Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 7, 1997
Publication Date: N/A
Technical Abstract: Sorption is arguably the most important process affecting pesticides in soil. It controls the availability of pesticides for leaching, degradation, and plant uptake. Changes in sorption of imidacloprid, dicamba, and metribuzin were determined after aging in soils. After different aging or residence time in soils, the chemicals were successively extracted from replicate soil samples using different solvents in order to characterize different degrees of chemical desorbability or availability. Sorption of all three chemicals, as indicated by Kd, increased by a factor of up to 3 with increased residence time in soil. The increase can be attributed to degradation of the chemicals in solution and the readily desorbable chemicals, leaving more strongly sorbed chemicals. The sorption increase can also be attributed, in part, to diffusion of the chemicals into less accessible sorption sites. Similar results were observed for atrazine after raging in field soil.