Disodium disilicate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was performed similar to OECD TG 475, with the restriction that no positive controls were used. For justification for read across see endpoint summary.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Safety of anticorrosives in building water-pipe metal inhibitors sodium polyphosphate and sodium metasilicate.

Author:

Ito, R. et al.

Year:

1986

Bibliographic source:

Toxicol. Lett. 31 (Suppl. P1-28), 44

Reference 2

Reference Type:

publication

Title:

Safety of the metal scavengers sodium metasilicate and sodium polyphosphate.

Author:

Saiwai, K. et al.

Year:

1980

Bibliographic source:

Internal Report Toho University

Reference 3

Reference Type:

secondary source

Title:

Unnamed

Year:

2004

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

Deviations:

not specified

GLP compliance:

no

Type of assay:

chromosome aberration assay

Test material

Test material information

Constituent 1

Reference substance name:

Disodium metasilicate

EC Number:

229-912-9

EC Name:

Disodium metasilicate

Cas Number:

6834-92-0

IUPAC Name:

disodium oxosilanediolate

Details on test material:

SOURCE: not reported
PURITY: not reported
IMPURITY/ADDITIVE/ETC.: not reported
ANY OTHER INFORMATION: the test substance was sodium metasilicate with an unknown concentration.

Test animals

Species:

mouse

Strain:

other: BDF1

Sex:

male

Details on test animals or test system and environmental conditions:

- Age: 9 weeks

Administration / exposure

Route of administration:

oral: feed

Duration of treatment / exposure:

24 hours

Frequency of treatment:

once, 4 mg/kg bw  colchicine was  administered intraperitoneally 2 hours before necropsy.

Post exposure period:

sampling time was 24 h after administration

Doses / concentrations

Remarks:

Doses / Concentrations:
740-1340 mg/kg bw (7 graduated  levels)
Basis:
nominal conc.

No. of animals per sex per dose:

4 - 6

Control animals:

yes, concurrent vehicle

Examinations

Tissues and cell types examined:

femur bone marrow cells

Evaluation criteria:

The chromosomes were examined blind by three persons. Slides from femur  bone marrow cells were prepared according to standard methods, and 100  metaphases per animal analyzed for chromosomal aberrations (including  gaps, breaks, deletions, and exchanges).

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

not specified

Negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

No significant increase of chromosomal aberrations compared to negative control even at dosage  levels exceeding the M.T.D. of 940 mg/kg bw.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
No significant increase of chromosomal aberrations compared to negative control even at dosage  levels exceeding the M.T.D. of 940 mg/kg bw.

Executive summary:

Sodium metasilicate was tested in a cytogenetic test for chromosome aberrations in bone marrow cells of male mice in a study similar to OECD TG 475 with the restriction that no information on the use of positive controls was available. Groups of 4 - 6 animals were administered single oral doses of sodium metasilicate at dose levels between 740 and 1340 mg/kg bw (in total, seven dose levels were used in this study). Animals were sacrificed 24 hours after the last administration of the test substance; 2 hours before sacrifice a metaphase arresting agent (colchicine; 4 mg/kg bw) was injected intraperitoneally. Slides from femur bone marrow cells were prepared according to standard methods, and 100 metaphases per animal analyzed for chromosomal aberrations (including gaps, breaks, deletions, and exchanges). No indication of chromosomal aberrations was detected. In a range-finding study, no mortality occurred within 4 days after administration in animals dosed up to 940 mg/kg bw. Mortality occurred at higher doses (Saiwai et al. 1980).