Iron cobalt black spinel

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:

10 July 2017 - 3 August 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

21 Jul 1997

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

30 May 2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

Version / remarks:

Aug 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

BASF SE Experimental Toxicology and Ecology, 67056 Ludwigshafen, Germany

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Iron cobalt black spinel

EC Number:

269-102-2

EC Name:

Iron cobalt black spinel

Cas Number:

68187-50-8

Molecular formula:

CoFe2O4

IUPAC Name:

Iron cobalt spinel

Test material form:

solid

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature

Method

Species / strain

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:

liver S9 mix from phenobarbital and β-naphthoflavone induced Wistar rats

Test concentrations with justification for top dose:

In agreement with the recommendations of current guidelines 5 mg/plate or 5 μL/plate were generally selected as maximum test dose at least in the 1st Experiment. In this study, due to the purity of the test substance 5.3 mg/plate was used as top dose in all experiments.
1st Experiment
Doses: 0; 33; 100; 333; 1000; 2650 and 5300 μg/plate
Type of test: Standard plate test with and without S9 mix
Number of plates: 3 test plates per dose or per control
2nd Experiment
Doses: 0; 33; 100; 333; 1000; 2650 and 5300 μg/plate
Type of test: Preincubation test with and without S9 mix
Number of plates: 3 test plates per dose or per control
Reason: No mutagenicity was observed in the standard plate test.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

- Justification for choice of solvent/vehicle: Due to the insolubility of the test substance in water, DMSO was used as vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical control data are available.

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (2-AA)

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylenediamine (NOPD)

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Controls 5

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation) and preincubation

DURATION
- Preincubation period: 20 min
- Exposure duration: 48-72 hours

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

The test substance was considered positive in this assay if the following criteria were met:
A dose-related and reproducible increase in the number of revertant colonies, i.e. at least doubling (bacteria strains with high spontaneous mutation rate, like TA 98, TA 100 and E.coli WP2 uvrA) or tripling (bacteria strains with low spontaneous mutation rate, like TA 1535 and TA 1537) of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.
A test substance was generally considered non-mutagenic in this test if:
The number of revertants for all tester strains were within the range of the historical negative control data under all experimental conditions in at least two experiments carried out independently of each other.

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

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

weak bacteriotoxic effect was observed in the standard plate without S9 mix at 5300 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

A weak bacteriotoxic effect was observed in the standard plate test using TA 98 with S9 mix at a concentration of 2650 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

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

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: none

HISTORICAL CONTROL DATA (with ranges, means and standard deviation and confidence interval (e.g. 95%)
- Positive historical control data:
TA 1535 (with S9 Mix): MNNG mean=3967 ± 1253.9
TA 1535 ( without S9 Mix): 2-AA mean=197 ± 56.3
TA 100 (with S9 Mix): MNNG mean = 3298 ± 1109.8
TA 100 (without S9 Mix): 2-AA mean = 1748 ± 587.2
TA 1537 (with S9 Mix): AAC mean = 1044 ± 404.3
TA 1537 (without S9 Mix): 2-AA mean = 141 ± 50.3
TA 98 (with S9 Mix):NOPD mean = 863 ± 206.8
TA 98 (without S9 Mix): 2-AA mean = 1524 ± 529.1
E.coli (with S9 Mix): mean = 860 ± 431.9
E.coli (without S9 Mix): mean = 133 ± 61.8
- Negative vehicle historical control data:
TA 1535 (with and without S9 Mix): mean=10 ± 2
TA 100 (with S9 Mix): mean = 100 ± 11.4
TA 100 (without S9 Mix): mean = 107 ± 13.7
TA 1537 (with S9 Mix): mean = 8 ± 1.7
TA 1537 (without S9 Mix): mean = 9 ± 2.1
TA 98 (with S9 Mix): mean = 21 ± 3.3
TA 98 (without S9 Mix): mean = 28 ± 4.5
E.coli (with S9 Mix): mean = 24 ± 3.9
E.coli (without S9 Mix): mean = 25 ± 4.4

In this study with and without S9 mix, the number of revertant colonies in the negative controls was within the range of the historical negative control data for each tester strain
The positive control substances with and without S9 mix induced a significant increase in the number of revertant colonies within the range of the historical positive control
data.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- A weak bacteriotoxic effect (slight decrease in the number of his+ revertants) was only observed in the standard plate test using the tester strain TA 1537 without S9 mix at a concentration of 5300 μg/plate and using TA 98 with S9 mix at a concentration of 2650 μg/plate. In the preincubation assay no bacteriotoxicity (reduced his- or trp- background growth, decrease in the number of his+ or trp+ revertants) was observed up to the highest concentration.