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Key value for chemical safety assessment

Additional information

Based on the variability of quality of studies and reports available, a global weight of evidence approach was used to evaluate the genotoxicity potential of 1,1,2 -trichloroethane.

In bacteria using the Ames test, 1,1,2 -trichloroethane showed no mutagenic action according to Barber et al. (1981) and Milman et al. (1988). A positive result was observed in a gene mutation assay conducted with Saccharomyces cerevisiae (Bronzetti et al., 1987).

Chromosome segregations were induced in aspergillus nidulans by substance (Crebelli et al. 1988). Positive results were also obtained by comet assay using human lymphocytes by observation of tail length and DNA contents increases induced by treatment.

Results of in vitro micro-nucleus and Unscheduled DNA Synthesis (UDS) assays were inconclusive. Weak effects of 1,1,2 -trichloroethane were found without concentration-activity relationships in the in vitro micronucleus test, with and without activation. Effects with metabolic activation were only seen in the second experiment (Tafazoli and Kirsch-Volders, 1996). Unscheduled DNA Synthesis was induced in primary rat hepatocytes, but not in mouse hepatocytes (Milman et al., 1988).

In vivo, chemical exposure was demonstrated to induce DNA binding in rat and mouse (Mazzulo et al., 1986). Nevertheless, no increase in UDS was induced by treatment in murine hepatocytes of B6C3F1 mice (Mirsalis et al., 1989).

To elucidate the genotoxic potential of 1,1,2 -trichloroethane in vivo, a mammalian erythrocyte micronucleus test according to OECD Test Guideline 474 was conducted. Only the study summary was available, but results were reported to be clearly negative, according to the absence of increase in the number of micronucleated PCE in any treated groups at 24 h and 48 h following single gavage administration of 1,1,2 -trichloroethane at 100, 200 and 400 mg/kg bw in male CD-1 mice (UNEP, 2002).

Based on this result, it was considered that 1,1,2-trichloroethane was not genotoxic.

Short description of key information:
Some uncertainties of genotoxic potential were exhibited because non-core studies showed positive results. However, core genotoxity studies such as reverse mutation in Salmonella typhimurium and unscheduled DNA synthesis and micronucleus testing in vivo demonstrated negative results, so that the substance is not considered as genotoxic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the negative results obtained in core genotoxity studies, no classification was recommended by EC authorities for genotoxicity potential of substance.