黄河三角洲表层土壤重金属环境质量评价

Assessment of heavy metal Contamination in the surface soil of the Yellow River Delta,China

主要针对黄河三角洲表层土壤及沉积物的重金属分布调查,在2006~2008年间采集表层土壤样品219个（其中浅海湿地25个）,并运用受普遍认可的生态危害指数法、单因子及内梅罗污染指数法对黄河三角洲整体进行环境质量评价,得出以下结论：（1）黄河三角洲表层土壤中重金属元素的污染指数从高到低为：Cr〉Pb〉Zn〉As〉Cu〉Cd〉Hg;（2）浅海湿地的近海表层沉积物中的重金属元素含量较上三角洲平原的表层土壤低,前者最大影响来源于As,土壤样品一级标准率达到96%;后者的最大威胁是As和Cd,土壤样品一级标准率达到88.5%;（3）黄河三角洲表层土壤及近海沉积物的Eri值、RI值、单因子污染指数及综合污染指数均较小,远未达到轻微污染的标准,表明黄河三角洲土壤环境状况较好,整体处于清洁水平。

The research focuses on the distribution of heavy metal elements in surface soil and sediments. Total 219 surface soil samples, including 25 samples of shallow coastal wetlands, were sampled. The content of heavy metal elements in these samples were tested using modern techniques. The potential ecological risk index （RI）, sin-gle-factor pollution index, and Nemerow index were used, which reflects Cr 〉 Pb 〉 Zn 〉 As 〉 Cu 〉 Cd 〉 Hg. Be-cause the sea water washes the shallow coastal wetlands, their samples have a lower content of heavy metal ele-ments. The greatest threat of heavy metal pollution in the upper delta plain is from As and Cd, and 88.5% of soils achieved the soil environmental standard of National First Grade. Further, the greatest threat of heavy metal pollu-tion in the shallow coastal wetlands is from As, and 96% of soils achieved the soil environmental standard of Na-tional First Grade. A deeper analysis of potential pollution disclosed that RI, single-factor pollution index, and Ne-merow index are too low. They do not reach the lowest pollution standard, implying that the soils in the Yellow River Delta are in good environmental condition.