雄安新区白洋淀表层沉积物重金属地球化学特征及生态风险评价

【研究目的】白洋淀为雄安新区核心生态功能区，为支撑白洋淀湿地生态修复与保护，系统开展了全淀区表层沉积物环境质量调查。【研究方法】在白洋淀湿地采集表层沉积物样品484组，查明了白洋淀表层沉积物重金属地球化学特征，并采用地累积指数法、潜在生态风险指数法等多种方法开展了重金属生态风险评价。【研究结果】白洋淀表层沉积物重金属含量普遍偏高于河北省表层土壤重金属含量背景值，府河入淀口及白沟引河入淀口为重金属元素主要富集区，入淀河流输入为白洋淀重金属主要来源；环境地球化学综合评价结果为清洁无污染等级分布面积144.54 km²，占表层沉积物分布总面积的96.68%；各重金属污染程度由重到轻排序为Cd＞Cu＞Hg＞Pb＞Zn＞Ni＞Cr＞As，Cd元素污染程度等级以中度和偏中度为主，Cu元素以轻度和清洁为主，其他元素以清洁无污染为主；重金属潜在生态风险以轻度和中度为主，河流入淀口所在淀区重金属潜在生态风险高于其他淀区，潜在生态风险由高到低排序为南刘庄＞烧车淀＞小白洋淀＞王家寨＞藻苲淀＞捞王淀＞池鱼淀＞泛鱼淀。【结论】白洋淀表层沉积物环境质量总体较好，南刘庄等局部淀区存在重金属污染潜在生态风险，以Cd元素污染最为突出。创新点：采用地累积指数法、潜在生态风险指数法等多种方法，系统评价白洋淀湿地表层沉积物重金属污染程度和生态风险；重金属地球化学特征分析与主成分分析法相结合，揭示表层沉积物重金属污染主要来源为河流输入。

Geochemical characteristics and ecological risk assessment of heavy metals in surface sediments of Baiyangdian Lake, Xiong'an New Area

This peper is the result of environmental geological survry engineering.Objective] Baiyangdian Lake(BYD Lake)is the main ecological function area of Xiong''an New Area. In order to provide support for ecological restoration and protection of BYD Lake, we conducted a comprehensive survey on the environmental quality of the surface sediments in BYD Lake.Methods] We collected 484 sets of surface sediment samples from Baiyangdian wetland, identified the geochemical characteristics of heavy metals in surface sediments of Baiyangdian lake, and used multiple methods such as geo- accumulation index method and potential ecological risk index method to evaluate the ecological risk of heavy metals.Results] The results indicate that the average content of most heavy metal elements in the surface sediments of BYD Lake is significantly higher than the soil background value in Hebei Province. The entrance of Fuhe river and Baigou river are the main rich areas of heavy metal elements, rivers are the main sources of heavy metals in the surface sediments of BYD Lake. The distribution area of clean and pollution-free grade is 144.54 km², accounting for 96.68% of the total surface sediment distribution area. The pollution degree of each heavy metal can be ranked as Cd > Cu > Hg > Pb > Zn > Ni > Cr > As. The pollution degree of Cd is mainly moderate, the pollution degree of Cu is mainly light and clean, and the pollution degrees of other elements are mainly clean and pollution-free. The potential ecological risk of heavy metals in the surface sediments of BYD Lake is mainly mild and moderate, and the potential ecological risk level of heavy metals near the river entrance is higher than that of other areas. The potential ecological risk levels can be ranked as Nanliuzhuang > Shaochedian > Xiaobaiyangdian > Wangjiazhai > Zaozhadian > Laowangdian > Chiyudian > Fanyudian.Conclusions] The environmental quality of the surface sediments in BYD Lake is generally good, with heavy metals exceeding the standard in some areas. The environmental quality of surface sediments in Baiyangdian is generally good. There are potential ecological risks of heavy metal pollution in Nanliuzhuang and other areas, and Cd is the main pollution element.Highlights: Geo- accumulation index method and potential ecological risk index method were used to evaluate the heavy metal pollution degree and ecological risk of surface sediments in Baiyangdian Wetland. The analysis of heavy metal geochemical characteristics combined with principal component analysis revealed that the heavy metal pollution in surface sediments were mainly from river input.