白洋淀府河影响区沉积物营养盐和重金属污染特征及风险评价

Pollution Characteristics and Risk Assessment of Nutrients and Heavy Metals in Sediments of the Fuhe River Influenced Area, Baiyangdian Lake

根据府河入淀水流的扩散,将府河影响区分为6个片区,2020年10月分层采集48个样点的沉积物,测定并研究白洋淀府河影响区沉积物营养盐和重金属污染特征及风险.结果表明,研究区域沉积物中平均ω(TN)、ω(TP)和ω(TOC)分别为1841 mg·kg^(-1)、769 mg·kg^(-1)和1.77%.沉积物重金属污染的主要元素为Cd、Cu、Zn、Hg和Pb,分别是区域土壤背景值的3.73、1.50、1.42、1.31和1.31倍.由府河入淀区、南刘庄至下游枣林庄方向,沉积物中TP和重金属(Cd、Cu、Zn、Hg和Pb)含量呈现明显减少规律,而TN和TOC含量没有明显规律.沉积物中TN、TP、TOC和重金属(Cd、Cu、Zn、Hg和Pb)主要蓄积在表层0~10 cm.府河入淀、府河-南刘庄和南刘庄片区沉积物TP属于重度污染等级,王家寨和光淀片区沉积物TP属于中度污染等级,枣林庄片区沉积物TP属于轻度污染等级.Cd和Hg是重金属主要污染贡献因子,分别为较重污染和中等污染等级.府河入淀、府河-南刘庄和南刘庄片区沉积物重金属属于重度生态风险等级,王家寨和光淀片区属于中等生态风险等级,枣林庄片区属于低生态风险等级.重度生态风险等级区域的沉积物重金属浸出浓度低于浸出毒性鉴别标准值,清淤后可作一般废物处理.

Based on the flow direction of the Fuhe River into Baiyangdian Lake, the impacted area of the Fuhe River was divided into 6 subareas, and sediments from 48 sites were collected in November 2020. The characteristics and risks of sediment nutrients and heavy metal pollution in these six subareas were investigated. The results showed that the average ω(TN), ω(TP), and ω(TOC) were 1 841 mg·kg^(-1), 769 mg·kg^(-1), and 1.77%, respectively. The major heavy metals were Cd, Cu, Zn, Hg, and Pb, which were 3.73, 1.50, 1.42, 1.31, and 1.31 times the soil background values for Hebei Province, respectively. The TP and heavy metal(Cd, Cu, Zn, Hg, and Pb) content showed a decreasing trend from the Fuhe River estuary to the downstream Zaolinzhuang, whereas the TN and TOC content showed no marked trends. TN, TP, TOC, and heavy metals(Cd, Cu, Zn, Hg, and Pb) were enriched in surface sediments(0-10 cm). The TP content in the surface sediments(0-10 cm) of the Fuhe River estuary, Fuhe River estuary-Nanliuzhuang, and Nanliuzhuang subareas were heavily polluted;the Wangjiazhai and Guangdian subareas were moderately polluted;and the Zaolinzhuang subarea was slightly polluted. Cd and Hg were the major contributors to heavy metal pollution, which were at considerable risk and moderate risk levels, respectively. The heavy metals in surface sediments(0-10 cm) of the Fuhe River estuary, Fuhe River estuary-Nanliuzhuang, and Nanliuzhuang subareas were at a considerable risk level, and the sediments below 30 cm presented a low risk level. The leaching concentrations of heavy metals in sediments from the subarea of severe ecological risk level were far less than the identification standard values of leaching toxicity, suggesting that the sediments can be treated as general waste after dredging.