赣江吉安河段水质变化及其趋势分析

Analysis on water quality variation trend in Ji’an section of Ganjiang River

基于吉安市水资源监测中心赣江吉安河段2008~2018年时间序列数据,采用单因子评价法、综合污染指数法和季节性肯达尔检验法,对该河段的地表水资源特性和水质趋势变化情况进行了分析研究。研究结果表明:①由基于年均值统计数据分析结果可以看出,赣江吉安河段历年水质总体较好,均优于或符合Ⅲ类水标准,达到了水功能区的目标要求;综合污染指数历年均控制在0.21~0.40之间,而且随着时间和空间的变化并没有表现出明显的变化,水质较平稳。②由基于月均值统计数据的分析结果可以看出,溶解氧、高锰酸盐指数指标趋于改善,五日生化需氧量无变化,氨氮和总磷两项指标趋于恶化,水质整体有变差的趋势。针对上述结果,通过探讨特征污染物的自然影响因素和人为影响因素,进一步分析了赣江吉安河段的水质污染成因。基于分析结果,建议后期应加强对赣江吉安河段的监管,以控制面源和点源污染。

Based on the time series data from 2008 to 2018 of Ji’an section of Ganjiang River obtained from Ji’an Water Resources Monitoring Centre,single factor evaluation method,comprehensive pollution index method and seasonal Kendall test method were adopted to analyze surface water resources characteristics and water quality variation trend in the river section.The results showed that:(1)According to the annual average statistical data,the water quality in Ji’an section of Ganjiang River was good,superior to or meeting classⅢwater standards,and the water quality of each functional area reached the target requirement;the comprehensive pollution index had been controlled between 0.21 and 0.40 over the years,with no significant change in time and space,and the water quality was relatively stable.(2)According to the monthly average statistical data,the indicators of dissolved oxygen and permanganate tended to be improved,BOD 5 remained unchanged,ammonia nitrogen and total phosphorus tended to deteriorate,and the water quality as a whole tended to deteriorate.In view of the above results,the causes of water pollution in Ji’an section of Ganjiang River were further analyzed by discussing the influencing factors of the natural and human pollutants.Based on the analysis results,it is suggested to strengthen the monitoring of Ji’an section of Ganjiang River to control non-point source and point source pollution.