| The pollution of pesticides has become a serious global problem. The residual pesticides in food and environment exceeding standard are harmful to human being's health and food safety. This problem also brought a lot of enormous losses in the international trade. So it is important to strengthen the research on the examination technology and the degradation of the pesticides residue in food. Degradation of pesticides by microorganisms has been proved to be high-efficiency, thorough, and without secondary pollution, which makes it be one of the most important methods in pollution control.The rapid quantitative determination method of lambda-cyhalothrin in food was developed by high performance liquid chromatography. The best extraction effect was given when acetone-n-hexane , acetone- petroleum and acetone- petroleum was used as the extractant of lambda-cyhalothrin in water , in greengrocery or in fish respectively. The HPLC conditions were determined as follows: the mobile phase consisted of acetonitrile-water (v/v:80/20) and the detection wavelength was 230nm. The average recoveries were 97.93%～103.02% , 91.4%～113.9% and 89.58%～103.22% when the lambda-cyhalothrin concentration was in the range of 0.1～10 ppm respectively. Relative standard deviation was between 0.58% and 9.9%; The rapid quantitative determination method of cypermethrin in food was developed by high performance liquid chromatography. The best extraction effect was given when acetone-dichloromethane , acetone- petroleum and acetone- petroleum was used as the extractant of cypermethrin in water , in greengrocery or in fish respectively. The HPLC conditions were determined as follows: the mobile phase consisted of acetonitrile-water (v/v: 80/20) and the detection wavelength was 225 nm. The average recoveries were 100.72 % - 101.98 %, 98.6 % - 115.3 % and 87.21 % - 117.20 % when the cypermethrin concentration was in the range of 0.1-10 ppm. Relative standard deviation were between 3.46 % and 6.87 %; The rapid quantitative determination method of triazophos in food was developed by high performance liquid chromatography. The best extraction effect was given when ethyl acetate , ethyl acetate and acetone was used as the extractant of triazophos in water , greengrocery or in fish respectively. The HPLC conditions were determined as follows: the mobile phase consisted of acetonitrile-water (v/v: 80/20) and the detection wavelength was 230nm. The average recoveries were 97.93 %-103.02% , 91.4 % - 113.9 % and 89.58% - 103.22 % when the lambda-cyhalothrin concentration was in the range of 0.1 - 10 ppm. Relative standard deviation were between0.58 % and 9.9% . This method is easy operation and rapid, may play an important role in the food safety detection.In this study , degrading bacteria were obtained by isolation and screening from orchard soil and pesticide manufacture plant .Three bacterial strains F37, ML9 and TF413 capable of degrading lambda-cyhalothrin, cypermethrin and triazophos respectively were isolated from the effluent of a pesticide manufacture plant, while no efficiently degrading strains were isolated from the soil. The strain F37 was identified as Citrobacter braaki by using Biolog Microorganism Identification System. The degradation process of lambda-cyhalothrin was monitored accurately by HPLC. The optimum degradation conditions were 37℃and pH7.0. Biodegradation of lambda-cyhalothrin by strain F37 was ascribed to co-metabolism. The degradation rate reached 80.88% after 72-hour incubation when the initial concentration of lambda-cyhalothrin was 200mg/L.The strain ML9 was identified as Acinetobacter junii by using Biolog Microorganism Identification System. The degradation process of cypermethrin was monitored accurately by HPLC. The optimum degradation conditions were 32℃and pH 7.0. Biodegradation of cypermethrin by strain TF413 was ascribed to co-metabolism. The degradation rate reached 70.05% after 84-hour incubation when the initial concentration of cypermethrin was 400mg/ L.The strain TF413 was identified as Alcaligenes faecalis by using Biolog Microorganism Identification System. The degradation process of triazophos was monitored accurately by HPLC. The optimum degradation conditions were 32℃and pH 7.0. Biodegradation of triazophos by strain TF413 was ascribed to co-metabolism. The degradation rate reached 70.83% after 72-hour incubation when the initial concentration of triazophos was 40mg/ L.The residual degradation of lambda-cyhalothrin, cypermethrin and triazophos in pH5, pH7, pH9 water and sea water was studied here. The results showed that the degradation rate of the three pesticides in water was relative with the pH value, higher in alkaline water (81.943%, 61.775% and 89.671%) and lower in acid water (52.130%, 47.397% and 73.594%) after 45 days-treatment. The half-life values of lambda-cyhalothrin in the pH5, pH7, pH9 water and sea water were 40.77 days, 30.14 days, 16.95days and 32.70days, respectively. The half-life values of cypermethrin in the pH5, pH7, pH9 water and sea water were 41.04 days, 30.54 days, 20.82days and 33.49days, respectively. The half-life values of triazophos in the pH5, pH7, pH9 water and sea water were 22.95 days, 17.68 days, 13.89 days and 19.90days, respectively.
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