Evaluation of hydrogeochemistry and water quality in Bist-Doab region, Punjab, India

Assessment of Long-Term Evolution of Groundwater Hydrochemical Characteristics Using Multiple Approaches: A Case Study in Cangzhou, Northern China

“…Groundwater hydrochemical characteristics are of great importance to determine water quality and the evolution tendency for domestic, agricultural and industrial purposes [40]. Based on the groundwater sampling test results ( Figure 5), the evolution tendency of major ions in groundwater of the study area for both shallow and deep groundwater is similar across decades.…”

“…In addition, different geochemical ratios are used to identify the potential mechanisms that influence the overall geochemical composition of groundwater [12,13,15,39,40]. For example, the (Ca…”

“…ratio is used to indicate ion-exchange processes [22,41]; ratios of Na/Cl and Ca 2+ /SO4 2− are used to indicate halite (NaCl) and gypsum (CaSO4) dissolution, respectively [22,40]; and the HCO3 − /Cl − ratio is used as an indicator of groundwater recharge type [22,42].…”

“…Moreover, Ca Cation exchange, which is one of the most important hydrogeological process occurring in aquifers, affects the content of cations in groundwater and modifies the groundwater quality [5,13,22]. According to the stratum structure and lithology characteristics revealed by drilling holes in the NCP [34], sediments in the study area mainly consist of silt, silt clay and clay (Figures 2 and 3), and Ca The ratio of Na can be estimated based on the ratio of their milligram equivalents, with 1:1 indicating that they originate from dissolution of gypsum [40]. The scatter diagrams (Figure 9) of Ca 2+ vs. SO4 2− show that both plots of shallow and deep groundwater samples deviate from the equi-line and approach the SO4 2− axis, and the ratio of Ca 2+ /SO4 2− in shallow groundwater is greater than that in deep groundwater, indicating that dissolution of gypsum is a secondary process and other reactions take place that affect the content of Ca 2+ and SO4 2− in shallow and deep aquifers.…”

“…The scatter diagrams (Figure 9) of Ca 2+ vs. SO4 2− show that both plots of shallow and deep groundwater samples deviate from the equi-line and approach the SO4 2− axis, and the ratio of Ca 2+ /SO4 2− in shallow groundwater is greater than that in deep groundwater, indicating that dissolution of gypsum is a secondary process and other reactions take place that affect the content of Ca 2+ and SO4 2− in shallow and deep aquifers. Purushothaman [40] stated that the absence or negligible amounts of gypsum may lead to a higher ratio of Ca 2+ /SO4 2− , while Xing [53] pointed out that sulfate reduction occurred in shallow aquifers of the NCP, which decreased the content of SO4 …”