Annette Ashizawa

Trichloroethylene in the Environment: Public Health Concerns

The Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxi-cological profiles for hazardous substances found at waste sites and elsewhere in the environment. In 1997 the agency updated its toxicological profile for trichloroethylene and included new and expanded information on the health effects associated with exposures to trichloroethylene. Several endpoints of concern are described in the profile. However, in this paper only results from studies reporting developmental and carcinogenic effects from trichloroethylene exposures in human and experimental animal studies are summarized and evaluated. Based on its assessment of the available studies and limitations in the reported findings, ATSDR has determined there is limited but suggestive evidence that developmental effects may be a concern for some persons exposed to TCE in drinking water. Moreover, developmental effects may be the most sensitive of all non-cancer health effects associated with trichloroethylene exposures. Significant questions remain about the likely mode(s) of action for TCE-induced carcinogenesis in humans and the basis for differences in pharmacokinetics handling of TCE across animal strains and sex. However, on the basis of animal data and the suggestive, yet inconclusive, human data available, ATSDR has determined that cancer should be an effect of concern for people exposed to TCE in the environment. ATSDR agrees that the available literature supports the premise that TCE is “reasonably anticipated to be a human carcinogen” as defined by the U.S. National Toxicology Program.