Das Tusar Kumar, Ahmed Shakir, Hossen Alamin, Rahaman Md Hasibur, Rahman Mohammad Mahfuzur
Department of Environmental Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
International Program in Hazardous Substance and Environmental Management, Chulalongkorn University, Bangkok 10330, Thailand.
Heliyon. 2022 Oct 22;8(10):e11206. doi: 10.1016/j.heliyon.2022.e11206. eCollection 2022 Oct.
Multivariate statistics and GIS alone with geochemical modeling were applied to investigate the hydro-geochemical characteristics of groundwater and their spatial distribution in the deep aquifer system of Bagherpara Upazila, Bangladesh. This Upazila consists of an area of 308.3 km and local people mostly rely on groundwater to meet the drinking water requirements. Water samples from one hundred randomly selected deep tube wells (152-198 m) were collected and analyzed for 14 water quality parameters to characterize the hydro-geochemical properties. The groundwater shows slight alkaline in nature throughout the study area. Most of the water samples were turbid and 68% of them failed to meet the drinking water quality standard prescribed by the World Health Organization (WHO). TDS concentration ranges between 280 mg/L and 1040 mg/L, with a mean value of 446.20 (±122.19) mg/L. The general order of cation and anion along the study area were Ca>Mg>Na>K and HCO >Cl>PO >SO >NO respectively. Carbonate weathering is the dominant process for releasing ions in groundwater. Besides, the ion exchange process is active in the study area, which leads to the reduction of Na ions. Gibb's plot suggests a rock dominance inheritance controls the dissolution and precipitation of minerals along with the ion-exchange process, and ultimately dictates the groundwater chemistry. Besides, the Piper diagram showed that Ca-Mg-SO is the dominant water type in 65% of the samples followed by Ca-Mg-HCO water type (35%). The abundance of Ca and Mg ions and the alkaline nature of groundwater indicate mixed geochemical facies and reverse exchange reactions. The principal component analysis (PCA) reveals that weathering and leaching of host rocks was the main natural source, while municipal solid waste dumping, sewage discharge, and fertilizer application could be other anthropogenic factors that affect the groundwater geochemistry. In fine, the chemical characteristics of groundwater were acquired through rock dissolution, percolation, and reverse exchange process.
运用多元统计、地理信息系统（GIS）以及地球化学建模方法，对孟加拉国巴格赫帕拉乌帕齐拉深含水层系统的地下水水文地球化学特征及其空间分布进行了研究。该乌帕齐拉面积为308.3平方千米，当地居民大多依靠地下水满足饮用水需求。从100口随机选取的深管井（152 - 198米）采集水样，分析了14项水质参数，以表征水文地球化学性质。研究区域内的地下水总体呈弱碱性。多数水样浑浊，68%的水样不符合世界卫生组织（WHO）规定的饮用水质量标准。总溶解固体（TDS）浓度在280毫克/升至1040毫克/升之间，平均值为446.20（±122.19）毫克/升。研究区域内阳离子和阴离子的一般顺序分别为Ca>Mg>Na>K和HCO>Cl>PO>SO>NO。碳酸盐风化是地下水中离子释放的主要过程。此外，离子交换过程在研究区域较为活跃，导致钠离子减少。吉布（Gibb）图表明，岩石主导性继承控制着矿物的溶解和沉淀以及离子交换过程，并最终决定了地下水化学性质。此外，派珀（Piper）图显示，65%的样品中Ca - Mg - SO为主要水型，其次是Ca - Mg - HCO水型（35%）。钙离子和镁离子的丰度以及地下水的碱性表明存在混合地球化学相和逆向交换反应。主成分分析（PCA）表明，基岩的风化和淋滤是主要的自然来源，而城市固体废弃物倾倒、污水排放和肥料施用可能是影响地下水地球化学的其他人为因素。总之，地下水的化学特征是通过岩石溶解、渗透和逆向交换过程形成的。
