Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/1999
Publication Date: N/A
Technical Abstract: Experiments were performed using low density (i.e., 0.25 g/mL) supercritical carbon dioxide, to remove linuron from the soil water phase only, thus allowing calculation of sorption coefficients (Kd) at low water contents. Soil water content and temperature affected sorption. Kd values increased with water content, and decreased with temperature. Linuron sorption coefficients for silt clay, and sandy loam soils at 12% water content were 3.9, and 7.0 mL/g, respectively. Isosteric heat of sorption, were -41 and -35 kJ/mol, for the silt clay and sandy loam soils respectively. Comparable sorption coefficients were obtained for SFE and batch slurry methods. The Kf value for the sandy loam soil was 7.9 mL/g. This application of SFE to determine sorption coefficients should give a more accurate overall perspective of linuron fate in the field, than by sorption characterized by the batch method.