Assessing Methods for Effects of Small Amounts of Chemicals such as Pesticides on Soil Ecosystem

在此之前，我们建议进行实验室测试，以评估农药对土壤生态系统的副作用。通过五个实验室之间的“环测试”对测试中的“硝化活性”方法进行了评估。该方法效果良好，但需要考虑土壤的pH值、培养温度等因素。五氯酚(PCP)和苯磺隆(BSM)对土壤微生物群落的影响被成功地用苯二酮分析来评价。异戊二烯类苯二酚的含量与微生物生物量相关，大多数微生物含有一种主要的苯二酚，不受生理条件的影响。这些结果表明，苯二酚组成的差异直接反映了土壤微生物群落结构的差异，是评价农药对土壤生态系统影响的一种有价值的方法。Biolog法是一种独立于分离的方法来表征施药水稻土中的微生物区系。通过比较显色反应模式可以评价农药对土壤微生物区系的影响。通过对土壤DNA中16S rRNA的变性梯度凝胶电泳(DGGE)分析，评价了农药对土壤微生物，特别是对氨氧化细菌的影响。扩增结果得到证实，但DGGE分析尚未完成。通过对水稻土微生物群落的PCR-DGGE分析，揭示了群落结构的变化。微温分析用于评估农药对土壤微生物活性的影响，但对化学胁迫的敏感性不足以检测到这种影响。特别是在稻田条件下，热释放量太小，无法准确测量；需要对底物浓度等测试条件进行进一步检查。

Previously we proposed recommended laboratory tests for assessing the side effects of pesticides on soil ecosystem. The method for 'nitrification activity' among the tests was evaluated by a 'ring test' between five laboratories. The protocol worked just about right but it was recognized that a few points such as pH arrangement of soil and incubation temperature should be considered.Quinone analysis was successfully used to assess the effect of Pentachlorophenol (PCP) and Bensulfronmethyl (BSM) on soil microbial community. The content of isoprenoid quinones is correlated with the microbial biomass, and most of microorganisms contain one major quinone does not change by the physiological conditions. Those results indicate that the difference in quinone composition directly reflects the difference in structure of microbial community in soil, and the analysis is a valuable method for the assessing pesticide effects on soil ecosystem.The Biolog method was examined as an isolation-independent method to characterize microbial flora in paddy soil treated with pesticides. Comparing the colored response pattern could assess the effect of pesticides on soil microbial flora.Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA amplified by PCR from soil DNA was evaluated for the assessing pesticide effects on soil microbes, especially on ammonium oxidizing bacteria. The amplification was confirmed but DGGE analysis was not completed. PCR-DGGE analysis for paddy soil microbial community elucidated a change in the community structure.Micro-thermo analysis was applied to the assessing pesticide effects on soil microbial activity but the sensitivity against chemical stress was not enough to detect it. Especially in paddy condition, thermo evolution was too small to measure with practical precision ; further examination for testing conditions such as substrate concentration should be needed.