1. Helmholtz Zentrum München—German Research Center for Environmental Health, Research Unit Analytical BioGeoChemistry, D-85764 Neuherberg, Germany
2. University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, Maryland 20688, United States
3. Helmholtz Zentrum München—German Research Center for Environmental Health, Institute of Groundwater Ecology, D-85764 Neuherberg, Germany
4. Technische Universität München, Chair
of Analytical Food Chemistry, D-85354 Freising-Weihenstephan, Germany