浐河、涝河河水硝酸盐氮污染来源的氮同位素示踪

通过分析河水和工业污染水体硝酸盐氮同位素组成,对西安市周边主要河流浐河和涝河的硝酸盐污染源进行了初步研究.结果发现,浐河、涝河从上游至下游,河水硝酸盐氮同位素组成δ15N-NO3-值呈逐渐升高的趋势(1.3‰～9.0‰和3.3‰～7.4‰),而沿河流域2个工业排污口废水样的δ15N-NO3-值为:11.5‰和11.1‰.不同来源的硝酸盐氮同位素表现出明显的差别,工业排污可能是该河流硝酸盐氮浓度增高主要原因之一.相对于河水硝酸盐浓度变化,河水中硝酸盐氮同位素能够作为示踪水系硝酸盐氮污染来源和过程的可靠手段.同时,本研究大致区分了浐河和涝河流域主要的氮源输入,为研究硝酸盐污染,营养元素流失提供了重要的信息.

Using Nitrate Isotope to Trace the Nitrogen Pollution in Chanhe and Laohe River

Nitrogen isotope tracing method was used to identify the dominate contamination source of Chanhe River and Laohe River. The results showed that the delta15N-NO3- values of Chanhe and Laohe River from upper to lower stream were 1.34 per thousand to 9.0 per thousand and 3.3 per thousand to 7.4 per thousand, respectively. And the delta15 N values of the sewage samples were 11.5 per thousand and 11.1 per thousand. Through comparing the upper and lower stream delta15N value with the sewage sample, this research found that nitrate isotope indicated the contamination sources, and the nitrate isotope value could provide more valuable messages relative to the nitrate concentration. Meanwhile, this research approximately divided the main nitrogen source in different river drainage areas. These results can offer important information for investigating the nitrate pollution and nutrient runoff in this area.