官厅水库沉积物重金属沉积通量及沉积物记录的生态风险变化规律  

The flux of sedimentary heavy metals and variation of ecological risks recorded by sediments from Guanting Reservoir

作　　者：张伯镇 王丹[1] 张洪[1] 孟鑫[1,3] 雷沛[1,4] 朱晓磊[1,4] 单保庆[1] 李杰[3] 

机构地区：[1]中国科学院生态环境研究中心环境水质学国家重点实验室,北京100085 [2]兰州兰石重工有限公司,兰州730314 [3]兰州交通大学环境与市政工程学院,兰州730070 [4]中国科学院大学,北京100049

出　　处：《环境科学学报》2016年第2期458-465,共8页Acta Scientiae Circumstantiae

基　　金：环境模拟与污染控制国家重点联合实验室(中科院生态环境研究中心)自主申请课题(No.14Z01ESPCR)~~

摘　　要：采集官厅水库沉积物柱状样,分析了沉积物中6种重金属（Cd、Cr、Cu、Ni、Pb和Zn）的垂直分布特征和沉积通量,并采用潜在生态危害指数评价其生态风险.结果表明：6种重金属平均含量分别为0.205、65.5、37.6、39.5、33.6和104 mg·kg-1,与北京市土壤背景值相比,超标1.4~2.2倍;随时间的变化,沉积物中Cd和Ni含量相对稳定,而Cr、Cu、Pb和Zn含量呈现先降低、80年代后趋于平稳的趋势;1980年以来,重金属沉积通量随时间呈现有规律的递减,到2014年减少了约40%.官厅水库沉积物中重金属Cd、Cr、Cu、Ni、Pb和Zn的年沉积量分别为0.0113、3.63、2.09、2.19、1.86和5.72 t.富集系数显示,表层沉积物中各重金属均未发生富集（富集系数小于1.5）.官厅水库表层沉积物重金属的潜在生态风险指数RI值范围为58.8~113.0,均值为80.9,总体属于低生态风险;垂直分布上,在1985年后,水库各采样点沉积物中重金属的风险程度RI随着时间均呈现减小的趋势.总体来说,官厅水库沉积物中重金属污染相对较轻,对水库水环境质量不构成威胁.Based on vertical distribution characteristics and deposition fluxes,environmental risks of six sedimentary heavy metals（ Cd,Cr,Cu,Ni,Pb and Zn） in Guanting Reservoir were assessed by Hkanson potential ecological risk index. The results showed that the average concentrations of these heavy metals were 0. 205,65. 5,37. 6,39. 5,33. 6 and 104 mg·kg- 1,respectively. All metals exceeded the background value of Beijing by 1. 4 ~ 2.2 times. The concentrations of Cd and Ni in the sediment were relatively stable,while concentrations of Cr,Cu,Ni and Zn decreased gradually and leveled off since 1980. Moreover,deposition flux of heavy metals reduced by 40% since 1980. The annual deposition of Cd,Cr,Cu,Ni,Pb,Zn were0. 0113,3. 63,2. 09,2. 19,1. 86 and 5. 72 t,respectively. Enrichment factors for these heavy metals in the surface sediments were less than 1. 5. The RI values of the Reservoir ranged from 58. 8 to 113,with an average value of 80. 9,which demonstrated low ecological risk. Since 1985,the RI values of metals in the sediment samples of our sites had been decreasing. In general,the pollution of heavy metals was not serious in the sediments fromGuanting Reservoir.

关 键 词：官厅水库 重金属 沉积物 垂向分布 沉积通量 潜在生态风险 

分 类 号：X52[环境科学与工程—环境工程]