复垦工业场地土壤和周边河道沉积物重金属污染及潜在生态风险

测定了上海郊区53个复垦工业场地土壤点位和23个周边河道沉积物点位中8项重金属(As、Cd、Cr、Cu、Ni、Pb、Zn和Hg)含量,通过内梅罗指数法和潜在生态风险指数法评价了复垦工业场地土壤和周边河道沉积物重金属污染及潜在生态风险.结果表明,复垦工业场地土壤中8项重金属均不同程度超过二级标准,其中Zn、Cu的点位超标率最为突出,分别达到了47. 17%和43. 40%;周边河道沉积物中重金属含量显著低于复垦工业场地土壤.复垦工业场地土壤重金属内梅罗综合污染指数为11. 41,处于重度污染水平,其中Cu、Zn最为突出;周边河道沉积物重金属内梅罗综合污染指数为1. 26,处于轻度污染水平.从单项潜在生态风险来看,复垦工业场地土壤重金属除Cd(较强)、Hg(较强)、Cu(中度)外,均处于轻度潜在生态风险水平,潜在生态风险指数(RI)为385. 79,总体处于较强潜在生态风险水平;周边河道沉积物重金属除Hg略高于轻度外,均处于轻度潜在生态风险水平,潜在生态风险指数(RI)为83. 91,总体处于轻度潜在生态风险水平.总之,复垦工业场地土壤重金属Cu、Zn污染较为突出,考虑到毒性响应因素则Cd、Hg更应引起关注;周边河道沉积物重金属污染较轻,处于轻度潜在生态风险水平.

Heavy Metal Pollution and Potential Ecological Risk of Soil from Reclaimed Industrial Sites and Surrounding River Sediments

Eight heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn, and Hg) in the soils from 53 reclaimed industrial sites and 23 river sediments in the Shanghai suburbs were determined using the Nemero pollution index and Hakanson potential ecological risk index (RI). The results show that the eight heavy metals exceed the secondary standard limits to different extents. The rate of standard excess is the most prominent for Cu and Zn; it accounts for 47.17% and 43.40%, respectively. The contents of heavy metals in the sediments from surrounding rivers are significantly lower than those in soil from reclaimed industrial sites. The comprehensive Nemero pollution index of heavy metals in reclaimed soil is 11.41, which represents a serious pollution level; Cu and Zn are the most prominent heavy metals. The Nemero pollution index of heavy metals in surrounding river sediments is 1.26, indicating slight pollution. Based on the single-potential ecological risk, the heavy metals at the reclaimed industrial sites all have a slightly latent ecological risk level, except for Cd (strong), Hg (strong), and Cu (moderate). The potential ecological RI is high (385.79). Heavy metals from the surrounding river sediments have a mild potential ecological risk level, except for Hg. Overall, the potential ecological level is mild (RI=83.91). In short, Cu and Zn are more prominent in reclaimed industrial soil. With respect to the toxic response factor, Cd and Hg should be focused on. The heavy metal pollution of surrounding river sediments is light, leading to a mild potential ecological risk level.