Silicic acid, potassium salt

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No tables provided with report; results only discussed qualitatively. Therefore, limited amount of information available.

Data source

Reference

Reference 1

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 2

Reference Type:

secondary source

Title:

Soluble Silicates. CAS No. 1344-09-8, 6834-92-0, 10213-79-3, 13517-24-3 and 1312-76-1.

Author:

OECD SIDS

Year:

2004

Bibliographic source:

SIDS Initial Assessment Report for SIAM 18 Paris, France 20-23 April, 2004

Materials and methods

Principles of method if other than guideline:

Application of Na-metasilicate via gavage from day 0 to 18 of gestation. Examination of fetuses and and newborns.

GLP compliance:

no

Limit test:

no

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

Molecular formula:

H2O3Si.2Na Soluble Silicates Category

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, 20% aqueous solution.

Test animals

Species:

mouse

Strain:

other: JLC-TCR

Details on test animals or test system and environmental conditions:

Well developed males and females 8-13 weeks of age and  27-35 g/animal.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

17-18 days

Frequency of treatment:

daily

Duration of test:

18 days

Doses / concentrations

Remarks:

Doses / Concentrations:
12.5, 50 or 200 mg/kg bw/d
Basis:
nominal conc.

Control animals:

yes

Details on study design:

Sex: male/female

Examinations

Maternal examinations:

body weight

Ovaries and uterine content:

counting of nidations, corpi lutei and living/dead fetuses

Fetal examinations:

weighing of living fetuses and important organs,  sex determination, examination of integument anomalies, naked eye  examination of other changes
Parameters evaluated were: number of neonates, parturition failures, body weight gain, behavioral development in the Running
and Rod Grasping Test (see below) and skeletal development.

Results and discussion

Results: maternal animals

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

12.5 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEL

Effect level:

> 200 mg/kg bw/day

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

TOXIC RESPONSE/EFFECTS BY DOSE LEVEL: 
- Parental data and F1: 
- Body weight: no treatment-related effects were observed in either mother animals, fetuses delivered by hysterectomy or

neonates. 

- Fertility index: 
Dose [mg/kg bw/d] pregnancies/mated female    % pregnancies
---------------------------------------------------------------
     0 (control)             20/26                   77%
    12.5                      22/24                   92%
    50                        20/31                   65%
   200                        21/25                   84%

- Duration of gestation: 18 days

- Mortality: 2/27 females administered 50 mg/kg and 2/33 females administered 200 mg/kg died during the exposure period. In

one female of  the highest dose group all fetuses died at an early stage. No parturition  fatalities were observed when mothers

were allowed to deliver their young  naturally. 
- Gross pathology incidence and severity: observed skeletal malformations  in neonates like cervical vertebrae, tail vertebrae

and vomer adhesion  occurred in the controls, too, and did not show a dosage correlation. No  malformations of the skeleton or

the inner organs of fetuses delivered by  hysterectomy were observed; the frequency of malformations and  abnormalities of the external integument, like opened eyes, cleft palate  and exencephaly showed a slight tendency toward dose dependance, but it  was lower than in the control. No effects on main organs of both mothers  and neonates as compared to controls.
- Number of corpora lutea: No significant differences between control and  test groups, but actual numbers not reported.
- Organ weight changes: No treatment-related effects of organ weights of  mother animals and neonates; not reported for

fetuses delivered by hysterectomy.

- Offspring toxicity F1: 
- Litter size and weights: There was a dose-related, but not  statistically significant decrease in litter size.
Dose [mg/kg bw/d]    average no. of neonates/litter
-----------------------------------------------------
     0 (control)            14.7 +- 2.4
    12.5                      13.8 +- 2
    50                        12.9 +- 2
   200                        12.8 +- 2

- Post natal survival until weaning: no treatment-related effects on body  weight gain. 
- Effects on offspring: a dose-related, but not statistically significant  decrease in embryo weight and delayed
ossification process was observed.
- Postnatal growth, growth rate: no treatment related effects
- Other observations: no treatment-related effects in the Running Test  and the Rod Grasping Test.