摘要
分析了三峡库区蓄水前后(1998～2009年)干流水质的变化及原因。结果表明,同蓄水前相比,蓄水后库区干流水质变好,库区干流断面月度达标率均值由蓄水前的62.3%变为蓄水后的78.3%,库区干流超标污染物主要为高锰酸盐指数、总磷、铅等。蓄水后水质时空分布出现新的特点,近坝水体悬浮物、浑样高锰酸盐指数、总磷、铅等可吸附污染物浓度显著降低。蓄水后年内悬浮物及浑样高锰酸盐指数、总磷和铅浓度仍然是丰水期>平、枯水期,但近坝水体不同水期间浓度差别比蓄水前明显减小。蓄水后,库区干流浑样高锰酸盐指数、总磷、铅浓度整体上表现为从库尾至库首沿程下降,尤以丰水期沿程下降最为突出。浑样高锰酸盐指数、总磷、铅浓度以上变化特征主要缘于库区水位抬高后,流速减小导致的澄清作用,即高锰酸盐指数所代表污染物、磷、铅等随泥沙发生了不同程度的沉降。蓄水前后清样高锰酸盐指数和总磷未发生明显变化,156m蓄水后至今,清样铅浓度明显低于蓄水前。
Water quality in the Yangtze River within the Three Gorges Reservoir area before and after the impoundment was analyzed. In general,water quality after the impoundment was better than that before the impoundment. Average percentage of water quality（according to monthly evaluation results）met or better than Ⅲ standard increased from 62.3% before the impoundment to 78.3% after the impoundment. The main parameters not meeting the standards were total phosphorus （TP）, permanganate index（CODMn）and plumbum（Pb）, etc. New characteristics in spatial and temporal distribution of water quality have been found. The concentrations of CODMn, TP, Pb of water column near the dam decreased significantly compared with that of pre-impoundment, especially for water area near the dam site. Concentrations of CODMn, TP,Pb were still wet season〉even,dry season. It is also showed that concentrations of the above parameters decreased along the direction from tail to head of the reservoir, especially in the wet season. Above changes of water quality features were mainly due to sedimentation of sands in the reservoir resulting from the increase of water level and the decrease of velocity,which meaned that part of pollutants settled with deposition of suspended solids and entered into sediment.
出处
《长江流域资源与环境》
CAS
CSSCI
CSCD
北大核心
2011年第3期305-310,共6页
Resources and Environment in the Yangtze Basin
基金
水利部公益性行业科研专项经费资助项目(200901013)
中国科学院知识创新工程重大项目(KZCX1-YW-08-01-01)
国务院三峡工程建设委员会办公室资助项目(SX2008-025)
关键词
三峡工程
建设期
干流
水质分析
蓄水前后
Three Gorges Project
construction period
the Yangtze River
water quality analysis
before and after impoundment
