title: Toxicity assessments of nanoscale zerovalent iron and its oxidation products in medaka (Oryzias latipes) fish.
abstract: Iron-based nanotechnologies are increasingly used for environmental remediation; however, toxicologic impacts of iron nanoparticles on the aquatic ecosystem remain poorly understood. We treated larvae of medaka fish (Oryzias latipes) with thoroughly characterized solutions containing carboxymethyl cellulose (CMC)-stabilized nanoscale zerovalent iron (nZVI), aged nanoscale iron oxides (nFe-oxides) or ferrous ion (Fe[II]) for 12-14 days' aqueous exposure to assess the causal toxic effect(s) of iron NPs on the fish. With the CMC-nZVI solution, the dissolved oxygen level decreased, and a burst of reactive oxygen species (ROS) was generated as Fe(II) oxidized to ferric ion (Fe[III]); with the other two iron solutions, these parameters did not significantly change. CMC-nZVI and Fe(II) solutions caused acute lethally and sublethally toxic effects in medaka larvae, with nFe-oxide-containing solutions causing the least toxic effects. We discuss modes of toxic action of iron NPs and chronic toxic effects in terms of hypoxia, Fe(II) toxicity and ROS-mediated oxidative damage.
authors: Department of Agricultural Chemistry, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan. chenpj@ntu.edu.tw
authors: Pei-Jen
authors: PJ
authors: Chen
authors: Chih-Hsiang
authors: CH
authors: Su
authors: Chi-Yen
authors: CY
authors: Tseng
authors: Shih-Wei
authors: SW
authors: Tan
authors: Chiung-Hsiang
authors: CH
authors: Cheng
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D052918:Environmental Restoration and Remediation; D015870:Gene Expression / Q000187:drug effects; D007501:Iron / Q000737:chemistry / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D009990:Oryzias; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D007501:Iron