Physiochemical data of groundwater samples.

The groundwater resources in different areas of Pakistan are heading towards depletion along with the deterioration of quality due to over-abstraction and urbanization. The main focus of this study is to map the current hydrostratigraphical and hydraulic conditions of the late Quaternary aquifers in the central part of Thal Doab of Punjab Plains. To achieve the target, a comprehensive approach was employed combining geophysical investigations using electrical resistivity surveys (ERS) and physiochemical analysis of groundwater specimens collected from the study area. Careful calibration of resistivity models was performed by comparing them with lithologs to ensure their accuracy. The current groundwater conditions were assessed through thirty vertical electrical soundings (VES) using the Schlumberger electrode configuration up to 300m of AB/2. The interpreted results revealed the presence of four to six geo-electric sublayers comprising the intermixing layers of clay, silt, sand, gravel, and kankar inclusions. These layers exhibited very low (230 Ω-m) resistivity zones at various depth intervals. The developed 2D/3D models of aquifer systems identify the promising areas of good/fresh quality groundwater in the regions characterized by medium to very high resistivity mainly within the sand with gravel layers. However, lower resistivity values indicate the presence of marginally suitable/fair and saline/brackish groundwater showing the existence of fine sediments such as clays/silts. Additionally, twenty groundwater samples were collected to assess various parameters including pH, TDS, arsenic, fluoride, iron, nitrate, and nitrite. The spatial distribution of these parameters was visualized using 2D maps. The suitability of the groundwater for drinking consumption was evaluated in accordance with WHO guidelines.

巴基斯坦各区域的地下水资源因过度开采与城市化进程，正同时面临储量枯竭与水质恶化的双重困境。本研究的核心目标是绘制旁遮普平原塔尔多阿布(Thal Doab)中部晚第四纪含水层的当前水文地层与水力条件分布图。为达成研究目标，本研究采用综合研究手段，结合了电阻率勘探(Electrical Resistivity Surveys, ERS)地球物理探测与研究区域内采集的地下水样品理化分析。通过将电阻率模型与岩性柱状剖面(lithologs)进行对比以完成严格校准，确保模型精度。本研究采用斯伦贝谢(Schlumberger)电极排列方式，开展了30次垂直电测深(Vertical Electrical Soundings, VES)，最大AB/2间距达300米，以此评估当前地下水状况。解释结果显示，研究区存在4至6个地电亚层，其由黏土、粉砂、砂、砾石及钙结核(kankar)夹层混合组成。这些层位在不同深度区间内呈现出电阻率低至230 Ω·m的异常区。所构建的含水层系统二维/三维模型，识别出了中至高电阻率区域的优质/淡水地下水富集有利区，这类区域主要赋存于含砾砂层中。反之，较低电阻率值则对应着边际适宜/一般及咸水/半咸水地下水，指示此处赋存黏土、粉砂等细粒沉积物。此外，本研究还采集了20组地下水样品，对pH、总溶解固体(Total Dissolved Solids, TDS)、砷、氟化物、铁、硝酸盐及亚硝酸盐等多项参数进行检测。通过二维地图可视化呈现了这些参数的空间分布特征。本研究依据世界卫生组织(World Health Organization, WHO)指南，评估了该区域地下水的饮用水适宜性。