西藏羊卓雍错流域水体水质评价及主要污染因子

Assessment of water quality and the pollution factors of waters in Yamzhog Yumco Basin,Tibet

水质是流域生态系统的重要指标,水质评价则是开展流域水体污染防治等工作的基础.基于2010-2014年羊卓雍错流域湖泊、河流水质及2012-2014年流域居民饮用井水、自来水水质监测资料,结合单因子污染评价法和内梅罗污染指数法,对流域水质现状进行分析和评价.结果表明,12处地表水体中,羊卓雍错和巴纠错受中度污染,其他水体清洁或尚清洁,硒及氟化物为主要污染因子;9处居民饮用水体中,自来水水质明显好于井水,但也仅有3处自来水达清洁标准,硒、铝及硝酸盐为主要超标项.污染因子通过水-土-植被-动物系统破坏流域生态环境、阻碍农业生产发展,并直接或间接影响人类身体健康.因此,必须做好流域环境的综合整治、控制农业面源污染、完善饮用水基础设施建设,同时继续加强水质监测.

As a vital indicator of watershed ecosystem,water quality has essential implications for the development of the ecological environment and economic society. Meanwhile,water quality assessment provides indispensable support for the integrated control of water pollution. The water quality of surface waters（ i. e. lake and river waters） and drinking waters（ i. e. well and tap waters）has been investigated in Yamzhog Yumco Basin since 2010 and 2012,respectively. Based on the annual average data,the pollution factors of waters in Yamzhog Yumco Basin were analyzed by utilizing the single factor pollution evaluation method,and the present situation of water quality exerted as well with the Nemerow pollution index method. The analysis revealed that the Yamzhog Yum Co and the Bajiu Co are both moderately polluted,while the other 10 surface waters are clean or almost clean. Moreover,the selenium and fluoride contents are generally exceeded or close to the upper limit of the standard range. Two thirds of the nine drinking waters are polluted to different degrees with the selenium,aluminum,and nitrate as the main pollution factors. In addition,the quality of tap waters is much better than that of well waters. Water pollutants,through the water-soil-plant-animal system,could cause the destruction of ecological environment,hinder the sustainable development of agriculture,and finally threaten human＇s health. Therefore,in order to control and reduce the water pollution in Yamzhog Yumco Basin,it is necessary to renovate the basin environment comprehensively,control the agricultural non-point pollution,and improve the drinking water facilities.Meanwhile,further water quality monitoring is valuable in such process.