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Key value for chemical safety assessment

Effects on fertility

Additional information

Specific investigations on fertility to current standards are not available for synthetic amorphous aluminum sodium silicate (NAS). The one-generation study conducted with a hydrophilic SAS type is not adequate to contribute reliable information for biostatistical reasons.

However, given the inherent physico-chemical properties and ubiquitous nature of this class of compounds, there is no structural alert to indicate a potential for reproductive and developmental toxicity.

Therefore, based on the weight of evidence, prolonged exposure to synthetic amorphous NAS, applied before and during pregnancy at high doses, is not expected to produce harmful effects on the reproductive performance or embryonic/foetal development in experimental animals (see: SIAR 2004).

Hence, further testing is not justified. Waiving of this toxicological endpoint is in line with REACH Regulation 1907/2006, Annex VIII, 8.7.1, Annexes IX and X, 8.7.

Summary of the result of the reproduction study:

A one-generation study on Wistar rats gave no evidence of any adverse effects arising from long-term feeding of Aerosil [500 mg/(kg bw*d)] to both genders for a premating period of 4.5 months and continued up to 6 months [Leuschner 1963]. Five pregnant test females and four pregnant untreated control females delivering 45 and 37 pups, respectively, were included in this test.

The study had shortcomings with respect to the low number of pregnant animals used and the mating ratio of 1(m):5(f) which was too low according to current standards.

Short description of key information:
No adverse effects from a structure-analogous substance [500 mg silica/(kg bw*d)] in rats on fertility and development in a limited one-generation study (see discussion).

Effects on developmental toxicity

Description of key information
No adverse maternal and embryo-/foetotoxic effects in four species (mouse, rat, rabbit and hamster) following doses of up to 1600 mg/(kg bw*d) during gestation. The NOAEL for synthetic amorphous aluminum sodium silicate (NAS) corresponds to the highest dose tested of 1600 mg/(kg*d).
Effect on developmental toxicity: via oral route
Dose descriptor:
1 600 mg/kg bw/day
Additional information

The experimental data on intra-uterine development produced in four animal species with a synthetic amorphous aluminum sodium silicate (NAS) suggest that there is no potential for adverse effects on embryonal/foetal development arising from exposure to this type of substances. This is in line with the negative results obtained with synthetic amorphous silica and calcium silicate.

Summary of test results

Within the scope of a comprehensive and valid testing programme, aluminum sodium silicate was examined for embryotoxic and developmental effects during the gestation phase in various animals species, rat, mouse, rabbit and hamster, at oral doses up to 1600 mg/(kg bw*d).

There were no significant signs of maternal or embryotoxic/developmental toxic effects in any species tested. The number of abnormalities seen in either soft or skeletal tissues of the test groups did not differ from the untreated control groups. Therefore, the top dose of 1600 mg/(kg bw*d) found in all four species corresponds to the NOAEL for maternal and developmental toxicity.

Justification for classification or non-classification

Additional information