^a Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, Minneapolis, Minnesota, USA
E-mail: novak010@umn.edu

^b Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
E-mail: kris.mcneill@env.ethz.ch

^c Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia, USA
E-mail: pvikes@vt.edu

^d Virginia Tech Institute of Critical Technology and Applied Science (ICTAS), Sustainable Nanotechnology Center (VTSuN), Blacksburg, Virginia, USA