Induction, Isolation And Degradation Effects Of Organophosphorous Insecticides Degrading Microorganisms

Chlopyrifos residues in soils were determined by gas chromatography. The average recovery rates were 90.2%, 95.0%and 94.0 in 1, 10 and 100mg/kg chlopyrifos respectively. And their variation coefficients were between 2.5 and 3.3%. The average recovery rates were 87.8%, 90.3% and 91.6% in 0.1, 1.0 and 10mg/kg methamidophos respectively. And their variation coefficients were between 3.1 and 4.2%. The average recovery rates were between 91.7% and 99.2% in different concentrations of chlopyrifos and methamidophos in water. The standard curve of chlopyrifos was Y=398421+2530507x (R=0.9998), and that of methamidophos was Y=-272561.1+2720306x (R=0.9917).The degradation of chlopyrifos was very slow in sterilized soils, but very quick in soils, which were previously treated with chlopyrifos. However, the degradation rate was between the rates mentioned-above, in unsteritized and untreated soils 30 days after being treated with chlopyrifos.Compared to the soils without treated with chlopyrifos, the number of bacteria and fungi were somewhat increased within a short period after treated with chlopyrifos at the concentration of 50mg/kg or 500mg/kg, and recovered to the normal level in 60 days later. But when treated with 5000mg/kg chlopyrifos, the growth of bacteria and fungi were inhibited so strongly that it couldn't recover even in 60 days. Under the same treatment condition, the number of bacteria or fungi was not different in soils, which pretreated with or without chlopyrifos. The results of methamidophos effect to the number of bacteria and fungi were similar with chlopyrifos.In the soils pretreated with chlopyrifos 60 days ago, the degradation rates of 50mg/kg chlopyrifos were the same as those in the soils pretreated with chlopyrifos 30 days ago. The degradation rate of chlopyrifos in the d soil was still rapid than that in the ck soil and s soil, but the difference become smaller 90 days after pretreatment. The degradation rate of chlopyrifos in the d soil was almost the same as that in the ck soil 120 days after pretreated with chlopyrifos.30 days after treated with chlopyrifos, 0.1%, 1%, 10% d soil were added to the s soil respectively, where the degradation rates of chlopyrifos increased at various degrees compared with the s soil.Five fungi strains were isolated from the soil pretreated with chlorpyrifos. They were identified as AspergillusY Micheli, Trichoderma Pers.ex Fr, Penicillium Link. Species, and named as Aspergillus Y, Trichoderma Y. PenicilliumY, PenicilliwriY1 and PenicilliumY2.IIITwo bacteria strains were isolated from the soil pretreated with chlorpyrifos. And Identified as Alcaligenes faecalis and Staphylococcus capitis.AspergillusY could degrade methamidophos when 5000mg/L or 1000mg/L methomidophos was used as sole carbon sources, but couldn't degrade to methamidophos when 500mg/L or 100 mg/L methomidophos was used as sole carbon sources. AspergillusY could degrade to chlopyrifos when 5000mg/L or lOOOmg/L methomidophos was used as sole carbon sources, but couldn't degrade to chlopyrifos when 500mg/L or lOOmg/L chlopyrifos was used as sole carbon sources.The degradation effect of AspergillusY, PenicilliwriY and Staphylococcus capitis to chlopyrifos and methamidophos when chlopyrifos and methamidophos were used as sole carbon sources was determined by GC. The results showed that they were little or even no effect at all. But the degradation effects were increased greatly when some carbon sources were added. The degradation effect of fungi to chlopyrifos and methamidophos was the best when adding 2g/100ml sugar. And that of bacteria was best when added Ig/100ml sugar.The degrading ability of all fungi and bacteria to chlopyrifos were increased with the temperature going up at the range of 8-28C. And the degradation effects of fungi were increased with their concentrations going up.The results also showed that the degradation effects of fungi and bacteria to chlopyrifos were different at different chlopyrifos concentrations. The degradation effect was better to 50 mg/...