| 青海湖流域河流生态系统重金属污染特征与风险评价 |
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| 引用本文： | 李少华,王学全,高琪,杨占武.青海湖流域河流生态系统重金属污染特征与风险评价[J].环境科学研究,2016,29(9):1288-1296. |
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| 作者姓名： | 李少华 王学全 高琪 杨占武 |
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| 作者单位： | 1.中国林业科学研究院荒漠化研究所, 北京 100091 |
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| 基金项目： | 国家自然科学基金重点项目(41130640)；国家林业公益性行业科研专项(201404304-03) |
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| 摘 要： | 为进一步摸清青海湖流域河流生态系统重金属(Zn、Cu、Pb、Hg、Ni、As、Cd和Cr)的污染状况,通过沿青海湖流域主要河流上、中、下游采集河流水体、河岸土壤及河岸植物样品,对样品中的重金属含量进行测定,并分析重金属的来源、污染状况和潜在生态风险.结果表明:①青海湖流域各介质中重金属从上游到下游均呈明显的累积效应,重金属含量均表现为河岸土壤>河岸植物>河流水体.河流下游水体中ρ(Pb)、ρ(Zn)和ρ(Cd)的平均值分别为11.17、61.22和1.13 μg/L,符合GB 3838—2002《地表水环境质量标准》中Ⅱ类水质要求；ρ(Hg)为0.06～0.49 μg/L,符合GB 3838—2002中Ⅱ类或Ⅲ类水质要求.河流下游河岸土壤中w(As)、w(Cd)和w(Hg)的平均值分别为65.61、0.33和0.20 mg/kg,均大幅超过青海湖流域相应环境背景值,但是w(Pb)在下游仅略微超过相应环境背景值.河岸下游植物中w(Ni)、w(Cu)、w(As)和w(Hg)的平均值分别为2.81、17.35、2.20和0.10 mg/kg,均高于《饲料工业标准汇编(下册)(第四版)》中风干草-牧草中重金属标准限值,但在中、上游均符合该标准要求.②Pearson相关分析、主成分分析和富集系数结果表明,河流水体、河岸土壤及河岸植物中Zn、Cu、Ni、Pb、Cr含量之间具有较强的相关性,主要受城镇生活、交通运输及岩石母质风化的影响；Hg、Cd、As含量之间具有较强的相关性,主要受流域旅游交通、农业生产活动和成土母质的影响.③潜在生态风险评价结果显示,河流水体、河岸土壤及河岸植物中Cu、Ni、Cr、Pb和Zn等单一重金属元素的潜在生态风险系数(Eri)均较低,Hg、Cd和As对综合潜在生态风险指数(RI)的平均贡献率分别为62.9%、18.4%和11.0%,其余5种重金属的平均贡献率仅为7.7%.因此,青海湖流域河流生态系统各介质中Hg、Cd和As的潜在生态风险较高,应给予高度重视.
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| 关 键 词： | 青海湖流域 河岸植物 河流水体 河岸土壤 重金属 污染 |
| 收稿时间： | 2016/1/21 0:00:00 |
| 修稿时间： | 2016/5/3 0:00:00 |
Distribution Characteristics and Pollution Evaluation of Heavy Metals in River Ecosystems of Qinghai Lake Basin |
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| LI Shaohu,WANG Xuequan,GAO Qi and YANG Zhanwu.Distribution Characteristics and Pollution Evaluation of Heavy Metals in River Ecosystems of Qinghai Lake Basin[J].Research of Environmental Sciences,2016,29(9):1288-1296. |
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| Authors: | LI Shaohu WANG Xuequan GAO Qi and YANG Zhanwu |
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| Affiliation: | 1.Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China2.College of Ecology and Environmental Science, Inner Mongolia Agriculture University, Hohhot 010019, China3.Qinghai Forestry Research Institute, Xining 810016, China |
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| Abstract: | Abstract:In order to understand the newest pollution characteristics of heavy metals(Zn,Cu,Pb,Hg,Ni,As,Cd and Cr) in river ecosystems of Qinghai Lake Basin,heavy metal pollution of the river ecosystem there was researched,which could provide a scientific basis for ecological environmental quality assessment.According to the types of land utilization and river hydrology combined with field survey,the sampling points were selected.Surface water,riparian soil and vegetation were collected from 11 major rivers,and their heavy metal contents were then measured in the laboratory to analyze the sources of heavy metals,the pollution situation and potential ecological risks in Qinghai Lake Basin.The results showed that:1) Heavy metals of each medium from upstream to downstream showed a cumulative process in the Qinghai Lake Basin.The descending order of heavy metal content was:riparian soil>riparian vegetation>river water.In river downstream water,the average contents of Pb,Zn and Cd were 11.17,61.22 and 1.13 μg/L respectively,which reached the Class Ⅱ standard；the average content of Hg was between 0.06 and 0.49 μg/L,which belonged to Class Ⅱ or Ⅲ standard.In riparian soil,the average contents of As,Cd and Hg were 65.61,0.33 and 0.20 mg/kg respectively,which exceeded environmental background values；content of Pb slightly exceeded the background values downstream.In downstream of riparian vegetation,the average contents of Ni,Cu,As and Hg were 2.81,17.35,2.20 and 0.10 mg/kg respectively,higher than the heavy metal standard limits of forage-hay,while they complied with forage heavy metal standards upstream.2) Pearson correlation analysis,principal component analysis and enrichment factor calculation showed that in the river water,riparian soil and riparian vegetation,there was a significant correlation among Zn,Cu,Ni,Pb and Cr,mainly originated from urban living activities,transportation and rock weathering；there was also a significant correlation among Hg,Cd and As,mainly originated from tourism transportation,agricultural production activities and natural geological background.3) Potential ecological risk evaluation showed that Cu,Ni,Cr,Pb and Zn had a relatively low Er i in the river water,riparian soil and riparian vegetation.Hg,Cd,As contributed the most to the RI,accounting for 62.9%,18.4%,11.0% respectively,while the remaining five kinds of heavy metals contributed only 7.7%.Therefore,more attention should be given to Hg,Cd,As,and restriction of emissions to the environment. |
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