Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

In vitro bacterial mutagenicity:

The in vitro mutagenicity of 4 -chloro-benzotrichloride has been tested in an in vitro bacterial system based on the Ames test. The reported GLP study is very similar to the OECD guideline 471.

Hence, the authors tested the mutagenicity of 4-chloro-benzotrichloride (CAS n° 5216 -25 -1) in the absence and presence of a metabolizing system with a methodology similar to the OECD guideline 471. The Salmonella typhimurium strains TA 100, TA 1535, TA 1537, TA 1538 and TA 98 and the Escherichia coli strain WP2uvrA were used and the metabolizing system was obtained from rat liver homogenates. The number of revertants per plate was estimated and was a basis for comparison with solvent controls.

Based on the range-finding/screening test, 500 µg/plate was chosen as top dose level for the mutagenicity test and the test compound proved to be toxic to most of the bacterial strains at 20 or 100 µg/plate according to observed diminuation or even complete absence of the bacterial lawn.

In the mutagenicity test, seven different doses ranging from 0.16 to 500 µg/plate were used (3 replicates per dose) and the strains were exposed for 48 to 72 h. Control plates without mutagen showed the described number of spontaneous revertant colonies reported in literature and all the positive control compounds gave the expected increase in the number of revertant colonies.

Furthermore the mutagenicity test showed a dose dependant increase in the number of revertant colonies with theS. typhimurium strain TA 98 in absence of the metabolic activation system (S-9 mix) after exposure to the test compound. In the presence of the metabolic activation system, treatment with the test substance resulted in a relevant increase in the number of revertant colonies in theS. typhimurium strain TA 98. Also slightly increased numbers of revertant colonies were obtained in the absence and presence of the metabolic activation system forS. typhimuriumstrains TA 100 and TA 1537. Considering the overall data, thus, 4 -chloro-benzotrichloride can be considered mutagenic with and without metabolic activation system for the tested strains.

So far, based on these results, further testing as required in the annex VIII should be required. However, according to the column 2 of the specific rules for adaptation from column 1 of the REACH regulation n° 1907/2006, an in vitro study on cytogenicity in mammalian cells or an in vitro micronucleus study of the annex VIII requirement does not usually need to be conducted if the substance is known to be carcinogenic category 1 or 2 or mutagenic category 1, 2 or 3. In this case, 4-chloro-benzotrichloride is classified in the CLP regulation n° 1272/2008 EC as a carcinogen category 1B, hence no study on cytogenicity in mammalian cells or an in vitro micronucleus is required.

Hence, no further testing is required on an in vitro Mammalian system. Besides, no information on in vivo testing was freely available, then no information will be here further discussed.


Short description of key information:
In vitro mutagenicity: positive in an in vitro bacterial system

Endpoint Conclusion:

Justification for classification or non-classification