Strontium hydroxide

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:

The study was performed between 10 December 1996 and 03 February 1997.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Further information is included as attachment in Section 13.

Reason / purpose for cross-reference:

read-across source

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Conclusions:

Based on the read-across from SrCl2, strontium hydroxide is considered to be non-mutagenic.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

; signed by the Department of Health of the Government of the UK (21.02.1996)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Strontium chloride hexahydrate

EC Number:

600-046-7

Cas Number:

10025-70-4

Molecular formula:

Cl2-Sr.6H2-O

IUPAC Name:

Strontium chloride hexahydrate

Constituent 2

Reference substance name:

Strontium dichloride hexahydrate

IUPAC Name:

Strontium dichloride hexahydrate

Test material form:

solid: crystalline

Details on test material:

- Name of test material (as cited in study report): Strontium chloride-6-hydrate extra pure
- EC number: 233-971-6
- Molecular formula (if other than submission substance): SrCl2*6H2O
- Physical state: solid, white crystalline
- Storage condition of test material: at ambient temperature (<25°C), stored under artificial light

Method

Target gene:

not applicable

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Details on mammalian cell type (if applicable):

not applicable (S. typhimurium strains are no mammalian cells); but prior to use, the strains were checked for characteristics, viability and spontaneous reversion rate and were all found to be satisfactory.

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Details on mammalian cell type (if applicable):

not applicable (S. typhimurium strains are no mammalian cells); but prior to use, the strain was checked for characteristics, viability and spontaneous reversion rate and was found to be satisfactory.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

Preliminary toxicity study: 0, 50, 150, 500, 1500 and 5000 µg/plate
Main study: 0, 50, 150, 500, 1500 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: sterile water

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

A solvent treatment group was used as the vehicle control.

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

with metabolic activation; strains TA100 and TA1535

Migrated to IUCLID6: 3.0 and 5.0 µg/plate

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

A solvent treatment group was used as the vehicle control.

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

with metabolic activation; strain TA1537

Migrated to IUCLID6: 80 µg/plate

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

A solvent treatment group was used as the vehicle control.

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-Nitro-o-phenylenediamine; 5 µg/plate

Remarks:

with metabolic activation; strain TA1538

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

A solvent treatment group was used as the vehicle control.

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitroquinoline-1-oxide; 0.2 µg/plate

Remarks:

with metabolic activation; strain TA98

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

A solvent treatment group was used as the vehicle control.

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene; 1.0, 2.0 and 0.5 µg/plate

Remarks:

without metabolic activation; all strains

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours at 37°C

NUMBER OF REPLICATIONS: The test material and the positive controls were assayed in triplicate, respectively.

NUMBER OF CELLS EVALUATED: not applicable; The frequency of revertant colonies was assessed using a Domino colony counter.

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth:
A mixture of 0.1 mL of bacterial suspension (TA100), 2 mL of molten, trace histidine supplemented media (histidine/biotin and top agar), 0.1 mL of test material and 0.5 mL phosphate buffer was overlaid onto sterile plates of Vogel-Bonner Minimal agar (30 mL/plate). 5 doses of test material and a vehicle control were tested in duplicate. In addition, the sterility of the test material was tested. After 48 hours incubation at 37°C the plates were assessed for revertant colonies using a Domino colony counter and examined for a thinning of the background lawn.

OTHER: The plate incorporation assay was repeated in an second experiment using fresh bacterial cultures, test material and control solutions.

Evaluation criteria:

For the substance to be considered positive in this test system, it should have induced a dose-related and statistically significant increase in mutation rate in one or more strains of bacteria in the presence and/or absence of S9 microsomal enzymes in both experiments at sub-toxic dose levels. In the event of the two experiments giving conflicting or equivocal results, then a third experiment may be performed to confirm the correct response.
To be considered negative the number of induced revertants compared to spontaneous revertants should be less than twofold at each dose level employed, the intervals of which should be between two and five fold and extend to the limits imposed by toxicity, solubility or up to the maximum recommended dose of 5000 µg/plate. In this case the limiting factor was the maximum recommended dose.

Statistics:

All data are statistically analysed using the methods recommended by the UKEMS (Kirkland, D.J. (Ed), 1989, Statistical Evaluation of Mutagenicity Test Data.) and normally Dunnett's method of linear regression is used to evaluate the results.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
No details are reported.

RANGE-FINDING/SCREENING STUDIES: The dose range of the test material used in the preliminary toxicity study was 0, 50, 150, 500, 1500 and 5000 µg/plate. The test material was non-toxic to the strain of S. typhimurium TA100.

COMPARISON WITH HISTORICAL CONTROL DATA: no data

ADDITIONAL INFORMATION ON CYTOTOXICITY:
No further details are reported.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Under the test conditions described the test material, strontium chloride-6-hydrate extra pure, was considered to be non-mutagenic either with or without metabolic activation at any concentration tested.

Executive summary:

S. typhimurium strains TA1535, TA1537, TA1538, TA98 and TA100 were treated with the test material using the Ames plate incorporation method at 5 dose levels, both with and without metabolic activation. The dose range was determined in a preliminary toxicity assay and was 50 to 5000 µg/plate in the first experiment. The experiment was repeated on a separate day using the same dose range as experiment 1.

Positive and vehicle controls were included in the test.

The test material caused no visible reduction in the growth of the bacterial lawn at any of the dose levels to any of the strains of Salmonella tested.

No significant increase in the frequency of revertant colonies was recorded for any of the bacterial strains with any of the concentrations tested, either with or without metabolic activation.