Document zjQ4rb8n0npqLqJa3r0nELmB

*W m HISTORICAL OVERVIEW: 2,9,5-T, Chloracne & 2,3,7,8-TCDD 1930s 1991 1999 1997 1998 1999 1950 1957 1962 Chloracne, a dermatitis characterized by blackheads similar to teen-age acne but often more severe, was noted among workers dealing with chlorinated aromatic hydrocarbons (chloracnegens). 2.9- D and 2,9,5-T first synthesized. 2.9- D and 2,9,5-T reported as herbicides and marketed by Amchem Products. Effectiveness of 2,9,5-T and derivatives against woody plants resistant to 2,9-D established by Dow. 2,9,5-T registered for control of weeds on rangelands, fence rows and rights of way. Explosion in Monsanto's 2,9,5-trichlorophenol (TCP) unit at Nitro, W.Va. exposed 250 workers to reaction mass causing 122 cases of chloracne, some very severe. TCP is intermediate in 2,9,5-T manufacture. Presence of a "highly toxic impurity" in production of TCP recognized by Dow. 2,3,7,8-TCDD first implicated as causative agent of chloracne associated with TCP production. (Kimmig and Schultz, Germany) U.S. military began spraying 2,9,5-T formulations in Vietnam to take away foliage cover from the enemy. CON^IDEN^ SUBJECT TO PROTECTIVE ORDER. HISTORICAL OVERVIEW (CONT'D.) 1965 1970 1973 1976 1978 1979 1982 2.3.7.8- TCDD recognized by Dow as causative agent of chloracne in TCP wastes. Alerted health authorities and other U.S. 2.4.5-T manufacturers. Shared analytical techniques. 2.3.7.8- TCDD's teratogenicity and fetotoxicity first reported in animals. U.S, military stopped spraying Agent Orange in Vietnam. U.S. Dept, of Agriculture suspended uses of 2.4.5-T. Vietnamese study linked liver cancer, abortions, and birth defects to Agent Orange spraying. Explosion at ICMESA chemical plant in Seveso. Italy released heavy concentration of 2.3.7.8-TCDD in densely populated area. Workers (156) and residents (37.000) exposed. More than 500 treated for presumed toxic symptoms; 134 cases of chloracne. Mortality rate normal to date. Event received worldwide publicity through news media. Dow announced chlorinated dioxins found in particulate matter in air emissions from various commercial and domestic combustion processes. Suit filed by Vietnam veterans against five U.S. chemical companies that produced Agent Orange. Companies, in turn, filed third party action against U.S. government for its negligent misuse of the chemical. Times Beach T SUBJECT TO PROTECTIVE ORDER. DIOXIN Chemical Nomenclature: Dioxin = Dibenzo-j>dioxin Media: Dioxin = 2.,3,7.18-Tetrachlorodibenzo-_-dioxin = 2,3,7,8-TCDD SUBJECT TO PROTECTIVE ORDER. CHLORINATED DIOXINS (CDDs) Clx Clx 75 CDDs 22 TCDDs 2,3.>7.>8-TCDD - most toxic isomer to the male guinea Dig CCDs 10 to 20 times more toxic than chlorinated dibenzofurans in the rabbit ear test Clx SUBJECT TO PROTECTIVE ORDER. STRUCTURE AND PHYSICAL PROPERTIES OF 2.3,7.8-TCDD ci ci Cl Cl Physical State: Molecular Weight: Melting Point, C.: Decomposition Point, C,: Solubility: White, crystalline solid 322 303-305 980-1000 Water = 2 x 10"8 g./L Benzene = 0.57 g./L o-Dichlorobenzene = 1,4 g./L SUBJECT TO PROTECTIVE ORDER, SOURCES AND FORMATION OF DIOXINS Formed during manufacture of chlorophenols, intermediates in synthesis of pesticides, Thus contaminants in chlorophenol derived pesticides, Pyrolysis (<750C) of chlorophenols or chlorophenol derived pesticides. Formed in a wide variety of commercial and domestic combustion processes, SUBJECT TO PROTECTIVE ORDER. REQUIREMENTS FOR DIOXIN FORMATION Precursor must contain an -substituted benzene ring with one of the substituents being an oxygen atom attached directly to the ring. The two substituents must be able to react with each other to form another compound. The reaction is favored by basic conditions (e.g., sodium hydroxide) and temperatures of 180-400C. Presence of a metal catalyst (e.g., copper or iron powder) promotes the reaction. SUBJECT TO PROTECTIVE ORDER. -'St ' % m MANUFACTURE OF 2 5-T Step 1 Step 2 Step 3 + 4 Cl2 Benzene Chlorine Cl (1,2,4,5-Tetrachlorobenzene) 4 HC1 Hydrogen chloride Cl + 2 NaOH + 2 CH3OH Sodium Methanol Cl hydroxide Cl + CH3OCH3 Dimethyl ether + NaCl + NaTCP Sodium (Sodium 2,4,5- chloride trichlorophenate) 2 H 20 Water Cl ONa Cl Cl + ClCH2C00Na -----> NaMCA (Sodium monochloro- acetate) f^ > 7 r OCH2COONa + ci^s^ Cl Na 2,4,5-T (Sodium 2,4,5-trichlorophenoxyacetate) NaCl --Step--4 Cl 0CH2C00Na Cl ^ H2S0i| Sulfuric acid Cl 1 T0CH2C00H + Cl^j^ Cl 2,4,5-T ichlorophenoxyic acid) % Na2S0i,, Sodium sulfate SUBJECT TO PROTECTIVE ORDER. 4, FORMATION OF 2.3,7,8-TCDD AS SIDE REACTION IN MANUFACTURE OF NnTCP NaTCP "Predioxin" sodium salt NaCl Sodium chloride Y 2,3,7,3-TCDD NaCl SU B JEC TTO PROTECTIVE1ORDER MANUFACTURF OF PENTA AND SANTOBRITF OH Phenol + 5 Cl2 60-190C Chlorine OH C1 J k Cl C l ^ ^C1 Cl + Penta (Pentachlorophenol) 5 HC1 Hydrogen chloride + NaOH 7Q-90C Sodium hydroxide ONa Cl ,cl V 1Cl' C1 Cl Santobrite h 2o Water SUBJECT TO PROTECTIVE ORDER. 0 FORMATION OF CHLORINATED DIBENZO-p-DIOXINS AND CHLORINATED DIBENZOFURANS AS SIDE REACTIONS IN MANUFACTURE OF PENTA Octachlorodibenzo-dioxin 1,2,3,4,5 ,7,8- Hep tachloro-6-hydroxy dibenzofuran SUBJECT TO PROTECTIVE ORDER. METHODS OF DESTRUCTION OF CHLORINATED DIOXINS .Incineration at temperatures of 1000 to 1500 in industrial incinerators. Future: molten salt combustion or microwave plasma destruction. Degraded quickly by sunlight or artificial ultraviolet light (photolysis). Chemical destruction by ozonolysis, chlorinolysis, catalytic wet oxidation (Zimpro process), and catalytic dechlorination processes. Biological destruction by new genetic engineered bacteria may hold future promise. * ,9.. r CHEMISTRY OF INCINERATION OF 2.3.7,8-TCDD Cl c YjriyrL ^ ^ r L Cl r^i XI 2,3,7,8-TCDD 12 02 + A [H ] 1000-1500C Oxygen Hydrogen from organic donor 12 C02 + 2 H20 Carbon dioxide Water A HC1 Hydrogen chloride subject TO PROTECTIVE order. CHEMISTRY OF PHOTOLYSIS OF 2,5.7.8-TCDD 2,3,7,8-TCDD Hydrogen from organic donor Dioxin + 4 HC1 Hydrogen chloride 2-Hydroxydiphenyl oxide Polymer SUBJECT TO PROTECTIVE ORDER.