School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China.
China Institute of Water Resources and Hydropower Research, Beijing 100038, China.
Environ Sci Process Impacts. 2020 Dec 16;22(12):2406-2417. doi: 10.1039/d0em00332h.
The impact of anthropogenic activity on chemical weathering is still an open and significant topic that requires clarification to improve the understanding of watershed evolution. We analyzed river water and rainwater samples to characterize the variation in hydrochemical characteristics and influencing factors. Samples were taken from the Liuxi River Basin (LRB), the only local drinking water supply for Guangzhou, and we studied geochemical parameters, major ions, and Si concentrations. Moreover, elemental ratios of end-members were determined and a modified-forward model was constructed to identify ion sources and estimate the chemical weathering rate (CWR) and anthropogenic input rate (AIR). Finally, we quantified the impacts of anthropogenic activity on the chemical weathering process. The results showed that the dominant hydrochemical type of river water was identified as HCO3-Ca, and rock weathering was the main contributor to river Na+, Mg2+, Ca2+ and HCO3-, whereas anthropogenic activity contributed the most to K+, Cl-, SO42-, and NO3-. The relatively high silicate weathering rate (SWR) (17.8-18.4 t per km2 per year) and AIR (37.8-60.3 t per km2 per year) were mainly attributed to erosion by nitric and sulfuric acid. The contribution rate of these acids to CWR could be regarded as a proxy quantifying the impact of anthropogenic activity on the chemical weathering process. This accounted for approximately 30% of the total SWR in the LRB. Our results demonstrate the effectiveness of hydrochemical source identification for quantifying the impacts of anthropogenic activity on chemical weathering.
人为活动对化学风化的影响仍是一个悬而未决的重要课题,需要加以澄清,以增进对流域演化的了解。我们分析了河水和雨水样本,以描述水化学特征和影响因素的变化。样本取自流溪河(LRB),这是广州唯一的当地饮用水供应源。我们研究了地球化学参数、主要离子和 Si 浓度。此外,还测定了端元元素比值,并构建了改进的正向模型,以确定离子源并估算化学风化率(CWR)和人为输入率(AIR)。最后,我们量化了人为活动对化学风化过程的影响。结果表明,河水的主要水化学类型为 HCO3-Ca,岩石风化是河水中 Na+、Mg2+、Ca2+和 HCO3-的主要来源,而人为活动对 K+、Cl-、SO42-和 NO3-的贡献最大。相对较高的硅酸盐风化率(SWR)(17.8-18.4 t 每平方公里每年)和 AIR(37.8-60.3 t 每平方公里每年)主要归因于硝酸和硫酸的侵蚀。这些酸对 CWR 的贡献率可以作为量化人为活动对化学风化过程影响的一个代理指标。这占 LRB 总 SWR 的约 30%。我们的结果表明,水化学源识别对于量化人为活动对化学风化的影响是有效的。