Titandioxid (alveolengängige Fraktion)
MAK-Begründung, Nachtrag
Andrea Hartwig1MAK 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 re‐evaluated titanium dioxide [13463‐67‐1]. Titanium dioxide causes lung tumours in rats at high concentrations. In 2009, titanium dioxide was evaluated and, because a maximum concentration at the workplace (MAK value) could not be established, it was classified in Carcinogen Category 3A. Titanium dioxide is a biopersistent granular dust and, in a later evaluation, inhalation studies with titanium dioxide were used to derive the general threshold limit value for granular biopersistent dusts. Therefore, the respirable fraction of titanium dioxide dust is reclassified in Carcinogen Category 4 and a MAK value of 0.3 mg/m3 × material density is established for the respirable fraction according to the general threshold value for biopersistent granular dusts. Reclassification in Carcinogen Category 4 is justified because the lung tumours are regarded as a consequence of the inflammatory mechanism of action, for which a threshold can be defined. Direct genotoxic effects appear to be of subordinate relevance for the carcinogenicity of biopersistent granular dusts. By analogy with the biopersistent granular dusts, Peak Limitation Category II is established for titanium dioxide with an excursion factor of 8. Since titanium dioxide is not systemically distributed and accumulates only locally in the lungs, damage to the embryo or foetus is unlikely when the MAK value is not exceeded. Titanium dioxide is classified accordingly in Pregnancy Risk Group C. Titanium dioxide is not expected to be a sensitizer and is not taken up via the skin in toxicologically relevant amounts.
