Heavy Metals in Surface Soils in the Upper Reaches of the Heihe River, Northeastern Tibetan Plateau, China.
Heavy Metals in Surface Soils in the Upper Reaches of the Heihe River, Northeastern Tibetan Plateau, China.
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DOI：
10.3390/ijerph13030247
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发表时间：
2016-02-23
影响因子：
--
通讯作者：
Liu M
中科院分区：
文献类型：
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作者：
Bu J;Sun Z;Zhou A;Xu Y;Ma R;Wei W;Liu M
黑河上游一直被视为植物生态、气候变化、水资源和水文研究的热点地区。由于该地区气候寒冷干旱、海拔高、地处偏远、交通条件差，针对土壤重金属污染的研究或报道较少。本研究首次对该地区的重金属浓度水平、来源、空间分布和环境风险进行了调查。对从研究区域采集的 56 个表层土壤样本进行了 Cr、Mn、Ni、Cu、Zn、As、Cd 和 Pb 浓度以及 TOC 水平的分析。利用基础统计、浓度比较、相关系数分析和多元分析与空间分布相结合的方法，勾画出不同重金属的特征和来源。还进行了风险评估，包括地累积指数、富集因子和潜在生态风险指数。结果表明，自 20 世纪 90 年代以来，重金属浓度一直在增加。除Cr外，各金属的平均值均高于青海省、西藏、中国和世界的平均背景值。特别值得注意的是镉的浓度，与所有背景值相比极高。独特的成矿条件和保存完好、分布广泛的石灰岩可能导致了镉的高浓度。研究区表层土壤中的重金属主要来自母质。尽管如此，人类活动可能加速了风化过程。镉的背景浓度水平很高，对整个地区造成严重的环境风险。尤其是银达、热水达坂、可可里和扎马胜的土壤对当地居民以及牲畜和野生动物的健康构成威胁。
The upper reaches of the Heihe River have been regarded as a hotspot for phytoecology, climate change, water resources and hydrology studies. Due to the cold-arid climate, high elevation, remote location and poor traffic conditions, few studies focused on heavy metal contamination of soils have been conducted or reported in this region. In the present study, an investigation was performed to provide information regarding the concentration levels, sources, spatial distributions, and environmental risks of heavy metals in this area for the first time. Fifty-six surface soil samples collected from the study area were analyzed for Cr, Mn, Ni, Cu, Zn, As, Cd and Pb concentrations, as well as TOC levels. Basic statistics, concentration comparisons, correlation coefficient analysis and multivariate analyses coupled with spatial distributions were utilized to delineate the features and the sources of different heavy metals. Risk assessments, including geoaccumulation index, enrichment factor and potential ecological risk index, were also performed. The results indicate that the concentrations of heavy metals have been increasing since the 1990s. The mean values of each metal are all above the average background values in the Qinghai Province, Tibet, China and the world, except for that of Cr. Of special note is the concentration of Cd, which is extremely elevated compared with all background values. The distinguished ore-forming conditions and well-preserved, widely distributed limestones likely contribute to the high Cd concentration. Heavy metals in surface soils in the study area are primarily inherited from parent materials. Nonetheless, anthropogenic activities may have accelerated the process of weathering. Cd presents a high background concentration level and poses a severe environmental risk throughout the whole region. Soils in Yinda, Reshui daban, Kekeli and Zamasheng in particular pose threats to the health of the local population, as well as that of livestock and wildlife.