**4. Conclusion**

The results showed that the introduction of LMWOA could accelerate the release of the tested organochlorine pesticides (relative to the water, increased 15%~18% for DDTs, 7%~25% for HCHs). It implied that the LMWOA induced the complication of the kinetics release mechanisms of organochlorine pesticides (The best kinetics equation describing the release of pesticide changed from the first-order kinetic equation in water system to parabola diffuse equation, double constant equation or Elovich equation in LMWOA systems). It also indicated that the kinetics release mechanisms of OCPs by LMWOA involved not only the simple granular surface diffusion mechanism in water system, but also the outward diffusion mechanism of soil particles internal, activation and inactivation function of granular surface, the non-uniform mechanism of surface energy distribution induced by the solution of soil mineral and structure change of soil inherent organic matter coating onto the soil mineral surface by LMWOA.

The release velocity of HCHs was far higher than that of DDTs by water and LMWOA. Their difference was nearly 3 times. The variation amplitude of the release velocity and the influence of elution volume on release velocity for DDTs by water were all small and not obvious. The release velocity curves of OCPs from soil by LMWOA were all peak-type curve, and it included 2 stages which are rapid release and low release.
