沱江流域(自贡市)2013~2018年水质时空变化特征分析及评价

Spatial and Temporal Variation Characteristics of Water Quality in Tuojiang River Basin(Zigong City)from 2013 to 2018

为了解沱江流域(自贡市)2013~2018年水质变化情况,以沱江流域自贡市境内的9个国、省控断面的水质监测数据为依据,按照《地表水环境质量评价办法(试行)》(环办〔2011〕22号)中的评价方法对沱江流域(自贡市)水质时空变化特征进行了全面分析。结果表明,2013~2018年沱江流域(自贡市)的水质明显改善,总体水质从2013年的重度污染逐渐改善为2018年的轻度污染,改善了两个水质类别。2018年基本实现了劣Ⅴ类和Ⅴ类水质的消除。沱江流域(自贡市)的劣Ⅴ类和Ⅴ类水质断面主要集中在支流,其中碳研所断面(釜溪河,一级支流)、雷公滩断面(旭水河,二级支流)和廖家堰断面(威远河,二级支流)的水质状况最差。从主要污染指标来看,2013~2018年沱江流域(自贡市)水质主要污染指标涉及总磷(TP)、氨氮(NH 3-N)、化学需氧量(COD Cr)、高锰酸盐指数(COD Mn)、五日生化需氧量(BOD 5)、氟化物和石油类等七类。TP、NH 3-N、氟化物和石油类等污染指标浓度在个别监测断面呈显著下降趋势,支流的污染指标较复杂,而干流水质主要受TP影响。

In order to understand the water quality changes in the Tuojiang River Basin(Zigong City)from 2013 to 2018,based on the water quality monitoring data of nine national and provincial control sections in Zigong City,Tuojiang River Basin,according to the evaluation method of“Surface Water Environmental Quality Assessment Method(Trial)(Office of the Ministry of Environmental Protection Released[2011]No.22)”,this paper analyzed the temporal and spatial variation characteristics of water quality in the Tuojiang River Basin(Zigong City).The results showed that the water quality of the Tuojiang River Basin(Zigong City)improved significantly from 2013 to 2018,and the overall water quality gradually improved from heavy pollution in 2013 to mild pollution in 2018,improving two water quality categories.In 2018,the elimination of poor V and V water quality was basically achieved.The inferior V and V water quality sections of the Tuojiang River Basin(Zigong City)were mainly concentrated in the tributaries.Among them,the Carbon Research Institute section(Fuxi River,primary tributary),Leigongtan section(Xushui River,secondary tributary)and Liaojia weir section(Weiyuan River,secondary tributary)had the worst water quality.From the main pollution indicators,the main pollution indicators of water quality in the Tuojiang River Basin(Zigong City)in 2013~2018 included Total Phosphorus(TP),Ammonia Nitrogen(NH 3-N),Chemical Oxygen Demand(COD Cr),Permanganate Index(COD Mn),five-day Biochemical Oxygen Demand(BOD 5),Fluoride and Petroleum.TP,NH 3-N,Fluoride and Petroleum showed a significant downward trend in individual monitoring sections.The pollution indicators of tributaries were more complex,while the main stream water quality was mainly affected by TP.