title: Fate of silver nanoparticles in wastewater and immunotoxic effects on rainbow trout.
abstract: Silver nanoparticles (AgNPs) are currently used in technology, medicine and consumer products, even though the fate and the ecotoxicological risks on aquatic organisms of these new materials are not well known. The purpose of this study was to investigate the fate, bioavailability of AgNPs and their effects on fish in presence of municipal effluents. Juvenile rainbow trout were exposed for 96h to 40μg/L of AgNPs or 4μg/L of dissolved silver (AgNO3) in diluted (10%) municipal wastewater. Silver (Ag) concentrations were measured both on water samples and fish tissues (liver and gills). Toxicity was investigated by following immunological parameters in the pronephros (viability, phagocytosis) and biomarkers in liver and gills (cyclooxygenase activity, lipid peroxidation, glutathione-S-transferase, metallothioneins, DNA strand breaks and labile zinc). Results indicated that AgNPs appeared as small non-charged aggregates in wastewaters (11.7±1.4nm). In gills, the exposure to AgNPs induced morphological modifications without visible nanoparticle bioaccumulation. Dissolved Ag(+) was bioavailable in diluted effluent and induced oxidative stress (lipid peroxidation), labile zinc and a marginal decrease in superoxide dismutase in fish gills. Ag(+) also increased significantly metallothionein levels and inhibited the DNA repair activity in the liver. Finally, the two silver forms were found in liver and induced immunosuppression and inflammation (increase in cyclooxygenase activity). This study demonstrated that both forms of Ag produced harmful effects and AgNPs in wastewater were bioavailable to fish despite of their formation of aggregates.
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7, Canada. Electronic address: audrey.bruneau@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Bruneau
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Turcotte
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Pilote
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Gagné
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, 105 McGill Street, Montreal, Quebec H2Y 2E7, Canada. Electronic address: christian.gagnon@ec.gc.ca.
authors.forename: C
authors.initials: C
authors.lastname: Gagnon
mesh_terms: D000818:Animals; D004260:DNA Repair / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005880:Gills / Q000737:chemistry / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000737:chemistry / Q000187:drug effects; D053768:Metal Nanoparticles / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D008668:Metallothionein / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010587:Phagocytosis / Q000187:drug effects; D012834:Silver / Q000032:analysis / Q000737:chemistry* / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D015032:Zinc / Q000378:metabolism
chemical_list: D008668:Metallothionein; D012834:Silver; D013482:Superoxide Dismutase; D062065:Wastewater; D014874:Water Pollutants, Chemical; D015032:Zinc
keywords: Biomarkers; Nanoparticle fate; Nanotoxicity; Rainbow trout; Silver ion; Wastewater