N-Phenyl-1-naphthylamine
MAK Value Documentation, addendum – Translation of the German version from 2021
Andrea Hartwig1 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)MAK Commission2
1 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
2 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany
Abstract
The German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) re-evaluted the maximum concentration at the workplace (MAK value) and the Pregnancy Risk Group of N-phenyl-1-naphthylamine [90-30-2]. Relevant studies were identified from a literature search and also unpublished study reports were used. The critical effect of N-phenyl-1-naphthylamine is haematotoxicity. A NAEL of 2.5 mg/kg body weight and day for haemosiderosis in the spleen, the most sensitive end point, was estimated from a 90-day gavage study in rats. On the basis of this NAEL, the MAK value for N-phenyl-1-naphthylamine has been set at 2 mg/m3 for the inhalable fraction. As the critical effect of N-phenyl-1-naphthylamine is systemic, Peak Limitation Category II with an excursion factor of 2 has been assigned. The NOAELs for developmental toxicity after oral application to rats were 150 and 100 mg/kg body weight and day. After toxicokinetic scaling to concentrations at the workplace, damage to the embryo or foetus is unlikely when the MAK value is not exceeded and N-phenyl-1-naphthylamine has been assigned to Pregnancy Risk Group C. On the basis of skin absorption models and a comparison with N-phenyl-2-naphthylamine, for which experimental data are available, skin contact is not expected to contribute significantly to systemic toxicity. The data for skin sensitizing effects confirm the previous “Sh” designation. There are no data on a potential sensitization of the airways.
