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Diss Factsheets

Administrative data

Description of key information

From the studies, it is concluded that dietary exposure to levels of Tin (II) oxide and Tin (IV) dioxide up to 1% for 13 and 4 weeks respectively, did not induce any effect in rats.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
NOAEL
500 mg/kg bw/day
Study duration:
subchronic
Species:
rat

Additional information

From existing studies of toxicokinetic profiles of Tin (IV) dioxide and Tin (II) oxide, it can be concluded that the toxicokinetic profiles of the two substances appear to be similar. Minor differences between Tin (II) and Tin (IV) in their absorption and distribution indicate that Tin (II) may be a bit more toxic than Tin (IV). Therefore Tin (II) oxide can be used as a structural surrogate for Tin (IV) dioxide in the 90 days repeated toxicity test.

In the test, groups of rats (Wistar; n=10/sex/group) were fed diets containing 0, 0.03, 0.10, 0.30, or 1.00% of various tin salts or oxides for periods of 13 weeks for Tin (II) oxide and 4 weeks for Tin (IV) dioxide, respectively. Effects on behaviour, mortality, body weights, food consumption, blood, urine, biochemical parameters, and organ weights were examined; and gross microscopic examinations were performed. No adverse effects were noted at any dose of tin oxides, as well as stannous sulphide and oleate. However, severe growth retardation, decreased food efficiency, slight anaemia, and slight histological changes in the liver were observed with 0.3% or more of stannous chloride, orthophosphate, sulphate, oxalate, and tartrate (De Groot et al, 1973). The authors concluded that the differences in response to different tin compounds suggested that insoluble tin compounds are relatively harmless whereas cationic tin compounds soluble in water or dilute acid may be toxic at dietary levels above 0.1%. From these studies, it is concluded that dietary exposure to levels of Tin (II) oxide and Tin (IV) dioxide up to 1% for 13 and 4 weeks respectively, did not induce any effect in rats.

Therefore the NOAEL of Tin (IV) dioxide was considered to be 1 % in diet for rat (NOECmammal, food_chr). (1% in diet is equivalent to 10000 mg/kg diet)

According to REACH guidance “Guidance on information requirements and chemical safety assessment Chapter R.10: Characterisation of dose [concentration]-response for environment” the NOAELmammal, food_chr= NOECmammal, food_chr/ CONVmammal(CONVmammal for Rattus norvegicus (> 6 weeks) was default as 20). The NOAEL of Tin (IV) dioxide to rat, 500 mg/kg bw per day can be estimated by above method.


Repeated dose toxicity: via oral route - systemic effects (target organ) other: all gross lesions and masses

Justification for classification or non-classification

Based on the NOAEL of 500 mg/kg bw/day is above the criteria value of STOT RE 100 mg/kg bw, the substance is not need to be classified under Regulation (EC) No 1272/2008 for any category of Specific target organ toxicity - repeated exposure. For the same reason it does not satisfy with the classification criteria of Directive 67/548/eec.