青海湖流域主要河口区沉积物中重金属元素生态风险评价

发布时间：2018-11-05 10:12

【摘要】：为摸清青海湖流域重金属的污染现状,对流域内11处河口区0~5 cm层沉积物进行调查取样,分析测定了表层沉积物中Zn、Cu、Pb、Hg、Ni、As、Cd和Cr 8种重金属元素含量,并对其来源、生态风险及污染状况进行评价。结果显示:(1)青海湖流域沉积物中8种重金属含量和介于151.61~277.31 mg·kg~(-1),平均值为209.65 mg·kg~(-1),略高于青海湖流域表层土壤环境背景值。重金属含量由高到低依次为As、Zn、Cr、Ni、Cu、Pb、Cd和Hg,其中As、Cr和Zn占8种重金属总含量的73.63%。青海湖流域重金属元素间具有相似来源,人类对重金属元素的影响主要体现在交通运输和农业活动上。重金属地累积系数I_(geo)从大到小依次为As、Hg、Cd、Cu、Cr、Ni、Zn和Pb,其中As的污染程度为偏中度,平均地累积指数I_(geo)为1.67。重金属潜在生态风险值从大到小依次为Hg、Cd、As、Cu、Ni、Pb、Cr和Zn,其中Hg、Cd和As对综合潜在生态风险指数I_R的平均贡献率分别为40.76%、25.56%和25.53%。(2)近年来青海湖流域内的交通运输、农业废水、小城镇化及旅游开发等人类活动造成的重金属排放问题已经开始显现,流域生态系统的自净能力不能将所有重金属元素均净化至低风险水平。因此,必须加强对中小河流与季节性河流中重金属元素的监测和预警,制定出针对性的治理和修复措施,保证青海湖流域内不受重金属污染的威胁。
[Abstract]:In order to find out the pollution status of heavy metals in Qinghai Lake Basin, the contents of 8 heavy metal elements Zn,Cu,Pb,Hg,Ni,As,Cd and Cr in surface sediments were analyzed and measured by investigating and sampling the sediments of 0 ~ 5 cm layer in 11 estuaries in the basin. And its source, ecological risk and pollution status were evaluated. The results showed that: (1) the contents of 8 heavy metals in the sediments of Qinghai Lake basin and the concentrations of heavy metals between 151.61 and 277.31 mg kg~ (-1), the average value was 209.65 mg kg~ (-1), which was slightly higher than the background value of the surface soil environment in the Qinghai Lake basin. The order of heavy metal content from high to low was As,Zn,Cr,Ni,Cu,Pb,Cd and Hg,. As,Cr and Zn accounted for 73.63 of the total contents of 8 heavy metals. There are similar sources of heavy metal elements in Qinghai Lake basin, and the effects of human on heavy metal elements are mainly reflected in transportation and agricultural activities. The soil accumulation coefficient I _ (geo) of heavy metals was As,Hg,Cd,Cu,Cr,Ni,Zn and Pb, respectively from large to small, in which the pollution degree of As was moderate, and the average accumulation index I _ (geo) was 1.67. The potential ecological risk values of heavy metals are Hg,Cd,As,Cu,Ni,Pb,Cr and Zn, from large to small. The average contribution rate of Hg,Cd and As to the comprehensive potential ecological risk index is 40.76, respectively. 25.56% and 25.53%. (2) in recent years, heavy metal emissions caused by human activities such as transportation, agricultural wastewater, small urbanization and tourism development in the Qinghai Lake basin have begun to appear. The self-purification ability of watershed ecosystem can not purify all heavy metal elements to low risk level. Therefore, it is necessary to strengthen the monitoring and early warning of heavy metal elements in middle and small rivers and seasonal rivers, and to formulate targeted measures to control and repair heavy metals, so as to ensure that there is no threat of heavy metal pollution in the basin of Qinghai Lake.
【作者单位】：中国林业科学研究院荒漠化研究所;内蒙古农业大学草原与资源环境学院;青海省林业科学研究所;
【基金】：国家自然科学基金重点项目(41130640) 林业公益性行业科研专项(201404304)
【分类号】：X52;X824

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