青海湖流域河流生态系统重金属污染特征与风险评价

发布时间：2018-01-14 04:13

本文关键词：青海湖流域河流生态系统重金属污染特征与风险评价　出处：《环境科学研究》2016年09期 　论文类型：期刊论文

【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1.13μg/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0.06~0.49μg/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.
[Abstract]:To further find out the heavy metals of Qinghai Lake basin ecosystem (Zn, Cu, Pb, Hg, Ni, As, Cd and Cr) pollution, through the Qinghai Lake along the major river basin, river, downstream water collection, riparian soil and riparian plant samples, the contents of heavy metal contents were measured and analyzed the sources of heavy metals, pollution status and potential ecological risk of heavy metals. The results showed that: 1 the Qinghai Lake basin in the medium from upstream to downstream showed a significant cumulative effect, heavy metal content showed water riparian soil of riparian plant rivers. River water downstream in the P (Pb), P (Zn) and P (Cd). The average values were 11.17,61.22 and 1.13 g/L, with 3838 GB - 2002< environmental quality standards for surface water quality requirements of class II >; P (Hg) 0.06~0.49 g/L, according to GB 3838 - 2002 in class II or III water quality requirements. River riparian soil in w (As), w (Cd) (H and W G) the average values were 65.61,0.33 and 0.20 mg/kg, were significantly more than the Qinghai Lake basin corresponding environmental background value, but w (Pb) than the corresponding background value in the lower reaches of the river bank. Only slightly in plants w (Ni), w (Cu), w (As) and w (Hg) respectively 2.81,17.35,2.20 and mg/kg were higher than 0.10, < feed industry standard compilation (2) (Fourth Edition) > limit standard of heavy metal stroke hay - grass, but in the upstream of.2Pearson correlation analysis are in line with the requirements of this standard, the principal component and enrichment coefficient analysis showed that the river water, riparian soil and riparian plants Zn, Cu, Ni, Pb, there is a strong correlation between the content of Cr, mainly by urban life, influence of weathering and rock material transportation; Hg, Cd, there is a strong correlation between the content of As, mainly by tourism traffic watershed, agricultural production activities and the impact of soil.3 potential ecological risk The evaluation results show that the river water, riparian soil and riparian plants in Cu, Ni, Cr, the potential ecological risk coefficient of single heavy metal elements Pb and Zn, (Eri) were lower, Hg, Cd and As on the comprehensive potential ecological risk index (RI). The average contribution rate were 62.9%, 18.4% and 11%. The average contribution of the rest of the 5 kinds of heavy metals was only 7.7%. therefore, the river ecosystem of Qinghai Lake basin in the media of Hg, Cd and As in the high potential ecological risk, should be paid more attention.

【作者单位】：中国林业科学研究院荒漠化研究所;内蒙古农业大学生态环境学院;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) 国家林业公益性行业科研专项(201404304-03)
【分类号】：X826;X522
【正文快照】： 河流重金属污染问题是科研工作者十分关注的区域生态环境问题之一,健康的河流生态系统是保障流域内社会经济可持续发展的基础[1].自然条件下青藏高原生态系统中重金属元素含量相对较低[2],但近年来青海湖地区社会经济迅速发展,小城镇建设、景点旅游、过度放牧、交通运输、工程

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