Ongetta Stephan, Mohan Viswanathan Prasanna, Sabarathinam Chidambaram, Ramasamy Nagarajan, Kuek Clem
Department of Applied Sciences, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, 98009, Miri, Sarawak, Malaysia; Curtin Malaysia Research Institute (CMRI), Curtin University Malaysia, CDT 250, 98009, Miri, Sarawak, Malaysia.
Department of Applied Sciences, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, 98009, Miri, Sarawak, Malaysia; Curtin Malaysia Research Institute (CMRI), Curtin University Malaysia, CDT 250, 98009, Miri, Sarawak, Malaysia.
Chemosphere. 2022 Nov;307(Pt 1):135721. doi: 10.1016/j.chemosphere.2022.135721. Epub 2022 Jul 16.
The extraction of mountain salt from the saline waters is the basic livelihood of the Ba'kelalan communities of Sarawak. The current integrated approach is the first attempt to study the sources and geochemical processes of the saline groundwaters in this mountain region. Hence, in this study, saline groundwater samples from five existing wells in different seasons were analysed for hydrochemical parameters and multi-isotope composition (δO, δD, δS, δB and δCl). The significant increase in TDS, EC and salinity was due to seasonal variation and fluctuation in water level based on hourly, daily and monthly observations. The geochemical ratios and the statistical techniques revealed that the salinity was due to the dissolution of marine evaporites as a dominant process, coupled with other factors such as water-rock interaction, ion exchange and sulphate reduction. From the isotopic signatures, it was inferred that the origin of saline groundwater was from the intense dissolution of marine evaporites such as halite dissolution and oxidation of -sulphide (pyrite). 2D electrical resistivity and seismic refraction methods were used to identify the lithological variations, depth of potential sources of saline groundwater, and the subsurface structures. It was inferred the probability of a conductive zone at a depth of 1-14 m, from which the saline groundwater plume migrates towards the perched aquifer. The presence of subsurface faults facilitated the movement of hypersaline groundwater from the saturated zone to the surface. The outcome of the study will support the dependent community to enhance their commercial salt production.
从盐水中提取岩盐是砂拉越巴克拉兰社区的基本生计。目前的综合方法是首次尝试研究该山区咸水地下水的来源和地球化学过程。因此，在本研究中，分析了不同季节从五口现有井中采集的咸水地下水样本的水化学参数和多同位素组成（δO、δD、δS、δB和δCl）。基于每小时、每日和每月的观测，TDS、EC和盐度的显著增加是由于季节变化和水位波动。地球化学比率和统计技术表明，盐度主要是由于海相蒸发岩的溶解，同时还伴有水岩相互作用、离子交换和硫酸盐还原等其他因素。从同位素特征推断，咸水地下水的来源是海相蒸发岩的强烈溶解，如石盐溶解和硫化物（黄铁矿）氧化。采用二维电阻率和地震折射方法来识别岩性变化、咸水地下水潜在来源深度和地下结构。推断在1至14米深度存在一个导电带，咸水地下水羽状物从该导电带向 perched 含水层迁移。地下断层的存在促进了高盐度地下水从饱和带向地表的运动。该研究结果将支持依赖该资源的社区提高其商业盐产量。
