Groundwater is a significant source of water, and evaluating its hydrochemical attributes, quality, and associated health risks holds paramount importance in guaranteeing safe water access for the population and fostering sustainable socio-economic progress. Situated within a semi-arid region, the Dianbu area (DBA) features numerous greenhouses interspersed amongst open farmlands. An examination revealed a discernible decline in the overall water chemistry environment in this area. This study extensively examined the fundamental water chemistry characteristics of groundwater and surface water samples through a statistical analysis, Piper’s trilinear diagram, ion ratios, and other analytical methods. The assessment of irrigation water quality was conducted using the entropy weight water quality index (EWQI), sodium adsorption ratio (SAR), percentage of soluble sodium (Na%), among other relevant indicators. The findings demonstrate multiple key aspects: 1. Water cations are chiefly composed of Ca²⁺ and Na⁺, while groundwater anions are notably NO₃⁻ and SO₄²⁻ dominant, defining the water type as NO₃-SO₄-Ca. Conversely, surface water primarily displays HCO₃⁻ and SO₄²⁻ anions, aligning it with an HCO₃-SO₄-Ca water type. 2. The extensive agricultural activities in the region, coupled with the excessive utilization of pesticides, chemical fertilizers, as well as the discharge of domestic sewage, contribute to heightened NO₃⁻ concentrations in groundwater. 3. The water quality assessments indicate that approximately 53% of agricultural water quality meets irrigation standards based on EWQI, with SAR results suggesting around 65.52% suitability for irrigation and Na% findings indicating approximately 55.88% viability for this purpose. Proper water selection tailored to specific conditions is advised to mitigate potential soil salinization risks associated with long-term irrational irrigation practices.

Groundwater is crucial for human survival and social development. In this study, ArcGIS 10.8, Origin 2024, and Excel were employed to investigate the hydrochemical properties of groundwater in the Rizhao reservoir (RZR) through statistical analysis, Durov plots, ion ratio analysis, and the entropy weight water quality index (EWQI). The analysis is based on monitoring data from six sites located both upstream and downstream of RZR, focusing on dynamic changes in groundwater quality and major ion concentrations. The findings suggest that the groundwater in RZR exhibits weak alkalinity and is categorized as hard freshwater. The predominant anion and cation are HCO₃⁻ and Ca²⁺, which together determine that the dominant water chemistry type in RZR is HCO₃-Ca type. Groundwater ions predominantly stem from the dissolution of silicate and evaporite rocks. In comparison to the dry season, the fluctuations in groundwater parameters are more pronounced during the wet season. Between 2020 and 2022, the concentrations of most ions exhibited an upward trend. Notably, nitrate (NO₃⁻) experienced significant fluctuations and relatively high concentrations, peaking in the wet season of 2023. The primary source of nitrate in RZR is agricultural activities. Overall, the quality of groundwater in RZR is good and suitable for human consumption. Nevertheless, the EWQI values are increasing at most monitoring sites, with the most significant rise observed at site R02. Moreover, while the upstream monitoring point exhibits better water quality, its EWQI value has increased significantly, and ion concentrations display substantial fluctuations. Local authorities are advised to adopt active measures to manage groundwater quality in RZR to ensure its sustainable use.

Groundwater is a vital and invaluable resource on our planet, serving as a critical water supply for human life, industrial activities, and agricultural production. It plays a pivotal role in sustaining human existence and driving societal progress. In this study, we conducted a comprehensive analysis of the hydrochemical characteristics and controlling factors of groundwater in the Upper Weihe River (UWR) using statistical analysis, Piper diagrams, Gibbs diagrams, correlation analysis, and ion ratio analysis. To evaluate the suitability of the regional groundwater for potable use, we employed the entropy weight water quality index (EWQI). Additionally, the sodium adsorption ratio (SAR) and percentage of soluble sodium (Na%) were utilized to evaluate the groundwater’s adaptability to irrigation. Furthermore, this study also assessed the health risks faced by adults and children in the UWR. The findings indicate that the main cations and anions in groundwater are Ca²⁺ and HCO₃⁻, respectively. The hydrochemical types are predominantly HCO₃-Ca, Cl-Ca, and mixed types. The composition of groundwater is primarily influenced by the dissolution of silicate and carbonate minerals, with cation exchange also playing a significant role in shaping its hydrochemical characteristics. The water quality assessment indicates that the majority of groundwater in UWR is classified as “excellent” or “good”, rendering it suitable for human consumption. However, 7.17% of the water samples were of poor quality and unsuitable for drinking; these were primarily located in a few areas in the northern and western parts of the study area. Regarding irrigation, 94.83% of the groundwater is deemed very suitable; however, a small fraction is not appropriate for such use. Additionally, non-carcinogenic risks are generally higher across most parts of the study area for both children and adults, with children exhibiting significantly higher risks than adults. These findings offer crucial insights regarding the sustainable management and environmental conservation of groundwater resources in the UWR.