黄河三角洲滨海滩涂湿地沉积物重金属空间分布及生态风险评价

为了解黄河三角洲滨海滩涂湿地沉积物中重金属的污染程度，对黄河三角洲位于渤海湾、黄河口附近、莱州湾等滨海滩涂样地的表层沉积物中4种重金属（Cd、As、Cu、Pb）的含量及其空间分布进行研究，分析其含量与环境因子的相关性，并采用地累积指数和潜在生态风险指数评价其污染程度及生态风险.结果表明:表层沉积物中Cu、As、Cd、Pb的平均含量分别为14.36、7.92、0.20、16.24 mg/kg.不同样地间除Pb以外，其他3种重金属含量均差异显著，黄河口附近滩涂Cu含量高于非河口滨海滩涂，Cd含量呈南高北低的分布特征，As含量在渤海湾东侧滨海滩涂中较高.相关性分析显示，Cu、As、Pb来源相同或相近，Cd与Cu来源相同或相近，Cd与As来源不同；粒径 < 4 μm的沉积物含量与Cu、Pb、As含量均呈显著正相关，粒径为4~63 μm的沉积物含量与Cu、As含量均呈显著负相关.地累积指数评价表明，研究区Cd为轻度污染，其他重金属无污染；综合潜在生态风险指数分析表明，研究区重金属潜在生态风险指数（RI）介于59.21~158.63之间，平均值为107.71，属于低风险，黄河口附近及莱州湾滨海滩涂沉积物中重金属潜在生态风险高于渤海湾滨海滩涂.研究显示，黄河三角洲位于莱州湾及黄河口附近的滨海滩涂湿地沉积物中重金属的潜在生态风险需要重点防控. 

Distribution and Risk Assessment of Heavy Metals of Surface Sediments in Intertidal Flats of the Yellow River Delta, China

This study explored heavy metal pollutants in the intertidal flats of the Yellow River Delta. The contents and spatial distribution of four heavy metals (Cd, As, Cu and Pb) in the surface sediment samples collected from the coastal tidal flats in the Yellow River Delta were determined. The Pearson correlation for heavy metals and the environmental factors was analyzed. The geo-accumulation index and potential ecological risk index were used to estimate the degree of heavy metal contamination in the surface sediments. The results indicated that the average content of Cu, As, Cd and Pb in surface sediments was 14.36, 7.92, 0.20 and 16.24 mg/kg, respectively. There were significantly different in the content of Cu, As, and Cd between the different sample sites. There were no significantly different in the content of Pb between the different sample sites. The content of Cu in the tidal flats near the Yellow River Estuary was higher than that in Laizhou Bay and Bohai Bay, and the content of Cd in the tidal flats in Laizhou Bay was higher than that in Bohai Bay, and the content of As in the tidal flats in northeast of the Yellow River Delta was higher than that of the other sample sites. According to the correlation analysis, the sources of Cu, Pb and As were same or similar, and the sources of Cd and Cu were same or similar, while the sources of Cd and As were different. Clay particle content (< 4 μm) of the sediments were significantly positively correlated with the content of Cu, Pb and As. Silt particle content (4-63 μm) of the sediments were significantly negatively correlated with the content of Cu and As. The evaluation results of the geo-accumulation index showed that Cd pollution level was low and Cu, Pb and As were not polluted. The average potential ecological risk index (RI) of heavy metals was 107.71 (ranged from 59.21 to 158.63), indicating low ecological risk. The RI of heavy metals of surface sediments in the coastal tidal flats of the Yellow River Estuary and Laizhou Bay was higher than that of Bohai Bay. This study shows that the potential ecological risk of heavy metals in the sediments of the coastal tidal flats in the Yellow River Delta needs to be controlled, especially in Laizhou Bay and the Yellow River Estuary.