Study on stable isotope ratio of environmental pollutants behavior in agricultural ecosystem

研究非农业领域污染物对农业生产领域的影响是一个十分重要和迫切的研究课题。此外，许多污染物（甲烷、硝酸根离子等）从农田中爆发出来。第一年对同位素比值（^<15>N，^<34>S，^<18>O）分析技术进行了研究和培训。建立了研究点，收集农作物（水稻、小麦、豆类等），在第二年进行了连续地下水采样和离子组分分析，研究了稻田甲烷气体的爆发机理和酸雨的传输过程。第三年对第二年的研究对象进行了更详细的研究。研究结果如下：（1）土壤中硝酸盐浓度随季节变化，主要取决于化肥施用量、堆肥施用量和生活污水施用量。(2)硫酸亚铁和硫酸铵对稻田甲烷的爆发有抑制作用。(3)对日本和中国大陆的酸雨进行了收集和分析。其中硫酸根离子浓度最高，硫酸根离子和硝酸根离子在森林雨中的浓度也很高。(4)大气中多环芳烃的沉降量取决于收集点，随着远离生成点，沉降量逐渐减少。多环芳烃在森林降雨中的降水量高于林外降雨，实用的微量同位素比值分析是环境化学污染物示踪研究的一种非常有用的分析方法

Research on influence of pollutants from non agricultural field to agricultural production fields is a very important and urgent research theme. Also, many pollutants breakout from agricultural fields (methane, nitrate ion, etc.). Establishment of a elimination method of these pollutants is very important.Analysis technics of isotope ratio (^<15>N,^<34>S,^<18>O) was discussed and trained as research during the first year. Research sites were set up, collection of agricultural crops (rice, wheat, beans etc.), continuous under ground water sampling and ion components analysis of it, outbreak mechanisms of methane gas from paddy field and transportation process of acid precipitation (acid rain) were researched in the 2nd research year. More detail study on the 2nd year research subjects were done in the 3rd research year. Research abstracts are as follows : (1) Nitrate ion concentration was changeable with seasons, depending on how much of chemical fertilizers is used and composts for crop production and waste water from housing sites. (2) Methane outbreak from paddy field was inhibited with ferrous and ammonium sulfate. (3) Acid rain of Japan and main land China were collected and analyzed. Sulfate ion concentration was most high and sulfate ion and nitrate ion in the forest rain was recognized as having very high concentration. (4) Precipitation amount of polyaromatic hydrocarbons from the atmosphere depended on collection point and these amounts gradually decreased with distance from the generation point. Precipitation amount of polyaromatic hydrocarbon in the forest rain was higher than outside rain of forest.Practiced minuteness isotope ratio analysis is distinctively a very useful analysis method for tracing study of environmental chemical pollutants