title: Ag Nanoparticles (Ag NM300K) in the Terrestrial Environment: Effects at Population and Cellular Level in Folsomia candida (Collembola).
abstract: The effects of nanomaterials have been primarily assessed based on standard ecotoxicity guidelines. However, by adapting alternative measures the information gained could be enhanced considerably, e.g., studies should focus on more mechanistic approaches. Here, the environmental risk posed by the presence of silver nanoparticles (Ag NM300K) in soil was investigated, anchoring population and cellular level effects, i.e., survival, reproduction (28 days) and oxidative stress markers (0, 2, 4, 6, 10 days). The standard species Folsomia candida was used. Measured markers included catalase (CAT), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (TG), metallothionein (MT) and lipid peroxidation (LPO). Results showed that AgNO₃ was more toxic than AgNPs at the population level: reproduction EC₂₀ and EC₅₀ was ca. 2 and 4 times lower, respectively. At the cellular level Correspondence Analysis showed a clear separation between AgNO₃ and AgNP throughout time. Results showed differences in the mechanisms, indicating a combined effect of released Ag⁺ (MT and GST) and of AgNPs (CAT, GR, TG, LPO). Hence, clear advantages from mechanistic approaches are shown, but also that time is of importance when measuring such responses.
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Aveiro 3810-193, Portugal. jsf@bios.au.dk.|Department of Bioscience, Aarhus University, Vejlsovej 25, PO BOX 314, Silkeborg DK-8600, Denmark. jsf@bios.au.dk.
authors.forename: Luís André
authors.initials: LA
authors.lastname: Mendes
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Aveiro 3810-193, Portugal. vmaria@ua.pt.
authors.forename: Vera L
authors.initials: VL
authors.lastname: Maria
authors.affiliation: Department of Bioscience, Aarhus University, Vejlsovej 25, PO BOX 314, Silkeborg DK-8600, Denmark. jsf@bios.au.dk.
authors.forename: Janeck J
authors.initials: JJ
authors.lastname: Scott-Fordsmand
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Aveiro 3810-193, Portugal. mjamorim@ua.pt.
authors.forename: Mónica J B
authors.initials: MJ
authors.lastname: Amorim
mesh_terms: D000818:Animals; D001181:Arthropods / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D015415:Biomarkers / Q000032:analysis; D008136:Longevity / Q000187:drug effects; D053768:Metal Nanoparticles / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects; D012834:Silver / Q000633:toxicity*; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D012989:Soil Pollutants; D012834:Silver
keywords: antioxidant defenses; mechanisms of response; soil invertebrates.