微生物降解四种农药的毒性效应

THE TOXIC EFFECTS OF AGRICULTURAL CHEMICALS AFTER DEGRADED BY MICROBES

为了解除草剂氯磺隆.甲磺隆、丁草胺和杀虫剂单甲脒经微生物降解后毒性有无变化,对环境是否造成危害,在分别以上述农药为碳源、氮源和能源的液体培养基中接种土样,振荡培养,以灭菌土样作对照,定时取样,经微孔滤膜抽滤后,以隆线蚤毒性试验和Ames试验、微核试验测其急性毒性和遗传毒性.结果表明,四种受试农药经微生物降解后,对水蚤的急性毒性均有所降低;氯磺隆、甲磺隆和单甲脒在微生物降解后,与降解前一样,均无致突变性;丁草胺在微生物作用过程中会产生诱变剂,但可继续被微生物降解而使其致突变性消失.对降解前后微生物混合种群的分离、鉴定表明,降解菌主要是假单胞菌.

In order to investigate the harmful effects to environment of tesed chemicals degraded by microbes, soil samples were inoculated and cultivated with oscillation in minimal medium containing tested chemicals as the sources of carbou, nitrogen and energy, with controls in which sterilized soil samples were inoculated. The samples were collected and filtered at regular intervals. Assays of water flea toxicity test, Ames test and micronucleus test were used to detect their acute toxicities and genetic toxicities before and afetr they were degraded by microbes. The results indicate that the toxicities of four tested chemicals were reduced after they were degraded by microbes. Butachlor showed mutagenic effect during the degradation by microbes. But these metabolites can be continually degraded and become nonmutagenic. The bacteria capable of degrading the agricultural chemicals are mainly pseudomonas.