Chlorinated-dibenzodioxins

SW-846, is used to measure emissions of semivolatile principal organic constituents. Method 0010 is designed to determine destruction and removal efficiency (DRE) of POHCs from incineration systems. The method involves a modification of the EPA Method 5 sampling train and may be used to determine particulate emission rates from stationary sources. The method is applied to semivolatile compounds, including polychlorinated biphenyls (PCBs), chlorinated dibenzodioxins and dibenzofurans, polycyclic organic matter, and other semivolatile organic compounds. 

This reaction has been also described for low chlorinated dibenzodioxins. Assuming an identical MS response factor for monoBrDD and monobromohydroxy-biphenyl ether (monoBrDPE) a quantification study shows that monoBrDPE is much more stable towards photolysis compared to monoBrDD, because it accumulates in the mixture of the reaction products. For the dibrominated dibenzodioxins the same reaction (ether fission) is observed but to a minor extent. With triBrDD and higher brominated BrDD no diaryl-ether products are observed at all. 

The use of aromatic brominated compounds as flame retardants has been a potential source of environmental contamination. Incomplete incineration of these compounds and wastes (plastics, textiles, oils etc...) containing brominated flame retardants caused formation of brominated/chlorinated dibenzodioxines (PBDDs/ PCDDs) and dibenzofurans (PCDFs/PBDFs) (refs. 1 - 4). 

Advantage was taken of these solubility differences in refining mixtures of the chlorinated dibenzodioxins. Digestion with boiling chloroform was effective in removing trichlorodibenzodioxin while recrystallization from anisole reduced the penta-substituted isomer content. In a typical purification (Table II) these two procedures were alternated through four cycles. The assays were made by mass spectroscopy using the batch injection method to introduce the sample into the spectrometer. X-ray studies 14) confirmed the structure. 

TLC Analysis. Samples were examined by TLC using standard procedures. Rf values were determined and compared with those of authentic reference materials. Radioactive components were located by scanning (Vanguard Instrument Corp., North Haven, Conn., Model 885) or by autoradiography (Eastman Kodak, Rochester, N. Y., type AA film). The relative Rf value of DCDD on silica gel plates (Brinkmann Instruments, Inc., Westbury, N. Y., type For,4) when developed with n-hexane dioxane acetic acid, 90 10 4, V/V/V, was 0.90. The observed impurity had a relative Rf value of 0.40. On Brinkmann alumina plates, developed with n-hexane, DCDD had a relative Rf of 0.32. Neither system separated the chlorinated dibenzodioxin isomers. 

Chlorinated dioxins occur in atmospheric deposition (Koester and Hites 1992), and will thereby enter the terrestrial environment and watercourses. The degradation of tetrachloro- through octa-chlorodibenzo[l,4]dioxins has been examined in low-nitrogen medium by Phanerochaete sor-dida YK-624 (Takada et al. 1996). All the compounds were extensively degraded, and the ring fission of 2,3,7,8-tetra- and octachlorodibenzo[l,4]dioxin produced 4,5-di- and tetrachlorocatechol. These results established important evidence for the biodegradability of even highly chlorinated dibenzodioxins. 

Zitko, V. 1992. Patterns of 2,3,7,8-substituted chlorinated dibenzodioxins and dibenzofurans in aquatic fauna. 

Commercial PCP preparations often contain variable amounts of chlorophenols, hexachloroben-zene, phenoxyphenols, dioxins, dibenzofurans, chlorinated diphenyl ethers, dihydroxybiphenyls, anisoles, catechols, and other chlorinated dibenzodioxin and dibenzofuran isomers. These contaminants contribute to the toxicity of PCP — sometimes significantly — although the full extent of their interactions with PCP and with each other in PCP formulations are unknown. Unless these contaminants are removed or sharply reduced in existing technical- and commercial-grade PCP formulations, efforts to establish sound PCP criteria for protection of natural resources may be hindered. 

Buser, H.R. Rapid photol34ic decomposition of brominated and brominated/chlorinated dibenzodioxins and dibenzofurans, Chemosphere, 17(5) 899-903, 1988. 

Santl, H., Brandsch, R., and Gruber, L. Experimental determination of Henry slaw constants (HLC) for some lower chlorinated dibenzodioxins, Chemosphere, 29(9-ll) 2209-2214, 1994. 

This technology is applicable for the treatment of polychlorinated biphenyls (PCBs) and other halogenated contaminants, such as insecticides, herbicides, pentachlorophenol (PCP), lindane, and chlorinated dibenzodioxins and furans. The contaminant matrix can be soil, sludge, sediments, or oil. It can treat oily sludges, coal by-products, and wood-treating compounds. 

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

Some Fumigants, the Herbicides 2,4-D and 2,4,6-T, Chlorinated Dibenzodioxins and Miscellaneous Industrial Chemicals... 

Johnson, R.L., Gehring, PJ., Kociba. R.J. Schwetz, B.A. (1973) Chlorinated dibenzodioxins and pentachlorophenol. Environ. Health Perspect., 5, 171-175... 

I ARC (1977) lARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Vol. 15, Some Fumigants, the Herbicides 2,4-D and 2,4,5-T, Chlorinated Dibenzodioxins and Miscellaneous Industrial Chemicals, Lyon, pp. 223-243... 

Ballschmiter, K., R. Bacher, A. Mennel, R. Fischer, U. Riehle, and M. Swerev, The determination of chlorinated biphenyls, chlorinated dibenzodioxins, and chlorinated dibenzofurans by GC-MS , J. High Res. Chromatogr., 15,260-270 (1992). 

Svenson, A., Kjeller, L-O. Rappe, C. (1989). Enzyme-mediated formation of 2,3,7,8-tetrasubstituted chlorinated dibenzodioxins and dibenzofurans. Environmental Science and Technology, 23, 900—2. 

Other chlorinated dibenzodioxins show markedly varied toxicological properties. Thus 2,7-dichloro and octachloro derivatives have low acute toxicity whereas hexachloro derivatives are much more toxic. However, none are as toxic as TCDD itself (77MI22602). 

Svenson A, Kjeller L-O, Rappe C (1989) Enzyme-Mediated Formation of 2,8-Tetra-Sub-stituted Chlorinated Dibenzodioxins and Dibenzofurans. Environ Sci Technol 23 900... 

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