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Carcinogenicity

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Description of key information

The chlorinated isocyanurates are unstable in the body, particularly the stomach, because the free available chlorine is rapidly reduced.  CYA, or its salt, is the stable degradation product.  Therefore, CYA, or its sodium salt, is the substance of interest for the carcinogenicity studies.
2 year carcinogenicity studies in rats and mice were carried out according to EU method B.33. Studies showed that the monosodium salt of cyanuric acid was non-oncogenic by the oral route.

Key value for chemical safety assessment

Additional information

The chlorinated isocyanurates are unstable in the body, particularly the stomach, because the free available chlorine is rapidly reduced. CYA, or its salt, is the stable degradation product. Therefore, CYA, or its sodium salt, is the substance of interest for the carcinogenicity studies. Two carcinogenicity studies are available with the sodium salt of cyanuric acid performed in both rats and mice.

Carcinogenicity study (rats):

A chronic toxicity and oncogenicity study was performed with the monosodium salt of cyanuric acid (Blair 1985) Rats were dosed with 400, 1200, 2400 and 5375 ppm in drinking water for a period of 24 months. Test substance related non-neoplastic lesions were only observed in the urinary tract in males from the 5375 ppm group sacrificed at the 6 and 12 month interims.The NOEL was 2400 ppm. (Males = 154 mg/kg bw/day, females = 266 mg/kg bw/day)   

Carcinogenicity study (mice):

A two year study designed to evaluate the oncogenic potential of monosodium cyanurate was performed (Serota 1986). Treated groups received monosodium cyanurate at levels of 100, 400, 1200 and 5375 ppm in drinking water. A concurrent control received tap water only.  No definitive treatment-related effects were observed in any of the levels of monosodium cyanurate tested. In addition, monosodium cyanurate was not found to be oncogenic in mice. The NOEL was considered to be ≥ 5375 ppm. (Males = 1523 mg/kg bw/day, females = 1582 mg/kg bw/day)

Justification for classification or non-classification

No classification for carcinogenic effects is required for troclosene sodium. The chlorinated isocyanurates are unstable in the body, particularly the stomach, because the free available chlorine is rapidly reduced. CYA, or its salt, is the stable degradation product.

CYA has shown no evidence of carcinogenicity via oral exposure in drinking water in doses up to 5375 ppm (equivalent to doses of 1523 mg/kg bw/day for males, and 1582 mg/kg bw/day for females), in carcinogenicity studies in both rat and mouse.