Fate and lability of silver in soils: effect of ageing.
The fate and lability of added soluble Ag in soils over time was examined by measurement of labile metal (E-value) by isotopic dilution using the (110m)Ag radioactive isotope and the solid-phase speciation of Ag by X-ray absorption near edge structure (XANES) spectroscopy. After two weeks of ageing the E-values for Ag decreased by 20-90% with a further decrease of 10-40% after six months. The overall decrease in labile Ag for all soils after the 6 month ageing period was 50-100%. The ageing was more rapid and pronounced in the alkaline soils. XANES results for Ag in soils indicated that for the majority of soils the added Ag(+) was reduced to metallic Ag over time, and associations with Fe-oxohydroxides and reduced S groups in organic matter also decreased Ag lability. Strong positive correlations were found between metallic Ag and non-labile Ag and between organic carbon and Ag bonded with S species.
Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, Waite Rd, SA 5064, Australia. Electronic address: Lara.Settimio@adelaide.edu.au.
Lara
L
Settimio
Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, Waite Rd, SA 5064, Australia; CSIRO Land and Water, Contaminant Chemistry and Ecotoxicology Program, Minerals Down Under Flagship, Waite Campus, Waite Rd, SA 5064, Australia.
Mike J
MJ
McLaughlin
CSIRO Land and Water, Contaminant Chemistry and Ecotoxicology Program, Minerals Down Under Flagship, Waite Campus, Waite Rd, SA 5064, Australia.
Jason K
JK
Kirby
CSIRO Land and Water, Contaminant Chemistry and Ecotoxicology Program, Minerals Down Under Flagship, Waite Campus, Waite Rd, SA 5064, Australia.
Kate A
KA
Langdon
Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
Enzo
E
Lombi
Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
Erica
E
Donner
National Risk Management Research Laboratory, US EPA, Cincinnati, US.
Kirk G
KG
Scheckel
D002412:Cations / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011868:Radioisotopes / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry; D056928:X-Ray Absorption Spectroscopy
D002412:Cations; D011868:Radioisotopes; D012987:Soil; D012989:Soil Pollutants; D012834:Silver
Ageing; Lability; Silver; Speciation