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EC number: 202-634-5
CAS number: 98-07-7
In vitro bacterial mutagenicity:
Thein vitro mutagenicity of
benzotrichloride has been tested in in vitro bacterial systems
based on the Ames test. The reported studies are similar to the OECD
In a study
from Yasuo (1978), the authors tested the mutagenic activity of
benzotrichloride (CAS n° 98-07-7) with (1) a bacterial reverse mutation
test by following a methodology similar to the OECD guideline 471 and
(2) with a recombination assay performed according to Kada, Tutikawa and
Sadaie (1972) (Mutation Research 16: 165-174).
bacterial reverse mutation test following strains were used:Salmonella
TA 98, TA 100, TA 1535 and Escherichia coliWP2 try hcr and
WP2 try B/r. All Salmonella strains are assumed to have been
tested with and without the metabolic activation system (i.e. rat liver
S9 mix) and the E. coli strains were tested both with and without
the metabolic activation system. For Salmonellastrains TA 98 and
TA 1535 reported tested concentrations are 0.5 and 1.0 µmoles/plate,
while for SalmonellaTA 100 1.0 and 2.0 µmoles/plate was tested.
The concentrations used to test theE. coliWP2 try hcr strain were
0.25, 0.51, 1.02, 1.53, 2.05 and 2.56 µmoles/plate, while for E.
coli WP2 B/r try 0.51, 1.02, 2.05, 2.56, 3.07 and 4.09 µmoles/plate
of the test substance were tested. However for all tested strains, it
does not appear very clear whether more concentrations were tested and
if only positive results were reported. The number of revertant colonies
were counted and compared to the control to assess the mutagenicity of
the test substance.
recombination assay the mutagenic potential of the test substance was
tested with Bacillus subtilis M45 (rec-) and H17 (rec+) with and
without metabolic activation system at concentrations of 1.5, 2.6 and
3.6 µmoles/plate. The assessment of the mutagenicity is based on the
inhibition of the growth zone.
all these experiments the test substance was dissolved in DMSO and
solvent controls were performed (study is unclear on this point for some
strains) while no positive controls were executed.
test conditions, the mutagenicity of benzotrichloride was clearly
positive in the reverse mutation assay with metabolic activation system
to Salmonella TA 98, TA 100, TA 1535 and E. coli WP2 try hcr.
Slight mutagenic activity was observed for E. coli WP2 try hcr
without metabolic activation and the peak value forE. coli WP2
B/r try with metabolic activation was about 3 -fold the control level.
Furthermore the mutagenicity of the test substance was also considered
positive in the recombination assay for Bacillus subtilis M45 and
H17 without metabolic activation.
considering the overall study, benzotrichloride may be considered a
potent mutagen with metabolic activation. Therefore, further testing
would be required to clarify the situation based on this experiment.
In an other
study from Kudoley (1986), the
authors tested mutagenic activity of benzotrichloride (CAS n° 98-07-7)
following a methodology also similar to the OECD guideline 471. Only,
three strains of S. typhimurium(i.e. TA 100, TA 98 and TA 1538)
were exposed with metabolic activation to the test substance using the
plate incorporation method. The metabolic activation system (liver S9)
was derived from arochlor treated rats. Furthermore solvent controls and
positive control substances (i.e. 2-acetylaminofluorene and
benzo(a)pyrene; both with metabolic activiation and
methylnitrosoguanidine without metabolic activation) were included. It
is not clear how the authors chose the tested strains.
Under the test conditions, a 2 to 5 fold
induction of mutants was observed in comparison to spontaneous
background levels after exposure to the test substance. Thus, the in
vitro mutagenicity assay exposing S. typhimurium TA 100, TA 98
and TA 1538 to benzotrichloride with metabolic activation revealed that
the test substance is mutagenic. This test should then be considered as
positive with metabolic activation. Hence, further testing would also be
required based on these results.
Both studies follows a methodology similar
the OECD guideline 471 based on the Ames test method but the study from
Yasuo (1978) contains less deviations to the guideline. Furthermore, the
double approach used in the Yasuo study brings more evidences that
benzotrichoride is a potent mutagen in in vitro bacterial systems
with a metabolic activation. Finally, more details are provided on the
criteria for interpretation of results in the study from Yaso (1978).
Altogether, these elements were the basis to chose this study as the key
So far, based on both results, according to Annex
VII further tesing would 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, 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, as no information on in vivo testing
was freely available, then no information will be here further discussed.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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