重庆园博园龙景湖的富营养化状态与水质分析

Analysis on Eutrophication and Water Quality of Longjing Lake in Chongqing Expo Garden

龙景湖位于重庆市北部新区园博园内,以自然降水为补给水源,在构建园博园景观、调节湖区小气候、改善周围生态环境、提供居民休闲等方面具有重要功能。为了及时掌握龙景湖水质变化情况,对水体中TN、TP、CODMn、Chla含量及水体透明度等进行监测分析,运用综合营养状态指数法对龙景湖营养状态进行评价。研究表明:龙景湖水体中TN、TP含量超标污染严重,Chla含量亦较高,其他指标处于正常景观用水范围内,水质总体处于轻度-中度富营养化范围。秋亭桥是全湖水质最差的地方。相关分析表明综合营养状态指数与透明度呈极显著负相关关系,与pH、溶解氧、CODMn、BOD5、Chla呈极显著正相关关系。开展监测以来,龙景湖水质明显恶化,治理工作刻不容缓,应从入湖污染源控制、湖水污染治理及管理工作三方面着手,采取综合治理措施。

Longjing Lake is located in Expo Garden of Chongqing＇ New North Zone, with natural precipitation as major water supply. It has important functions in constructing the landscape of Expo Garden, adjusting microclimate, improving ecological en- vironment and providing leisure sites to residents, etc. In order to determine the water quality changes of Longjing Lake, water quality indicators, including TN, TP, CODMn, Chla, transparency, etc. had been monitored and analyzed. Eutrophication as- sessment method was used to evaluate the eutrophy of Longjing Lake. The results showed that the content of TN and TP in Longjing Lake exceeded the GB 3838 -2002 standard, which indicates seriously water pollution. Chlorophyll a content was rela- tively high, while other indicators were in normal range for landscape water quality. The eutrophication range was between light and moderate. Qiuting Bridge had the lowest water quality among sampling sites. Comprehensive nutrition index and transparency were negatively correlated. Comprehensive nutrition index was positively correlated with pH, dissolved oxygen, CODMn, BOD5 and Chla. The water quality of Longjing Lake deteriorated remarkably, so the monitoring, management job admitted of no delay. People should take the comprehensive management measures, which contained pollution sources control, polluted water manage- ment and daily administration work.