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UID:20251105T111324EST-5904J1DLgp@132.216.98.100
DTSTAMP:20251105T161324Z
DESCRIPTION:Abstract  Metal oxide nanoparticles (MONPs) are increasingly be
 ing incorporated in domestic and industrial products. They are expected to
  pass into waste water treatment facilities\, and may inadvertently be app
 lied in biosolids to agricultural soils. Very few nanotoxicity studies hav
 e been conducted in soils and the risk that MONPs pose to soil organisms a
 re poorly understood. The aim of this study was to investigate the behavio
 ur and effects of two MONPs with different solubilities on terrestrial org
 anisms in soils. Exposure of earthworms to soils amended with up to 10\,00
 0 mg/kg nano-sized TiO2\, a virtually insoluble nanomaterial\, resulted in
  no adverse effects on earthworm population parameters such as survival or
  reproduction. Earthworms avoided nano-TiO2 amended soils\, but only at na
 noparticle concentrations higher than those expected for agricultural soil
 s. The mechanisms resulting in the avoidance response\, and nano-TiO2 tran
 sformations in soils\, could not be further investigated because technique
 s to track nanoparticles in complex media are lacking. Subsequent studies 
 focused on a sparingly soluble nanomaterial\, nano-CuO\, which releases Cu
 2+ ions as it dissolves. To identify nanoparticle-specific effects on orga
 nisms\, the effects of the Cu2+ ions must be determined but little is know
 n about the effect of nano-CuO on Cu2+ activity in soils. Tests revealed t
 hat Cu2+ activity in nano-CuO amended soils increased over a 56 d period\,
  but were not comparable to those in soils amended with similar concentrat
 ions of micrometer-sized CuO or Cu(NO3)2\, which are commonly used as trea
 tments to control for the effects non-nanosized Cu in nanotoxicity tests. 
 These results have implications for the design of experiments that test ef
 fects of dissolving particulates.  A subsequent barley growth test demonst
 rated that there was no significant difference in plant growth or shoot Cu
  concentrations between soils amended with nano-CuO\, micrometer-sized CuO
  or Cu(NO3)2 once growth was normalised to Cu2+ activity. These results de
 monstrate that release of metal ions can play an important role in toxicit
 y of soluble metal-based nanoparticles and highlight the importance of dir
 ect measurement of potentially toxic products of nanoparticle dissolution.
  There was no evidence of nanoparticle-specific toxicity under the conditi
 ons studied either for earthworms exposed to nano-TiO2 or barley exposed t
 o nano-CuO. The study highlighted some of the challenges of understanding 
 the fate and effects of nanomaterials in soils\, including the lack of tec
 hniques to track nanomaterials in complex media and the difficulty in desi
 gning toxicity tests that control for temporal changes to both nanoparticl
 es and soils.  
DTSTART:20130410T131500Z
DTEND:20130410T160000Z
LOCATION:R2-013\, Raymond Building\, CA\, QC\, St Anne de Bellevue\, H9X 3V
 9\, 21111 Lakeshore Road
SUMMARY:Heather McShane PhD Oral Defense: Metal oxide nanoparticle chemistr
 y and toxicity in soils
URL:/nrs/channels/event/heather-mcshane-phd-oral-defen
 se-metal-oxide-nanoparticle-chemistry-and-toxicity-soil
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