Sorption of penconazole applied as a commercial water-oil emulsion in soils devoted to vineyards.
The objective of this work was to assess the effect of surfactants and oils of a commercial formulation on the potential mobility of penconazole in agricultural soils that have been subjected to a high rate of application of agricultural chemicals. Soil-water partition tests on a commercial water-oil emulsion formulation of penconazole (WOEP) in 0.01 M CaCl(2) containing 35 mg L(-1) penconazole, incubated for 24 h, showed a maximum retention of approximately 250-300 mg penconazole kg(-1) soil. Approximately 70% of the total penconazole retained by the solid phase was sorbed on the soil (175-200 mg kg(-1)). The other 30% was retained by the adjuvants present in the commercial formulation. The formulation also influenced the water-soil partition, increasing the sorption in tests on batch studies using technical-grade penconazole (TGP). Soils with high total copper and organic matter had the greatest affinity for penconazole when added as WOEP. Additionally, adsorption of penconazole followed an S-type isotherm, whose behavior was consistent with the ability of the technical-grade penconazole to form aggregates. In the case of the WOEP, the S-type behavior could be attributed to the surfactant present in the formulation, which could be adsorbed onto soil as hemimicelles, which in turn may facilitate adsorption of penconazole.
Pose-Juan
E
E
Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Sciences, University of Vigo, E-32004 Ourense, Spain.
Rial-Otero
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R
López-Periago
J E
JE
D002851:Chromatography, High Pressure Liquid; D004655:Emulsions; D005659:Fungicides, Industrial / Q000737:chemistry*; D007700:Kinetics; D009821:Oils; D012989:Soil Pollutants / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014230:Triazoles / Q000737:chemistry*; D014867:Water; D014920:Wine
D004655:Emulsions; D005659:Fungicides, Industrial; D009821:Oils; D012989:Soil Pollutants; D014230:Triazoles; D014867:Water; C087058:penconazole