Search Results (80)

Groundwater is the main source of water for both domestic and agricultural use in arid regions. This study assessed the hydrogeochemical characteristics and suitability of groundwater for drinking and irrigation in Kenya’s Ewaso Ng’iro–Lagh Dera Basin. A total of 129 borehole groundwater samples were collected and analyzed for pH, electrical conductivity (EC), total hardness, and major ions. The groundwater was found to be mostly neutral to slightly alkaline and ranged from marginal to brackish in salinity. The dominant water type is Na-HCO₃, with the ionic order Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ and HCO₃⁻ > Cl⁻ > SO₄²⁻ > NO₃⁻. Mineral saturation indices indicate that the water is undersaturated with gypsum and anhydrite but is saturated with calcite, dolomite, and aragonite. Groundwater chemistry is primarily influenced by ion exchange, the mixing of fresh and paleo-saline water, and rock weathering processes. The water quality index (WQI) reveals that 80.5% of groundwater is suitable for drinking. The rest have high levels of sodium, EC, and bicarbonate. Thus, they are not suitable. The irrigation water quality index (IWQI) places most samples in the moderate-to-severe restriction category due to high salinity and sodicity. These findings highlight the importance of properly treating groundwater before use. Full article

Water plays a critical role in the growth and management of fresh produce, being a vital resource and a potential vector for pathogens. To address these concerns, guidelines for the microbiological quality of treated wastewater, recreational, irrigation, and drinking water have been established worldwide. With multiple outbreaks linked to Escherichia coli (E. coli) contamination, monitoring and improving water quality standards have become essential, especially for small-scale and limited-resource farmers. The Food Safety and Modernization Act (FSMA, 2014) in the United States was introduced to regulate microbiological safety of produce, focusing on irrigation water. Approximately 77% of farmers in Kentucky are small farmers, of which, 4.2% supply directly to consumers through various avenues, accounting for approximately USD 24 million a year. This study examined the microbial quality of irrigation water used in Kentucky, focusing on the presence and number of coliform bacteria and E. coli. The report covers findings from a year-long program providing free microbial water quality testing to producers (n = 90), analyzing groundwater and surface water samples (n = 296). Results indicate surface water showing a significantly higher risk of exceeding FSMA thresholds. The findings emphasize the need for continued outreach, education, and accessible testing resources to support compliance with evolving Produce Safety Rule regulations, especially among small-scale producers. Full article

Fresh groundwater is essential for sustaining life and socio-economic development, particularly in regions with limited safe drinking water alternatives. However, contamination from natural and anthropogenic sources poses severe health and environmental risks. This research examines the health risks linked to groundwater quality in the agroeconomic region of Boudh district, Odisha, India, where residents depend on untreated groundwater due to limited access to alternative sources. A total of 82 groundwater samples were analyzed during pre- and post-monsoon of the year 2023 using multivariate statistical methods (PCA, correlation analysis) to determine pollutant sources and regulatory factors, while XRD was employed to characterize fluoride-bearing minerals in associated rock samples. Fluoride concentrations range from 0.14 to 4.6 mg/L, with 49% of samples exceeding the WHO limit of 1.5 mg/L, which raises significant health concerns. Nitrate levels fluctuate between 1.57 and 203.51 mg/L, primarily due to agricultural fertilizers. A health risk assessment (hazard quotient and hazard index) indicates that 63% of samples fall into the low-risk category, 21% into moderate-risk, and 16% into high-risk. Children (HI = 29.23) and infants (HI = 19.51) are at the greatest health risk, surpassing that of adult males (HI = 12.2) and females (HI = 11.2). Findings provide scientific evidence for policymakers to implement groundwater protection and remediation strategies. Immediate interventions, including water quality monitoring, defluoridation measures, and community awareness programs, are essential for ensuring long-term water security and public health. Full article

Wetland lakes are crucial ecosystems that serve as vital ecosystems that harbor rich biodiversity and provide essential ecological services, particularly in regulating regional water resources, purifying water quality, and maintaining ecological equilibrium. This study aims to conduct an in-depth investigation into the hydrochemical characteristics and their controlling factors during the dry season of the Hengshui Lake wetland system. By collecting water samples from the lake and shallow groundwater, and using water chemistry diagrams, ion ratios, mineral saturation indices, and multivariate statistical methods, the study systematically analyzes the hydrochemical characteristics of Hengshui Lake Wetland and its controlling factors. The results show: there is significant stratified differentiation in the water chemical composition: the lake water is weakly alkaline and fresh, while the shallow groundwater is highly mineralized and saline. Both are dominated by Na⁺, Mg²⁺, SO₄²⁻, and Cl⁻. Significant differences exist in water chemistry types between the lake and shallow groundwater. The lake water exhibits homogenized characteristics with a dominant SO₄·Cl·HCO₃-Na·Mg type, whereas shallow groundwater displays five distinct hydrochemical facies indicative of multi-source recharge processes. Evaporation–rock interaction mechanisms dominate the system, as evidenced by a Gibbs diagram analysis showing evaporation crystallization as the primary control. Ion ratio calculations demonstrate synergistic effects between silicate weathering and evaporite dissolution, while mineral saturation indices confirm cooperative processes involving calcite/dolomite oversaturation and ongoing gypsum dissolution. Cation exchange indexes combined with chloro-alkaline indices reveal unidirectional recharge from lake water to shallow groundwater accompanied by active cationic exchange adsorption. Although the wetland predominantly maintains natural hydrological conditions, elevated γ(NO₃⁻)/γ(Na⁺) ratios in nearshore zones suggest initial agricultural contamination infiltration. This study shows that, as a typical example of a closed wetland, the hydrochemistry evolution of Hengshui Lake during the dry season is primarily dominated by the coupled effects of evaporation and rock–water interaction, with silicate weathering and evaporation rock dissolution as secondary factors, and human activity having a weak influence. The findings provide new insights into the understanding of the hydrochemical evolution process and its controlling factors in closed lakes, offering valuable data support and theoretical basis for the ecological restoration and sustainable management of closed lakes. Full article

Groundwater is crucial for domestic, agricultural, and ecological uses, particularly in the lower reaches of arid basins, where its quality often limits availability. A total of 26 phreatic groundwater samples were collected from a typical endorheic watershed on the Tibetan Plateau to assess the hydrochemical characteristics of phreatic groundwater in the lower reaches of arid inland watersheds. The hydrochemical characteristics, quality, and formation mechanisms of groundwater were analyzed using the Entropy-Weight Water Quality Index (EWQI), irrigation water quality indexes (such as sodium adsorption ratio, soluble sodium percentage, and permeability index), hydrochemical diagrams, and correlation analysis. The findings indicate that phreatic groundwater in the lower reaches is slightly alkaline, with a substantial TDS variation from 252.58 to 1810.41 mg/L. Groundwater is predominantly characterized by fresh hydrochemical facies of HCO₃-Ca and HCO₃-Na types, with a few saline Cl-Na types present. The concentrations of NO₃⁻, NO₂⁻ and NH₄⁺, in groundwater range from 0.32 to 100.00 mg/L, 0.00 to 0.48 mg/L, and 0.00 to 0.20 mg/L, respectively, and 3.59%, 26.92%, and 7.69% of the samples exceeding the permissible drinking limits recommended by Chinese guideline and World Health Organization. Groundwater is classified as fresh at 80.8% of sampling sites and brackish at 19.2%. Approximately 96.2% of the sampled groundwaters is rated as excellent to medium quality according to EWQI assessments, suitable for domestic use, while 3.8% is of extremely poor quality and should be avoided for direct consumption. Groundwater from all sampling sites is suitable for agricultural irrigation and does not pose permeability hazards to the soil. Most groundwaters are suitable for long-term irrigation in terms of sodium hazards, with only 3.8% and 7.7% of samples falling into the “Permissible to Doubtful” and “Doubtful to Unsuitable” categories, respectively. Salinity poses the primary threat in long-term irrigation, with 38.5%, 53.8%, and 7.7% of sampled groundwaters exhibiting moderate, high, and very high salinity risks, respectively. Groundwater chemistry is primarily governed by water-rock interaction and evaporation, with additional impacts from agricultural inputs of nitrogen contaminants and chemicals. Agricultural practices contribute to elevated groundwater salinity in the study area, while natural evaporation drives salinity accumulation in the lower parts. In managing and utilizing groundwater resources in the study area and similar arid regions globally, attention should be paid to salinity caused by agricultural activities and natural evaporation, as well as nitrogen pollution from farming. Full article

Mineralization of groundwater for drinking purposes is a complex parameter of groundwater chemical composition. In the Shaim oil- and gas-bearing area, as in the whole West Siberian megabasin, the main target horizon for solving the issues of domestic and technical water supply is the Oligocene aquifer. It has significant groundwater reserves to cover the needs of the population and production requirements. However, it also faces a huge anthropogenic load in the form of water withdrawal and possible contamination from the surface with oil products. In Western Siberia, various deviations in the chemical composition of groundwater of the Oligocene horizon are recorded in connection with significant water withdrawal; for example, a sharp increase in chromaticity or total iron concentration, with changes in mineralization acting as a factor necessarily accompanying these deviations. Based on the data obtained in the course of monitoring for the period from 2013 to 2023, the main factors and trends of changes in the components of mineralization of the Oligocene horizon were determined. The lithological and mineralogical peculiarities of the water-bearing rocks of the horizon, the paleogeographic conditions of its formation and their relation to trends in mineralization change were studied. Water withdrawal data were processed for two cluster water withdrawal sites (50 and 5 wells, respectively). Analysis of the results showed that the increase in water withdrawal leads to an increase in infiltration from the overlying Neogene-Quaternary aquifer, which leads to the dilution of groundwater of the Oligocene horizon and a decrease in its mineralization. Here, we show that, during further monitoring, it is necessary to pay attention to the appearance of sites where significant amounts of chloride ions are fixed in the anion composition, which can potentially lead to a sharp deterioration in the quality of drinking groundwater. Full article

In this study, hydrogeochemistry and environmentally stable isotopes were employed to examine the processes involved in recharging aquifer systems and the changes in the groundwater chemistry caused by the interaction between the water and the aquifer matrix. Based on data derived from 113 groundwater wells, various tools and techniques, including stable environmental isotopes Oxygen-18 and Deuterium (δ¹⁸O and δD) for 33 samples and geochemical modeling with NETPATH, were used to evaluate the recharge mechanism and the evolution of the groundwater, combining GIS with hydrological and hydrochemical methods. The results revealed that groundwater from the Quaternary was the main source for irrigation; the water quality was categorized as relatively fresh to saline, with the total dissolved solids (TDSs) ranging from 261.3 to 8628.56 mg/L, exhibiting an average value of 2311.68 mg/L. The results of the environmental isotope analysis showed that the range of oxygen δ¹⁸O isotopes in the groundwater was from −5.65‰ to +0.39‰, while the range of hydrogen δD isotopes was from −32.60‰ to 4.73‰. Moreover, the δ¹⁸O–δD relationship indicated that the groundwater samples fell around the global meteoric precipitation line, showing a strong relationship, with a coefficient (R²) of approximately 0.82. The NETPATH model revealed that the dissolved chemical species within the groundwater system primarily originated from processes such as mineral weathering and dissolution, ion exchange, and evaporation. Full article

Groundwater resource is crucial for the development of agriculture and urban communities in valley basins of arid and semiarid regions. This research investigated the groundwater chemistry of a typical urbanized valley basin on the Tibetan Plateau to understand the hydrochemical status, quality, and controlling mechanisms of groundwater in arid urbanized valley basins. The results show groundwater is predominantly fresh and slightly alkaline across the basin, with approximately 54.17% of HCO₃-Ca type. About 12.5% and 33.33% of sampled groundwaters are with the hydrochemical facies of Cl-Mg·Ca type and Cl-Na type, respectively. Groundwater is found with the maximum TDS, NO₃⁻, NO₂⁻, and F⁻ content of 3066 mg/L, 69.33 mg/L, 0.04 mg/L, and 3.12 mg/L, respectively. Groundwater quality is suitable for domestic usage at all sampling sites based on EWQI assessment but should avoid direct drinking at some sporadic sites in the urban area. The exceeding nitrogen and fluoride contaminants would pose potential health hazards to local residents, but high risks only existed for infants. Both minors and adults are at medium risk of these exceedingly toxic contaminants. Groundwater quality of predominant sites in the basin is suitable for long-term irrigation according to the single indicator of EC, SAR, %Na, RSC, KR, PI, and PS and integrated irrigation quality assessment of USSL, Wilcox, and Doneen diagram assessment. But sodium hazard, alkalinity hazard, and permeability problem should be a concern in the middle-lower stream areas. Groundwater chemistry in the basin is predominantly governed by water-rock interaction (silicate dissolution) across the basin in natural and sporadically by evaporation. Human activities have posed disturbances to groundwater chemistry and inputted nitrogen, fluoride, and salinity into groundwater. The elevated nitrogen contaminants in groundwater are from both agricultural activities and municipal sewage. While the elevated fluoride and salinity in groundwater are only associated with municipal sewage. It is imperative to address the potential anthropogenic contaminants to safeguard groundwater resources from the adverse external impacts of human settlements within these urbanized valley basins. Full article

The Tibetan Plateau is the “Asia Water Tower” and is pivotal for Asia and the whole world. Groundwater is essential for sustainable development in its alpine regions, yet its chemical quality increasingly limits its usability. The present research examines the hydrochemical characteristics and origins of phreatic groundwater in alpine irrigation areas. The study probes the chemical signatures, quality, and regulatory mechanisms of phreatic groundwater in a representative alpine irrigation area of the Tibetan Plateau. The findings indicate that the phreatic groundwater maintains a slightly alkaline and fresh status, with pH values ranging from 7.07 to 8.06 and Total Dissolved Solids (TDS) between 300.25 and 638.38 mg/L. The hydrochemical composition of phreatic groundwater is mainly HCO₃-Ca type, with a minority of HCO₃-Na·Ca types, closely mirroring the profile of river water. Nitrogen contaminants, including NO₃⁻_, NO₂⁻, and NH₄⁺, exhibit considerable concentration fluctuations within the phreatic aquifer. Approximately 9.09% of the sampled groundwaters exceed the NO₂⁻ threshold of 0.02 mg/L, and 28.57% surpass the NH₄⁺ limit of 0.2 mg/L for potable water standards. All sampled groundwaters are below the permissible limit of NO₃⁻ (50 mg/L). Phreatic groundwater exhibits relatively good potability, as assessed by the entropy-weighted water quality index (EWQI), with 95.24% of groundwaters having an EWQI value below 100. However, the potential health risks associated with elevated NO₃⁻ levels, rather than NO₂⁻ and NH₄⁺, merit attention when such water is consumed by minors at certain sporadic sampling locations. Phreatic groundwater does not present sodium hazards or soil permeability damage, yet salinity hazards require attention. The hydrochemical makeup of phreatic groundwater is primarily dictated by rock–water interactions, such as silicate weathering and cation exchange reactions, with occasional influences from the dissolution of evaporites and carbonates, as well as reverse cation-exchange processes. While agricultural activities have not caused a notable rise in salinity, they are the main contributors to nitrogen pollution in the study area’s phreatic groundwater. Agricultural-derived nitrogen pollutants require vigilant monitoring to avert extensive deterioration of groundwater quality and to ensure the sustainable management of groundwater resources in alpine areas. Full article

No single spatial interpolation method reigns supreme for modelling the precise spatial distribution of groundwater quality data. This study addresses this challenge by evaluating and comparing several commonly used geostatistical methods: Local Polynomial Interpolation (LPI), Ordinary Kriging (OK), Simple Kriging (SK), Universal Kriging (UK), and Empirical Bayesian Kriging (EBK). We applied these methods to a vast dataset of 3033 groundwater records encompassing a substantial area (11,100 km²) in the coastal lowlands of the western Netherlands. To our knowledge, no prior research has investigated these interpolation methods in this specific hydrogeological setting, exhibiting a range of groundwater qualities, from fresh to saline, often anoxic, with high natural concentrations of PO₄ and NH₄. The prediction performance of the interpolation methods was assessed through statistical indicators such as root means square error. The findings indicated that EBK outperforms the other geostatistical methods in forecasting groundwater quality for the five variables considered: Cl, SO₄, Fe, PO₄, and NH₄. In contrast, SK performed worst for the species except for SO₄. We recommend not using SK to interpolate groundwater quality species unless the data exhibit low spatial variation, high sample density, or evenly distributed sampling. Full article

In coastal plains, saline water intrusion (SWI) and potentially hazardous pollutants are harmful to local human health. The southern Laizhou Bay has become a typical representative of the northern silty coast due to its extensive silt sedimentation and the significant impact of human activities. This research focuses on a portion of the southern Laizhou Bay, using GIS-based spatial analysis, water quality index methods and health risk assessments to evaluate the impact of saltwater intrusion and potential hazardous pollutants. The results show that the groundwater in the study area is significantly impacted by saline water intrusion, leading to major ion concentrations that far exceed World Health Organization (WHO) standards. The groundwater chemical types of brine and brackish water in the study area are mainly Cl-Na, and the main chemical types of fresh water are HCO₃-Ca·Na. The average concentration sequence of the main ions in groundwater is K⁺ > HCO₃⁻ > Cl⁻ > Na⁺ > SO₄²⁻ > Ca²⁺ > Mg²⁺. The average hazard quotient (HQ) sequence in typical pollutants is Cl⁻ > F⁻ > NO₃-N > Se > Mn > NO₂-N > Cu > Pb > Zn > Fe, and the carcinogenic risk (CR) sequence caused by carcinogenic heavy metals is Cd > As > Cr. The noncarcinogenic health risk area is mainly distributed in the northwest of the study area, while the potential carcinogenic risk area is in the central region. The Cl is the greatest noncarcinogenic risk to adults and children. The mean HQ values for adults and children were 95.69 and 146.98, indicating a significant noncarcinogenic risk. The mean CR values for adults and children were 0.00037 and 0.00057, suggesting a relatively low carcinogenic risk. SWI is the main influencing factor on human health; therefore, it is necessary to prevent and control SWI. Moreover, potentially hazardous pollutants are carcinogenic and noncarcinogenic risks and are caused by agriculture, industry and other human activities. The findings of this research offer scientific insights for groundwater pollution control and saline water intrusion management in similar coastal areas. Full article

Groundwater represents a critical resource for sustaining the livelihoods of both urban and rural populations, facilitating economic and social development, and preserving ecological equilibrium. This study leverages groundwater quality monitoring data from the northern Baiquan spring basin (NBSB) to elucidate groundwater hydrochemical characteristics and decipher the temporal variability in water quality. Findings suggest that groundwater within the NBSB is predominantly weakly alkaline and characterized as hard-fresh, with HCO₃⁻ and Ca²⁺ as the predominant ions, which collectively demarcate the hydrochemical type as predominantly HCO₃-Ca. The principal constituents of NBSB groundwater are influenced predominantly by the weathering of carbonates and silicates alongside the dissolution of gypsum and halite. Moreover, agricultural operations and similar human activities have exerted an impact on the hydrochemical attributes of NBSB’s groundwater. Generally, fluctuations in groundwater anion concentrations over time are more pronounced than those of cations, exemplified by a significant upward trend in the major ion concentrations at the BQ03 monitoring site in the later stages. While the general groundwater quality within the NBSB is deemed satisfactory, most monitoring sites have experienced an escalation in water quality indices over time, notably at BQ03, which warrants serious attention. The findings of this research contribute to the efficient management and sustainable utilization of groundwater resources in the NBSB. Full article

The objective of this study is to assess the suitability of the AquaCrop model for growing maize using brackish water irrigation in Northwest China. Additionally, this study aims to examine how maize utilizes water in various soil layers when irrigated with varying water qualities. The AquaCrop model was calibrated and verified using experimental data from the years 2022 and 2023 in this research. (1) The findings indicated that the AquaCrop model effectively simulated the canopy cover, biomass, and yield of maize when irrigated with brackish water. The validation year’s R², MAPE, and RMSE values for canopy cover, biomass, and yield of maize were 0.95, 5.36%, and 4.77%, respectively. For biomass, the R², MAPE, and RMSE values were 0.91, 16.61%, and 2.12 t·hm⁻², respectively. For yield, the R², MAPE, and RMSE values were 0.84, 3.62%, and 0.42 t·hm⁻², respectively. (2) Irrigation with water of high mineral content, measured at 1.6 ds/m, as well as with fresh water over the whole reproductive period, resulted in an increased reliance on groundwater for maize cultivation. There was no notable disparity in the usage of various soil layers between the irrigation with alternating freshwater and brackish water. (3) The AquaCrop model simulated the effects of seven different irrigation water quality treatments. It was shown that using water with mineralization levels of 0.5 and 0.8 ds/m resulted in decreased freshwater use without causing a substantial decrease in maize yield and biomass. Full article

With continued sea level rise and over-exploitation, saline water extends farther inland, causing changes in soil salinity and water quality and leading to permanent land salinization and ecosystem damage. Saltwater intrusion (SWI), causing numerous ecosystem problems and disasters, brings risk to urban ecosystems in coastal cities. Ecological risk, in the Greater Bay Area in China, should be assessed based on the effect of SWI status on ecosystem health. In this study, we built a new ecological risk-assessment model based on the geographic information system (GIS) technique and spatial data. At the conceptual level, four main stressors were identified based on literature reading and fieldwork. Four stress factors (SFs) were thoroughly investigated, namely, SF1: the intensity gradient immersed in saltwater; SF2: the mountain phreatic water supply; SF3: the salinity tolerance of urban greenbelt vegetation; and SF4: the supply capacity of irrigation water to suppress saline water. After a comprehensive evaluation using GIS and the analytic hierarchy process (AHP), we mapped and assessed the ecological risk level of the urban greenbelt for the SWI. Our results showed that the area of urban green space affected by the SWI was approximately 49.31 km², almost 12.05%. Ecological risk was sorted into five ranks: (1) very low risk 47.53%, (2) low risk 26.29%, (3) medium risk 22.92%, (4) high risk 2.45%, and (5) very high risk (0.8%). The ecological infrastructure of sponges should include freshwater conservation in coastal cities, and more attention should be paid to fresh groundwater discharge from coastal ecosystems in Shenzhen. Full article

Around the world, groundwater supply is critical for vital needs such as drinking and irrigation. This work investigates groundwater in the carbonate aquifer of the Middle Miocene in the east El Minia area, Egypt. In this regard, thirty-two groundwater samples were collected. The water samples were analyzed for Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl⁻, SO₄²⁻, NO₃⁻, CO₂⁻, HCO₃⁻, Fe, Mn, Cd, As, Cr, Cu, and Pb. Groundwater has been evaluated using two methods, which are water quality index (WQI) and health risk assessment (HRA). The predominant groundwater is soft water, and the samples range in salinity from fresh to slightly salty. The groundwater mostly falls into the alkaline water type. All the groundwater samples under study are deemed low quality for human consumption due to water contamination. Fe, Mn, Cd, Cu, and Pb have high HQnc values, which can result in non-carcinogenic health issues in adults, while Mn, Cu, and Pb can give rise to non-carcinogenic health issues in children. Full article