1. Center of Epidemiology, Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz, Bochum, Germany
2. Human Biomonitoring, Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz, Bochum, Germany
3. Unit 1.3 Monitoring of Working Conditions, Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA), Alte Heerstrasse, Sankt Augustin, Germany
4. Unit 2.1 Metal Analysis, Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA), Alte Heerstrasse , Sankt Augustin, Germany
5. Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz, Bochum, Germany