| The average recovery rates of bifenthrin, fenpropathrin and cypermethrin in water and tea were determined by gas chromatography of HP6890 in this paper. Three kinds of concentrations as Img/L, 10mg/L, 100mg/L in water and 0.1mg/kg, 1.0mg/kg, 10.0mg/kg in tea respectively were devised for additive recovery experiments of these synthetic pyrethroid insecticides. The results showed the average recovery rates were between 95.47% and 103.21% in water and between 84.32% and 93.34% in tea while the former's variation coefficients were between 2.21% and 4.72% and the latter's were between 2.95% and 4.22%. The standard curves of bifenthrin, fenpropathrin and cypermethrin were yi = 106X! +106(R|2 = 0.9987), y2 = 106x2 + 619406 (R22 = 0.9976), y3 = 741527x3 + 686486 (R32 = 0.9982),respectively.Three bacterial strains named w10j15,t6f2 and clf6, which had high and stable degradation ability to bifenthrin, fenpropathrin and cypermethrin, were isolated from activated sludge (got from a pharmaceutical factory) and from tea leaves (got from tea garden pretreated by synthetic pyrethroid insecticides) by enrichment with enriched medium and minimal one. They were identified as Enterobacter cloacap, Pseudomonas fluorescens and Pseudomonas putida, respectively. The removal rates of bifenthrin, fenpropathrin and cypermethrin whose concentrations were the same as lOOmg/L by the third screened strains w10j15 were 52.43%,50.76% and 56.89%, t6f2 were 50.96%, 48.79% and 44.57%, and clf6 were 55.64%, 44.56% and 52.19%, respectively.The relationship curve about the growth of strains and the removal rate of pesticides showed w10j15, t6f2 and clf6 all grew in step with the degradation of bifenthrin, fenpropathrin and cypermethrin. Moreover, cultured on the plane-tables of minimal medium which were added only with pesticides as sole carbon sources, these strains grew well. All these indicated these strains were able to utilize these synthetic pyrethroid insecticides as sole carbon and energy sources.The effect of different environmental conditions on the degradation abilities of strains was determined. The result of degradation effect by stains to 30, 50, 100,200, 300,400, 500,600 mg/L 3 kinds of synthetic pyrethroid insecticides showed too high or too 10w pesticides concentrations were not favorable to the growth of strains, which resulted in the declination of degradation rates. The strain w10j15 had higher degradation rates when the pesticides concentrations were 50 and 100mg/L. Furthermore, the degradation rate was the highest at the concentration of 100mg/L. The strain t6f2 had better degradation effect when the pesticides concentrations were 50, 100 and 200mg/L. The strain c1f6 had higher degradation rates at the pesticides concentrations of 50 and 100mg/L than at the other ones.The degradation ve10cities to the 3 kinds of 100mg/L synthetic pyrethroid insecticides by the strains w10j15, t6f2 and clf6 almost increased harmoniously with the inoculation quantity. Considered from the degradation effect and degradation efficiency (that is the ratio of the degradation rates to inoculation quantity),the D415nm amount 0.1 for inoculation is suitable for both w10j15 and clf6 while D415nm amount 0.1 or 0.3 is suitable fort6f2.The effect of the different temperatures of 10,15,20,25,30,35,40 and 45 C on degradation efficiency indicated too high and too 10w temperature both inhibited the growth and degradation efficiency of 3 strains. The optimal temperatures for w10j 15 are between 30 and 35 C, for t6f2 are between 25 and 35 C while the suitable temperatures are between 20 and 35C and for clf6 are between 25 and 30C.The effect of the different pH of 4.0,5.0,6.0,7.0,8.0,9.0 and 10.0 on degradation efficiency showed that too high and too 10w pH both inhibited the growth of 3 strains, which resulted in the declination of degradation rates. The suitable pH for w10j15 were between 6.0 and 8.0, and the optimal pH was 7.0 or so, at which the degradation rates of 3 synthetic pyrethroid insecticides were all more than 50%. The s...
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