|Singh, G - UC RIVERSIDE|
|Spencer, W - 5310 20 20|
Submitted to: Integrated Weed Management for Sustainable Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: June 5, 1993
Publication Date: N/A
Technical Abstract: Most agricultural chemicals, while travelling either through or over the soil, undergo multiple reactions, such as biotic and abiotic degradation, adsorption & desorption and volatilization. Uncertainty prevails in complete understanding many of the above processes. Fate of degraded/ activated byproducts has not received adequate attention in transport studies. Hence, column displacement experiments were conducted to measure the effluent concentrations of atrazine and its metabolites viz., hydroxyatrazine, deisopropylatrazine, deethylatrazine and diaminoatrazine. A pulse of C-14 atrazine was applied and leached with 0.01N CaCl 2 solution at a rate of 2.75 pore volumes per day. Effluent break through curves (BTC) did not show any definite pattern. Sixty-two percent of the applied chemical was recovered through organic phase extraction. Further analysis led to the identification of the four metabolites which were separated with hHigh Pressure Liquid Chromatography and the fractions quantified by radioactivity assay. The measured BTC for the Ca(N03)2, atrazine and its metabolites were compared with predictions from a two-site/two-region non-equilibrium transport prediction model that included a degradation term. The simulated results with metabolites were in good agreement with the measured data.