贵港市近十年主要河流水质评价及变化趋势分析

Water quality evaluation and change trend analysis for main rivers of Guigang City in the last 10 years

依据2013—2022年贵港市主要河流水质监测数据,应用季节性肯达尔趋势分析法、平均污染指数法、营养状态指数法对贵港市主要河流近10年水质进行趋势分析,以期总结区域性的水质污染特征,为贵港市水资源保护提供水文技术支撑。结果表明:2013—2022年贵港市主要河流水质总体趋势向好,多年平均水质类别为Ⅱ类,水质优良,多年平均污染指数为0.145,为清洁水体。从分析的指标看,pH、溶解氧的上升趋势最为明显,氰化物和挥发性酚的下降趋势最为显著,贵港市主城区废污水排放对郁江的水质影响最大,武思江流域水质变化趋势向好,鲤鱼江流域水质有所恶化。

Based on the water quality monitoring data of main rivers in Guigang City from 2013 to 2022,analysis was made on the water quality trends of these rivers in the last 10 years by seasonal Kendall trend analysis method,aver-age pollution index method and nutrient status index method,so as to summarize the regional water quality pollution characteristics and provide hydrological technical supports for water resources protection in Guigang City.The re-sults of analysis demonstrate the overall trend of water quality of main rivers in Guigang City was improving from 2013 to 2022;the water quality was good with a mean annual water quality of II class;the water was clean with a mean annual pollution index of 0.145.The pH value and dissolved oxygen index showed the most obvious upward trend.The downward trend of cyanide and volatile phenols was most significant.The discharge of wastewater and sewage in the main urban area of Guigang City had the greatest impact on the water quality of the Yujiang River.The trend of water quality change in the Wusijiang River Basin was improving.The water quality in the Liyujiang River Basin had deteriorated.