密云水库沉积物中重金属元素分布及形态研究

主要研究了北京市密云水库沉积物中重金属的总量以及形态分布特征,采用风险评价准则法(RAC)和Tucker3模型探讨沉积物中重金属的潜在危害性.结果表明,各重金属元素的平均含量都超过北京市土壤背景值,重金属元素有一定的富集.Cu有机结合态约占总量的3%～68%;Mn可交换态、碳酸盐结合态约占总量的1%～18%、7%～31%;Pb、Zn的铁锰氧化物结合态分别占总量的12%～53%、4%～27%;其它重金属均以铁锰氧化物结合态和残渣态为主,平均含量占总量的80%以上.根据RAC法得出,Mn(除采样点18)处于中等风险甚至高风险等级;Pb、Zn、Cu属从低风险到中等风险级;Ni、V、Cr、Ti的潜在生态风险较低.该结论将为北京市密云水库保护、人体健康安全保护措施的制定提供科学依据.

Analysis on Distribution and Partition of Heavy Metal in Sediments of Miyun Reservoir

Contents and spatial distribution of heavy metals in the sediments of Miyun Reservoir in Beijing were researched in this article, and the potential hazards of heavy metals was analyzed by the method of Risk assessment code（RAC） and Tucker3 model. The results showed that the contents of all heavy metals were higher than the background values of Beijing soils, and Heavy metals appeared certain enrichment. Organic matter fraction content for Cu accounted for 3% -68% of the total concents; exchangeable and Bound to carbonates for Mn respectively accounted for about 1% - 18% , 7% - 31% of the total concents; Fe - Mn fractions contents for Pb, Zn respectively accounted for 12% -53% , 4 % -27% of the total concents; other heavy metals were dominated by Fe - Mn oxides fraction and residual fraction, they accounted for more than 80% of the total contents. RAC showed Mn （except the sampling point 18） was a medium risk or high risk level;Pb, Zn and Cu were from low -risk to moderate risk level; Ni, V and Cr, Ti potential ecological risk was low. The conclusions will help in Beijing water source protection and providing a scientific basis for the formulation of security measures to protect human health.