Health Assessment Document for 1,2-Dichloroethane (Ethylene Dichloride). External Review Draft. Parts 1 and 2
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Ethylene Dichloride (EDC), a clear, colorless volatile liquid, is principally emitted to the environment during manufacturing. Monitoring data, including ambient urban areas, indicate a concentration of equal to or less than 0.5 ppb for most locations. EDC is rapidly absorbed, metabolized, and eliminated. Unmetabolized EDC is eliminated almost exclusively via the lungs. In humans, the symptoms of acute toxicity from repeated exposures exceeding 60 ppm are irritation of the respiratory tract and eyes and CNS depression. According to available evidence EDC does not adversely affect the reproductive or development process in animals except at maternally toxic levels. Additional human epidemiologic studies are needed to establish conclusively that EDC is not a teratogen and does not cause adverse reproductive effects. Positive responses in different text systems indicate that EDC is a weak, direct-acting mutagen; however, several of its metabolites, formed in animals, are more potent mutagens than EDC. As a carcinogen, EDC induces tumors in rats and mice by various routes of exposure (gavage, intraperitoneally, dermally). However, lifetime inhalation exposure conditions did not produce tumors in rats or mice. Results from animal carcinogen studies, when considered with the positive evidence of mutagenicity and the presence of reactive metabolites and covalent bonding to DNA, suggest that EDC is a potential human carcinogen.