中文摘要：

水体pH值是水体水化学特征的综合反映,是评价水质的重要指标之一,对水体酸化和富营养化等都有最直接响应。为弄清城市纳污河雨季径流pH值变化机理及其与水环境因子的响应关系,选取滇池第二大入湖河流宝象河为研究对象,结合流域土地利用类型,对雨季宝象河径流pH值及主要水环境指标展开系统监测和研究。研究结果表明：宝象河径流pH值空间特征为上游呈弱酸性,下游呈弱碱性,城市化程度越高,pH值越高;时间特征为雨季期间自上游向下游,人为干扰越明显,变化幅度越大;滇池宝象河径流水质参数指标和营养盐指标总体呈现出自河源到入湖口不断积累的过程;雨季滇池宝象河径流pH值与温度、溶解氧呈非常显著正相关,与BOD5呈显著正相关,与氧化还原电位呈非常显著负相关。研究结果可为快速城市化区域水资源及水环境保护提供参考和依据。

英文摘要：

pH value reflects the comprehensive chemical characteristics of water and it is an important assessment index of water quality,which has direct response to water acidification and eutrophication. To reveal pH variation mechanism of urban polluted river in rainy season and its response to water environmental factors,Baoxiang River,the second largest river in Dianchi Lake basin was taken as an example to carry out overall monitoring and study on pH value and the main environment indexes with consideration of land utilization type in the basin. The results show that：（1） The spatial characteristics of pH values in the Baoxiang River Basin are subacidity in the upper reaches,and alkalescence in the lower reaches. The pH values are higher in more urbanized regions. From upper stream to lower stream,the greater variation magnitude of pH value appears in more intensive human activity area during rainy season.（2） The water quality and nutrient indexes of the Baoxiang River present a trend of continuous accumulation from upstream to downstream gradually.（ 3） Correlation statistical analysis results present that pH values show a very significant positive correlation with temperature,dissolved oxygen,and positively correlation with BOD5,but very significant negative correlation with redox potential. The results can provide reference for water resources and water environment protection in the process of quick urbanization.