Hydrochemical Analysis Research Articles

New approach to predict wastewater quality for irrigation utilizing integrated indexical approaches and hyperspectral reflectance measurements supported with multivariate analysis

Irrigation water quality is critical to maintaining agricultural output. Reusing wastewater is a global activity that serves as an alternative water resource in agriculture. This study integrates water quality indices and hyperspectral reflectance measurements to assess and predict the drain water quality for irrigation in Egypt. For that, 50 drain water samples were collected surrounding Rosette Branch in Egypt. Four major findings emerge from this Nile Delta wastewater irrigation study: First, the integrated index approach revealed significant spatial variability, with 4% of drains (IWQI < 60) requiring pretreatment and 94% showing low metal contamination (PI < 1), except for Zn hotspots near industrial areas. Second, the newly developed spectral indices such RSI566, 1140 and RSI564, 1140 were strongly related to Total Chlorophyll with R2 = 0.73, and RSI456,422 was strongly related to irrigation water quality index (IWQI) with R2 = 0.67. As well as RSI500, 400 had good relationship with Biochemical Oxygen Demand (BOD) with R2 = 0.75. Third, optimized PLSR models demonstrated higher accuracy in estimating WQIs. For instance, the PLSR model produced reliable estimates of T Chl., achieving R2 = 0.87 and 0.77 for the calibration and validation dataset. Similarly, the model provided accurate predictions for BOD, with R2 = 0.96 and 0.81 for calibration and validation. Finally, hydrochemical analysis established evaporation dominance (Gibbs ratio > 0.8) in 72% of samples, explaining the Ca-Mg-SO4 facies prevalence. While currently validated for Nile Delta conditions, the methodology’s 89% cross-region accuracy in preliminary tests suggests broad applicability to wastewater irrigation schemes. Future implementation should focus on: (1) farmer-adoptable spectral sensors for the identified optimal bands (566–570 nm, 1140 nm), (2) targeted filtration for Zn/Mn reduction in high-PI drains, and (3) seasonal model calibration to account for Nile flow variations. This work establishes a new paradigm for combining precision spectroscopy with traditional water quality assessment in water-scarce agricultural systems.

Hydrogeochemical characteristics of cold and warm (hot) springs in the Mahallat Geothermal Region, Iran

This study presents a hydrogeochemical evaluation of warm (hot) and cold springs in the Mahallat hydrothermal region of Iran. Sampling and hydrochemical analyses were conducted, and aquifer temperatures were estimated using various geothermometers. Results indicate that most of the warm (hot) waters in the study area fall within the steam-heated water field of Giggenbach, formed through the interaction of warm (hot) water with sulfate minerals and mixing with shallow groundwater. They are classified as Ca-SO₄ type, with higher sulfate concentrations compared to chloride and bicarbonate. Travertine layers, primarily composed of calcium carbonate, promote geochemical processes like gypsum dissolution, increasing sulfate levels. In cold springs, water types are influenced by the leaching of Ca⁺, K⁺, Mg²⁺, and Na⁺, with Na⁺ concentration affected by Na-feldspar dissolution. Geothermometry revealed that in the Mahallat geothermal massif, amorphous silica controls solubility, with aquifer temperatures ranging between 95 and 100 degrees Celsius. The region exhibits high lithium concentrations in thermal waters, primarily sourced from lithium silicate minerals in granite and granodiorite, influenced by biotite chloritization and feldspar sericitization. Overall, Mahallat represents a developing geothermal system with significant geochemical interactions between groundwater and thermal resources.

Expanding cryospheric landform inventories – quantitative approaches for underestimated periglacial block- and talus slopes in the Dry Andes of Argentina

There is a clear spatial discrepancy between the area potentially underlain by permafrost and the landforms recorded in the national inventory of cryospheric landforms in the Dry Andes of Argentina (∼22°–35°S). In the periglacial belt around 30°S, these areas are often covered by extensive block- and talus slopes, whose distribution and potential permafrost content have received little attention so far. We present the first geomorphological mapping and predictive modeling of these underestimated landforms in a semi-arid high Andean catchment with representative cryospheric landform cover (30°S, 69°W). Random forest models produce robust and transferable predictions of both target landforms, demonstrating a high predictive power (mean AUROC values ≥0.95 using non-spatial validation and ≥0.83 using spatial validation). By combining geomorphological mapping, predictive modeling, and geostatistical analysis of block- and talus slopes, we enhance our knowledge of their distribution characteristics, formative controls and potential ground ice content. While both landforms provide suitable site conditions for permafrost occurrence, talus slopes are expected to contain significantly higher ground ice content than blockslopes due to their more favorable characteristics for ice formation and preservation. Given their widespread distribution across almost 79% of the modeled area, block- and talus slopes constitute potentially important ground ice storages and runoff contributors that are not included in current hydrological assessments of mountain permafrost. Our results underscore the need to expand existing cryospheric landform inventories to achieve a more comprehensive quantification of underrepresented periglacial landforms and thus a realistic acquisition of cryospheric water resources in high mountain environments. The newly compiled inventories can serve as a basis for further investigations (e.g., geophysical surveys, hydrochemical analysis, permafrost distribution models) at different spatial scales.

Potential appraisal of drainage water reclamation and indirect reuse for irrigation in the Nile Delta, Egypt.

Sustaining freshwater supplies has become a global challenge, especially for arid and semi-arid countries. Egypt is now categorized as a water-scarce country facing an exacerbated water deficit. Thus, it has recently adopted a strategy for recycling agricultural drainage water (ADW) to fulfil the irrigation water requirements. This study aims to appraise the feasibility of reusing ADW in the Nile Delta. Accordingly, water samples were gathered from six irrigation streams in a district where mixing stations are intensively installed. The hydro-chemical analysis of 23 water quality parameters sufficiently aligned with the local tolerance limits for the ADW indirect reuse. Nine indicators, including ratios of adsorption, soluble and exchangeable sodium, permeability index (PI), Kelly's ratio (KR), and magnesium hazard (MH), along with the irrigation water quality index (IWQI), were estimated to measure the water suitability for cultivation purposes. The ADW was unfavorable for irrigation due to excess salts, sodium, and chloride, which can cause soil salinization and yield reduction. The blending approach of the ADW with canal waters was critical to retrieving highly suitable irrigation water, saving a significant proportion of the water requirements, and increasing irrigation efficiency. The potential to reclaim and reuse the ADW through membrane-based desalination was promising. However, reverse osmosis (RO) membranes were superior in recovering more suitable water than nanofiltration (NF) membranes. The findings offer insights to water managers on feasible solutions to meet increasing water demand. Conjunctive adoption of recycled water with groundwater for ongoing reclamation projects in Egypt is advocated.

Spatial variability of lacustrine groundwater discharge and pollutant fluxes in the sandy-land lake group basins: Influence from land use types.

Spatial variability of lacustrine groundwater discharge and pollutant fluxes in the sandy-land lake group basins: Influence from land use types.

Advancing groundwater sustainability: Strategy combining hydro-chemical analysis, pollution mitigation, and community-based water resource governance

Advancing groundwater sustainability: Strategy combining hydro-chemical analysis, pollution mitigation, and community-based water resource governance

Groundwater Vulnerability in the Kou Sub-Basin, Burkina Faso: A Critical Review of Hydrogeological Knowledge

Groundwater resources in the Kou sub-basin of southwestern Burkina Faso play a critical role in supporting domestic water supply, agriculture, and industry in and around Bobo-Dioulasso, the second-largest city in Burkina Faso. This study synthesizes over three decades of research on groundwater vulnerability, recharge mechanisms, hydrochemistry, and residence time across the region’s sedimentary aquifers. The Kou basin hosts a complex stratified system of confined and unconfined aquifers, where hydrochemical analyses reveal predominantly Ca–Mg–HCO3 facies, alongside local nitrate (0–860 mg/L), iron (0–2 mg/L) and potassium (&lt;6.5 mg/L–190 mg/L) contamination. Vulnerability assessments—using parametric (DRASTIC, GOD, APSU) and numerical (MODFLOW/MT3D) models—consistently indicate moderate to high vulnerability, especially in alluvial and urban/peri-urban areas. Isotopic results show a deep recharge for a residence time greater than 50 years with deep groundwater dating from 25,000 to 42,000 years. Isotopic data confirm a vertically stratified system, with deep aquifers holding fossil water and shallow units showing recent recharge. Recharge estimates vary significantly (0–354 mm/year) depending on methodology, reflecting uncertainties in climatic, geological, and anthropogenic parameters. This review highlights major methodological limitations, including inconsistent data quality, limited spatial coverage, and insufficient integration of socio-economic drivers. To ensure long-term sustainability, future work must prioritize high-resolution hydrogeological mapping, multi-method recharge modeling, dynamic vulnerability assessments, and strengthened groundwater governance. This synthesis provides a critical foundation for improving water resource management in one of Burkina Faso’s most strategic aquifer systems.

Geoinformation and Analytical Support for the Development of Promising Aquifers for Pasture Water Supply in Southern Kazakhstan

Ensuring water resources for livestock production in Kazakhstan presents a multifaceted challenge. Pastoral systems in Southern Kazakhstan are facing a critical groundwater shortage, with 56.5% of pastures currently unused due to limited water access, jeopardizing around 2 million head of livestock and the region’s food security. This study presents the first comprehensive groundwater assessment in over 40 years, integrating hydrochemical analysis (55 samples) and field surveys conducted in the Almaty and Zhetysu regions. Key findings include: the total water demand for livestock is estimated at 53,735 thousand m3/year, with approximately 40% of samples exceeding WHO guidelines for total mineralization. It was determined that 45% of exploitable groundwater reserves in the Almaty region and 15–17% in the Zhetysu region are suitable for irrigation. This study also provides updated hydrogeological data, identifying three priority aquifer systems. A novel Groundwater Sustainability Index for pastoral zones of Central Asia is introduced, demonstrating that strategic aquifer development could expand watered pastureland by 30–40%. These findings directly inform Kazakhstan’s Agricultural Development Plan through 2030 and provide a replicable framework for sustainable water management in arid regions. With 69,836 rural residents currently lacking access to safe water, our results underscore the urgent need for infrastructure investment to meet SDG 6 targets (ensure availability and sustainable management of water and sanitation for all).

Effect of Mine Water Environment on Durability of Solid Backfilling Based on Carbonated Coal-Based Waste.

The durability of solid backfilling based on carbonated coal-based waste (CCBW) under mine water environments is critical for its engineering feasibility. This study investigates the deterioration mechanisms of CCBW exposed to acid solution (Acid W), alkaline solution (Alkaline W), and mine water (Mine W) through hydrochemical analysis, XRD, and SEM. Results reveal that the uniaxial compressive strength of CCBW decreased by 10.05, 3.93, and 1.62% after 28 days of immersion in the groups, respectively. Acid conditions induced CaCO3 dissolution and gypsum formation, while alkaline environments triggered alkali-silica reaction expansion. Mine water exhibited minimal impact due to suspended particles mitigating ion exchange. Carbonation also enhanced the durability of CCBW by forming dense CaCO3 clusters and C-A-S-H gels, thus reducing ion leaching. Notably, the average erosion resistance of carbonated samples (CCBW-5, 10, 30) was 2.32% higher than that of noncarbonated counterparts. These findings confirm the feasibility of CCBW applications in weakly alkaline mine water and highlight its potential for sustainable coal mining practices, aligning with carbon capture and circular economy principles.

Innovative Machine Learning, Isotopic, and Hydrogeochemical Techniques for Groundwater Analysis in Arid Landscapes in Egypt’s Eastern Desert

Abstract Groundwater serves as a lifeline in Egypt’s hyper-arid Eastern Desert, particularly for agricultural and domestic uses. However, a comprehensive understanding of groundwater origin, quality, and recharge dynamics in the region remains limited due to geological complexity, data scarcity, and the high cost of isotopic analysis. This study addresses these challenges by integrating stable isotopes (δ¹⁸O and δ²H), hydrogeochemical parameters, remote sensing, and explainable artificial intelligence (AI) to investigate groundwater dynamics and support sustainable water management strategies. A total of 34 groundwater samples were collected from three key aquifers: the Quaternary alluvium, Nubian Sandstone, and fractured Basement aquifers. Hydrochemical analyses and isotopic signatures distinguish meteoric water from paleowater sources, revealing significant mixing and recharge processes. The findings indicate that the Quaternary aquifer is increasingly influenced by upward leakage from the Nubian aquifer, facilitated by deep-seated faults. Between 2014 and 2021, water levels in the Quaternary aquifer declined by up to 14 m due to over-extraction, particularly in agricultural zones. To enhance predictive capabilities, a Support Vector Machine (SVM) model was developed to estimate δ¹⁸O values using multiple hydrochemical indicators, achieving strong performance (R² = 0.92, MSE = 2.89). SHapley Additive exPlanations (SHAP) analysis identified Mg²⁺, HCO₃⁻, and SO₄²⁻ as dominant factors influencing isotope variation. This integrated approach represents a novel application of explainable machine learning in hydrogeology and offers a scalable, cost-effective tool for assessing groundwater systems in arid regions. The study contributes directly to national water security goals and supports the global Sustainable Development Goal 6 (SDG 6) for clean water and sanitation.

Comprehensive analysis of groundwater hydrochemistry and nitrate health risks in the Baiquan basin, Northern China.

Groundwater is a crucial water source and strategic resource, essential for sustaining both urban and rural livelihoods, supporting economic and social development, and maintaining ecological balance. This study investigates the hydrochemical properties and controlling factors of groundwater in the Baiquan basin (BQB) by analyzing water quality data collected during both dry and wet periods. Additionally, the suitability of groundwater for drinking and agricultural irrigation was evaluated. The findings reveal that groundwater in BQB is generally weakly alkaline and primarily consists of hard-fresh water. Although there are seasonal variations in the main ion concentrations, HCO3 - and Ca2+ are the predominant anions and cations, respectively. Consequently, the hydrochemical type is mainly HCO3-Ca⋅Mg type, with a secondary classification of SO4⋅Cl-Ca ⋅ Mg. The hydrochemical composition is primarily influenced by the dissolution of carbonate and silicate minerals, as well as cation exchange processes. Additionally, it is affected by anthropogenic inputs, particularly from the use of agricultural fertilizers. The water quality assessment results indicated that all water samples are classified as either good or moderate, with a significant majority falling into the good category. Additionally, the northern section of the BQB exhibited lower entropy weight water quality index (EWQI) values during the dry season in comparison to the wet season. For irrigated agriculture, groundwater in the BQB serves as a high-quality water source for irrigation throughout both the dry and rainy seasons. Furthermore, non-carcinogenic risks are notably concentrated in the north-western and south-eastern regions of the study area. Health risks associated with nitrates in groundwater are elevated during the rainy season. Notably, non-carcinogenic risks for infants were significantly high across both seasons and substantially exceeded those for children and adults. These results provide valuable scientific insights for the management and development of groundwater resources in the BQB.

Assessment of Mercury Contamination in the Chalk Aquifer of the Pays de Caux and Its Implications for Public Health (France)

Mercury is naturally present in soils at trace concentrations, but its cycle is increasingly disrupted by anthropogenic activities, which affect its distribution and behavior. Due to its toxic nature, mercury has become a significant focus in environmental and public health policies. Following the detection of mercury anomalies during groundwater quality monitoring at the Pays de Caux study site (France), a comprehensive multidisciplinary research effort was initiated. This included geological and hydrogeological studies aimed at tracking mercury concentrations in piezometric wells and identifying the sources of these anomalies. This study seeks to assess the groundwater quality and characteristics from ten hydrogeological wells. The evaluation will focus on key hydrogeological parameters, including pH, redox potential (Eh), suspended solids, and groundwater levels, as well as a detailed geochemical analysis of elements such as Hg, Fe, Mn, Zn, Pb, and Cu. The mobilization of mercury and other metallic traces elements is strongly governed by environmental factors. Hydrochemical analyses highlight the complex interplay of various parameters that influence the chemical forms and behavior of mercury in both soil and groundwater. The results from the piezometric measurement campaigns (Pz1 to Pz7) have provided crucial insights, enabling the development of hypotheses about mercury’s behavior in the chalk aquifer. It is hypothesized that impermeable areas may trap groundwater for extended periods, leading to the accumulation and abnormal concentration of mercury. This could cause mercury to be intermittently released, potentially affecting the surrounding environment. Mercury concentrations in groundwater are highly sensitive to pH and redox potential (Eh), with low pH and reducing conditions promoting mercury mobilization and the formation of toxic methylated species. The study suggests the chalk aquifer is generally in equilibrium with mercury, but fluctuations in mercury levels between Pz7 and Pz4 are likely due to the heterogeneity of the clay and geological factors such as mineral composition and fracturing. This research provides insights into mercury transfer in heterogeneous environments and emphasizes the need for continuous hydrogeological monitoring, including piezometer readings, to manage mercury dispersion in the aquifer.

Hydrochemistry and Evolutionary Processes During Saltwater Intrusion in the Saline–Fresh Groundwater Transition Zone in Southern Laizhou Bay, China

Saltwater intrusion is one of the most significant groundwater challenges in the southern Laizhou Bay. Previous studies have predominantly focused on regional scales, leaving the vertical saltwater intrusion pattern relatively underexplored. This knowledge gap hinders the effective prevention and control of saltwater intrusion. This study utilized hydrochemical and stable isotopic methods combined with hydrochemical facies evolution diagrams to investigate the groundwater evolution and the processes of saltwater intrusion in a typical profile and saline–fresh groundwater transition zones. The results showed that the groundwater types in the study area were complex and diverse, with fresh groundwater, saline groundwater, and brine. Stable isotope and hydrochemical analyses indicated that mixing and evaporation of seawater were the predominant processes governing the evolution and salinity of groundwater. In the south of the typical profile, carbonate dissolution played a significant role, and the silicate dissolution may represent the primary water–rock interaction in the saline–fresh groundwater transition zones. Groundwater samples from various locations within the study area exhibited different stages of hydrochemical facies evolution, and the majority of the typical profile samples were in the salinization phase during the mixing process. The saltwater intrusion in the saline–fresh groundwater transition zone primarily occurred between −20 and −30 m, exhibiting a wedge-shaped saltwater intrusion pattern. This study enhanced the understanding of vertical saltwater intrusion.

New insights into nitrate sources and transformations in riparian groundwater of a sluice-controlled river: An integrated approach using major ions, stable isotopes and microbial gene methods.

New insights into nitrate sources and transformations in riparian groundwater of a sluice-controlled river: An integrated approach using major ions, stable isotopes and microbial gene methods.

Hydrochemical analysis of surface water flow from an abandoned iron ore mine

Purpose. The purpose of this research is to investigate the potential formation of contaminants in abandoned mining areas due to the interaction between rocks, water, and air, as well as their impact on surface water quality around the mine area. Methods. Mineralogical analysis using an optical microscope and X-ray diffraction (XRD) on iron ore samples obtained from the stockpiles and chemical analysis of water obtained from the mining site and downstream river. Findings. Iron ore at the study site is dominated by iron oxide minerals such as magnetite, hematite, and goethite. Additionally, quartz, birnessite, pyrite, and chalcopyrite minerals were also found. The mineral content indicates the presence of two sulfide minerals that have the potential to form acid mine drainage, namely; pyrite (FeS2) and chalcopyrite (CuFeS2). The pH measurement results of the water flowing from the iron ore stockpile have a pH of 2.9, while the void and surrounding river vary from 6.4 to 8.2. Originality. Identifying iron ore minerals by combining polarized light microscopy and XRD can enhance the reliability of the observation results. Both methods showed the same results in identifying sulfide minerals, with chalcopyrite in the excavated iron ore stockpile and pyrite in the crushed iron ore stockpile. The formation of acid mine drainage at abandoned mine sites is only a local phenomenon, and after being diluted by other water flows, the water's pH returns to neutral. Practical implications. This research activity was conducted during the rainy season when overflow occurred, with water spilling from the mine pit lake to the surrounding areas. The results show that the formation of acid mine drainage and the high concentration of total Fe that occurred in one of the stockpiles did not affect the change in water quality around the mine, and there is potential for water in the mine void to be used as a water source for the surrounding community.

САНИТАРНО-МИКРОБИОЛОГИЧЕСКАЯ ОЦЕНКА ОЗЕР БОЛЬШОЙ ТАЛДЫКОЛЬ И ЖАЛТЫРКОЛЬ

Hydrochemical, bacteriological, and parasitological parameters were studied in Big Taldykol and Zhaltyrkol lakes: pH, suspended solids, oxygen conditions (dissolved oxygen, BOD5, COD); mineralization (dry residue, chlorides, sulfates, total hardness, total alkalinity); biogenic substances (phosphates, ammonium nitrogen, nitrites, nitrates, boron); metals (iron, copper, chromium, nickel, zinc, manganese, molybdenum); organic substances (fluorides, synthetic surfactants, oil products). According to the results of hydrochemical analyses Big Taldykol Lake belongs to the sixth class of water quality, where high value of COD 42.8 mg O2/l, suspended solids - 46.0 mg/l, total iron 0.83 mg/l were observed. In Lake Zhaltyrkol suspended solids were 18.62 mg/l, so Lake Zhaltyrkol also belongs to the sixth class of water quality. According to other indicators in the lakes there is no toxicological hazard. The excess of a number of components may be related to the natural xenobiotic profile of the environment. According to the results of bacteriological studies, the content of lactose-positive Escherichia coli and coliphages did not exceed permissible levels. According to the results of parasitological studies, no viable eggs of ascarids, vlagoslav, toxocaria, fasciola, oncospheres of tennidae, or cysts of pathogenic intestinal protozoa were found in the water of the lakes. A large number of infusoria, rotifers, and gastrotrichia, along with the dominance of diatom algae, indicate eutrophication of the water body and a high risk of water blooms.

Geophysics and Geochemistry Reveal the Formation Mechanism of the Kahui Geothermal Field in Western Sichuan, China

This study investigated the formation mechanism of the Kahui Geothermal Field in Western Sichuan, China, using geophysical and geochemical approaches to elucidate its geological structure and geothermal origins. This study employed a combination of 2D and 3D inversion techniques involved in natural electromagnetic methods (magnetotelluric, MT, and audio magnetotelluric, AMT) along with the analysis of hydrogeochemical samples to achieve a comprehensive understanding of the geothermal system. Geophysical inversion revealed a three-layer resistivity structure within the upper 2.5 km of the study area. A geological interpretation was conducted on the resistivity structure model, identifying two faults, the Litang Fault and the Kahui Fault. The analysis suggested that the shallow part of the Kahui Geothermal Field is controlled by the Kahui Fault. Hydrochemical analysis showed that the water chemistry of the Kahui Geothermal Field is of the HCO3−Na type, primarily sourced from atmospheric precipitation. The deep heat source of the Kahui Geothermal Field was attributed to the partial melting of the middle crust, driven by the upwelling of mantle fluids. This process provides the necessary thermal energy for the geothermal system. Atmospheric precipitation infiltrates through tectonic fractures, undergoes deep circulation and heating, and interacts with the host rocks. The heated fluids then rise along faults and mix with shallow cold water, ultimately emerging as hot springs.

Research on the Features and Driving Factors of Shallow Groundwater Quality in Arid Areas, Northwest China

Given the increasing threat of groundwater pollution, comprehending the trends and influencing factors of groundwater quality variation is essential for effective mitigation strategies. This study addresses groundwater quality variations in the Beichuan River, a critical area in China’s arid region. Using hydrochemical analysis and multivariate statistics, we identified key factors influencing groundwater quality. Groundwater is mildly alkaline, with HCO3−-Ca as the dominant hydrochemical type. The concentrations of major ions increase during the high-flow period due to rainfall effects. The dissolution of rock salt primarily contributes to the presence of Na+ and Cl− ions. Meanwhile, the weathering of silicate and carbonate rocks is the main origin of Ca2+, Mg2+, and HCO3− ions. Additionally, the dissolution of evaporite rocks is identified as the principal source of SO42−. Human activities, particularly sewage discharge and fertilization, significantly contribute to nitrate contamination. Principal component analysis revealed that the weathering of rocks and industrial activities are the main controlling factors during the high-flow season, while the hydrochemistry of groundwater during the low-flow season is mainly influenced by the weathering of silicate rocks, evaporite rocks, and rock salt. Our findings provide a scientific basis for preventing groundwater quality deterioration and ecological environmental protection in arid regions.

Exploring the Hydrochemical Properties of Groundwater in Madurai District for Sustainable Water Management

Groundwater is one of the most critical water resources on earth and it is a significant source of water for domestic consumption, agriculture and industry. Its reliability makes it invaluable, especially where there is a lack of surface water or seasonally varying surface water. In Madurai District, groundwater has been a lifeline to generations, supporting local communities and agricultural systems. Sadly, the present status of groundwater in Madurai is a cause for concern in terms of quantity and quality. Excessive extraction over the past decades has resulted in a noticeable reduction in groundwater levels in Madurai. Coupled with this, uncontrolled waste disposal, agricultural runoff and industrial effluent has dumped pollutants into the aquifers. Recent hydro-chemical investigations indicate high salinity, hardness and nitrates in some areas, which indicates that pollution is exerting a negative effect on water quality. Such changes undermine not only human health but also the long-term sustainability of agricultural production in the district. Resolution of these issues involves the adoption of sustainable water management practices appropriate to the particular context of Madurai District. Implementing best practices for groundwater management is essential for sustainable water resources. This involves promoting recharge initiatives to replenish aquifers, limiting water withdrawal to prevent over-extraction and establishing comprehensive monitoring systems to assess both water quantity and quality. Utilizing advanced hydro-chemical analysis and spatial mapping techniques, pollution hotspots can be accurately identified, allowing for targeted remediation efforts. These measures collectively contribute to maintaining a balanced groundwater supply, ensuring safe and reliable water for domestic, agricultural, and industrial needs.

Saltwater intrusion in coastal Lebanon: evolution of patterns, and database for groundwater quality monitoring and management

ABSTRACT Half a century after the only national-scale report on saltwater intrusion (SWI) in Lebanon, the evolution of this hazard is re-examined. SWI proxies from 4000+ field measurements and chemical samplings are collected from a network of 276 sites. To interpret this dataset, the coast is divided into seven large coastal areas which are then sub-divided into 14 smaller coastal hydrogeological zones (CHZs) reflecting uniform hydrogeological conditions and properties. Hydrochemical analyses characterized the groundwater types of the coast. Fresh–brackish to brackish–salt NaCl or CaCl water types attaining elevated salt content are present in several zones, and ongoing salinization to variable extents affects four CHZs. Porous-unconsolidated aquifers suffered the largest salinization spread compared to fractured karstic aquifers. Over-pumping is the main SWI driver in many zones. Comparing to older results, fast-ascending SWI impacts most coastal groundwater resources. The database from this study is shared to serve urgently needed continuous monitoring of SWI proxies and groundwater resources management.