title: In field conditions, commercial pigment grade TiO2 was not harmful to terrestrial isopods but reduced leaf litter fragmentation.
abstract: We investigated the effects of a commercial pigment grade rutile TiO2 on the terrestrial isopod Porcellio scaber in three locations that differed in terms of abiotic and biotic conditions: the laboratory, open air, and the closed barn. Mortality and isopod energy reserves (digestive gland total proteins, lipids and carbohydrates) were not affected following 14days exposure to up to 1000mg TiO2 per kg dry leaves (mg/kg) under any experimental scenario. However, in the field tests, isopods consumption of TiO2-coated leaves was reduced compared to that of uncoated leaves and the decrease was not dose-dependent. The highest reduction was in the closed barn (45-56%) rather than in the open-air (38-40%). In laboratory-based food choice tests, isopods neither preferred nor avoided leaves coated with TiO2, suggesting that rather than sensing the TiO2 on the leaves directly, the isopods under open-air and barn exposure responded to altered attractiveness and/or palatability of the TiO2 amended leaves. We propose that this could be due to altered microbial population on the leaves, a hypothesis that requires further investigation. Although short-term exposure to atmospheric deposition of up to 1000mg/kg commercial TiO2 is unlikely to pose an immediate threat to isopod mortality and energy balance, reduced leaf feeding may have implications for the decomposition of plant material.
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana, Slovenia. Electronic address: anita.jemec@bf.uni-lj.si.
authors.forename: Anita
authors.initials: A
authors.lastname: Jemec
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana, Slovenia.
authors.forename: Monika
authors.initials: M
authors.lastname: Kos
authors.affiliation: University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana, Slovenia.
authors.forename: Damjana
authors.initials: D
authors.lastname: Drobne
authors.affiliation: The Danish Nanosafety Centre, National Research Centre for Working Environment, Lersø Park Alle 105, DK-2100 Copenhagen, Denmark.
authors.forename: Ismo Kalevi
authors.initials: IK
authors.lastname: Koponen
authors.affiliation: University of Montenegro, Faculty of Natural Sciences and Mathematics, Department of Biology, Džordža Vašingtona bb, 81000 Podgorica, Montenegro.
authors.forename: Jovan
authors.initials: J
authors.lastname: Vukić
authors.affiliation: Department of Biology and CESAM, University of Aveiro - Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Nuno G C
authors.initials: NG
authors.lastname: Ferreira
authors.affiliation: Department of Biology and CESAM, University of Aveiro - Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Loureiro
authors.affiliation: McGill University, Department of Natural Resource Sciences, 21,111 Lakeshore Drive, St-Anne-de-Bellevue, Quebec H9X 3V9, Canada.
authors.forename: Heather V A
authors.initials: HV
authors.lastname: McShane
mesh_terms: D000818:Animals; D004396:Coloring Agents / Q000633:toxicity*; D031211:Corylus / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D033321:Isopoda / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects*; D014025:Titanium / Q000633:toxicity*
chemical_list: D004396:Coloring Agents; D004785:Environmental Pollutants; C009495:titanium dioxide; D014025:Titanium
keywords: Avoidance behaviour; Energy reserves; Litter breakdown; Porcellio scaber