Bu Jianwei, Sun Ziyong, Zhou Aiguo, Xu Youning, Ma Rui, Wei Wenhao, Liu Meng
Geological Survey, China University of Geosciences, Wuhan 430074, China.
Laboratory of Basin Hydrology and Wetland Eco-restoration, China University of Geosciences, Wuhan 430074, China.
Int J Environ Res Public Health. 2016 Feb 23;13(3):247. doi: 10.3390/ijerph13030247.
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 1990 s. 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.
黑河上游地区一直被视为植物生态学、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、位置偏远且交通条件差，很少有关于土壤重金属污染的研究在此开展或报道。在本研究中，首次进行了一项调查，以提供该地区重金属的浓度水平、来源、空间分布和环境风险等信息。对研究区域采集的56个表层土壤样本进行了铬、锰、镍、铜、锌、砷、镉和铅浓度以及总有机碳含量的分析。利用基本统计、浓度比较、相关系数分析和多元分析并结合空间分布来描绘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上升。除铬外，每种金属的平均值均高于中国青海省、西藏以及全球的平均背景值。特别值得注意的是镉的浓度，与所有背景值相比都极高。该地区独特的成矿条件以及保存完好、分布广泛的石灰岩可能是镉浓度高的原因。研究区域表层土壤中的重金属主要继承自母质。尽管如此，人为活动可能加速了风化过程。镉呈现出高背景浓度水平，对整个地区构成严重的环境风险。特别是银达、热水大板、可可里和扎麻生的土壤对当地居民以及牲畜和野生动物的健康构成威胁。
