title: Remobilisation of silver and silver sulphide nanoparticles in soils.
abstract: Manufactured nanoparticles (NPs) present in consumer products could enter soils through re-use of biosolids. Among these NPs are those based on silver (Ag), which are found sulphidised (e.g. silver sulphide, Ag2S) in biosolids. Herein, our aim was to examine the release of retained Ag(0) and Ag2S NPs in soils and biosolids as facilitated by environmentally and agriculturally relevant ligands. Under natural soil conditions, exemplified by potassium nitrate and humic acid experiments, release of Ag retained in soil was limited. The highest total Ag release was facilitated by ligands that simulated root exudates (citrate) or fertilisers (thiosulphate). Released Ag was predominantly present in the colloidal phase (>3 kDa-< 0.45 μm); intact NPs only identified in Ag2S-NP extracts. For biosolids containing nanoparticulate-Ag-S, release was also enhanced by thiosulphate, though mostly as colloidal-Ag - not intact NPs. These results suggest that exposure to NPs as a result of its release from soils or biosolids will be low.
authors.affiliation: CSIRO Land and Water, Advanced Materials Transformational Capability Platform-Nanosafety, Biogeochemistry Program, PMB 2 Glen Osmond, SA 5064, Australia. Electronic address: divina.navarro@csiro.au.
authors.forename: Divina A
authors.initials: DA
authors.lastname: Navarro
authors.affiliation: CSIRO Land and Water, Advanced Materials Transformational Capability Platform-Nanosafety, Biogeochemistry Program, PMB 2 Glen Osmond, SA 5064, Australia.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Kirby
authors.affiliation: CSIRO Land and Water, Advanced Materials Transformational Capability Platform-Nanosafety, Biogeochemistry Program, PMB 2 Glen Osmond, SA 5064, Australia; Soil Science, School of Agriculture, Food and Wine, University of Adelaide, PMB 1 Glen Osmond, SA 5064, Australia.
authors.forename: Mike J
authors.initials: MJ
authors.lastname: McLaughlin
authors.affiliation: CSIRO Materials Science and Engineering, Advanced Materials Transformational Capability Platform-Nanosafety, Royal Parade, Parkville, VIC 3052, Australia.
authors.forename: Lynne
authors.initials: L
authors.lastname: Waddington
authors.affiliation: CSIRO Land and Water, Advanced Materials Transformational Capability Platform-Nanosafety, Biogeochemistry Program, PMB 2 Glen Osmond, SA 5064, Australia.
authors.forename: Rai S
authors.initials: RS
authors.lastname: Kookana
mesh_terms: D019343:Citric Acid / Q000737:chemistry; D053768:Metal Nanoparticles / Q000032:analysis*; D012834:Silver / Q000032:analysis*; D018030:Silver Compounds / Q000032:analysis*; D012987:Soil / Q000737:chemistry*
chemical_list: D018030:Silver Compounds; D012987:Soil; D019343:Citric Acid; D012834:Silver; C013251:silver sulfide
keywords: Biosolids; Environmental fate; Nanoparticles; Remobilisation; Silver; Silver sulphide; Soil