title: Time-Dependent Toxicity Responses in Daphnia magna Exposed to CuO and ZnO Nanoparticles.
abstract: Aggregation and dissolution of CuO and ZnO nanoparticles (NPs) increased with increasing exposure time (24, 48, and 72 h). Acute toxicity of CuO NPs to Daphnia magna also increased significantly with increasing exposure time (p < 0.05), whereas exposure time did not significantly affect acute toxicity of ZnO NPs. The dissolved Cu concentration of CuO NPs was much lower than the median effective concentration (EC50) value (44 μg L-1at 72 h), implying that the increase in acute toxicity was caused by particles rather than by dissolved ions. However, the dissolved Zn concentration of ZnO NPs was higher than the EC50value (600 μg L-1at 72 h), suggesting this acute toxicity may be caused by dissolved ions. Moreover, CuO NPs induced greater lipid peroxidation than Cu ions did at an exposure time of 72 h, whereas converse results were observed for ZnO NPs.
authors.affiliation: Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
authors.forename: Soyoun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
authors.forename: Palas
authors.initials: P
authors.lastname: Samanta
authors.affiliation: Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
authors.forename: Jisu
authors.initials: J
authors.lastname: Yoo
authors.affiliation: System Toxicology Research Center, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea.
authors.forename: Woo-Keun
authors.initials: WK
authors.lastname: Kim
authors.affiliation: Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea. jjung@korea.ac.kr.
authors.forename: Jinho
authors.initials: J
authors.lastname: Jung
mesh_terms: D000818:Animals; D003300:Copper / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects*; D065546:Drug Liberation; D007477:Ions / Q000032:analysis / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis; D015032:Zinc / Q000032:analysis; D015034:Zinc Oxide / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; D014867:Water; D003300:Copper; D015032:Zinc; D015034:Zinc Oxide; C030973:cupric oxide
keywords: Acute toxicity; Copper; Daphnid; Nanotoxicology; Oxidative stress; Zinc