title: Toxicity of nanosized and bulk ZnO, CuO and TiO2 to bacteria Vibrio fischeri and crustaceans Daphnia magna and Thamnocephalus platyurus.
abstract: As the production of nanoparticles of ZnO, TiO2 and CuO is increasing, their (eco)toxicity to bacteria Vibrio fischeri and crustaceans Daphnia magna and Thamnocephalus platyurus was studied with a special emphasis on product formulations (nano or bulk oxides) and solubilization of particles. Our innovative approach based on the combination of traditional ecotoxicology methods and metal-specific recombinant biosensors allowed to clearly differentiate the toxic effects of metal oxides per se and solubilized metal ions. Suspensions of nano and bulk TiO2 were not toxic even at 20 g l(-1). All Zn formulations were very toxic: L(E)C50 (mg l(-1)) for bulk ZnO, nanoZnO and ZnSO4.7H2O: 1.8, 1.9, 1.1 (V. fischeri); 8.8, 3.2, 6.1 (D. magna) and 0.24, 0.18, 0.98 (T. platyurus), respectively. The toxicity was due to solubilized Zn ions as proved with recombinant Zn-sensor bacteria. Differently from Zn compounds, Cu compounds had different toxicities: L(E)C50 (mg l(-1)) for bulk CuO, nano CuO and CuSO4: 3811, 79, 1.6 (V. fischeri), 165, 3.2, 0,17 (D. magna) and 95, 2.1, 0.11 (T. platyurus), respectively. Cu-sensor bacteria showed that toxicity to V. fischeri and T. platyurus was largely explained by soluble Cu ions. However, for Daphnia magna, nano and bulk CuO proved less bioavailable than for bacterial Cu-sensor. This is the first evaluation of ZnO, CuO and TiO2 toxicity to V. fischeri and T. platyurus. For nano ZnO and nano CuO this is also a first study for D. magna.
authors.affiliation: National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
authors.forename: Margit
authors.initials: M
authors.lastname: Heinlaan
authors.forename: Angela
authors.initials: A
authors.lastname: Ivask
authors.forename: Irina
authors.initials: I
authors.lastname: Blinova
authors.forename: Henri-Charles
authors.initials: HC
authors.lastname: Dubourguier
authors.forename: Anne
authors.initials: A
authors.lastname: Kahru
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects* / Q000254:growth & development; D000818:Animals; D033202:Anostraca / Q000187:drug effects* / Q000254:growth & development; D003300:Copper / Q000737:chemistry / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development; D007928:Lethal Dose 50; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D019055:No-Observed-Adverse-Effect Level; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*; D018675:Toxicity Tests; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*
chemical_list: C009495:titanium dioxide; D003300:Copper; D014025:Titanium; D015034:Zinc Oxide; C030973:cupric oxide