The fact that the nitrate contents in water body and its percentage rate in DIN are a bit high shows not only the inputting effects of the nitrogenous compounds from the land, but also the purifying results of the nitrogenous organic matter during the chemical purification process. 水体中硝酸盐含量及其所占DIN的百分比值较高,既体现了陆源含氮化合物的输入影响,也体现了含氮有机物在化学净化过程中的净化效果;