An organophosphorus pesticide, ethoprophos, has been widely used in agriculture to control major insect pests. As ethoprophos is a well-known neurotoxin, its accumulation in soils and groundwater is concerning worldwide. In this study, we constructed an artificial ethoprophos-enrichment soil system, and its active concentration in soils was measured by gas chromatography on 15-days intervals during 90 days after ethoprophos treatment. Furthermore, the changes in bacterial community and microorganisms responsible for efficient bioremediation were investigated while ethoprophos was degraded in soils. From 15 to 60 days after the treatment, ethoprophos was actively degraded in soils and members of genera Collimonas and Sphingobium appeared dominantly in a natural microbial community especially in 60-days-after-treatment soil. We isolated a bacterium EP60845 from this soil sample, showing significant ethoprophos biodegradation activity in vitro. When we challenged EP60845 strain into ethoprophos-enrichment soils (250 mg/kg of soil), most ethoprophos was removed within 5-days. Phylogenetic 16S rRNA gene sequence analysis and biochemical properties by API 20GN kit demonstrated that the EP60845 strain was a novel Sphingobium sp., which could be used as an efficient ethoprophos- degrading agents for bioremediation purposes.

야외에서 채집한 거세미나방(Agrotis fucosa Butler) 1~6령충에 대한 5개 토양살충제를 국소처리하여 LD50치를 구하여 령충별 독성과 내성을 비교 검토하였다. 유충의 령기가 진행됨에 따라 LD50치가 현저히 증가하였으며 그 차이는 약제의 종류에 따라 차이가 현저하였는데 그 독성은 phoxim (Volaton®)이 가장 높았고 다음이 carbofuran(Curaterr®), chlorpyrifos (Dursban®) Mocap, diazinon의 순위였다. 그리고 1~2령충까지의 LD50치는 비교적 낮았으나 3령충부터 LD50치는 급격히 증가하였다. (2) 령충별 내성비(2~6령충의 LD50/1령충의의 LD50)에 있어서 phoxim은 11.1~251.6배, diazinon은 1.2~126.6배, chlorpyrifos는 4.3~97.5배, carbofuran은 1.6~44.3배, Mocap은 11.5~18.7배로서 령기가 진행됨에 따라 약제에 대한 내성이 크게 증가하였으며 그 정도는 약제의 종류에 따라 차이가 있었다. (3) diazinon에 대비한 phoxim, carbofuran, chlorpyrifos, Mocap의 령충별 독성비는 3령충까지는 낮거나 높아 일관성이 없었으나 4령에서 6령까지는 대조약제 diazinon에 비하여 모드 높은 독성비를 나타내었다. 1령충에서 6령충까지의 평균 독성비(각 령충별 LD50치 기준)는 diazinon에 대하여 phoxim은 5.2배 carbofuran은 1.9배 chlorpyrifos는 1.7배, Mocap은 1.1배 이었다.