黄河三角洲滨海湿地表层沉积物重金属区域分布及生态风险评价

对黄河三角洲滨海湿地表层沉积物重金属含量变化区域分布特征进行了分析,探讨了沉积环境对重金属分布的影响,采用Hakanson潜在生态风险指数法综合评价了黄河三角洲滨海湿地沉积物中重金属污染状况和潜在风险程度.结果表明,黄河三角洲滨海湿地表层沉积物Hg、Cu、Pb、Zn、Cd和Cr的均值分别为0.034、18.733、19.393、65.317、0.235和62.940μg.g-1.黄河三角洲滨海湿地重金属分布存在区域差异,现行河口区重金属含量最高,鲁北古代黄河三角洲区重金属含量次之,废弃河口区为最低.重金属区域分布受水动力条件的影响显著,黏土含量对重金属的富集和分布也起到一定控制作用.黄河三角洲滨海湿地表层沉积物质量状况良好,综合污染指数为0.10～4.14,处于低污染状态,Cr是主要污染因子,均值为0.63.6种污染物的污染程度由高到低的顺序为Cr>Cu>Zn>Cd>Pb>Hg.综合潜在生态风险指数介于0.46～51.88之间,具有较低的潜在生态风险.6种污染物潜在生态风险参数由大到小顺序为Cd>Hg>Cu>Cr>Pb>Zn,Cd是黄河三角洲的主要潜在生态风险因子.

Regional Distribution and Ecological Risk Evaluation of Heavy Metals in Surface Sediments from Coastal Wetlands of the Yellow River Delta

Characteristics of heavy metal distributions in surface sediments of different areas in the Yellow River Delta coastal wetland are analyzed, and the influences of sediment environment on heavy metal distributions are discussed. Heavy metal pollution and potential ecological risk in surface sediments of the Yellow River Delta coastal wetland are estimated by using Hakanson potential ecological risk (PER) factors method. The analyzed results indicate that the average contents of Hg, Cu, Pb, Zn, Cd and Cr are 0.034, 18.733, 19.393, 65.317, 0.235 and 62.940 microg x g(-1), respectively. The heavy metal distributions vary with regional environment changes. The accumulating index of heavy metals in the current outfall area is the highest of the three regions assigned by author,the second is that of the ancient Yellow River Delta in the north of Shandong province, and the lowest is that of the abandoned delta. Heavy metal distributions in the Yellow River Delta coastal wetland are affected significantly by hydrodynamic system. In addition, the content of clay in surface sediments plays an important role in the distribution and accumulation of heavy metals. The results also suggest that the heavy metal pollution in the Yellow River Delta coastal wetland is in a low pollution level, with a comprehensive pollution index varying from 0.10 to 4.14. And element Cr is the major pollution factor and its average of single pollution index is 0.63. The order of pollution extents of six typical pollutants is Cr > Cu > Zn > Cd > Pb > Hg. The comprehensive potential ecological risk index is between 0.46 and 51.88, indicating a low potential ecological risk. The order of potential ecological risk parameter is Cd > Hg > Cu > Cr > Pb > Zn. Element Cd is also the major factor of potential ecological risks in the Yellow River Delta coastal wetland.