title: Behaviour of Au-citrate nanoparticles in seawater and accumulation in bivalves at environmentally relevant concentrations.
abstract: The degree of aggregation and/or coalescence of Au-citrate nanoparticles (AuNPs, mean size 21.5 ± 2.9 nm), after delivery in simulated seawater, are shown to be concentration-dependent. At low concentrations no coalescence and only limited aggregation of primary particles were found. Experiments were performed in which the marine bivalve (Ruditapes philippinarum) was exposed to AuNPs or dissolved Au and subsequently, bivalve tissues were studied by Scanning and Transmission Electron Microscopy and chemical analyses. We show that the bivalve accumulates gold in both cases within either the digestive gland or gill tissues, in different concentrations (including values of predicted environmental relevance). After 28 days of exposure, electron-dense deposits (corresponding to AuNPs, as proven by X-ray microanalysis) were observed in the heterolysosomes of the digestive gland cells. Although non-measurable solubility of AuNPs in seawater was found, evidence is presented of the toxicity produced by Au(3+) dissolved species (chloroauric acid solutions) and its relevance is discussed.
authors.affiliation: Instituto de Ciencia de Materiales de Sevilla (CSIC - Univ. Sevilla), Avda. Américo Vespucio nr. 49, CIC Cartuja, 41092 Sevilla, Spain.
authors.forename: C A
authors.initials: CA
authors.lastname: García-Negrete
authors.forename: J
authors.initials: J
authors.lastname: Blasco
authors.forename: M
authors.initials: M
authors.lastname: Volland
authors.forename: T C
authors.initials: TC
authors.lastname: Rojas
authors.forename: M
authors.initials: M
authors.lastname: Hampel
authors.forename: A
authors.initials: A
authors.lastname: Lapresta-Fernández
authors.forename: M C
authors.initials: MC
authors.lastname: Jiménez de Haro
authors.forename: M
authors.initials: M
authors.lastname: Soto
authors.forename: A
authors.initials: A
authors.lastname: Fernández
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000378:metabolism* / Q000648:ultrastructure; D019343:Citric Acid / Q000032:analysis / Q000378:metabolism*; D006046:Gold / Q000032:analysis / Q000378:metabolism*; D053768:Metal Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological; D008956:Models, Chemical; D012623:Seawater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D019343:Citric Acid; D006046:Gold