改进综合水质标识指数法在珠江口水系水质评价中的应用

Application of improved comprehensive water quality identification index method in water quality evaluation of the Pearl River Estuary

为了解珠江口水系近年来水质变化特征,基于2018—2020年51个采样点的逐月水质数据,运用主因子分析法对评价指标进行筛选,结合不同赋权法对传统综合水质标识指数法的权重进行改进,对珠江口水系河道水质进行了评价并分析了水质时空分布特征。结果表明:组合集成赋权的综合水质标识指数法综合了超标污染物和其他指标的客观权重,结果合理可信,适合于时空尺度大的流域水质评估;各河道水质呈现出逐年改善的趋势,由以劣Ⅴ类为主转变为以Ⅲ类为主,满足水环境功能区划目标;研究区西部地区河道水质整体略低于东部地区,西部地区南山片区河道水质优于大空港片区,但大空港和前海片区河道水质提升效果显著;河道上游水质总体较下游好,入海口水质随季节波动较大且普遍受海水污染和挡潮闸运行的影响。

To study the characteristics of water quality variation in the Pearl River Estuary during the recent years,the water quality in the Pearl River Estuary is evaluated and the tempo-spatial distribution characteristics of water quality is analyzed,based on data from 51 monthly collected water quality sampling points from 2018 to 2020,with evaluation indices filtered using principal factor analysis and improvement on traditional comprehensive water quality identification index method using combinatorial integration method.Results show that the comprehensive water quality identification index method combined with combinatorial integration method takes both excessive pollutants index and other indices into account,so as to obtain reasonable and reliable results,which means the method is suitable for large-scale watershed water quality assessment.The water qualities in all drainages tend to improve over the years,mainly from class of inferiorⅤtoⅢ,which met the water quality goals in water environment function zones.The water quality in the western regions was slightly worse than that in the eastern regions.The river water quality in the Nanshan district was better than that in the Dakonggang district,however the improvement in river water quality in Dakonggang and Qianhai district was more significant.The water quality of the upstream was generally better than that of the downstream.Estuary water quality fluctuates greatly with the seasons,which was generally affected by sea water pollution and the tidal sluice operations.