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

在此之前，我们提出了评估农药对土壤生态系统副作用的实验室测试建议。试验中的“硝化活性”方法通过五个实验室之间的“环试验”进行评估。该方案工作大致正确，但认识到一些问题，如土壤的pH值排列和孵育温度应予以考虑。采用醌分析方法成功地评价了五氯酚（PCP）和甲磺隆（BSM）对土壤微生物群落的影响。类异戊二烯醌类化合物的含量与微生物生物量有关，并且大多数微生物含有的一种主要醌类化合物不随生理条件的变化而变化。结果表明，醌类成分的差异直接反映了土壤微生物群落结构的差异，为评价农药对土壤生态系统的影响提供了一种有价值的方法。研究了Biolog法作为一种独立于分离的方法来鉴定农药处理水稻土中微生物区系。通过比较颜色响应模式，可以评价农药对土壤微生物区系的影响。采用变性梯度凝胶电泳（DGGE）技术对土壤DNA中PCR扩增的16S rRNA进行分析，评价农药对土壤微生物特别是铵氧化菌的影响。扩增得到确认，但DGGE分析未完成。PCR-DGGE分析表明，水稻土微生物群落结构发生了变化。微热分析用于评价农药对土壤微生物活性的影响，但对化学胁迫的敏感性不够。特别是在水田条件下，热演化量太小，无法精确测量；需要进一步检查测试条件，如底物浓度。

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.