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United States Department of Agriculture

Agricultural Research Service

Title: Influence of Soil Properties on Sorption-Desorption of Imidacloprid

Authors
item Cox, L - UNIVERSITY OF MINNESOTA
item Koskinen, William
item Yen, P - BAYER CORPORATION

Submitted to: International Association of Environmental and Analytical Chemistry
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 1997
Publication Date: N/A

Technical Abstract: Imidacloprid [1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine] is a new systemic insecticide used as soil treatment, seed dressing, and foliar treatment. Sorption-desorption studies were conducted with seven U.S. soils varying in their physicochemical properties (OC = 0.3-4 percent, Clay = 3-43 percent, pH = 5.7-7.8, CEC = 3.62-41) using the batch equilibration method. Initial imidacloprid concentrations ranged from 3 to 300 mg L**-1, since although the normal field application rate is 0.2-1 Kg ha**-1, it is also used for termite control at rates 100 times greater. Sorption coefficients Kf and the soil properties organic carbon and CEC gave the higher single correlation coefficients; the latter due to the positive correlation between OC and CEC. Sorption was irreversible, and hysteresis coefficients, in general, were higher at low soil solution concentrations. Sorption coefficients Kf were significantly lower at 1:5 soil/solution ratio than at 1:1. This suggests a possible effect of a soluble soil component, such as salt concentration, on sorption; no significant differences in pH between solutions were detected.

Last Modified: 9/21/2014
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