Chlorothalonil
MAK Value Documentation, supplement – 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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has reviewed an unpublished inhalation study of chlorothalonil [1897-45-6] to evaluate whether its findings can be used to derive a maximum concentration at the workplace (MAK value). As described in the 2018 supplement, chlorothalonil is corrosive to the eyes of rabbits. Workers reported irritation of the eyes, nose and throat at exposure concentrations of 0.3 to 1.2 mg/m3. An unpublished 2-week inhalation study with exposure of rats to chlorothalonil aerosol concentrations of 0, 1.1, 2.9, 9.6 or 14.3 mg/m3 has been made available to the MAK Commission. Squamous metaplasia and necrosis in the U-shaped cartilage of the larynx were observed in all 10 exposed animals at the low concentration of 1.1 mg/m3 and above; higher concentrations induced additional effects in the larynx, lungs and respiratory tract. It is still not possible to derive a MAK value and chlorothalonil remains assigned to Section II b of the List of MAK and BAT Values. No other end points were re-evaluated.
