2,3,7,8-Tetrachlorodibenzo-/?-dioxin

Dioxin and Furan Emissions. The emissions of polychlorinated dibenzo-/)-dioxins (PCDD) and polychlorinated dibenzo-furans (PCDF) from incinerators (4) are of interest to the pubHc, scientists, and engineers. The U.S. EPA classifies 2,3,7,8-tetrachlorodibenzo-/)-dioxin (2,3,7,8-TCDD) as the most potent carcinogenic compound it has evaluated. It is also Hsted as the agency s most potent reproductive toxin (4). 

Fernandez-Salguero, P.M., Hilbert, D.M., and Rudikoff, S. et al. (1996). Aryl-hydrocarbon receptor-deficient mice are resistant to 2,3,7,8-tetrachlorodibenzo- -dioxin-induced toxicity. Toxicology and Applied Pharmacology 140, 173-179. 

The Preparation of Uniformly Labeled C-2,7-Dichlorodibenzo- -dioxin and C-2,3,7,8-Tetrachlorodibenzo- -dioxin... 

Table III. Tissue Distribution in Dams Following a Single Oral Dose of 200 /Ag/kg of C -2,3,7,8-Tetrachlorodibenzo- >-Dioxin on Gestation Day 16, 17, or 18 (/ g/gram of tissue)...

Heat Stability of 2,3,7,8-Tetrachlorodibenzo- -dioxin. A sample boat containing 1-3 mg of 2,3,7,8-tetrachlorodibenzo-p-dioxin was placed in a Sargent Tube Heater (Model J-807) which contained a 1/2 inch i.d. quartz tube. Air was aspirated through the tube at a velocity of 0.02 ft/sec. This velocity gave a residence time of 21 sec. (Residence time was extended by connecting a second heater in series with the first.)... 

Stability of 2,3,7,8-Tetrachlorodibenzo- >-dioxin Towards Air Oxidation Under Simulated Conditions. Air was bubbled through two borosilicate glass gas absorption bottles equipped with fritted glass bubblers. The first bottle contained 1-octanol for presaturation of the air, and the second bottle contained 1-octanol solutions of the dioxin treated as follows (1) octanol only, (2) octanol mixed with 74-105ju, glass beads to increase the surface area, and (3) octanol mixed with magnesium oxide to simulate a basic soil. The original solution and the sample solutions were scanned with a UV spectrophotometer at various time intervals for 4 days to determine the stability of 2,3,7,8-tetrachlorodibenzo-p-dioxin. 

Albrecht ID, AL Barkovskii, P Adriaens (1999) Production and dechlorination of 2,3,7,8-tetrachlorodibenzo-/)-dioxin in historically-contaminated estuarine sediments. Environ Sci Technol 33 737-744. 

Owens, J.W., S.M. Swanson, and D.A. Birkholz. 1994. Bioaccumulation of 2,3,7,8-tetrachlorodibenzo-/>-dioxin, 2,3,7,8-tetrachlorodibenzofuran and extractable organic chlorine at a bleached-kraft mill site in a northern Canadian river system. Environ. Toxicol. Chem. 13 343-354. 

Tietge, J.E., R.D. Johnson, K.M. Jensen, P.M. Cook, G.E. Elonen, J.D. Fernandez, G.W. Holcombe, D.B. Lothenbach, and J.W. Nichols. 1998. Reproductive toxicity and disposition of 2,3,7,8-tetrachlorodibenzo--dioxin in adult brook trout (Salvelinus fontinalis) following a dietary exposure. Environ. Toxicol. Chem. 17 2395-2407. 

Wannemacher, R., A. Rebstock, E. Kulzer, D. Schrenk, and K.W. Bock. 1992. Effects of 2,3,7,8-tetrachlorodibenzo-/>-dioxin on reproduction and oogenesis in zebrafish (Brachydanio rerio). Chemosphere 24 1361-1368. Webb, K.E. (ed.). 1984. Dioxin lessons from the Missouri experience. Bull. Environ. Contam. Toxicol. 33 629-734. Weber, H., M.W. Harris, J.K. Haseman, and L.S. Bimbaum. 1985. Teratogenic potency of TCDD, TCDF, and TCDD-TCDF combinations in C57BL/6N mice. Toxicol. Lett. 26 159-167. 

Birnbaum, L.S., H. Weber, M.W. Harris, J.C. Lamb IV, and J.D. McKinney. 1985. Toxic interaction of specific polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-/)-dioxin increased incidence of cleft palate in mice. Toxicol. Appl. Pharmacol. 77 292-302. 

Ernst, M., et. al., Immune cell functions in industrial workers after exposure to 2,3,7,8-tetrachlorodibenzo-/ -dioxin Dissociation of antigen-specific T cell responses in cultures of diluted whole blood and of isolated peripheral blood mononuclear cells, Environ. Health Perspect. 106 (Suppl. 2), 701, 1998. 

Bend, J.R., Pohl, R.J., Davidson, N.P. and Fouts, J.R. Response of hepatic and renal microsomal mixed-function oxidases in the little skate, Ra.ja erinacea, to pretreatment with 3-methyl-cholanthrene or TCDD (2,3,7,8-tetrachlorodibenzo- -dioxin). Bull. Mt, Desert Is. Biol. 

Determination of 2,3,7,8-Tetrachlorodibenzo-/>dioxin in Municipal and Industrial Discharges using LLE and... 

Figure 3 Averaged dioxin responsive-chemically activated lucerferase (DR CALUX ) results by participant for the sediment extracted by the participants (phase 3). Participants were free to choose their own dilution factor for analysis. Data presented are Ox to 200x diluted samples 2,3,7,8-TCDD = 2,3,7,8-tetrachlorodibenzo- dioxin ...

Tetrachlorodibenzo-/>-dioxin (commas are left out of all formulae for brevity) Semi-permeable membrane device... 

The toxicologic profile for these agents, particularly that of 2,4,5-T, has been confusing because of the presence of chemical contaminants (dioxins) produced during the manufacturing process (see below). 2,3,7,8-Tetrachlorodibenzo-/ -dioxin (TCDD) is the most important of these contaminants. 

Dioxin, 2,3,7,8-tetrachlorodibenzo-dioxin Receptor implicated in endotoxic shock... 

Data are available suggesting that DEHP might act as an antagonist for the hepatic damage caused by other chemicals. DEHP was combined with 2,3,7,8-tetrachlorodibenzo-/ -dioxin (TCDD) to determine if the hypolipidemic effects of DEHP could counteract the hyperlipidemic effects of the TCDD (Tomaszewski et al. 1988). Pretreatment with DEHP mitigated many of the toxic effects of TCDD. 

Rn 6). Similar approaches could be applied to the development of an immunoassay for tetrachlorodibenzo-p-dioxin using the recently synthesized l-amino-2,3,7,8-tetrachlorodibenzo- -dioxin as a hapten (28). 

Perhaps the most renowned example is the extensively-used 2,4,5-T (2,4,5-trichlorophenoxyacetic acid), or rather the 2,3,7,8-tetrachlorodibenzo- -dioxin (TCDD) impurity which sometimes accompanies it. During massive use of the herbicide as a defoliant in the Vietnam war, TCDD was found almost by accident to be one of the most toxic synthetic substances ever tested. Soon, it was shown to be present in domestic 2,4,5-T as well as in the chemical warfare agents. Tests in laboratory animals demonstrated that some of the observed levels indeed were quite high enough to cause toxic effects (32). 

If official regulations permit this method to be used, it can be useful provided that the analyst is aware of the problem of species differences which can lead to erroneous conclusions. If the animal is more sensitive to the toxin than man (e.g. benzoic acid in the cat), a false positive result would be obtained. Alternatively, a false negative result would be obtained if the animal were more resistant (e.g. Amanita phalloides and the rabbit). This aspect is illustrated by TCDD (2,3,7,8-tetrachlorodibenzo-/ -dioxin), the extremely persistent impurity, present in the systemic herbicide trichlorophenoxy-acetic acid, which was released in the Seveso... 

Figure 1 Transcriptional regulation of the rat GSTA2 and NQOl genes by bifunctional and mono functional inducers. The bifunctional inducers and the dioxin TCDD bind to and activate the AhR, which then translocates into the nucleus and associates with ARNT to activate transcription through the XRE. The bifunctional inducers can also activate transcription through the ARE via a separate pathway following their biotransformation into reactive metabolites that have characteristics of the monofunctional inducers. The monofunctional inducers can only act through the ARE-mediatedpathway. 3-MC, 3-methylcholanthrene B(a)P, benzo(a)pyrene TCDD, 2,3,7,8-tetrachlorodibenzo-/>-dioxin.

Dong, W., H. Teraoka, S. Kondo and T. Hiraga. 2,3,7,8-tetrachlorodibenzo-/)-dioxin induces apoptosis in the dorsal midbrain of zebrafish embryos by activation of arylhydrocarbon receptor. Neurosci. Lett. 303 169-172, 2001. 

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