Polychlorinated dibenzodioxins 2 ,3 ,7,8-TCDD

Phiet PH, Anh TK, Vu DQ, et al. 1989. Preliminary observations on the clinical histories, polychlorinated dibenzodioxin and dibenzofiiran tissue levels and 2,3,7,8-TCDD toxic equivalents of potentially dioxin-exposed patients living in the south of Vietnam. Chemosphere 19 937-940. 

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... 

An industrial site contaminated with polychlorinated dibenzodioxin (PCDD) presents a set of complex problems to those charged with the assessment of site contamination and the development of a remediation plan. In the suiTe of PCDD compounds, TCDD is of particular concern. The U.S. Environmental Protection Agency (U.S. EPA) has designated TCDD as a potent animal carcinogen and very acutely toxic(l). 

Polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are chemically classified as halogenated aromatic hydrocarbons. The chlorinated and brominated dibenzodioxins and dibenzofurans are tricyclic aromatic compounds with similar physical and chemical properties, and both classes are similar structurally. Certain of the PCBs (the so-called coplanar or mono-ortho coplanar congeners) are also structurally and conformationally similar. The most widely studied of these compounds is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This compound, often called simply dioxin, represents the reference compound for this class of compounds. The structure of TCDD and several related compounds is shown in Figure 4.1. 

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. 

Chlorinated dibenzodioxins (other than TCDD) see also Polychlorinated dibenzo-para-dioxins)... 

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