1,2-Ethanediol, reaction products with branched 2-[(4-nonylphenoxy)methyl]oxirane

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Bacterial Mutagenicity Assay.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat liver S9

Test concentrations with justification for top dose:

In the initial toxicity-mutation assay, the dose levels tested were 1.50, 5.00, 15.0, 50.0, 150, 500, 1500 and 5000 μg per plate. Precipitate was observed beginning at 1500 μg per plate with all conditions. Toxicity was observed beginning at 150 or at 5000 μg per plate with a few conditions. No positive mutagenic responses were observed with any of the tester strains in either the presence or absence of S9 activation. Based upon these results, the maximum dose tested in the confirmatory mutagenicity assay was 5000 μg per plate with all tester strains in the presence and with tester strains TA98, TA1537 and WP2 uvrA in the absence of S9 activation and 1500 μg per plate with tester strains TA100 and TA1535 in the absence of S9 activation.
In the confirmatory mutagenicity assay, the dose levels tested were 5.00, 15.0, 50.0, 150, 500, 1500 and 5000 μg per plate with all tester strains in the presence of S9 activation and with tester strains TA98, TA1537 and WP2 uvrA in the absence of S9 activation and 0.500, 1.50, 5.00, 15.0, 50.0, 150, 500 and 1500 μg per plate with tester strains TA100 and TA1535 in the absence of S9 activation. Precipitate was observed beginning at 500 or 1500 μg per plate with all conditions.

Vehicle / solvent:

DMSO, purity 99.95%

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

methylmethanesulfonate

other: 2-aminoanthracine

Rationale for test conditions:

The following criteria must be met for each assay to be considered valid:
All Salmonella tester strain cultures must demonstrate the presence of the deep rough mutation (rfa) and the deletion in the uvrB gene. Cultures of tester strains TA98 and TA100 must demonstrate the presence of the pKM101 plasmid R factor. All WP2 uvrA cultures must demonstrate the deletion in the uvrA gene.
Based on historical control data (95% control limits), all tester strain cultures must exhibit characteristic numbers of spontaneous revertants per plate with the vehicle controls. The mean revertants per plate must be within the following ranges (inclusive). Untreated controls, when part of the design, must also be within the ranges cited below.
95% Control Limits (99% Upper Limit)
TA98 TA100 TA1535 TA1537 WP2 uvrA
-S9 6-26 (31) 66-114 (126) 3-23 (28) 1-13 (16) 9-41 (49)
+S9 9-37 (44) 68-128 (143) 3-23 (28) 3-15 (18) 12-44 (52)
With Study Director justification, values including the 99% control limit and above are acceptable.
To ensure that appropriate numbers of bacteria are plated, tester strain culture titers must be greater than or equal to 0.3x109 cells/mL.
The mean of each positive control must exhibit at least a 3.0 fold increase in the number of revertants over the mean value of the respective vehicle control.
A minimum of three non toxic dose levels is required to evaluate assay data. A dose level is considered toxic if one or both of the following criteria are met: (1) A >50 % reduction in the mean number of revertants per plate as compared to the mean vehicle control value. This reduction must be accompanied by an abrupt dose dependent drop in the revertant count. (2) At least a moderate reduction in the background lawn (background code 3, 4 or 5).

Evaluation criteria:

For each replicate plating, the mean and standard deviation of the number of revertants per plate were calculated and are reported.
For the test substance to be evaluated positive, it must cause a dose-related increase in the mean revertants per plate of at least one tester strain over a minimum of two increasing concentrations of test substance as specified below:
Strains TA98, TA1535, TA1537 and WP2 uvrA
Data sets were judged positive if the increase in mean revertants at the peak of the dose response was equal to or greater than 3.0-times the mean vehicle control value and above the corresponding acceptable vehicle control range.
Strains TA100
Data sets were judged positive if the increase in mean revertants at the peak of the dose response was equal to or greater than 2.0-times the mean vehicle control value and above the corresponding acceptable vehicle control range.
An equivocal response is a biologically relevant increase in a revertant count that partially meets the criteria for evaluation as positive. This could be a dose-responsive increase that does not achieve the respective threshold cited above or a non-dose responsive increase that is equal to or greater than the respective threshold cited. A response will be evaluated as negative if it is neither positive nor equivocal

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Conclusions:

All criteria for a valid study were met as described in the protocol. The results of the Bacterial Reverse Mutation Assay indicate that, under the conditions of this study, the test material did not cause a positive mutagenic response with any of the tester strains in either the presence or absence of Aroclor induced rat liver S9.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

One Bacterial Mutagenicity Assay is available and it is Negative      .

Justification for classification or non-classification

GHS criteria for classification are not met.