滇池流域地下水硝酸盐污染特征及影响因素研究

Groundwater Nitrate Pollution and the Influencing Factors in Dianchi Watershed

在滇池流域5个功能区采集了41个地下水的水样,对其硝酸盐含量状况进行分析。结果表明,滇池流域浅层地下水位硝酸盐含量高于深层地下水位,地下水硝酸盐含量变化范围为0.3~326 mg.L-1,平均含量为26.93 mg.L-1,已超出国家饮用水卫生标准,不同功能区对地下水硝酸盐含量影响的大小顺序为:蔬菜-花卉种植区>传统农作物种植区>城郊结合部>工矿区>昆明市主城区。分析氮肥投入量、地下水位深度等因素对污染地下水硝酸盐的影响可知,氮肥投入量和地下水中硝酸盐含量呈明显正相关。

Nitrate content of 41 groundwater samples collected from main function area of Dianchi Lake valley were studied.The result showed that the NO^(-)_(3)content of groundwater from different function area of Dianchi Lake valley varied from 0.3 to 326 mg·L^(-1),with an average value of 26.93 mg·L^(-1),which exceeded the Chinese drinking water standard.The nitrate pollution was serious in agricultural area and the content of NO^(-)_(3)exceeded the Groundwater Criterion V of China.The effect of different function areas in Dianchi Lake on the content of NO^(-)_(3)was as following: vegetable-flower area>traditional crop area>suburb>work area>main city zone of Kunming.There existed a significant positive correlation between the application of N fertilizer and the content of nitrate,the correlation coefficient being 0.9653.Depth of groundwater also affected the content of NO^(-)_(3),and the content of nitrate in shallow layer was higher than that in deep layer.When the depth of groundwater was over 15 m,the content of nitrate maintained normal; when it was below 10 m,the average value of nitrate reached 59.56 mg·L^(-1 )that could pollute the water body.Some suggestions were put forward to avoid the pollution of groundwater in Dianchi Lake.