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Toxicological information

Carcinogenicity

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Description of key information

The substance was found to be non carcinogenic in two valid feeding studies in rats (Hunter 1981) and mice (Gfeller 1981).

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Study duration:
chronic
Species:
mouse

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The carcinogenic potential was investigated in two feeding studies. The study in mice (Gfeller, 1981) is chosen as key study as it was specifically designed as a carcinogenicity study. Its procedure is equivalent to the OECD testing guidline 451, which was published a few months prior to finalization of that study. Its performance was supervised by the internal quality assurance unit which is certified in the study report.

Specifically, 400 MAGf (SPF) mice (50 male and 50 female per dose group) were treated at dose level of 0, 5, 50 or 500 ppm per day for 24 months. No clinical symptoms and no substance-related mortality were observed. A mean daily intake of 500 ppm (corresponding to 62-64 mg/kg bw) did not produce inflammatory, degenerative, proliferative or neoplastic lesions and was considered to be the NOEL.

The study in rats (Hunter et al, 1981) was designed as a chronic feeding study in rats (OECD testing guideline 452), but in regard to the number of animals and mortality, it is similarly suitable to assess the endpoint of carcinogenicity. Due to the overall low toxicity of this substance, high doses were tested. No indication of an increased tumour incidence or preneoplastic lesions were recorded.

Specifically, a total of 500 CFY rats (50 male and 50 female per dose group) were treated with the test article in the diet, at dose levels of 0, 100, 300, 1000 and 3000 ppm in the diet per day for 104 weeks. No clinical symptoms and no substance-related mortality were observed. At 3000 ppm a small reduction of body weight gain during the second year of treatment and slightly reduced food intake among females during the period 53 to 80 weeks of treatment were observed.

The findings are consistent with a life-time feeding study in mice for which only limited details are reported (Neukomm,1961).

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is considered to be not classified as a carcinogen under Regulation (EC) No. 1272/2008.