Title: TCDD
CAS Registry Number: 1746-01-6
CAS Name: 2,3,7,8-Tetrachlorodibenzo[b,e][1,4]dioxin
Additional Names: 2,3,7,8-tetrachlorodibenzo-p-dioxin; 2,3,6,7-tetrachlorodibenzodioxin; dioxin; TCDBD
Molecular Formula: C12H4Cl4O2
Molecular Weight: 321.97
Percent Composition: C 44.76%, H 1.25%, Cl 44.05%, O 9.94%
Literature References: Highly toxic contaminant; produced as a by-product during the manuf of chlorinated phenols (2,4,5-trichlorophenol, q.v.) and phenoxyherbicides (2,4-D and 2,4,5-T, q.q.v.), chlorine bleaching of paper pulp and combustion of chlorine-containing waste. Prepn: W. Sandermann, Ber. 90, 690 (1957); M. Tomita et al., Yakugaku Zasshi 79, 186 (1959), C.A. 53, 13152d (1959). Crystal structure: F. P. Boer et al., Acta Crystallogr. 28B, 1023 (1972). Environmental degradation: D. G. Crosby, A. S. Wong, Science 195, 1337 (1976). Comprehensive review of formation, chemistry, and toxic and environmental effects: Adv. Chem. Ser. 120, entitled "Chlorodioxins: Origin and Fate," E. H. Blair, Ed. (ACS, Washington DC, 1973) 141 pp. Toxicity and metabolism: B. A. Schwetz et al., ibid. 55-69; A. Poland, A. Kende, Fed. Proc. 35, 2404 (1976). Special issue: Chem. Eng. News 61 (June 6, 1983). Review of toxicology and human exposure: Toxicological Profile for 2,3,7,8-Tetradichlorodibenzo-p-dioxin (PB89-214522, 1989) 135 pp; of epidemiological data: L. Tollefson, Regul. Toxicol. Pharmacol. 13, 150-169 (1991); of receptor binding and mechanism of toxicity: J. P. Whitlock, Jr., Annu. Rev. Pharmacol. Toxicol. 30, 251-277 (1990); of carcinogenicity: J. Huff et al., ibid. 34, 343-372 (1994). Review of GC high resolution mass spectrometric analysis: J.-F. Focant et al., J. Chromatogr. A 1067, 265-275 (2005).
Properties: Needles, mp 295° (Tomita); crystals from anisole, mp 320-325° (Sandermann). LD50 in male, female rats (mg/kg): 0.022, 0.045 orally (Schwetz).
Melting point: mp 295° (Tomita); mp 320-325° (Sandermann)
Toxicity data: LD50 in male, female rats (mg/kg): 0.022, 0.045 orally (Schwetz)
NOTE: An industrial accident during the manufacture of 2,4,5-trichlorophenol in Seveso, Italy on July 10, 1976 caused the release of an estimated two to ten pounds of TCDD into the environment. Concentrations as high as 51.3 ppm TCDD were found in some samples: R. Rawls, D. A. O'Sullivan, Chem. Eng. News 54, 27 (Aug. 23, 1976); A. Hay, Nature 262, 636 (1976). TCDD, as a contaminant created in the manufacture of Agent Orange, a widely used defoliant in Vietnam during the 1960's, has also been implicated as the causative agent of various symptoms described by veterans exposed to the defoliant, see C. Holden, Science 205, 770 (1979).
CAUTION: Potential symptoms of overexposure to TCDD are eye irritation; allergic dermatitis, chloracne; porphyria; GI disturbances; possible reproductive and teratogenic effects. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 298. Toxic effects in animals include the wasting syndrome, gastric ulcers, immunotoxicity, hepatotoxicity, hepatoporphyria, vascular lesions, chloracne, teratogenicity, fetotoxicity, impaired reproductive performance, endometriosis and delayed death. See Poland, Kende, loc. cit.; C. D. Carter et al., Science 188, 738 (1975). This substance is listed as a known human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-241. |