title: Acute and chronic effects of nano- and non-nano-scale TiO(2) and ZnO particles on mobility and reproduction of the freshwater invertebrate Daphnia magna.
abstract: Among the emerging literature addressing the biological effects of nanoparticles, very little information exists, particularly on aquatic organisms, that evaluates nanoparticles in comparison to non-nanocounterparts. Therefore, the potential effects of nano-scale and non-nano-scale TiO(2) and ZnO on the water flea, Daphnia magna, were examined in 48-h acute toxicity tests using three different test media, several pigment formulations--including coated nanoparticles--and a variety of preparation steps. In addition, a 21-d chronic Daphnia reproduction study was performed using coated TiO(2) nanoparticles. Analytical ultracentrifugation analyses provided evidence that the nanoparticles were present in a wide range of differently sized aggregates in the tested dispersions. While no pronounced effects on D. magna were observed for nano-scale and non-nano-scale TiO(2) pigments in 19 of 25 acute (48-h) toxicity tests (EC50>100 mg L(-1)), six acute tests with both nano- and non-nano-scale TiO(2) pigments showed slight effects (EC10, 0.5-91.2 mg L(-1)). For the nano-scale and non-nano-scale ZnO pigments, the acute 48-h EC50 values were close to the 1 mg L(-1) level, which is within the reported range of zinc toxicity to Daphnia. In general, the toxicity in the acute tests was independent of particle size (non-nano-scale or nano-scale), coating of particles, aggregation of particles, the type of medium or the applied pre-treatment of the test dispersions. The chronic Daphnia test with coated TiO(2) nanoparticles demonstrated that reproduction was a more sensitive endpoint than adult mortality. After 21d, the NOEC for adult mortality was 30 mg L(-1) and the NOEC for offspring production was 3 mg L(-1). The 21-d EC10 and EC50 values for reproductive effects were 5 and 26.6 mg L(-1), respectively. This study demonstrates the utility of evaluating nanoparticle effects relative to non-nano-scale counterparts and presents the first report of chronic exposure to TiO(2) nanoparticles in D. magna.
authors: BASF, Product Safety--Regulations, Toxicology and Ecology, GUP/CB-Z470, Ludwigshafen, Germany. karin.wiench@basf.com
authors: Karin
authors: K
authors: Wiench
authors: Wendel
authors: W
authors: Wohlleben
authors: Volker
authors: V
authors: Hisgen
authors: Kristin
authors: K
authors: Radke
authors: Edward
authors: E
authors: Salinas
authors: Sabine
authors: S
authors: Zok
authors: Robert
authors: R
authors: Landsiedel
mesh_terms: D000818:Animals; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development; D005618:Fresh Water; D053768:Metal Nanoparticles / Q000032:analysis / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects; D014025:Titanium / Q000737:chemistry*; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide