Calcination products of titanium dioxide, tin monoxide, zinc oxide and dihydrogen wolframate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

(21 Jul 1997)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

(BASF SE, Experimental Toxicology and Ecology, Ludwigshafen, Germany)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Calcination product of titanium dioxide, tin monoxide, zinc oxide and dihydrogen wolframate

EC Number:

941-788-4

Molecular formula:

Ti 1 Sn 0,6 Zn 0,5 W 0,15 O 4

IUPAC Name:

Calcination product of titanium dioxide, tin monoxide, zinc oxide and dihydrogen wolframate

Test material form:

solid: particulate/powder

Details on test material:

Solid / red
stored at room temperature
The test substance was homogeneous by visual inspection.
The test item is not surface-treated or otherwise coated.

Method

Target gene:

his+ / trp+

Species / strain

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

phenobarbital and beta-naphthoflavone induced rat liver S9 microsomal fraction

Test concentrations with justification for top dose:

1st Experiment (Standard plate test with and without S9 mix): 0; 33; 100; 333; 1000; 2500 and 5000 μg/plate
2nd Experiment (Preincubation test with and without S9 mix): 0; 33; 100; 333; 1000; 2500 and 5000 μg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in ultrapure 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

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (2-AA), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitro-o-phenylenediamine (NOPD), 9-aminoacridine (AAC), 4-nitroquinoline-N-oxide (4-NQO)

Details on test system and experimental conditions:

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

Standard plate test:
- Exposure duration: 48 – 72 hours

Preincubation test:
- Preincubation period: 20 min
- Exposure duration: 48 – 72 hours


NUMBER OF REPLICATIONS: 3


DETERMINATION OF CYTOTOXICITY
- Method: decrease in the number of revertants, clearing or diminution of the background lawn, reduction in the titer


OTHER:
Titer determination: The titer was determined only in the experimental parts with S9 mix both for the negative controls (vehicle only) and for the two highest doses in all experiments.

Positive controls:

With S9 mix: 2-aminoanthracene (2-AA), 2.5 μg/plate, dissolved in DMSO / TA 1535, TA 100, TA 1537, TA 98; 60 μg/plate, dissolved in DMSO / Escherichia coli WP2 uvrA
Without S9 mix: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 5 μg/plate, dissolved in DMSO / TA 1535, TA 100; 4-nitro-o-phenylenediamine (NOPD), 10 μg/plate, dissolved in DMSO / TA 98; 9-aminoacridine (AAC), 100 μg/plate, dissolved in DMSO / TA 1537; 4-nitroquinoline-N-oxide (4-NQO) (SIGMA, N-8141), 5 μg/plate, dissolved in DMSO / E. coli WP2 uvrA

Evaluation criteria:

Acceptance criteria:
Generally, the experiment is considered valid if the following criteria are met:
• The number of revertant colonies in the negative controls was within the range of the historical negative control data for each tester strain.
• The sterility controls revealed no indication of bacterial contamination.
• The positive control substances both with and without S9 mix induced a distinct increase in the number of revertant colonies within the range of the historical positive control data or above.
• Fresh bacterial culture containing approximately 10^9 cells per mL were used. For approval the titer of viable bacteria was ≥ 10^8 colonies per mL.

Assessment criteria:
The test substance is considered positive in this assay if the following criteria are met:
• A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.

A test substance is generally considered non-mutagenic in this test if:
• The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in at least two experiments carried out independently of each other.

Results and discussion

Test results

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Test substance precipitation was found from about xxx μg/plate onward with and without S9 mix.

COMPARISON WITH HISTORICAL CONTROL DATA: yes

Any other information on results incl. tables

Table 1 (P=Precipitation)

Standard plate test			Without metabolic activation
		Dose (μg/plate)	Mean revertants per plate	Standard deviation	Factor	Individual revertant colony counts
	Water	-	9.7	3.2	-	11, 6, 12
TA 1535	Test item	33	11.7	3.2	1.2	14, 8, 13
		100	9.7	2.1	1.0	8, 12, 9
		333	11.3	3.8	1.2	13, 14, 7
		1000	8.0	1.0	0.8	9, 7, 8
		2500	12.7	5.1	1.3	7 P, 17 P, 14 P
		5000	15.3	3.2	1.6	19 P, 13 P, 14 P
	MNNG	5.0	4188.7	629.0	433.3	4773, 4270, 3523
TA 100	Water	-	124.3	8.7	-	134, 117, 122
	Test item	33	111.7	6.1	0.9	117, 105, 113
		100	108.7	15.0	0.9	94, 124, 108
		333	126.3	13.5	1.0	126, 113, 140
		1000	118.0	5.6	0.9	113, 124, 117
		2500	128.0	2.6	1.0	125 P, 129 P, 130 P
		5000	119.3	12.5	1.0	105 P, 128 P, 125 P
	MNNG	5.0	4078.3	173.9	32.8	3895, 4099, 4241
TA 1537	Water	-	6.7	1.5	-	8, 7, 5
	Test item	33	10.3	1.5	1.6	12, 9, 10
		100	10.3	2.5	1.6	10, 8, 13
		333	9.0	1.0	1.4	10, 9, 8
		1000	6.0	1.0	0.9	7, 5, 6
		2500	6.0	1.0	0.9	7 P, 5 P, 6 P
		5000	6.3	3.2	1.0	5 P, 4 P, 10 P
	AAC	100	931.7	171.0	139.8	852, 815, 1128
TA 98	Water	-	26.0	5.2	-	29, 29, 20
	Test item	33	22.7	3.5	0.9	23, 19, 26
		100	24.0	4.6	0.9	20, 29, 23
		333	24.7	2.5	0.9	25, 27, 22
		1000	26.7	6.5	1.0	33, 20, 27
		2500	25.3	2.9	1.0	27 P, 27 P, 22 P
		5000	25.0	3.0	1.0	25 P, 22 P, 28 P
	NOPD	10	1073.0	79.7	41.3	1120, 1118, 981
E. coli	Water	-	28.7	3.8	-	33, 26, 27
	Test item	33	28.0	10.1	1.0	17, 37, 30
		100	26.0	6.9	0.9	18, 30, 30
		333	29.3	10.8	1.0	37, 34, 17
		1000	27.3	5.0	1.0	22, 28, 32
		2500	27.7	8.1	1.0	19 P, 29 P, 35 P
		5000	26.3	6.5	0.9	26 P, 33 P, 20 P
	4-NQO	5	1121.7	41.3	39.1	1144, 1147, 1074

Table 2 (P = precipitation)

Standard plate test		With metabolic activation
		Dose (μg/plate)	Mean revertants per plate	Standard deviation	Factor	Individual revertant colony counts
	Water	-	10.3	2.1	-	8, 12, 11
TA 1535	Test item	33	8.7	3.1	0.8	8, 12, 6
		100	8.7	2.3	0.8	10, 6, 10
		333	12.7	1.5	1.2	14, 11, 13
		1000	13.0	3.6	1.3	17, 12, 10
		2500	11.7	2.3	1.1	13 P, 13 P, 9 P
		5000	12.3	3.2	1.2	10 P, 11 P, 16 P
	2-AA	2.5	198.0	9.5	19.2	193, 192, 209
TA 100	Water	-	135.3	9.3	-	131, 146, 129
	Test item	33	110.7	11.9	0.8	116, 97, 119
		100	149.7	11.0	1.1	156, 137, 156
		333	130.0	16.5	1.0	139, 111, 140
		1000	165.0	16.5	1.2	154, 184, 157
		2500	142.0	10.4	1.0	147 P, 149 P, 130 P
		5000	156.3	10.4	1.2	153 P, 148 P, 168 P
	2-AA	2.5	1887.3	60.5	13.9	1929, 1915, 1818
TA 1537	Water	-	6.3	2.5	-	6, 9, 4
	Test item	33	7.7	3.2	1.2	10, 4, 9
		100	7.7	1.5	1.2	9, 6, 8
		333	9.0	3.5	1.4	7, 7, 13
		1000	8.0	5.2	1.3	5, 5, 14
		2500	7.0	3.6	1.1	4 P, 11 P, 6 P
		5000	5.3	1.5	0.8	4 P, 5 P, 7 P
	2-AA	2.5	159.7	20.7	25.2	156, 182, 141
TA 98	Water	-	32.0	2.0	-	30, 34, 32
	Test item	33	25.7	5.5	0.8	31, 20, 26
		100	34.0	4.6	1.1	30, 39, 33
		333	28.0	6.1	0.9	32, 21, 31
		1000	33.0	6.2	1.0	35, 38, 26
		2500	32.0	2.6	1.0	35 P, 30 P, 31 P
		5000	32.0	6.2	1.0	25 P, 34 P, 37 P
	2-AA	2.5	1582.7	59.8	49.5	1540, 1557, 1651
E. coli	Water	-	27.7	7.5	-	35, 20, 28
	Test item	33	39.0	5.2	1.4	45, 36, 36
		100	31.3	3.5	1.1	35, 31, 28
		333	32.7	6.4	1.2	40, 30, 28
		1000	27.0	2.0	1.0	29, 25, 27
		2500	30.0	2.6	1.1	27 P, 31 P, 32 P
		5000	20.0	2.6	0.7	19 P, 23 P, 18 P
	2-AA	60	136.3	26.9	4.9	167, 125, 117

Applicant's summary and conclusion

Conclusions:

The substance is not mutagenic in bacteria.