1. Center for the Environmental Implications of NanoTechnology (CEINT), Duke University, Durham, North Carolina 27708, United States
2. Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
3. Department of Biology, Duke University, Durham, North Carolina 27708, United States
4. Key laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, People’s Republic of China 430074
5. Department of Civil and Environmental Engineering, Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, United States