title: Photocatalytic properties of titanium dioxide nanoparticles affect  habitat selection of and food quality for a key species in the leaf litter  decomposition process.
abstract: Interactions with environmental parameters may alter the ecotoxicity of nanoparticles. The present study therefore assessed the (in)direct effects of nanoparticulate titanium dioxide (nano-TiO(2)) towards Gammarus fossarum, considering nano-TiO(2)'s photocatalytic properties at ambient UV-intensities. Gammarids' habitat selection was investigated using its feeding preference on leaf discs either exposed to or protected from UV-irradiation in presence of nano-TiO(2) as proxy (n = 49). UV-irradiational one induced a significant preference for UV-protected habitats, which was more pronounced in simultaneous presence of nano-TiO(2). This behaviour may be mainly explained by the UV-induced formation of reactive oxygen species (ROS) by nano-TiO(2). Besides their direct toxicity, ROS may have lowered the leaf-quality in UV-exposed areas contributing (approximately 30%) to the observed behavioural pattern. Since the predicted no effect concentration of nano-TiO(2) in combination with UV irradiation falls below the predicted environmental concentration this study underpins the importance of considering environmental parameters during the risk assessment of nanoparticles.
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany. feckler@uni-landau.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Feckler
authors.forename: Ricki R
authors.initials: RR
authors.lastname: Rosenfeldt
authors.forename: Frank
authors.initials: F
authors.lastname: Seitz
authors.forename: Ralf
authors.initials: R
authors.lastname: Schulz
authors.forename: Mirco
authors.initials: M
authors.lastname: Bundschuh
mesh_terms: D033304:Amphipoda / Q000187:drug effects; D000818:Animals; D059001:Aquatic Organisms / Q000502:physiology*; D017753:Ecosystem; D063427:Food Quality; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D055668:Photochemical Processes; D018515:Plant Leaves; D017382:Reactive Oxygen Species; D014025:Titanium / Q000737:chemistry* / Q000633:toxicity; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000633:toxicity
chemical_list: D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium