by high resolution GC/MS. These compounds are generally present in pigments derived from chlorinated aromatic compounds... 

Polychlorinated dibenzodioxins and furans (PCDD/Fs) are persistent, bioaccumulative toxic by-products of incomplete combustion—whether manmade or natural—and certain chemical processes. 2,3,7,8-tetrachlorodibenzodioxin (TCDD) is the most toxic of the family of 210 compounds. 

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