Addendum to Ethylbenzene
Assessment Values in Biological Material – Translation of the German version from 2016
Ulrike ReuterThomas Göen1
Hans Drexler1 (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 Hartwig2 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
MAK Commission3
1 Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute and Outpatient Clinic of Occupational, Social, and Environmental Medicine, Henkestraße 9–11, 91054 Erlangen, Germany
2 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
3 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) and the exposure equivalents for carcinogenic substances (EKA) for ethylbenzene [CAS No. 100‐41‐4], considering mandelic acid and phenylglyoxylic acid in urine as well as 2‐ and 4‐ethylphenol in urine (after hydrolysis) to characterise the internal exposure. Ethylbenzene was classified in category 4 for carcinogenic substances. It can easily pass through the skin, so biological monitoring is necessary for a valid individual risk assessment.
The BAT value for styrene, which also considers the sum of mandelic acid and phenylglyoxylic acid, was evaluated as creatinine related value. For practical reasons, the BAT value and the EKA for ethylbenzene are transformed into creatinine related values as well. Therefore, volume‐related results of studies were re‐calculated using a conversion factor of 1.2 g creatinine/l urine. The available studies are in good accordance. A BAT value for the sum of mandelic acids plus phenylglyoxylic acid of 250 mg/g creatinine was evaluated. Sampling should be performed at the end of exposure or end of shift.
For the EKA correlation, the values for the parameter mandelic acid plus phenylglyoxylic acid were also re‐calculated using a conversion factor of 1.2 g creatinine/l urine. Sampling time is at the end of exposure or end of shift. For the parameter 2‐ plus 4‐ethylphenol, data differ in the two available older studies. While in one study only 2‐ethylphenol was found as metabolite of ethylbenzene, in the other study only 4‐ethylphenol was determined. In a more recent study, solely 4‐ethylphenol, but no 2‐ethylphenol could be analysed. Because of the inconsistency of the data, the EKA for the parameter 2‐ plus 4‐ethylphenol is withdrawn.
