The Absorption And Degradation Of Termite-prevent Pestcide In The Soil Chemical Barrier

Chlorpyrifos, bifenthrin, fenvalerate are the typical termite-prevention pesticides which recommended by the Chinese Association of Property Management. In addition, chlorpyrifos is the most widely used pesticide for termite-prevention in China. Four typical regions located in the south of Chang Jiang or near that were selected for the investigation, which included Wuhan, Hefei, Hangzhou and Quanzhou. In each trial site, the soil treated with peticides was collected by layer. And then the soil was carried back to for laboratory tests. The laboratory tests consist of simulated adsorption experiment, column leaching experiment, and tests concerning effect of four pesticides on the ground water. All the trials were referred to the four selected pesticides, and four types of soils. At the same time, the field trials were also carried out, which mainly included the distribution behavior and degradation of the pesticides. The field trials were performed to validate the results of the lab trials.My papers do some research on Pesticides absorpt, degradate, migrate in the soil,which can give a reasonable forecast to chemical barrier strength in the soil, and also provide a scientific basis to prevent groundwater pollution.Adsorption of the simulation test results showed that the adsorption behavior of pesticides in the soil had a relationship with the property of the pesticides, and with physical and chemical properties of the soil. As termite prevention pestcides, they have their own particularity. Firstly, they are mainly applied in non-arable land, and organic matter content in such land is relatively low. Secondly, the pestcides are applied at higher concentration.Mobile test showed that chlorpyrifos and bifenthrin had low solubility in water. The R1 was more than 50% in soil column leaching test,and the pesticide adsorption were mainly concentrated in the upper 10cm of the soil columns. This meant that the pesticides were difficult to leach. So it was less dangerous to Pollution ground water.Indoor and outdoor soil test distribution agreement on that 1-7 three days after application, more than 90 percent of chlorpyrifos, bifenthrin, fenvalerate and imidacloprid, which were applied in Hangzhou, Hefei, Quanzhou, were concentrated in 0 to 10cm in the soil column.Outdoor degradation tests showed that chlorpyrifos in three different soil indicated the half-life of 35.7d-62.7d. Bifenthrin has the half-life of 68.3 d and 68.9d in the soil of gluten and yellow brown earth, has the half-life of 152.3d. in the red loam.