不同水质评价方法在南水北调东线断面的研究与应用

Study and Application of Different Water Quality Assessment Methods in the Section of Eastern Route of South-to-North Water Diversion Project

以2019年南水北调东线工程12个水质监测断面为研究对象,选取溶解氧、高锰酸盐指数、氨氮、总磷、重金属(铜、锌、铅、镉)、粪大肠菌群等9个参评指标的监测结果,采用单因子评价法、内梅罗指数法、综合水质标识指数法和模糊综合矩阵评价法4种水质评价方法对12个断面水质情况进行评价分析。结果表明,12个断面的水质情况较好,老山乡断面(湖库)采用单因子评价法的水质评价结果为Ⅴ类,主要超标因子为总磷,其他断面水质采用4种方法的评价结果均为Ⅲ类或Ⅱ类。相对其他3种方法而言,单因子评价法计算简单,考核标准严格,得出的水质类别整体最差。在具体应用实践中,应根据评价目的和断面功能,采用较为合适的评价方法,为南水北调水环境管理提供更加客观的依据。

Taking 12 water quality monitoring sections of the eastern route of the South-to-North Water Diversion Project as the research object,according to the monitoring results of 9 indexes such as dissolved oxygen,permanganate index,ammonia nitrogen,total phosphorus,heavy metals(copper,zinc,lead and cadmium)and fecal coliform group,four water quality evaluation methods such as single factor evaluation method,Nemero index method,comprehensive water quality identification index method and fuzzy comprehensive matrix evaluation method are used to evaluate and analyze the water quality of 12 sections.The results show that the water quality of 12 sections is good.The water quality of Laoshan Township section(Lake and reservoir)is identified as class V using the single factor evaluation method,and the main exceeding factor is total phosphorus.The water quality of other sections was evaluated as Class III or Class II using either of the four methods.Compared with the other three methods,the single-factor evaluation method is simple to calculate,and the water quality category obtained is the worst overall due to its strict assessment standard.In the specific application practice,a more appropriate evaluation method should be adopted according to the evaluation purpose and section function,so as to provide a more objective basis for the environmental management of the South-to-North Water Diversion.