1. Medical Institute of Environmental Hygiene at Heinrich-Heine-University (HHU) Düsseldorf, Düsseldorf, Germany (retired)
2. IUF-Leibniz Research Institute of Environmental Medicine, Düsseldorf, Germany
3. Department of Hygiene, Social and Environmental Medicine, Ruhr-University Bochum, Bochum, Germany
4. Chemical and Veterinary Analytical Institute Münsterland-Emscher-Lippe, Münster, Germany