北江干流清远段近10a水质综合评价及变化趋势

Water Quality Status and Change Trend of Qingyuan Section of Beijiang River in the Past 10 Years

为明确北江干流清远段近10 a水质状况和变化趋势,选取了6个断面9项水质指标进行了分析,结果表明:单因子评价北江干流清远段5/6的断面水质类别较好,Ⅰ-Ⅲ类水比例达到80%以上。断面水质类别比例法表明河段水质状况有8年次为优或良好;2018和2019年为轻-中度污染。综合污染评价中,白石窑水库多数年份出现了污染或重污染,其余断面基本满足Ⅱ类水功能区标准。水库断面长期存在TP超标,TP浓度波动具有中等变异性。秩相关系数法趋势性检验表明,DO、BOD_(5)、TP和Cu变化趋势不显著,COD_(Mn)、NH_(4)^(+)-N和Zn具有明显变化趋势。

In order to clarify the water quality status and change trend of the Qingyuan section of the Beijiang River main stream in the past 10 years,9 water quality indicators of 6 stations were analyzed.The results show that 5/6 of the stations in the Qingyuan section of the Beijiang River are relatively good,and the proportion of class Ⅰ-Ⅲ water is more than 80%.Water quality is excellent or good in 80%of the years;light-moderate pollution in 2018 and 2019.In the comprehensive pollution evaluation,Baishyao Reservoir has pollution or heavy pollution in most years,and the other sections basically meet the standards of class Ⅱ water functional zones.The reservoir section exceeds the standard for a long time,and the fluctuation of total phosphorus concentration has medium variability.The trend test showed that the change trend of DO,BOD_(5),TP and Cu was not significant,while the three indexes of COD_(Mn),NH_(4)^(+)-N and Zn showed a significant change trend.