Trimellitsäureanhydrid
MAK-Begründung, Nachtrag
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 Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) summarized and re-evaluated the data for trimellitic anhydride (TMA) [552-30-7] to derive an occupational exposure limit value (maximum concentration at the workplace, MAK value) considering all toxicological end points. Relevant studies were identified from a literature search. The critical effects of trimellitic anhydride are irritation and respiratory sensitization. In workers, the occurrence of TMA-specific IgE antibodies or of respiratory disease associated with elevated IgE or IgG antibodies was observed with a NOAEC of 0.5 µg TMA/m3, which has been set as the MAK value. The MAK value is assumed to protect also against irritation as no such effects were reported. Sensitization and elicitation of a respiratory allergy may occur also via exposure of the upper respiratory tract; therefore, the MAK value applies for the inhalable fraction. As TMA is a respiratory sensitizer, it remains designated with “Sa” and classified in Peak Limitation Category I with an excursion factor of 1. Studies in guinea pigs and mice as well as results obtained using non-animal methods indicate a sensitizing potential. However, there are no reports of patch testing or case reports of allergic contact dermatitis due to TMA exposure in humans. Therefore, TMA continues not to be designated with "Sh". Nevertheless, in different animal models, sensitization occurred with TMA not only via inhalation exposure but also via the skin. Therefore, skin contact with TMA should be avoided. Dermal exposure is expected to contribute little to systemic toxicity, which is not a primary concern for TMA. As no developmental toxicity studies are available, the substance has been assigned to Pregnancy Risk Group D. TMA is not mutagenic or clasogenic in vitro; studies investigating genotoxicity in vivo or carcinogenicity are not available. There are, however, no structural alerts for genotoxic or carcinogenic effects.
