The Environmental Behavior Of Two Acetamiprid Mixed-pesticides In Soils

With the development of industrialization, more and more contamination were pour into the soil environment. A great deal of studies had been conducted to examine the fate of pesticides in the environment. However, little information is available to describe the fate of multiple pesticides co-existed in the environment.In this study, two mixed-pesticides (Acetamiprid and Abamectin, Acetamiprid and Chlorpyrifos) were chose as models of pesticides to examine their environmental behaviors alone and in combination. The main results were summarized as follows:1. Residual analysisA method was developed for determination two Acetamiprid Mixed-pesticides residues in soil by HPLC. As to Acetamiprid and Abamectin, Chromatographic column Venusil C18 250 mm×4.6 mm was used for analysis. 245nm was chose for UV wavelength, flow liquid were methanol and water (96:4). The peak time of Acetamiprid was 2.95 min and that of Abamectin was 5.39 min. As to Acetamiprid and Chlorpyrifos, Chromatographic column Venusil C18 250 mm×4.6 mm was used for analysis. 230nm was chose for UV wavelength, flow liquid were methanol and water (90:10) The peak time of Acetamiprid was 3.00 min and that of Chlorpyrifos was 7.70 min.Under the optimize condition for residues, average recoveries of Acetamiprid from soil were in the range from 89.8%～97.2%, the coefficient of variant was 3.4%～4.0%; average recoveries of Abamectin from soil were in the range from 88.6%～98.8%, the coefficient of variant was 3.3%～5.8%; average recoveries of Chlorpyrifos from soil were in the range from 88.6%～98.0%, the coefficient of variant was 1.5%～4.1%; All accorded with qualification of CIPAC.2. Adsorption and mobility of two Acetamiprid Mixed-pesticidesThe adsorption experiments of pesticide in soils were conducted by the batch equilibration. For single used pesticide, the results showed that the adsorption isotherms of three pesticides in the tested soils were fitted with Frendlich equation well. Furthermore, the difference of adsorption capability occurred in different soils to the pesticide. Competitive adsorption experiments showed that absorption of Abamectins was reduced by its combination with Acetamiprid, but the absorption of Acetamiprid was not affected by Abamectin and Chlorpyrifos.The mobility of three pesticides in four soils was studied by thin layer chromatography. The results suggested that the mobility of Acetamiprid, Chlorpyrifos and Abamectin was not affected when used in combination. Acetamiprid could moved in Shandong dongying soil and Chongqing beibei soil, but in guangxi Guilin soil and Liaoning fengcheng soil was middle movable; Abamectins was not easily movable in four soils; Chlorpyrifos could not move in guangxi Guilin soil and was not easily movable in rest of three soils.3. Degradation of two Acetamiprid Mixed-pesticidesAs to Acetamiprid and Abamectin, the degradation rate of Acetamiprid was not affected by Abamectin at low concentration (10mg/kg), but middle and high concentrations (20mg/kg and 40mg/kg) addition of Abamectin would inhibited the degradation rate of Acetamiprid. The degradation half-lives of Acetamiprid combined with Abamectin at middle and high concentrations were determined to be 6.51d,6.99d, which were longer than contrast (5.98d) by 0.53d, 1.10d, respectively. The degradation rate of Abamectin was almost no affected by Acetamiprid.There was no influence on the degradation between Acetamiprid and Chlorpyrifos...