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Administrative data

Description of key information

The main phase of Si/FeSi silicate consists of practically insoluble silicates, and therefore it is seen as justified to use read-across in studies on calcium silicate, sodium aluminium silicate, kaolin (an Al-silicate), nonfibrous glass (containing Ca-, Al, Mg- and borosilicates) and silica gel. As no data were found on repeated dose toxicity of Si/FeSi silicate, studies with these substances were useful for read-across.
The experimental repeated dose toxicity by inhalation or by oral route of the read-across materials has appeared to be low.

Key value for chemical safety assessment

Additional information

There are no repeated dose toxicity studies on Si/FeSi silicate. The main phase of Si/FeSi silicate consists of practically insoluble silicates, and therefore it is seen justified to use read-across to studies on calcium silicate, sodium aluminium silicate, kaolin (an Al-silicate), nonfibrous glass (containing Ca-, Al, Mg- and borosilicates) and silica gel.

No significant pathological lung effects attributable to occupational long-term exposure to synthetic amorphous silicates have been reported, and no signs of pneumoconiosis, silicosis and fibrosis were evident.

The experimental repeated dose toxicity by inhalation or by oral route of the read-across materials has appeared to be low.

Nonfibrous glass dust (17–19 mg/m3) and kaolin (23–27 mg/m3) have induced only minimal pulmonary changes without fibrosis when rats or guinea pig were exposed for a year. In another study, no toxicity was observed in rats, which were exposed to kaolin at 10 mg/m3for up to 12 months. Calcium silicate (three commercial grades) exposed (10 mg/m3) rats had perinuclear fibrotic nodules when exposed to one of the materials. The effect was, however, supposed to be caused by the detected quartz contents of the lung.  

After long-term (2-year) oral application in the diet of rats and mice, no adverse effects were demonstrable for silica gel. There were no biological or any other meaningful alterations in body weight, food consumption or physical features of the exposed animals. No significant dose-related effects were seen at any dose level in clinical laboratory examinations. The pathological examinations revealed no gross or microscopic changes in the examined tissues.

Following the feeding of 0.625 to 10 % sodium aluminium silicate in the diet for 14 days, only occasional growth depression or a slight elevation in organ weight was observed with the highest doses.

Justification for classification or non-classification

No classification for repeated dose toxicity is suggested because of the low toxicity seen in animals and also the observations of workers exposed to the read-across materials do suggest low toxicity.