title: Effects of water chemistry on the dissolution of ZnO nanoparticles and their toxicity to Escherichia coli.
abstract: The dissolution of ZnO nanoparticles (nano-ZnO) plays an important role in the toxicity of nano-ZnO to the aquatic organisms. The effects of water chemistry such as pH, ionic components, and dissolved organic matter (DOM) on the dissolution of nano-ZnO and its toxicity to Escherichia coli (E. coli) were investigated in synthetic and natural water samples. The results showed that the toxicity of nano-ZnO to E. coli depended on not only free Zn(2+) but also the coexisting cations which could reduce the toxicity of Zn(2+). Increasing solution pH, HPO(4)(2), and DOM reduced the concentration of free Zn(2+) released from nano-ZnO, and thus lowered the toxicity of nano-ZnO. In addition, both Ca(2+) and Mg(2+) dramatically reduced the toxicity of Zn(2+) to E. coli. These results highlight the importance of water chemistry on the toxicity evaluation of nano-ZnO in natural waters.
authors.affiliation: Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.forename: Daohui
authors.initials: D
authors.lastname: Lin
authors.forename: Lizhong
authors.initials: L
authors.lastname: Zhu
mesh_terms: D002118:Calcium / Q000737:chemistry; D060766:Drinking Water / Q000737:chemistry; D004926:Escherichia coli / Q000187:drug effects; D005618:Fresh Water / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*
chemical_list: D060766:Drinking Water; D014874:Water Pollutants, Chemical; D008274:Magnesium; D015034:Zinc Oxide; D002118:Calcium