Antimony and its inorganic compounds except for stibine
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) summarized and re-evaluated the data on the genotoxicity and carcinogenicity of antimony [7440-36-0] and its inorganic compounds except for stibine. The critical effects of antimony and its inorganic compounds are the carcinogenic effects on the lung after inhalation exposure in rats and mice; similar effects may be induced in humans. Overall, the available epidemiological studies indicate that antimony and its inorganic compounds have carcinogenic effects on the human lung. However, because the persons examined were exposed to mixtures of substances and no data for concentrations are available, the classification cannot be made on the basis of these studies alone. A recent 2-year carcinogenicity study in male and female rats and mice showed that exposure to antimony trioxide particles causes lung neoplasms. Mice reacted more sensitively than rats, developing neoplastic lesions beginning at the lowest antimony trioxide concentration of 3 mg/m3 (2.5 mg Sb/m3). As a NOAEC for lung tumours and lung effects cannot be derived from the animal or human data and a NOAEC cannot be determined for possible mechanisms of action, no maximum concentration at the workplace (MAK value) can be established, thereby confirming the classification of antimony and its inorganic compounds in Carcinogen Category 2. The clastogenicity of inorganic antimony compounds in vitro is well established. In a recent study, exposure to antimony trioxide by inhalation for 12 months increased the number of micronucleated erythrocytes and DNA strand breaks in lung cells in male and female mice, but not in male or female rats. The lowest effective concentration was 3 mg/m3 and led to increased DNA strand breaks in lung tissue in male mice. Thus, trivalent antimony was shown to induce genotoxic effects in soma cells after inhalation. This, together with evidence that the substance reaches the testes and ovaries, led to the classification of antimony and its inorganic compounds in Germ Cell Mutagenicity Category 3 A. There are still no reliable positive data for sensitizing effects in humans and no positive results from animal experiments or in vitro investigations. Therefore, antimony and its inorganic compounds continue not to be designated with the “Sh” or “Sa” notation.
