Study On Organophosphorous Pesticides Multiresidues In Edible Forest Products And Residual Degradation Of Chlorpyrifos In The Cultivation Of Pleurotus Ostreatus

The edible forest products is traditional export industry which plays an important role in improving the income of the farmers and providing the opportunity for the jobs. However, the problems of excessive pesticide residues perplex the healthy and steady development of the industry- of edible forest products. So it is necessary to build a rapid detecting method for pesticide residues in edible forest products, which contributes to controlling the quality and guiding the use of pesticides in edible forest products.Based on these practical issues above, the first aim of this paper is to optimize of different parameters of multiresidues method to determine Organophosphorus pesticides in edible forest products such as Kiwi fruit,Pleurotus ostreatus,Baboo shoot. Secondly, to research chlorpyrifos and its metabolites residues in the cultivation of Pleurotus ostreatus, the dissipation rate and final residues were studied.The main results were as following:1. A analytical method of organphosphorous pesticide residues in edible forest products was developed. Samples were extracted by acetonitrile and detected by gas chromatography with a flame phtometric detector. The external standard method was used for quantification. The average recoveries ranged from 56.87% to 115.20%, the relative standard deviations (RSD) were less 15%. The detectable limits were 11-36μg/kg for all pesticides. This method can separate efficiently and determine 20 kinds of organophosphorous pesticides in edible forest products. It's simple, sensitive and meets the requirement of pesticide residue analysis.2. The methods were developed to determine the residues of chlorpyrifos and its metablite in Pleurotus ostreatus and its substate. TCP was verified by liquid chromatography-mass spectrometry(LC-MS). Chlorpyrifos was determined by GC with FPD-detector, and its metabolite—3,5,6-tirchloro-2-pyridinol(TCP) was determined by HPLC with UV-detector. The average recoveries of method for chlorpyrifos in Pleurotus ostreatus and substrate were 87.68%-91.94% and 89.45%-95.14% with the RSDs were less 13.82%, the limit of quantification were 0.0025mg/kg and 0.01mg/kg, respectively; The average recoveries of method for TCP in Pleurotus ostreatus and substrate were 81.56%-93.67% and 68.28%-74.86% with the RSDs were less 7.64%, the limit of quantification were 0.025mg/kg and 0.05mg/kg, respectively. This method can meet the requirement of pesticide residue analysis.3. The dissipation rate and final residues of chlorpyrifos in the cultivation of Pleurotus ostreatus were studied. The result showed that half-lives of chlorpyrifos in inoculated substrate and no-inoculated substrate were 29d-37d, and 103d-105d , respectively. The primary metabolite of chlorpyrifos, 3,5,6-trichloropyridinol (TCP) was detected in inoculated substrate with sterilization and was at maximum on 3th day which decreased progressively to non-detectable level (NDL) on 186th day for all the treatment doses. The amount of residue in Pleurotus ostreatus were in the range of 0.0069-0.016mg/kg in the substrate spiked chlorpyrifos at 5-50mg/kg levels and there were no TCP being detected.