Identification of seawater intrusion in Gapura Sub-district, Sumenep Regency, East Java, Indonesia

Gapura sub-district is located in the Sumenep Regency, Madura Island, that also recognized as the center of salt production. Due to not availability of a clean water network from the municipal water network (PDAM), the daily water need of the community is provided by groundwater. Local people have reported several brackish waters in the wells since a few years ago. Therefore, the purpose of this research is to identify seawater intrusion potential in this area. The seawater intrusion is analyzed based on the value of electrical conductivity (EC) and groundwater hydrochemistry. From the analysis of EC values, it can be concluded that there are two out of thirty groundwater samples classified as moderately saline water, while in the study of groundwater ion values, both two samples have chloride values that are more than 240 mg/L. However, the Cl and HCO3 ratio show that the two samples will only have a small effect on seawater. Therefore, it can be concluded that the Gapura sub-district does not have seawater intrusion. High salinity in some wells is mostly coming from salt production in this area.

Assessment of the Evolution of Groundwater Chemistry and Its Controlling Factors in the Huangshui River Basin of Northwestern China, Using Hydrochemistry and Multivariate Statistical Techniques

Groundwater is an eco-environmental factor and critical resource required for human life and socioeconomic development. Understanding the evolution of groundwater chemistry and its controlling factors are imperative for preventing its deterioration and ensuring its sustainable use. We studied the characteristics of groundwater chemistry in the Huangshui River Basin in Qinghai Province, China using hydrochemical techniques. Additionally, we identified the controlling factors of groundwater chemistry in this region using multivariate statistical techniques. Seventeen hydrochemical parameters of groundwater were investigated at 156 sites in June 2019. The results showed that total hardness, Fe, NO3−, SO42−, and Cl− were primary pollution factors of groundwater in this region, and that 33.3%, 35.3%, 8.97%, 23.1%, and 7.69% of the samples exceeded Grade III standards for groundwater quality in China, respectively. Land use types also significantly affected groundwater hydrochemistry. The hydrochemical composition of groundwater in industrial areas is more strongly influenced by human activities. The major hydrochemical types identified in the region were HCO3-Ca·Mg and HCO3·SO4-Ca·Mg. Additionally, high proportions of SO4 (50.6%), Na (32.1%), and Cl (13.5%) groundwater types revealed the influence of anthropogenic activities on the groundwater hydrochemistry. Rock weathering was the major factor influencing the groundwater hydrochemistry, while evaporation–condensation and anthropogenic activities also influenced the hydrochemical characteristics of groundwater. The hydrochemical composition of groundwater was mainly controlled by silicate rock weathering. The main controlling factors of groundwater hydrochemistry were water–rock interactions, “physicochemical” factors (nature processes), domestic sewage, chemical fertilizer, and industrial sewage (human activities).

Hydrogeochemical evolution processes and evaluation of groundwater suitability for domestic and agricultural utility in Southern Punjab, Pakistan

Groundwater is a vital resource for human life and economic growth. In the Khanewal district of Punjab, Pakistan, environmental changes, and anthropogenic activities have made groundwater extremely vulnerable in the past forty years. Sixty-eight groundwater samples were collected from the study area, major ions and trace elements were analyzed. The Principal Component Analysis and Cluster Analysis were used to identify the major factors influencing groundwater quality, as well as to assess its suitability for drinking and irrigation in southern Punjab. The aquifers are slightly acidic to alkaline, according to the pH (6.9–9.2) of groundwater. Significant cations are distributed as follows: Na+ > Ca2+ > Mg2+ > K+, while anions are distributed as HCO3− > SO42− > Cl−. The main hydrochemical facies are mixed Na·Ca-HCO3 and Na·Ca (Mg)-HCO3·SO4. Rock weathering processes, such as the dissolution of calcite, dolomite, and gypsum minerals, governed groundwater hydrochemistry. The water quality index (WQI) indicates that 17.64% of the water samples are unsuitable to drink. However, according to the Wilcox diagram, the USSL diagram, and some other agricultural indices, approximately 68% of the groundwater samples are suitable for irrigation.