Silicon

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Remarks:

other: dominant lethal assay

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable well-documented study report which meets basic scientific principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1974

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 478 (Genetic Toxicology: Rodent Dominant Lethal Test)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Calcium silicate

EC Number:

233-250-6

EC Name:

Calcium silicate

Cas Number:

10101-39-0

IUPAC Name:

calcium oxosilanediolate

Details on test material:

- Name of test material (as cited in study report): FDA-Compound 71-41 = Silene, calcium silicate (hydrated)

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Flow laboratories
- Age at study initiation: 10-12 weeks
- Weight at study initiation: 300-350 g
- Fasting period before study: no data
- Housing: 1-5 rats / cage
- Diet (e.g. ad libitum): commercial 4% fat diet ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 4-11 days

ENVIRONMENTAL CONDITIONS: no data

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

physiological saline

Details on mating procedure:

- M/F ratio per cage: 1 M / 2 F
- Length of cohabitation: 5 days
- After 2 days of rest, the male rat was housed with two other females for 5 days. This was repeated for 8 weeks (7 weeks in the subacute study).
- After successful mating each pregnant female was caged (how): 2 feamles / cage

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Acute: single administration, subacute: 5 days.

Frequency of treatment:

One dose per day.

Details on study schedule:

The females were killed 14 days after separation from the males.

Doses / concentrations

Remarks:

Doses / Concentrations:
15, 150, 1500, 5000 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Positive control:

Triethylene melamine

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: No data


DETAILED CLINICAL OBSERVATIONS: No data


BODY WEIGHT: No data


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data

Litter observations:

Corpora lutea, early fetal deaths, late fetal deaths, total implantations per uterine horn.

Statistics:

t-tests, regression analyses, Freeman-Tukey transformations, chi-square test, Armitage's trend.

Reproductive indices:

fertility index, average number of implantations, average corpora lutea, average preimplantation losses, average resorptions, dead implants/total implants

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Histopathological findings: non-neoplastic:

not specified

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not specified

Reproductive performance:

no effects observed

Details on results (P0)

No differences in fertility index, preimplantation losses or embryo resorptions were observed between the calcium silicate groups and the control animals.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

5 000 mg/kg bw/day

Sex:

male

Basis for effect level:

other: Dominant lethal test negative.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Calcium silicate did not have any fertility effects in rats studied by the dominant lethal assay.

Executive summary:

The toxicity of calcium silicate was studied by the dominant lethal assay after exposure of male rats given with oral doses up to 5000 mg/kg for 1 or 5 days (Litton 1974). No differences in fertility index, preimplantation losses or embryo resorptions were observed between the calcium silicate groups and the control animals.