Guan Qingyu, Wang Lei, Pan Baotian, Guan Wenqian, Sun Xiazhong, Cai Ao
Key Laboratory of Western China's Environmental Systems, Ministry of Education, Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Key Laboratory of Western China's Environmental Systems, Ministry of Education, Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Chemosphere. 2016 Feb;144:29-42. doi: 10.1016/j.chemosphere.2015.08.036. Epub 2015 Sep 4.
Fifty-six riverbed surface sediment (RSS) samples were collected along the Ningxia-Inner Mongolian reaches of the Yellow River (NIMYR). These samples were analyzed to determine their heavy metal concentrations (Co, Cr, Ni, Cu, V and Zn), grain sizes, sediment sources and the causes of their heavy metal contamination. The cumulative distribution functions of the heavy metals in RSS of these reaches are plotted to identify the geochemical baseline level (GBL) of each element and determine the average background concentration of each heavy metal. Principal component analysis and hierarchical cluster analysis are conducted based on the grain sizes of RSS, and the samples are classified into two groups: coarse grained samples (CGS) and fine grained samples (FGS). The degree of heavy metal contamination for each sample is identified by its enrichment factor (EF). The results reveal that the coarse particle component (medium sand and coarse sand) in the bed materials is chiefly from the bordering deserts along the Yellow River. The clay and silt in the bed materials chiefly originate from the upper reaches of the Yellow River, and the fine sand is identified as a hybrid sediment derived from the upper reaches of the Yellow River and the bordering deserts. The CGS primarily appear in the reaches bordering deserts, and the sites are near the confluence of gullies and the Yellow River. The FGS are located adjacent to cities with especially strong industrial activity such as Wuhai, Bayan Nur, Baotou and Togtoh. The Cr, Ni, Cu, V and Zn concentrations (mg kg(-1)) are 84.34 ± 49.46, 30.21 ± 7.90, 25.01 ± 7.61, 73.17 ± 18.92 and 55.62 ± 18.93 in the FGS and 65.07 ± 19.51, 23.86 ± 6.84, 18.04 ± 3.8, 53.47 ± 10.57 and 34.89 ± 9.19 in the CGS respectively, and the concentrations of Co in the CGS (213.40 ± 69.71) are notably higher than in the FGS (112.02 ± 48.87) and greater than the Co GBL (210). The most contaminated samples in the NIMYR are adjacent to the cities of Wuhai (EF(Cr) = 5.19; EF(Ni) = 1.96), Bayan Nur (EF(Cr) = 5.88; EF(Ni )= 2.08) and Baotou (EF(Cu) = 1.55; EF(Zn) = 1.68) where the Cr, Ni, Cu, V and Zn concentrations are above the correlated GBLs (85, 34, 27, 75 and 62 mg kg(-1), respectively), which are mostly affected by industrial processes, and samples that are only moderately contaminated by heavy metals are found in the reaches bordering desert (Wuhai-Baotou) because contaminated sediments are diluted by uncontaminated desert sand. In contrast, all of the Cu, Cr, Ni, V and Zn concentrations in RSS of the Qingtongxia-Wuhai reach are lower than the correlated GBLs of elements.
在黄河宁夏-内蒙古段（NIMYR）沿线采集了56个河床表层沉积物（RSS）样本。对这些样本进行分析，以确定其重金属浓度（钴、铬、镍、铜、钒和锌）、粒度、沉积物来源及其重金属污染原因。绘制了这些河段RSS中重金属的累积分布函数，以确定每种元素的地球化学基线水平（GBL），并确定每种重金属的平均背景浓度。基于RSS的粒度进行主成分分析和层次聚类分析，样本分为两组：粗粒样本（CGS）和细粒样本（FGS）。通过富集因子（EF）确定每个样本的重金属污染程度。结果表明，河床物质中的粗颗粒成分（中砂和粗砂）主要来自黄河沿岸的毗邻沙漠。河床物质中的黏土和粉砂主要源自黄河上游，细砂被确定为源自黄河上游和毗邻沙漠的混合沉积物。CGS主要出现在毗邻沙漠的河段，且这些地点靠近沟壑与黄河的交汇处。FGS位于乌海、巴彦淖尔、包头和托克托等工业活动特别活跃的城市附近。FGS中铬、镍、铜、钒和锌的浓度（mg kg⁻¹）分别为84.34±49.46、30.21±7.90、25.01±7.61、73.17±18.92和55.62±18.93，CGS中分别为65.07±19.51、23.86±6.84、18.04±3.8、53.47±10.57和34.89±9.19，CGS中钴的浓度（213.40±69.71）明显高于FGS（112.02±48.87）且大于钴的GBL（210）。NIMYR中污染最严重的样本毗邻乌海（EF（Cr）=5.19；EF（Ni）=1.96）、巴彦淖尔（EF（Cr）=5.88；EF（Ni）=2.08）和包头（EF（Cu）=1.55；EF（Zn）=1.68）等城市，其中铬、镍、铜、钒和锌的浓度高于相关GBL（分别为85、34、27、75和62 mg kg⁻¹），这些主要受工业过程影响，而在毗邻沙漠的河段（乌海-包头）发现了仅受重金属中度污染的样本，因为受污染的沉积物被未受污染的沙漠沙子稀释。相比之下，青铜峡-乌海段RSS中所有的铜、铬、镍、钒和锌浓度均低于相关元素的GBL。
