Dimethoxymethan
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 Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) and the Pregnancy Risk Group of dimethoxymethane [109‐87‐5].
The critical effect is depression of the central nervous system, which was observed in a 13‐week study in rats at 9650 ml/m3. A MAK value of 500 ml/m3 is derived from the NOAEC of 1908 ml/m3, taking into account the increased respiratory volume at the workplace because the blood:air partition coefficient of dimethoxymethane is > 5 (see List of MAK and BAT Values, Sections I b and I c). Since a systemic effect is critical, classification in Peak Limitation Category II is retained. As the half‐life is somewhat longer than one hour, the excursion factor of 2 is confirmed.
The NOAEC for developmental toxicity in rats is 10 068 ml/m3 and, after considering the increased respiratory volume at the workplace, the difference to the MAK value is sufficient. Therefore, damage to the embryo or foetus is unlikely when the MAK value is not exceeded and dimethoxymethane remains assigned to Pregnancy Risk Group C.
Skin contact is not expected to contribute significantly to systemic toxicity. Limited data show no sensitization.
