Addendum to xylene (all isomers)
Assessment Values in Biological Material – Translation of the German version from 2016
Thomas Jäger1Hans 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 BASF SE, Corporate Health Management, 67056 Ludwigshafen, 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 2015 the German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the biological tolerance value at the work place (BAT value) for xylene and its isomers [1330‐20‐7], considering xylene in blood and methylhippuric (toluric) acid (all isomers) to characterise the internal exposure. Xylene can easily pass through the skin, so biological monitoring is necessary for a valid individual risk assessment.
Xylene shows a fast elimination in the blood compartment. Thus, the concentration of xylene in blood is halved 30 minutes after the end of exposure. Therefore, sampling should be performed directly at the end of exposure. This is, however, difficult to realize in practice. Therefore, the BAT value for xylene (all isomers) in blood was withdrawn. Methylhippuric (toluric) acid in urine is available as a diagnostically specific parameter. The BAT value for methylhippuric acid is confirmed.



