Chlorinated toxicology

The toxicological problems associated with asbestos have been widely pubHshed and asbestos has been banned from most uses by the EPA. However, modem diaphragm cell chlorine plants have not had difficulty meeting the required exposure limits for asbestos fibers, and, as of 1990, the chlorine industry had an exemption allowing the continued use of asbestos as a diaphragm material. 

Toxicity of Chlorine Sanitizers. Chlorine-based swimming-pool and spa and hot-tub sanitizers irritate eyes, skin, and mucous membranes and must be handled with extreme care. The toxicities are as follows for chlorine gas, TLV = 1 ppm acute inhalation LC q = 137 ppm for 1 h (mouse) (75). The acute oral LD q (rats) for the Hquid and soHd chlorine sanitizers are NaOCl (100% basis) 8.9 g/kg (76), 65% Ca(OCl)2 850 mg/kg, sodium dichloroisocyanurate dihydrate 735 mg/kg, and trichloroisocyanuric acid 490 mg/kg. Cyanuric acid is essentially nontoxic based on an oral LD q > 20 g/kg in rabbits. Although, it is mildly irritating to the eye, it is not a skin irritant. A review of the toxicological studies on cyanuric acid and its chlorinated derivatives is given in ref. 77. 

Table 3. Toxicology of Side-Chain Chlorinated Toluenes...

Acute toxicides (LD q rats) for CA and chloroisocyanurates are CA > 5.0, SDCC 1.67, PDCC 1.22, and TCCA 0.75 (126). A review of toxicological studies on CA and its chlorinated derivatives is given in Reference 127. These studies show that the compounds are safe for use in swimming pool and spa/hot tub disinfection, sanitizing, and bleaching appHcations when handled and used as directed. 

HowlandMA. 1990. Insecticides Chlorinated and other forms. In Goldfrank LR, Flomenbaum NE, Lewin NA, et al. eds. Goldfrank s toxicologic emergencies. 4th ed. Norwalk, CT Appleton Lange, 693-697. 

Brooks, G.T. (1974). The Chlorinated Insecticides, Vols 1 and 2—A detailed and authoritative standard reference work on the chemistry, biochemistry, and toxicology of organochlo-rine insecticides. 

Elliott, J.E., Wilson, L.K., and Henny, C.J. et al. (2001). Assessment of biological effects of chlorinated hydrocarbons in osprey chicks. Environmental Toxicology and Chemistry 20, 866-879. 

Jansson, B., Andersson, R., and Asplund, L. et al. (1993). Chlorinated and brominated persistent organic compounds in biological samples from the environment. Environmental Toxicology and Chemistry 12, 1163-1174. 

Variations in the manufacturing process of 2,4,5-trichloro- and pentachlorophenol (but not 2,4-dichlorophenol) have sometimes resulted in contamination of the product by small amounts of heterocyclic impurities (4,5). Of these, the chlorinated dibenzo-p-dioxins such as TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) have received much scientific and public attention because of their real or potential toxicity 6, 7), [Chick edema factor, a curious toxicological problem to poultry producers for several years, has been shown to be composed of chlorodibenzo-p-dioxins (8).]... 

Chlorinated dibenzo-ip-dioxins were prepared on the gram scale for use as toxicological standards, 2,7-Dichlorodi-henzo-p-dioxin was prepared by catalytic condensation of potassium 2-bromo-4-chlorophenate in 70% yield. Thermal condensation of the potassium salt of 2,4,4 -trichloro-2 -hydroxy diphenyl ether gave a mixture of the 2,8- and 2,7-dichlorodibenzo-p-dioxins which were separated by fractional recrystallization. 2,3,7,8-T etrachlorodibenzo-p-dioxin of 99.9- -% purity was prepared by catalytic condensation of potassium 2,4,5-trichlorophenate. An isomeric mixture of hexachlorodibenzo-p-dioxins was prepared by pyrolytic condensation of sodium 2,3,4,6-tetrachlorophenate. Chlorination of pentachlorophenol (containing < 0.07% tetrachlorophenol) in trichlorobenzene gave octachlorodi-benzo-p-dioxin in 80% yield contaminated by 5-15% heptachlorodibenzo-p-dioxin. Oxidative methods were used to produce octachlorodibenzo-p-dioxin at 99.9% purity. 

Chlorinated solvents are extremely efficient cleaning agents. Unfortunately, significant toxicological and environmental hazards have caused many companies to stop using them altogether. Could suppliers find a way of using them safely and responsibly for applications where they are the best choice ... 

Shiu, W.-Y., Gobas, F. A. P. C., Mackay, D. (1987) Physical-chemical properties of three congeneric series of chlorinated aromatic hydrocarbons. In QSAR in Environmental Toxicology II. Kaiser, K. L. E., Ed., pp. 347-362, D. Reidel Publishing, Dordrecht, The Netherlands. 

Elliott, J.E., R.J. Norstrom, and G.EJ. Smith. 1996. Patterns, trends, and toxicological significance of chlorinated hydrocarbon and mercury contaminants in bald eagle eggs from the Pacific coast of Canada, 1990-1994.Arch. Environ. Contam. Toxicol. 31 354-367. 

U.S. Public Health Service (USPHS). 1998. Toxicological profile for chlorinated dibenzo-p-dioxins (update). U.S. Dept. Health Human Serv., Agen. Toxic Subst. Dis. Regis. 709 pp. 

Baeten, A., Tafazoli, M., Kirsch-Volders, M., and Geerlings, P. 1999. Use of the HSAB principle in quantitative structure-activity relationships in toxicological research Application to the genotoxicity of chlorinated hydrocarbons. Int. J. Quantum Chem. 74 351-355. 

The most serious toxicological effect of endrin is central neurotoxicity (Klaasen et al. 1986). Organo-chlorines interfere with the normal flux of cations across the axon, disrupting central nervous system homeostasis (Finkel 1983 Klaasen et al. 1986). Endrin is one of the most toxic cyclodienes, and seizure activity may develop rapidly after exposure (Proctor et al. 1988). In most cases, recovery is rapid. However, headaches, dizziness, weakness, and anorexia may persist for 2-4 weeks. 

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