Sodium Nickel Manganese Magnesium Titanium Dioxide (Crystal phase: O3/P2/RS)

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Oct. 02, 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

2008

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1997

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Sodium Nickel Manganese Magnesium Titanium Dioxide (Crystal phase: O3/P2/RS)

EC Number:

951-477-5

Molecular formula:

Na1-δNivMnwMgxTiyO2, where the ranges are 0 < δ < 0.2, 0.2 < v < 0.4, 0.4 < w < 0.6, 0.02 < x < 0.2, 0.02 < y < 0.2

IUPAC Name:

Sodium Nickel Manganese Magnesium Titanium Dioxide (Crystal phase: O3/P2/RS)

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain / cell type:

bacteria, other: Salmonella typhimurium (TA97a, TA98, TA100, TA102 and TA1535)

Metabolic activation:

with and without

Metabolic activation system:

Source of S9: produced from the livers of male Sprague-Dawley rats which were treated with 500 mg Aroclor 1254/kg body weight intra-peritoneally.

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

sodium azide

benzo(a)pyrene

other: 2-Amino-Anthracene

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

other: S. typhimurium TA 97a

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Based on the results of the study it is concluded that the substance is not mutagenic in the Salmonella typhimurium strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in this study.

Executive summary:

Three valid experiments were performed.

The study procedures described in this report were based on the most recent OECD Guideline and EU method.

The test material was tested in the Salmonella typhimurium reverse mutation assay with five strains of Salmonella typhimurium (TA97a, TA98, TA100, TA102 and TA1535). The test was performed in three experiments in the presence and absence of S9 metabolic activation.

Experiment 1:

In the first experiment, the test item (dissolved in dimethyl sulfoxide) was tested up to concentrations of 5000 µg/plate in the absence and presence of S9 mix in the strains TA97a,TA98, TA100, TA102 and TA1535 using the plate incorporation method.

The test item showed precipitates on the plates at the highest concentration only, the precipitates did not influence the colony counting.

The bacterial background lawn was not reduced at any of the concentrations but a relevant decrease in the number of revertants was observed in all bacteria strains. The test item showed toxicity towards all bacteria strains both in the absence and presence of metabolic activation at the highest concentration (5000 µg/plate) and towards TA98 with and without S9 metabolic activation and TA97a without metabolic activation at the concentration 1500 µg/plate.

The results of this experiment showed that none of the evaluated non- toxic concentrations showed a significant increase in the number of revertants in the tested strains, in the presence and the absence of metabolic activation.  Since the guideline prescribes at least five evaluable non-toxic concentrations, the first experiment was repeated with adapted concentrations (experiment 1b).

 Experiment 1b:

Based on the toxicity results of the experiment 1, the experiment 1b was repeated under the same conditions with additional lower concentrations:

The test item (dissolved in dimethyl sulfoxide) was tested up to concentrations of 1500 µL/plate in the absence and presence of metabolic activation in the bacteria strains TA97a and TA98 and up to 5000 µg/plate in the strains TA100, TA102 and TA1535.

The test item showed precipitates on the plates at the highest concentration 5000 µg/plate on the strains TA100, TA102 and TA1535, but the precipitates did not influence the colony counting.

The bacterial background lawn was not reduced at any of the concentrations.

Toxicity was observed in the bacteria strains TA100, TA102 and TA1535 with and without metabolic activation at the highest concentration (5000 µg/plate) and in the bacteria strains TA97a and TA98 without metabolic activation at the concentration 1500 µg/plate. In the lower concentrations no signs of toxicity were observed.

The results of this experiment showed that none of the tested non-toxic concentrations showed an increase in the number of revertants in all tested strains, in the presence and the absence of metabolic activation.

 Experiment 2:

Based on the results of the experiment 1 and 1b, the test item was tested up to concentrations of 5000 µg/plate (TA100, TA102 and TA1535) resp. 1500 µg/plate (TA97a and TA98) in the absence and presence of metabolic activation using the pre-incubation method.

The test item showed precipitates on the plates at the highest concentration 5000 µg/plate only, but the precipitates did not influence the colony counting.

The bacterial background lawn was not reduced at any of the concentrations. Toxicity was observed in the bacteria strains TA100 and TA1535 at the concentrations 5000 and 2500 µg/plate without metabolic activation and in TA102 with and without metabolic activation at the concentration 5000 µg/plate.

Moreover, toxicity was observed in the bacteria strains TA97a without metabolic activation at 1500 µg/plate and 750 µg/plate and in TA98 with and without metabolic activation at the concentration 1500 µg/plate. The results of this experiments showed that the test item caused no increase in the number of revertants in all bacteria strains compared to the solvent control, both in the absence and presence of metabolic activation. The test item did not induce a dose-related increase in the number of revertant colonies in all strains, in the presence and absence of metabolic activation.