Source identification of fine-grained suspended sediment in the Kharaa River basin, northern Mongolia.
Source identification of fine-grained suspended sediment in the Kharaa River basin, northern Mongolia.
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DOI：
10.1016/j.scitotenv.2015.03.134
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发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
P. Theuring;A. Collins;M. Rode
中科院分区：
文献类型：
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作者：
P. Theuring;A. Collins;M. Rode
进入河流系统的细泥沙可能是营养物和重金属的主要来源，对河流和湖泊的水质和生态系统功能，包括半干旱地区的河流和湖泊的水质和生态系统功能产生重大影响。然而，迄今为止，对中亚大部分大型流域泥沙来源的空间分布知之甚少。为此，应用沉积物源指纹技术对蒙古北方哈拉河流域15 000 km 2细颗粒（< 10 μm）沉积物的空间来源进行了研究。利用Ti、Sn、Mo、Mn、As、Sr、B、U、Ca和Sb等地球化学成分的变化，基于遗传算法（GA）驱动的判别函数分析、Kruskal-Wallis H检验和主成分分析，利用地球化学复合指纹进行沉积物源判别。所有的复合指纹都得到了令人满意的GOF（> 0.97），随后用于数值质量平衡建模和不确定性分析。单个子流域空间沉积物来源的贡献从6.4%（Sugnugur Gol的上游子流域）到36.2%（研究流域中游的Kharaa II子流域）不等，通常表现出较高的贡献，而不是研究区域的上游部分。河岸侵蚀的重要性从上游到中游支流增加。源追踪程序提供的结果与研究区域以前的研究结果合理一致，并证明了该方法在大规模半干旱流域细颗粒沉积物源调查中的适用性和相关的不确定性。
Fine sediment inputs into river systems can be a major source of nutrients and heavy metals and have a strong impact on water quality and ecosystem functions of rivers and lakes, including those in semiarid regions. However, little is known to date about the spatial distribution of sediment sources in most large scale river basins in Central Asia. Accordingly, a sediment source fingerprinting technique was used to assess the spatial sources of fine-grained (< 10 μm) sediment in the 15 000 km2Kharaa River basin in northern Mongolia. Variation in geochemical composition (e.g. in Ti, Sn, Mo, Mn, As, Sr, B, U, Ca and Sb) was used for sediment source discrimination with geochemical composite fingerprints based on Genetic Algorithm (GA)-driven Discriminant Function Analysis, the Kruskal–Wallis H-test and Principal Component Analysis. All composite fingerprints yielded a satisfactory GOF (> 0.97) and were subsequently used for numerical mass balance modelling with uncertainty analysis. The contributions of the individual sub-catchment spatial sediment sources varied from 6.4% (the headwater sub-catchment of Sugnugur Gol) to 36.2% (the Kharaa II sub-catchment in the middle reaches of the study basin), generally showing higher contributions from the sub-catchments in the middle, rather than the upstream, portions of the study area. The importance of river bank erosion is shown to increase from upstream to midstream tributaries. The source tracing procedure provides results in reasonable accordance with previous findings in the study region and demonstrates the applicability and associated uncertainties of the approach for fine-grained sediment source investigation in large scale semi-arid catchments.