n‐Butylbenzol
MAK-Begründung
Andrea Hartwig1 (Vorsitz der Ständigen Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft)MAK Commission2
1 Institut für Angewandte Biowissenschaften, Abteilung Lebensmittelchemie und Toxikologie, Karlsruher Institut für Technologie (KIT), Adenauerring 20a, Geb. 50.41, 76131 Karlsruhe, Deutschland
2 Ständige Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Deutschland
Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated n‐butylbenzene [104‐51‐8], considering all toxicological endpoints. Available publications are described in detail. In an oral two‐generation study in rats, increased kidney weights and centrilobular hypertrophy in the liver is observed with n‐butylbenzene. The corresponding NOAEL of 100 mg/kg body weight and day is scaled to a maximum concentration at the workplace (MAK value) of 10 ml/m3. Studies on the possible irritation of the airways after repeated inhalation exposure are lacking, however, the acute RD50 value of 710 ml/m3 in mice is indicative of an irritation threshold of about 20 ml/m3 in humans. Therefore, the systemic effect is critical and Peak Limitation Category II is designated. As the half‐life of n‐butylbenzene is not known, the default excursion factor of 2 for systemically acting substances is established.
There are no developmental toxicity studies. Therefore, n‐butylbenzene is assigned to Pregnancy Risk Group D. There are no data on genotoxicity, carcinogenicity and sensitization. According to skin absorption models, percutaneous absorption can contribute significantly to systemic toxicity and n‐butylbenzene is designated with an “H” notation.
