title: How do physicochemical properties influence the toxicity of silver nanoparticles on freshwater decomposers of plant litter in streams?
abstract: AgNP physicochemical properties may affect AgNP toxicity, but their effects on plant litter decomposition and the species driving this key ecosystem process in freshwaters have been poorly investigated. We assessed the impacts of AgNPs with different size and surface coating (100nm PVP (polyvinylpyrrolidone)-dispersant, 50-60nm and 35nm uncoated) on freshwater decomposers of leaf litter by exposing leaf associated microbial assemblages to increasing concentrations of AgNPs (up to 200mgL-1) and of AgNO3(up to 25mgL-1). We further conducted a feeding preference experiment with a common invertebrate shredder, Limnephilus sp., which was allowed to feed on microbially-colonized leaves previously exposed to AgNPs and AgNO3. Leaf decomposition and microbial activity and diversity were inhibited when exposed to increased concentrations of 100nm AgNPs (≥25mgL-1), while microbial activity was stimulated by exposure to 35nm AgNPs (≥100mgL-1). Invertebrate shredders preferred leaves exposed to 35nm AgNPs (25mgL-1) and avoided leaves exposed to AgNO3(≥2mgL-1). Results from the characterization of AgNPs by dynamic light scattering revealed that AgNps with PVP-dispersant were more stable than the uncoated AgNPs. Our results highlight the importance of considering the physicochemical properties of NPs when assessing their toxicity to litter decomposers in freshwaters.
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. Electronic address: danimbatista@bio.uminho.pt.
authors.forename: Daniela
authors.initials: D
authors.lastname: Batista
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Pascoal
authors.affiliation: Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Cássio
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D017753:Ecosystem; D005247:Feeding Behavior / Q000187:drug effects; D007448:Invertebrates / Q000187:drug effects* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D059013:Microbial Consortia / Q000187:drug effects*; D010316:Particle Size; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D011205:Povidone / Q000737:chemistry; D029963:Quercus / Q000737:chemistry* / Q000378:metabolism; D045483:Rivers / Q000737:chemistry* / Q000382:microbiology; D012834:Silver / Q000737:chemistry / Q000633:toxicity*; D013499:Surface Properties
chemical_list: D012834:Silver; D011205:Povidone
keywords: Feeding behavior; Invertebrate shredders; Leaf litter decomposition; Microbial decomposers; Silver nanoparticles; Size and coating