中文摘要：

蟒蛇河是盐城市区主要的地表饮用水源地，其水质通常在Ⅳ～V类标准。为改善原水水质，中国首个平原上开挖的饮用水源生态净化湖——盐龙湖于2012年6月建成启用。通过水质监测，分析了近年来蟒蛇河原水水质及其污染特征，并对盐龙湖工程水质的净化效果进行了评价。研究表明：（1）蟒蛇河原水在春、秋、冬季水质主要指标基本能满足《地表水环境质量标准》（GB3838—2002）Ⅲ类标准，但夏季水质相对较差；（2）蟒蛇河原水呈现出典型的有机污染特征，营养盐类多是以有机形态存在，但TN与TP的主要污染来源并不一致，在不同季节原水污染特性存在波动规律；（3）近年来蟒蛇河原水中有机物及营养盐浓度有升高趋势；（4）盐龙湖工程水质净化效果在夏季最佳，春、秋季次之，冬季则一般；（5）近一年来，盐龙湖工程累计削减原水高锰酸盐指数、氨氮、TN、TP、SS的量分别达到56．6、35．6、59．8、8．9、1000．0t（干质量）。

英文摘要：

Mangshe River is one of the main sources of drinking water for Yancheng City,and its water quality is usually assessed between class IV to V standard. In order to improve the raw water quality,China＇s first artificial lake for drinking water source purification of the plain area,named as Yanlong Lake was built in June,2012. Based on long term monitoring,the raw water quality and the characteristics of Mangshe River were analyzed, and the water purification effect of Yanlong Lake project was evaluated. The result showed that： （1） the main indicators of the raw water of Mangshe River maintained ＂Environmental quality standard for surface water＂ Ill class quality in spring,au- tumn and winter,but deteriorated in summer; （2） the raw water of Mangshe River showed a typical organic pollution characteristic,the main pollution sources of TN and TP were different,and the pollution characteristics varied in dif- ferent seasons; （3） in recent years,the organic matter and nutrient salt of the raw water of Mangshe River showed a rising tendency; （4） the purification effect of Yanlong Lake could be sorted as summer〉autumn/spring〉winter; （5） on account of Yanlong Lake project, during the last year, the reduction amount of permanganate index, ammonia nitro gen,TN,TP and SS were 56.6,35.6,59.8,8.9,1 000.0 t （dry weight）,respectively.