Linked Life Data

12931895

Source:http://linkedlifedata.com/resource/pubmed/id/12931895

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2003-8-22
pubmed:abstractText
Nonequilibrium disc-flow techniques may better reproduce dynamic soil-pesticide interactions than traditional batch sorption studies. Batch kinetic and equilibrium experiments and dual-label thin-disc flow experiments were conducted with atrazine (6-chloro-N-ethyl-N'-isopropyl-1,3,5-triazine-2,4-diamine) and imazaquin [2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-3-quinolinecarboxylic acid] using a Demopolis silt loam (loamy-skeletal, carbonatic, thermic, shallow Typic Udorthent; 8% clay, 62 g kg(-1) organic matter, 7.6 pH). Batch kinetic studies with both herbicides revealed an almost instantaneous rapid phase and a much slower gradual phase. The rapid phase was complete after 5 min and equilibrium was reached at 24 h. The rapid phase accounted for 74% and 12 to 30% of the total amounts adsorbed for atrazine and imazaquin, respectively. The sorption of both the rapid and 24-h isotherms for each herbicide best fit the Freundlich equation. The rapid and 24-h K(f) values of atrazine were 1.38 and 2.41, respectively, and the N value of both phases was approximately 0.93. For imazaquin, the rapid and 24-h K(f) values were 0.056 and 035, respectively, and the N value for the rapid phase of imazaquin was 0.71, compared with 0.86 for the 24-h isotherm. In the dual-label thin-disc flow experiments, the average partition coefficient for atrazine at the peak soil concentration point was 1.54. This value closely agreed with the observed rapid-phase K(f) value of 1.38. In contrast, the thin-disc flow experiments failed to detect any imazaquin retention. The thin-disc flow method can allow for a greater resolution of rapid sorption kinetics, which is impractical with batch studies. Along with dynamic partitioning data, the thin-disc flow method may provide kinetics data that may better complement environmental models than coefficients generated with batch techniques.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0047-2425
pubmed:author
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1393-404
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:articleTitle
Using nonequilibrium thin-disc and batch equilibrium techniques to evaluate herbicide sorption.
pubmed:affiliation
Department of Plant and Soil Sciences, Box 9555, 117 Dorman Hall, Mississippi State University, Mississippi State, MS 39762, USA. csmith@pss.msstate.edu
pubmed:publicationType
Journal Article