海沧湖表层底泥污染物分布特征及污染评价

Distribution Characteristic and Evaluation of Surface Sediment Pollutant in Haicang Lake

底泥是湖泊水环境和水生态的重要组成部分,了解底泥污染情况对评估水环境质量及控制水生态风险具有重要指导意义。海沧湖是厦门市海沧新城的城市内湖,承担着排涝和景观功能。通过监测海沧湖表层底泥营养盐、有机质及重金属含量,分析了表层底泥污染物分布特征,并对表层底泥污染程度及潜在生态风险进行了评价。结果显示海沧湖表层底泥中总氮(TN)、总磷(TP)和有机质(OM)含量分布差异显著,均表现为东湖含量较南湖和北湖高。根据营养盐综合污染指数法和有机污染指数法评价结果,海沧湖表层底泥处于营养盐重度污染状态及有机污染状态,且东湖污染程度较南湖和北湖严重。海沧湖表层底泥中不同重金属含量及其分布特征有所差异,Cu、Zn、Cd和Hg在东湖含量较南湖和北湖高,Cr和Ni含量在全湖分布较为均匀,As和Pb则表现为全湖含量均较低,且东湖平均值低于南湖和北湖。地积累指数法评价结果显示海沧湖表层底泥中的重金属Cd和Hg在部分点位达到了中度~偏重度污染状态;潜在生态风险指数法评价结果显示海沧湖表层底泥平均处于重度潜在生态风险水平,最主要的风险因子为Hg和Cd;东湖的重金属污染程度及潜在生态风险水平均高于南湖和北湖。

Sediment plays an important role in water environment and water ecology.Investigating sediment pollution is of great significance for assessing water environmental quality and controlling water ecological risk.Haicang Lake is an urban lake in Xiamen City with functions of drainage and landscape.According to the investigation of the nu-trients,organic matter and heavy metals in surface sediment of Haicang Lake,the distribution characteristics was analyzed as well as the potential ecological risk.It was found that the contents distribution of TN,TP and OM were significant different.One in the East Haicang Lake was higher than in South and North Haicang Lake.According to the results of the nutrients comprehensive pollution index and the organic pollution index,there was serious nutrients pollution and the organic pollution in surface sediment of Haicang Lake.The pollution in East Haicang Lake was more severe than in South and North Haicang Lake.In terms of heavy metals,it showed different distribution char-acteristics with different elements.The contents of Cu,Zn,Cd and Hg in the East Haicang Lake were significantly higher than those in the South and North Haicang Lake.The contents of Cr and Ni were average distributed.The contents of As and Pb were at a low level and the average value in the East Haicang Lake was lower than the South and North Haicang Lake.The results of the geo-accumulation index method indicated that Cd and Hg were moder-ately polluted at some points;The results of potential ecological risk index method showed that the surface sediment of the lake was at a severe potential pollution.And Cd and Hg were the main risk factors;The heavy metals pollution and potential ecological risk were higher than the ones in South and North Haicang Lake.