Tetrabrombisphenol A
MAK-Begründung
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 evaluated tetrabromobisphenol A [79-94-7] considering all toxicological end points. Epidemiological studies of tetrabromobisphenol A are not available. After repeated administration by gavage, the target organs of toxicity were the endocrine system in male and female rats with decreased total T4 concentrations and the kidneys in male mice with cytoplasmic changes in the tubules. Tetrabromobisphenol A induces uterine tumours in female Wistar-Han rats and hepatoblastomas and haemangiosarcomas in male B6C3F1/N mice. Due to its non-genotoxic mechanism of action, it is assumed that a NAEL (no adverse effect level) can be determined for carcinogenic effects. Therefore, tetrabromobisphenol A could be classified in Carcinogen Category 4. However, there are no data that can be used to establish a NOAEL for atypical hyperplasia (preneoplasia) in the endometrium, to clarify whether the observed uterine tumours are specific to the strain, and to further characterize the mechanism of tumourigenesis. Therefore, a maximum concentration at the workplace (MAK value) cannot be established and tetrabromobisphenol A has been classified in Carcinogen Category 2 and given the footnote “Prerequisite for Category 4 in principle fulfilled, but insufficient data available for the establishment of a MAK or BAT value”. Tetrabromobisphenol A is not mutagenic in bacteria or clastogenic in mammalian cells. In vivo data do not provide evidence of genotoxic effects in soma cells, even at concentrations that cause systemic toxicity. In vivo studies suggest that transdermal uptake may be relevant. As tetrabromobisphenol A has been classified as a Category 2 carcinogen and no threshold for the carcinogenic effects can be established at present, the substance has provisionally been designated with “H”. Data for humans, animals and from in vitro studies show no sensitizing potential.
