1,1,2,2-Tetrachloroethane - PSL1

4.0 Recommendations for Research and Evaluation

1,1,2,2-Tetrachloroethane is no longer produced or imported into Canada; therefore, exposure of biota and humans is currently low and is expected to decrease over time. Since available data are too limited to determine trends in concentrations in air, which is the primary source of exposure in Canada, continued monitoring of this substance is recommended. If exposure continues to decrease, the priority for the following research is considered to be low. However, if exposure to 1,1,2,2-tetrachloroethane increases, then the priority for obtaining the additional data outlined below should be reassessed.

1. It would be desirable to obtain monitoring data on levels of 1,1,2,2-tetrachloroethane in food (using more sensitive analytical methodology than that in currently available surveys), drinking water, and human breast milk in Canada, to more accurately determine the exposure of the general population to 1,1,2,2-tetrachloroethane in these media.
2. To investigate the potential effects of exposure to 1,1,2,2-tetrachloroethane on health, more complete subchronic studies are required. In these studies, a range of endpoints should be examined in experimental animals exposed to several dose levels of 1,1,2,2-tetrachloroethane by inhalation (the route of exposure most relevant to humans).
3. A carcinogenicity bioassay is desirable in which non-neoplastic endpoints, such as organ weight changes, and biochemical and hematological effects, are also examined in two species of experimental animals exposed to 1,1,2,2-tetrachloroethane by inhalation (the route of exposure most relevant to humans) in order to more completely assess the potential effects of this compound in humans.
4. It would be desirable to conduct additional investigations into the mechanism of liver tumor induction by 1,1,2,2-tetrachloroethane in mice, to interpret the relevance of these tumors to humans.
5. Additional data are desirable on the developmental toxicity, reproductive toxicity, neurotoxicity and immunotoxicity, and the in vivo genotoxicity of 1,1,2,2-tetrachloroethane to determine the potential for these effects on health.
6. To investigate the potential effects of exposure to 1,1,2,2-tetrachloroethane on terrestrial biota, toxicity studies on terrestrial plants, and oral and inhalation subchronic studies on wild mammals and birds are desirable.