Department of Earth Sciences, Indian Institute of Technology Kanpur, Kanpur, India.
Physical Research Laboratory, Navrangpura, Ahmedabad, 380009, India.
Environ Monit Assess. 2023 Sep 5;195(10):1150. doi: 10.1007/s10661-023-11665-0.
Understanding the spatiotemporal dynamics of river water chemistry from its source to sinks is critical for constraining the origin, transformation, and "hotspots" of contaminants in a river basin. To provide new spatiotemporal constraints on river chemistry, dissolved trace element concentrations were measured at 17 targeted locations across the Ramganga River catchment. River water samples were collected across three seasons: pre-monsoon, monsoon, and post-monsoon between 2019 and 2021. To remove the dependency of trace element concentrations on discharge, we used molar ratios, as discharge data on Indian transboundary rivers are not publicly available. The dataset reveals significant spatiotemporal variability in dissolved trace element concentrations of the Ramganga River. Samples collected upstream of Moradabad, a major industrial city in western Uttar Pradesh, are characterized by ~ 1.2-2.5 times higher average concentrations of most of the trace elements except Sc, V, Cr, Rb, and Pb, likely due to intense water-rock interactions in the headwaters. Such kind of enrichment in trace metal concentrations was also observed at sites downstream of large cities and industrial centers. However, such enrichment was not enough to bring a major change in the River Ganga chemistry, as the signals got diluted downstream of the Ramganga-Ganga confluence. The average river water composition of the Ramganga River was comparable to worldwide river water composition, albeit a few sites were characterized by very high concentrations of dissolved trace elements. Finally, we provide an outlook that calls for an assessment of stable non-traditional isotopes that are ideally suited to track the origin and transformation of elements such as Li, Mg, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Sr, Ag, Cd, Sn, Pt, and Hg in Indian rivers.
了解河流从源头到汇流处的水化学时空动态对于约束河流流域中污染物的来源、转化和“热点”至关重要。为了提供河流化学的新时空约束，我们在拉姆甘加河流域的 17 个目标位置测量了溶解微量元素浓度。在 2019 年至 2021 年期间，我们在三个季节（前季风期、季风期和后季风期）采集了河水样本。为了消除微量元素浓度对流量的依赖性，我们使用了摩尔比，因为印度跨界河流的流量数据尚未公开。该数据集揭示了拉姆甘加河溶解微量元素浓度的显著时空变化。在莫拉达巴德（位于西北方 Uttar Pradesh 的一个主要工业城市）上游采集的样本中，除 Sc、V、Cr、Rb 和 Pb 外，大多数微量元素的平均浓度高出约 1.2-2.5 倍，这可能是由于源头处的强烈水岩相互作用。在大城市和工业中心下游的站点也观察到了这种微量元素浓度的富集。然而，这种富集不足以使恒河的化学性质发生重大变化，因为在拉姆甘加河与恒河的汇合处下游，这些信号被稀释了。拉姆甘加河的河水平均成分与世界范围的河水成分相当，尽管有几个站点的溶解微量元素浓度非常高。最后，我们展望未来，呼吁评估稳定的非传统同位素，这些同位素最适合追踪 Li、Mg、Ca、Ti、V、Cr、Fe、Ni、Cu、Zn、Sr、Ag、Cd、Sn、Pt 和 Hg 等元素在印度河流中的起源和转化。
