1. Department of Geological Sciences, School of Earth, Energy & Environmental Sciences, Stanford University, Stanford, California 94305-2115, United States
2. Center for Environmental Implications of NanoTechnology (CEINT), Duke University, Durham, North Carolina 27708, United States
3. Soil Chemistry and Chemical Soil Quality Group, Wageningen University, 6708 PB Wageningen, The Netherlands
4. Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
5. Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
6. Department of Earth System Sciences, School of Earth, Energy & Environmental Sciences, Stanford University, Stanford, California 94305, United States