| The entrance of chlorpyrifos to environment such as atmosphere, soils,ponds, rivers, lakes is inevitable because of the application of chlorpyrifos,which may cause the environmental pollution and ecology destruction.Chlorpyrifos was extracted from soils, water and pakchois with petroleunether according to "Experimental Guideline for Environmental SafetyEvaluation of Chemical Pesticides" in this paper, and was quantitativeanalyzed by capillary gas chromatography. The main environmentalbehaviors of chlorpyrifos in soils such as absorption, mobility, volatilizationand degradation, the hydrolysis and photodegradation in different pHconditions, degradation characteristic in pakchoi were studied.Chlorpyrifos-degrading microorganisms were isolation and the degradationefficiency was also tested.The results showed that soils had better absorption for Chlorpyrifosthan the others, the absorption constant (K_d) of chlorpyrifos in loam, clayand sandy soil was 213.51, 182.82 and 157.01, respectively. Chlorpyrifoswas uneasy to move in loams and sandy soil, and didn't move in clay. Itwas difficult to volatilize in loams and clay for chlorpyrifos but easy insandy soil. It was easily degraded in the tested soils, and the half-life ofchlorpyrifos in loam, clay and sandy soil were 23.9d, 12.6d and 9.8d, respectively. The degradation of chlorpyrifos could quicken with theincrease of pH and that was more markedly in darkness. The hydrolysishalf-life in water of pH4.0, 7.0and 10.0 was 22.4d, 18.9d and 1.2drespectively, and the photodegradation half-life was 12.8d, 10.7d and 0.9drespectively. Anyway, chlorpyrifos could be degraded easily in waterwheather had illumination or not. According to the standard ofFAO/WHO (china carries out limitly), the safe interval period ofchlorpyrifos was 7-8d in pakchoi cultivated in greenhouse, which wasshorter than that of USA and European Union (13-14d). The results alsodemonstrated that microorganisms played an important role in thedegradation of pesticides. In other way, chlorpyrifos-degradingTrichoderma GX was isolated from pesticides polluted soil in presentedstudy.In this paper, the environmental behaviors of chlorpyrifos werestudied completely, combining the soil, water, and climate fact in GuangXi.And the results should be a scientific evidence for the environmental andecological safety evaluation measument and the application of chlorpyrifosin vegetabals. A noval chlorpyrifos-degrading fungus Trichoderma wasisolated from pesticides polluted soil in Guangxi.
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