硅藻指数筛选及水质多指标评价体系构建

为了更科学地监测水质,解决水质理化分析的片面性,在柳江的不同水功能区设置实验点,以构建河水质的多指标评价体系。通过不同水功能区及不同水质等级的实验点的对应分析,认定AMIN,GOLI,DDEL,AMSA,ACLI,NAAN,NRHY等是柳江河流清洁种,菱形藻和端泥生藻是柳江耐污种。典型对应分析表明,河流水质参数是影响硅藻群落分布的主要因素,硝酸盐、氯化物、粪大肠杆菌群和总磷等是主要的变量,因子分析的结果亦表明理化参数是主要变量。研究结果表明,理化变量与硅藻指数IPS,IBD,TID,IDG,SLA的关系紧密,依据水功能区长期水质级别并参考水质参数聚类与硅藻种群聚类,划出3组水质不同的类别,IPS,IBD,CEE硅藻指数对该3组水质状况判别效果较好,而硅藻生物多样性指数不适宜评价柳江河流水质。河流水质及生态质量利用IBD和IPS生物指数、VAN类群划分富营养种百分比及理化参数多指标共同评价,可以提高评价结果的可靠度。

Diatom Index Screening and Multi-index System to Assess Water Quality

Experiment points were set up in Liujiang river and a multi-index system of diatom is built up in order to effectively monitor water quality and improve physicochemical analysis.According to the results of correspondence analysis in different water functional zones of different water quality,AMIN,GOLI,DDEL,AMSA,ACLI,NAAN and NRHY are classified as clean species in the Liujiang river whereas Nitzschia and Luticola are stain species.Ca-nonical correspondence analysis shows that the river water quality parameters are the main factors affecting the dis-tribution of diatom communities.Nitrates,chlorides,total number of Fecal coliform and total phosphorus are the main variables,and physicochemical parameters are main variables based on the results of factor analysis.The re-sults show that physicochemical variables are closely related with diatom indices IPS,IBD,TID,IDG and SLA.Ac-cording to the water quality level from long-term monitoring and the data about clustering of water quality parameters and diatoms population,they are classified into three different water quality categories.IPS,IBD and CEE work well on the evaluation of water quality of the three categories while the diatom’s bio-diversity index are unsuitable for the evaluation.Through biological indices IBD and IPS,and VAN groups to divide eutrophic species percenta-ges and physicochemical parameters,multi-index evaluation can be used to evaluate the quality of river water and ecological quality in order to improve the reliability of the evaluation.