Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The impact of soil organic matter and soil sterilisation on the bioaccessibility of (14)C-azoxystrobin determined by desorption kinetics
AU - Clegg, Helen
AU - Riding, Matthew J.
AU - Oliver, Robin
AU - Jones, Kevin C.
AU - Semple, Kirk T.
PY - 2014/8/15
Y1 - 2014/8/15
N2 - As soils represent a major sink for most pesticides, factors influencing pesticide degradation are essential in identifying their potential environmental risk. Desorption of (14)C-azoxystrobin was investigated over time in two soils under sterile and non-sterile conditions using exhaustive (solvent) and non-exhaustive (aqueous) methods. Desorption data were fitted to a two-compartment model, differentiating between fast and slow desorbing fractions. With increased ageing, rapid desorption (Frap) (bioaccessibility) decreased with corresponding increases in slowly desorbing fractions (Fslow). The rapid desorption rate constant (kfast) was not affected by ageing, sterility or extraction solvent. The non-exhaustive extractions had similar desorption profiles; whereas exhaustive extractions in aged soils had the highest Frap. In non-sterile soil, Frap was lower resulting in higher Fslow, while desorption rates remained unaffected. Organic matter (OM) reduces Frap; but not desorption rates. Microorganisms and OM enhanced ageing effects, reducing the fraction of fast desorbing chemicals and potentially the bioaccessibility of pesticides in soil.
AB - As soils represent a major sink for most pesticides, factors influencing pesticide degradation are essential in identifying their potential environmental risk. Desorption of (14)C-azoxystrobin was investigated over time in two soils under sterile and non-sterile conditions using exhaustive (solvent) and non-exhaustive (aqueous) methods. Desorption data were fitted to a two-compartment model, differentiating between fast and slow desorbing fractions. With increased ageing, rapid desorption (Frap) (bioaccessibility) decreased with corresponding increases in slowly desorbing fractions (Fslow). The rapid desorption rate constant (kfast) was not affected by ageing, sterility or extraction solvent. The non-exhaustive extractions had similar desorption profiles; whereas exhaustive extractions in aged soils had the highest Frap. In non-sterile soil, Frap was lower resulting in higher Fslow, while desorption rates remained unaffected. Organic matter (OM) reduces Frap; but not desorption rates. Microorganisms and OM enhanced ageing effects, reducing the fraction of fast desorbing chemicals and potentially the bioaccessibility of pesticides in soil.
KW - Azoxystrobin
KW - Soil
KW - Organic matter
KW - Desorption kinetics
KW - Bioaccessibility
U2 - 10.1016/j.jhazmat.2014.06.029
DO - 10.1016/j.jhazmat.2014.06.029
M3 - Journal article
C2 - 24997252
VL - 278
SP - 336
EP - 342
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
ER -