Vinyl chloride – Addendum: Re-evaluation of the BAR
Assessment Values in Biological Material – Translation of the German version from 2023
Michael Nasterlack1Hans Drexler2 (Head of the working group “Assessment Values in Biological Material” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
Andrea Hartwig3 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
MAK Commission4
1 68526 Ladenburg, Germany
2 Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute and Outpatient Clinic of Occupational, Social, and Environmental Medicine, Henkestraße 9–11, 91054 Erlangen, Germany
3 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
4 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany
Abstract
In 2022, the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has withdrawn the exposure equivalents for carcinogenic substances (EKA) for vinyl chloride [75-01-4] based on urinary excretion of thiodiglycolic acid (TdAA) because of its poor reliability at low exposure. Therefore, also the biological reference value (BAR) has to be re-evaluated. To this end, the existing literature was updated and taken into account. Four published studies showed that the excretion of TdAA in humans occupationally exposed to vinyl chloride and non-exposed persons largely overlaps, especially in the exposure range < 5 ml/m3. This may lead to a situation where unexposed persons may falsely be considered exposed to vinyl chloride as well as – on the other hand – real exposures may not be identified. Nevertheless, in order to keep an instrument for the assessment of higher exposures, notably after accidents or leakages, the Commission decided to confirm the existing BAR of 1.5 mg TdAA/l urine, however with the additional remark “This BAR is not suitable for the assessment of vinyl chloride exposures < 5 ml/m3”. Owing to the different excretion characteristics after high vs. low vinyl chloride exposures it is further recommended to obtain two separate urine samples after 12–18 and 48 hours, respectively, after an accidental exposure.
