Simulation analysis of release kinetic of organochlorine pesticides from hydragric acrisols influenced by low-molecular weight organic acids leaching

摘要

The kinetic release behaviors of organochlorine pesticides (OCPs) from hydragric acrisols with three kinds of low-molecular weight organic acids (LMWOAs) solution and water leaching system were investigated by kinetic device designed by ourselves. Results showed that the release percentage of OCPs from soil by LMWOAs can increase by 15-18% for DDTs and 7-25% for HCHs more than that by water leaching system, especially for the initial 240 mL leaching solution. The release velocity of HCHs is far higher than that of DDTs (about 3-4 times) in the leaching systems studied. When using water as leaching solution, the data of release kinetics of OCPs from soil conformed to the apparent first dynamics equation (R-2 > 0.99, p < 0.0001), it implied that the surface diffuse of OCPs on soil mineral is primary release mechanism of OCPs from soil in water leaching system. The kinetic release behaviors of OCPs in LMWOAs solution leaching systems can be described by parabola diffuse equation, double constant equation, or Elovich equation. It implied that the introduction of LMWOAs into leaching system induced the complication of release mechanisms of OCPs from soil. It may be related to the dissolution of soil mineral surface and structure change of soil inherent organic matters that coating onto soil mineral surface induced by LMWOAs.