The Situ Remediation Of Pesticide Contaminated Soil By Immobilized White-rot Fungi

Corn stalks, wheat straw, peanut shells are common agricultural wastes, part of them always using as feed, and the others directly burning which is low utilization and do great harm to the environment. Carbofuran and chlorpyrifos as two common broad-spectrum insecticide, are widely used in agricultural production. But carbofuran and chlorpyrifos have a long half-life, not easily degrade in the soil and the residues would do harm to crop and human health. Thus, repairing carbofuran and chlorpyrifos contaminated soil without delay. This paper focuses on degradation of polluted soil through immobilized white rot fungi which made by adsorption method and hope to provide a new way for the pesticide contaminated soils situ remediation.In this study, we elect corn stalks, wheat straw, peanut shells, etc. as the carrier to immobilized three white rot fungi to degradate carbofuran and chlorpyrifos,and using the degradation rate as the marker to screened excellent degrading strains and optimum support. The results showed that corn stalks and wheat straw are more suitable as the carrier for immobilized white rot fungi, and C and W are the advantages of carbofuran degradation strains, C and Y are for chlorpyrifos. The optimum temperature is 28℃ for the cultures of white rot fungi, and under acidic conditions of white rot fungi grew better on the carrier. The degradation rate of carbofuran was 69.83% after W within 5days by corn stalks. The degradation rate of chlorpyrifos was 74.69% after C within 6days by corn stalks.Furthermore,the environmental factors influenced with immobilized white rot fungi showed that when the initial concentration of pollutants significantly changed, immobilized white rot fungi on degradation of two pesticides fluctuations changed a little, its ability to degrade less affected by the concentration. However,when the pH value, temperature and the initial dosage changed, immobilized white rot fungi on pesticide degradation varies greatly, the degradation ability of white rot fungi are greatly affected by these three environmental factors. Orthogonal experiment subsequent to verify this conclusion that carbofuran degradation in the orthogonal experiment, the reaction temperature is a key factor affecting the degradation rate, pH value is an important factor, dosage and initial concentration of carbofuran are general factors. In chlorpyrifos degradation orthogonal experiments, the reaction temperature and pH value are the key factors affect the degradation rate of chlorpyrifos, the initial concentration and dosage of chlorpyrifos was general factors.