1. Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
2. Center for Environmental Implications of Nanotechnology, Pittsburgh, Pennsylvania 15213, United States
3. Geological
and Environmental Science, Virginia Tech, Blacksburg, Virginia 24061, United States
4. Civil & Environmental Engineering, Duke University, Durham, North Carolina 27708-0287, United States
5. Aix Marseille Univ., CNRS, IRD, Coll. France, CEREGE, Aix en Provence, France
6. Chevron Energy Technology Company, Richmond, California 94802, United States