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Toxicological information

Carcinogenicity

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Description of key information

Oral NOAEL: 542 mg/kg bw/day (chronic; rat)
Dermal chronic mouse: the test substance does not contribute to carcinogenicity induced by UV-irradiation

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
521 mg/kg bw/day
Study duration:
chronic
Species:
rat

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

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

Additional information

The tests were performed on a similar substance within the category of Stilbene Fluorescent Whitening Agents, the analogous dihydroxyethyl derivative tetrasulphonated sodium salt (CAS 16470-24-9). This substance has the same organic functionalities, with a higher sulphonation degree. For further detail refer to the Category Justification Report attached to the section 13 of the dossier.

In a combined chronic/carcinogenicity studies (Bayer AG., 1978), the test substance was administered to 50 Wistar rats/sex/dose in diet at dose levels of 0, 100, 1000, 10000 ppm for 24 months. There were no compound related effects in mortality, clinical signs, body weight, food consumption, hematology, clinical chemistry, urinalysis, organ weights, or gross and histological pathology. The NOAEL was recorded for both females and males at 10000 ppm/day. The various statistically significant differences observed with CAS 16470-24-9 (increase/decrease) in organ weights (absolute in males), number of reticulocytes/trombocytes, and ALAT (GPT) activities and serum protein were considered to be of no toxicological relevance and did therefore not provide any evidence of toxicity of the test substance at any of the dose levels tested. At the doses tested, there were in tested substances not a treatment related increase in tumour incidence when compared to controls.

Further studies were done in order to investigate whether the test substance has a carcinogenic effect onto skin under light exposure. Photocarcinogenesis testing involved pretreating hairless mouse skin with the test compounds, 8 -methoxypsoralen (8 -MOP; known phototoxic agent), or solvent only before each daily exposure to simulated solar ultraviolet light. In terms of tumour yield and tumour development time, photocarcinogenesis was enhanced by 8 -MOP, but not by test substances (Bayer AG., 1979 and P.D. Forbes and F. Urbach, 1975).


Justification for selection of carcinogenicity via oral route endpoint:
Test procedures cannot be subsumed under testing guideline, nevertheless are well documented and scientifically acceptable.

Justification for selection of carcinogenicity via dermal route endpoint:
Test procedures cannot be subsumed under a testing guideline, nevertheless they are well documented and scientifically acceptable.

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.6 Carcinogenicity section, carcinogen means a substance, which induce cancer or increase its incidence. Substances, which have induced benign and malignant tumours in well performed experimental studies on animals are considered also to be presumed or suspected human carcinogens unless there is strong evidence that the mechanism of tumour formation is not relevant for humans. For the purpose of the classification for carcinogenicity, substances are allocated to one of two categories (known or presumed human carcinogens and Suspected human carcinogens) based on strength of evidence and additional considerations (weight of evidence). In certain instances, route-specific classification may be warranted, if it can be conclusively proved that no other route of exposure exhibits the hazard.

The combined chronic/carcinogenicity studies available did not provide any evidence of carcinogenicity.

In conclusion, the available experimental data are adequate for classification and labelling and the substance is not classified for carcinogenicity according to the CLP Regulation (EC 1272/2008).