Deterioration Of Groundwater Quality Research Articles

Early Warning of Regional Groundwater Pollution： A Case Study for Plain Area of Barkol-Yiwu Basin

Groundwater pollution early warning is an effective means for regional groundwater pollution prevention. The groundwater pollution early warning model coupled with the current situation of groundwater quality, groundwater quality variation trend, and groundwater pollution risk were applied to the plain area of Barkol-Yiwu Basin, and the regional scale groundwater pollution early warning was realized by combining the early warning of groundwater quality status and trend. The TOPSIS method based on comprehensive weight was used to evaluate the current situation of groundwater quality. The variation trend of groundwater quality was analyzed by calculating the trend interpolation results of 18 in-situ groundwater quality monitoring wells. The groundwater vulnerability map, groundwater pollution load map, and groundwater function value map were superimposed using the superposition index method to evaluate groundwater pollution risk. The results showed that the groundwater quality was good and relatively good, and the poor groundwater quality in some areas was mainly affected by the shallow groundwater depth and the large porosity of the vadose zone. Groundwater quality was stable from 2011 to 2022, mainly due to the leakage of wastewater generated by industries and agriculture into groundwater, resulting in the deterioration of groundwater quality in some areas. Groundwater pollution risk was generally low, and the dual effects of high vulnerability and high pollution load of groundwater led to local areas with high pollution risk. The early warning level of groundwater pollution was generally low, and the heavy and highly heavy warning areas accounted for 16.4% and 17.5% of the study area, respectively, mainly distributed in Xiamaya Township of Yiwu County and northern Santanghu Town, Dahongliuxia Township, and Dahe Town of Barkol County. The quaternary sediments exposed were mainly sandy pebbles, with developed pores and strong water permeability. The interception and adsorption capacity of pollutants were weak. Pollutants produced by industries, agriculture, and life easily leaked into groundwater aquifers, resulting in poor groundwater quality and high risk of groundwater pollution, which ultimately led to a high early warning level of groundwater pollution in some areas. The research on early warning of groundwater pollution provided an important theoretical basis for the development of groundwater pollution remediation.

Unveiling nitrate origins in semiarid aquifers: A comparative analysis of Bayesian isotope mixing models using nitrate and boron isotopes and a Positive Matrix Factorization model

Nitrate contamination of groundwater is a pressing global concern, affecting over 80 million people worldwide, with agricultural activities being the primary contributor to nitrogen inputs into aquifers. The primary objective of this study was to identify the predominant sources of nitrate pollution and biogeochemical transformations in the semiarid region of the Meoqui-Delicias aquifer, Mexico. In this region, the uncontrolled use of chemical fertilizers and manure leads to excessive nutrient input, which accelerates the deterioration of groundwater quality. This study introduces an innovative dual-model approach (δ15NNO3 vs. δ11B) to compare the Bayesian Isotope Mixing Model (BIMM) with Positive Matrix Factorization (PMF) for nuanced source apportionment. This approach enhanced the differentiation between manure and sewage as nitrate sources. Results from the δ15NNO3 vs. δ11B model revealed that manure (52.4%) was the most significant source of nitrate pollution in the aquifer, followed by soil (37.4%), chemical fertilizers (5.5%), and sewage (4.7%). The PMF model corroborated this finding and indicated that 60.2% of the NO3–-N pollution in the aquifer was attributed to manure and sewage, confirming the superior performance of the proposed BIMM in source differentiation. Our findings enhance the understanding of nitrate dynamics in semi-arid regions and can serve as a scientific evidence base for targeted interventions in nutrient management in the study area and elsewhere.

MODELING OF GROUND WATER DYNAMICS AND ITS POLLUTION

Problem statement. Large accumulators of liquid waste (e.g., mine water ponds, tailing ponds, etc.) are long-term sources that change the hydrological regime. A negative consequence of this process is flooding of the territory. In addition, the infiltration of contaminated water from such hazardous sources changes the quality of groundwater. Therefore, it is important to analyze the impact of such anthropogenic sources on the process of flooding and deterioration of groundwater quality. To solve this problem, it is very important to use the method of mathematical modeling as an effective mean of researching problems of this class, since the use of physical modeling is practically impossible within the scope of problems of this class. The purpose of the article. Development of numerical models for predicting changes in the hydrological regime (flooding of the territory) and groundwater quality under the influence of anthropogenic pollution sources. Methodology. To assess the dynamics of changes in the hydrological regime, a two-dimensional equation of filtration of a non-pressure groundwater flow is used. A two-dimensional geomigration equation (planned model) is used to analyze changes in groundwater quality during infiltration of contaminated water from the settling pond. This equation takes into account the convective transfer of contaminants in the filtration flow, dispersion, and the intensity of contaminant infiltration into the groundwater flow. The method of total approximation is used for numerical integration of the filtration equation. For the numerical integration of the geomigration equation, an implicit splitting scheme is used. Scientific novelty. Effective numerical models for rapid assessment of changes in groundwater dynamics and quality under the influence of anthropogenic sources that change the hydrological regime are proposed. The constructed numerical models take into account a set of important physical factors that affect the process of geomigration and flooding of the territory, namely: filtration coefficient, variable depth of free-flowing groundwater, dispersion, intensity of the source of impurity emission into the groundwater flow. This makes it possible to obtain a comprehensive assessment of the process of flooding and groundwater pollution.. Practical significance. A computer code has been created that allows practical usage of the developed numerical models. This code is an effective tool for theoretical study of non-stationary processes of territory flooding and anthropogenic groundwater pollution. Conclusions. A numerical model for calculating groundwater dynamics has been developed. The model allows to predict the level of groundwater rise under the influence of a man-made source of wastewater infiltration from a settling pond. A numerical model for calculating the process of geomigration from an anthropogenic source of emissions has been developed. The model makes it possible to predict the dynamics of contamination zone formation in a non-pressure groundwater flow. The developed numerical models take into account the most important parameters that affect the formation of flooding zones and groundwater contamination.

Analysis on the spatiotemporal evolutions of groundwater hydrochemistry and water quality caused by over-extraction and seawater intrusion in eastern coastal China

The over-extraction of groundwater has resulted in seawater intrusion and the southward migration of the saltwater interface, gradually deteriorating the groundwater quality in the Weibei Plain. In this research, groundwater samples were gathered from 46 monitoring wells for shallow groundwater during the years 2006, 2011, 2016, and 2021. The hydrochemical features of regional groundwater and the factors influencing the issue were subjected to statistical analysis. Additionally, the assessment of spatiotemporal variations in groundwater quality was conducted using the customized entropy-weighted water quality index (EWQI) method. The relationship between groundwater over-extraction and the southward intrusion of the saltwater interface was compared and analyzed. The results of this paper revealed that the Weibei Plain has been in a state of long-term over-extraction of groundwater from 2000 to 2021, with an average annual over-extraction of 118.49 million m3. The groundwater depression cone areas in the northern part of the study area increased from 3,247.37 to 4,581.34 km2 from 2006 to 2021, with the center of the cone experiencing a drop in groundwater level from −22 to −85 m. The saltwater interface shifted southward by 711.71 km2 from 2006 to 2021. In groundwater, the high concentrations of TH, TDS, and Cl− were primarily related to the seawater intrusion, while higher concentrations of NO3− were mainly determined by frequent agricultural production, industrial wastewater, and domestic sewage discharges. The groundwater hydrochemical types in the study area transitioned from predominantly HCO3·Ca-Mg type in 2006 to HCO3-Na type and SO4·Cl-Ca·Mg type in 2021 due to seawater intrusion. The results of PCA and HCA show the effects of seawater intrusion, human activities, and rock weathering on groundwater hydrochemistry. The evaluation results based on the EWQI revealed that the average value of the samples in 2021 was 101.36, which belonged to Class IV water quality standards, representing the poorest water quality among the 4 years. The southward migration of the saltwater interface led to the deterioration of groundwater quality in the groundwater depression cone areas, which gradually worsened from 2006 to 2021. The maximum increase in EWQI value was 174.68 during the period, shifting from Class III water quality to Class V water quality. Groundwater quality remained relatively better in the western and southern regions which were less affected or unaffected by seawater intrusion. The results of the study can provide a certain reference value for the sustainable management of groundwater resources and the management of groundwater pollution and seawater intrusion in the Weifang City area in the future.

Nitrate fate in coastal unconfined aquifers influenced by preferential flows

This study examined the influence of preferential flow on pore water flows and marine nitrogen transport reaction in variable saturation and variable density coastal aquifers. The 2-D unconfined aquifer model established was based on the software COMSOL by coupling the dynamic and chemical processes together. The results showed that preferential flow affects groundwater flow and salinity distribution, leading to a more complicated mixing process. The preferential flow resulted in an increase in mixing zone area and the upper saline plume area of 10.33 and 2.62 m2, respectively, a decrease in saltwater wedge area of 7.22 m2, and an increase in nitrate (NO3-) removal efficiency from 7.9% to 8.97%. The NO3- removal efficiency increases progressively with the depth (h) and quantity (n) of preferential flows; however, it decreases after a certain quantity. Further quantitative analysis revealed an increase in the intensity of nitrification and dissolved oxygen inflow flux with preferential flow depth and quantity increase. This phenomenon usually occurs on coasts where biological caves are abundant. The results also offer significant implications for designing engineering measures to mitigate saltwater intrusion and are significant to prevent groundwater quality deterioration in coastal zones.

Assessing groundwater quality dynamics in Madhya Pradesh: Chemical contaminants and their temporal patterns

Groundwater is essential for maintaining ecosystem health and overall well-being as a pivotal resource for plants and animals. The increasing public consciousness of the deterioration of groundwater quality has emphasized the significance of undertaking extended evaluations of groundwater water quality, particularly in regions undergoing substantial hydrological alterations. This study primarily aims to investigate the spatio-temporal variations in groundwater quality and evaluate its suitability for potable purposes in the region of Madhya Pradesh. The study combines the Mann-Kendall (MK) test and Sen's Slope (SS) to analyze the changes in groundwater quality of all 51 districts of Madhya Pradesh, India, utilizing 12 water quality indices using MATLAB. Data was sourced from the Central Ground Water Board (CGWB) in India from the year 2001–2021. The data was then tested for homogeneity at all 1154 sampling stations using the software XLSTAT. Piper plot clustering characterized the state's groundwater as bicarbonate-calcium-magnesium (HCO3−-Ca2+-Mg2+) type. The study found that the groundwater in the area is heavily impacted by high levels of nitrate and hardness, which is caused by an increase in multivalent cations. The water was classified as ranging from hard to extremely hard, and approximately 25.49% of the state's groundwater has nitrate levels that exceed the acceptable limits. The MK test showed a significant increasing correlation in trends for parameters such as nitrate, sulfate, fluoride, chloride, bicarbonate, total hardness, and electrical conductivity. It also showed a significant decreasing correlation for calcium, magnesium, potassium, and sodium. These results were observed at a confidence level of 95%. The analysis of trends has shown that human-related factors have a considerable effect on the characteristics of groundwater quality. It is therefore recommended that such human-related factors be taken into consideration when developing policies for managing groundwater resources. Consequently, these policies should emphasize the strict enforcement of rules and standards that limit the overuse of fertilizers, ensure the appropriate disposal of municipal solid and liquid wastes, and regulate industrial pollutants.

Impact of Concepts and Spatial Scales on Irrigation Efficiency for Sustainable Water Resources Management: A Review

This paper provides a review of different ‘irrigation efficiency’ concepts evolved over the time since the term was originally conceived, from an engineering perspective; the impact of scale, i.e., from field to basin, on savings in water demands through hightech irrigation—the efficiency paradox; the role of rice cultivation—water guzzler or recharge basin; and policies for transforming high-tech irrigation into water-conserving interventions. As these issues are interlinked, their synergetic resolution is necessary for establishing sustainable irrigated-agriculture at basin scale. There is a consensus on the utility of classical irrigation for designing the capacity of different components of an irrigation system; and also appreciation of the fact that it does not represent the true picture of water savings/losses at the basin scale. Consumed fraction-based water accounting makes a better representation of irrigation performance from field to basin scales. In literature, studies from different countries revealed the positive impact of hightech irrigation in improving land productivity and income at the field scale but without any significant water conservation for further use to other sectors/locations. Many studies also indicate that introduction of high-tech irrigation in water-scarce but abundant irrigable land regions led to increased water use, which resulted in further decline of water table and/or deterioration of groundwater quality. The increase in water demand on improving irrigation efficiency is known as the efficiency paradox or rebound effect. In water-scarce areas, high-tech irrigation should be promoted with caps on water withdrawals even if the water transfer to downstream areas or other uses is not required. High-tech irrigation is helpful in reducing transaction costs for achieving water conservation, but gold plating of irrigation infrastructure alone would not be sufficient. This study emphasizes on enactment and enforcement of policies for regulating total water withdrawal, limiting irrigated area, and adopting ecologically-compliant cropping patterns for establishing sustainable irrigated-agriculture without the rebound effect.

Spatio-temporal prediction of groundwater vulnerability based on CNN-LSTM model with self-attention mechanism: A case study in Hetao Plain, northern China

Located in northern China, the Hetao Plain is an important agro-economic zone and population centre. The deterioration of local groundwater quality has had a serious impact on human health and economic development. Nowadays, the groundwater vulnerability assessment (GVA) has become an essential task to identify the current status and development trend of groundwater quality. In this study, the Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM) models are integrated to realize the spatio-temporal prediction of regional groundwater vulnerability by introducing the Self-attention mechanism. The study firstly builds the CNN-LSTM model with self-attention (SA) mechanism and evaluates the prediction accuracy of the model for groundwater vulnerability compared to other common machine learning models such as Support Vector Machine (SVM), Random Forest (RF), and Extreme Gradient Boosting (XGBoost). The results indicate that the CNN-LSTM model outperforms these models, demonstrating its significance in groundwater vulnerability assessment. It can be posited that the predictions indicate an increased risk of groundwater vulnerability in the study area over the coming years. This increase can be attributed to the synergistic impact of global climate anomalies and intensified local human activities. Moreover, the overall groundwater vulnerability risk in the entire region has increased, evident from both the notably high value and standard deviation. This suggests that the spatial variability of groundwater vulnerability in the area is expected to expand in the future due to the sustained progression of climate change and human activities. The model can be optimized for diverse applications across regional environmental assessment, pollution prediction, and risk statistics. This study holds particular significance for ecological protection and groundwater resource management.

Determination of Some Heavy Metal Concentrations and Physical/Chemical Properties of Well Water in Babylon Governorate/ Iraq

The presence of One of the most significant is heavy metals in water. risks, which may cause health problems. In this work, we tried to determine the amount of three heavy metals (lead, nickel, and cadmium) in groundwater in different locations in Babylon Governorate The current study aims to estimate the quality of groundwater by evaluating its physical and chemical properties, as well as evaluating lead, nickel, and cadmium (Pb, Cd, Ni) in this water and monitoring the variation in their concentration rates during the seasons of the year. Groundwater samples were collected and analyzed using an atomic absorption spectrometer to determine their lead, nickel and cadmium content and compare their levels with the maximum level of contaminants specified by the World Health Organization. Water samples were collected from 15 wells in different areas (Abu Ghariq, Sinjar, Hilla, Al-Mahawil, Al-Imam, Al-Nile, Jableh, Al-Mashrou, Al-Hashimiya, Al-Qasim, Madhatiya, Al-Taliah, Al-Musayyab, Alexandria and Al-Sada) during the period from September 25, 2022 to July 25, 2023.The concentrations of lead and cadmium were higher than the permissible limits suggested by the World Health Organization. As for nickel it did not exceed the permissible limit. The study can then be concluded that it is contaminated with some heavy metals due to the influence of several activities in the study area. Decreased treatment, regulations and integrated management have led to the deterioration of groundwater quality. Total dissolved salts, turbidity, conductivity, and total hardness in the groundwater of these sites were also studied.

Mapping saltwater intrusion via Electromagnetic Induction (EMI) for planning a Managed Aquifer Recharge (MAR) facility in Maltese Island

In coastal areas, saltwater intrusion causes a depletion of the resource by reducing potable and irrigation freshwater supplies and causing severe deterioration of groundwater quality. This trend is observed in Pwales Valley, in the North part of Malta where the management of water resources plays a crucial role for the environmental sustainability of the area, given the importance of intensive agricultural activity along this valley. In order to tackle such phenomenon, actions or adaptation measures against climate change are strongly required. For example, Managed Aquifer Recharge (MAR) is an increasingly important water management strategy to maintain, enhance and secure stressed groundwater systems and to protect and improve water quality. To accurately plan a Managed Aquifer Recharge scheme, it is crucial to define a hydrogeological model of the studied area, with the use of traditional hydrogeological measurements and innovative unconventional techniques. In recent years, Electromagnetic Induction measurements, based on induction of em fields, have been increasingly used for investigating the saltwater intrusion dynamics due to their high sensitivity to the salinity. In the study area of Pwales Valley, a Managed Aquifer Recharge scheme is being planned and, for this aim, a hydrogeological model has been developed through an Electromagnetic Induction survey. More than 20,000 apparent electrical conductivity (ECa) data were collected to generate a quasi 3D high-resolution model of electrical conductivity of the Pwales Valley. The results highlighted the spatial extension of the tongue-shape salt water intrusion from east to west along the valley, as well as some geological-hydrogeological peculiarities such as the thickness of the salt wedge and the irregular top surface of the bottom impermeable layer, otherwise undetectable with other direct techniques at the field scale resolution. The approach was confirmed to be a useful tool for an effective hydrogeological characterisation, essential for planning adaptation measures to a changing climate, such as the implementation of a Managed Aquifer Recharge scheme.

Antibiotic resistome in landfill leachate and impact on groundwater

Landfill leachate is a hotspot in antibiotic resistance development. However, little is known about antibiotic resistome and host pathogens in leachate and their effects on surrounding groundwater. Here, metagenomic sequencing was used to explore profiles, host bacteria, environmental risks and influencing factors of antibiotic resistome in raw and treated leachate and surrounding groundwater of three landfills. Results showed detection of a total of 324 antibiotic resistance genes (ARGs). The ARGs conferring resistance to multidrug (8.8 %–25.7 %), aminoglycoside (13.1 %–39.2 %), sulfonamide (10.0 %–20.9 %), tetracycline (5.7 %–34.4 %) and macrolide-lincosamide-streptogramin (MLS, 5.3 %–29.5 %) were dominant in raw leachate, while multidrug resistance genes were the major ARGs in treated leachate (64.1 %–83.0 %) and groundwater (28.7 %–76.6 %). Source tracking analysis suggests non-negligible influence of leachate on the ARGs in groundwater. The pathogens including Acinetobacter pittii, Pseudomonas stutzeri and P. alcaligenes were the major ARG-carrying hosts. Variance partitioning analysis indicates that the microbial community, abiotic variables and their interaction contributed most to the antibiotic resistance development. Our results shed light on the dissemination and driving mechanisms of ARGs from leachate to the groundwater, indicating that a comprehensive risk assessment and efficient treatment approaches are needed to deal with ARGs in landfill leachate and nearby groundwater. Environmental implicationsAntibiotic resistance genes are found abundant in the landfill sites, and these genes could be disseminated into groundwater via leaching of wastewater and infiltration of leachate. This results in deterioration of groundwater quality and human health risks posed by these ARGs and related pathogens. Thus measures should be taken to minimize potential negative impacts of landfills on the surrounding environment.

Simulation of Groundwater Quality in Xi 'an,Shaanxi Province Based on Visual Modflow

The so-called groundwater quality simulation is to study the spatial and temporal variation law of the concentration of a certain soluble substance (element or other component) when it is dispersed and transported by simulation method, to predict the instantaneous dynamics and expansion range of polluted groundwater, and to provide scientific basis for formulating reasonable and effective prevention measures. In recent years, the environmental hydrogeology survey results of some provinces, cities and regions in China show that the groundwater in most cities in China has been polluted to varying degrees. This situation directly affects industrial and agricultural production and people's health. However, in the past, environmental hydrogeology work was mostly limited to surface investigation, lacking quantitative and predictive evaluation research. Monitoring groundwater quality dynamics and forecasting the development trend of groundwater pollution is one of the main tasks of groundwater pollution investigation and research. Relevant information shows that some countries in the world have already carried out this research and established a predictive groundwater quality model. Among them, the United States has established 22 material transport models and 5 heat transport models; France has established 5 models of material transport and 4 models of heat transport. The following countries have only established material transport models: 7 in Israel; 2 in the UK; 2 in Canada; 1 in West Germany and 1 in Japan. Therefore, we believe that the study of groundwater quality simulation experiment, which is still blank in China's scientific field, has become an important subject that needs to be carried out urgently to ensure the four modernizations and people's health. The hydrogeological conditions and dynamic characteristics of groundwater resources have been comprehensively analyzed and studied. It points out that the continuous exploitation of groundwater resources in 2018 has led to the deterioration of groundwater quality, land degradation, underground, cracks and depletion of groundwater resources, and puts forward some preventive measures.

Evaluation on quality and health risk of groundwater in a highly urbanized watershed, China.

Urbanizations and industrializations may accelerate the contamination and deterioration of groundwater quality. This study aimed to evaluate the quality and potential human health risks associated with shallow groundwater in Shenzhen, China, a city characterized by high levels of urbanization and industrialization. The hydrochemistry characteristics, water quality levels, and human health risks of main ions, nutrient elements, and metals in 220 samples collected from Maozhou River Basin (MRB) located in the northwest of Shenzhen were investigated. It showed that chemical constituents of the groundwater were further complicated by seawater intrusion and urbanization expansion. Water quality evaluated by fuzzy comprehensive method showed that 21.05% of samples distributed around reservoirs were classified into grade II or better. Nearly 79% of samples distributed in the densely populated urban land were classified into grade III or worse, indicating pollution from anthropogenic factors cannot be ignored. For the river tidal reach where river stage fluctuated about 0.5 to 1.5 m within a tidal cycle, the chemical composition of groundwater was influenced by frequent water exchange with the river. The carcinogenic and non-carcinogenic health risks for different age groups, from the high to the low, were children, adult women, adult men, adolescent women, and adolescent men, respectively. Approximately 39% of groundwater samples distributed around the densely populations area with health risk larger than 5 × 10-5 were unacceptable for children. This investigation would be helpful for improving groundwater management and as a practical reference for sustainable groundwater exploitation in the MRB.

Geochemical and Isotopic Constraints on the Recharge and Salinization Origin of Groundwater Aquifers in El Rina–Nihayaat, South Sinai, Egypt

The Sinai Peninsula is located in the arid regions of Egypt where groundwater is the sole source for drinking and irrigation and future development. Regular assessment of the geochemical processes governing the groundwater quality is important in arid regions and paleo-aquifers. This research focuses on investigating the groundwater sustainability of the Upper Cretaceous Aquifer (UCA) located at El Rina–Nihayaat area, Southwestern Sinai Peninsula. The study aims to evaluate the main source of groundwater recharge and investigate factors deteriorating groundwater quality. The study is based on the geochemical and isotopic analyses of 31 groundwater samples tapping the UCA. The groundwater flows toward the Gulf of Suez. The groundwater salinity ranges from 1078 mg/L to 13090 mg/L indicating brackish to saline water. Two main water types have been delineated: Cl-Na and Cl-Ca indicating the final stage of groundwater evolution and leaching and dissolution of aquifer matrix of marine origin. The spatial distribution of the groundwater salinity and major ions (Na+, K+, Ca2+, Mg2+, SO42-, and Cl-) increase toward the Gulf which coincides with the direction of the groundwater flow, while bicarbonate increases toward the upstream watershed. Most of the groundwater samples tapping the UCA are depleted with the isotopic content of the stable isotopes where they range from -4.43 ‰ to -6.37 ‰ for δ18O and -28.3 ‰ to -40.2 ‰ for δ2H. The groundwater samples are depleted relative to the recent rainwater and enriched to the Nubian Sandstone located underneath the UCA indicating mixing from both source(s). The mixing estimated percentages from the recent rainwater using calibrated geochemical NETPATH model range between 48.6% to 88.5% while the upward Leakes from the Nubian water ranges between the recent rain and the paleo-Nubian water ranges between 48.6 % and 88.5 % from the meteoric rainwater, while the upwelling recharge from the paleo-Nubian groundwater ranges between 11.5 % to 51.4 %. The factorial analyses indicate three main factors governing the geochemistry of groundwater in the UCA: including water-rock interactions, meteoric recharge from annual precipitation, and upward leakages from the underneath paleowater. 
 Further exploration for the UCA is recommended to determine the promising zones receiving a considerable amount of the recent rainfall.

Hydrogeochemical and anthropogenic controls on quality and quantitative source-specific risks of groundwater in a resource-based area with intensive industrial and agricultural activities

Groundwater contamination in resource-based cities/areas generally suffers from complex superposition of multiple hydrogeological and anthropogenic factors, of which control mechanism and quantitative allocation of health risks need more in-depth understanding. Thus, integrated-weight water quality index (IWQI) and source-specific health risk assessment model built on the combination of Hazard Index (HI) and Total Cancer Risk (TCR) standard models and Positive Matrix Factorization (PMF) model were utilized to investigate the controls simultaneously from hydrogeological processes and anthropogenic activities on groundwater quality and quantitative health risks in a representative resource-based city/area (i.e., Handan area). The results indicated that localized-disequilibrium of hydrochemical characteristics was mainly controlled by weathering processes of outcropped rocks and aquifers with different lithology. Most of groundwater (94.47 %) can be classified as excellent and good levels, while groundwater quality deterioration occurred in eastern plain. Traditional hydrochemical analysis approaches together with saturation index (SI) and Pearson's correlation analysis indicated that water-rock interaction, semi-arid climate, positive cation exchange and agricultural activities can intensify groundwater quality deterioration. There was a moderate non-carcinogenic risk and a high carcinogenic risk induced by PTMs in groundwater. Non-carcinogenic risk was mainly caused by heavy industry (34.93 %) and agricultural activities (32.94 %), while carcinogenic risk was dominated by agricultural activities (37.92 %) and heavy industry (35.58 %). Coal mining accounted for 18.16 % of non-carcinogenic risk and 20.98 % of carcinogenic risk respectively. Traffic contamination and geogenic source merely made a minor contribution. These results suggested that source-specific health risk assessment model can clearly quantify the allocations of different sources to the health risks, which was worth being popularized in the field of groundwater researches. This study contributed to profound understanding on groundwater quality deterioration and contamination collectively induced by various hydrogeological and anthropogenic factors, and provided a reference for developing contamination source-oriented countermeasures of groundwater pollution to other resource-based cities/areas worldwide.

Controlling Factors of Groundwater Salinization and Pollution in the Oasis Zone of the Cherchen River Basin of Xinjiang

Groundwater is a vital resource for local human life and production in the oasis zone of the Cherchen River Basin of Xinjiang. Understanding the controlling factors of groundwater salinization and pollution is of great significance for the sustainable utilization of groundwater resources and protection of the ecological environment in desert oasis areas. In light of this, a total of 36 single structure unconfined groundwater samples and 54 multi-layered structure unconfined and confined groundwater samples were collected from the oasis zone of the Cherchen River Basin and evaluated for the distribution characteristics and pollution status of major ions. Hydrogeochemical methods (e.g., Piper diagram, multivariate statistics, Gibbs model, and relationships among ions) were used to determine the main controlling factors of groundwater salinization and pollution. Differences in hydrogeochemical zonation were found from the single structure unconfined aquifers in sloping plains of piedmont areas to the multi-layered structure unconfined and confined aquifers in alluvial-proluvial plain areas, and Cl-Na (87.8%) was the main hydrochemical type in the groundwater of the study area. The quality of single structure unconfined groundwater was starkly better than that of the multi-layered unconfined and confined groundwater, which was mainly caused by Na+ (mean value of 9 969 mg·L-1), Cl- (13 687 mg·L-1), and SO42- (5 840 mg·L-1). Moreover, the natural hydrogeochemical process was the main reason for the deterioration of groundwater quality. The hydrochemistry was mainly controlled by the water-rock interaction and evaporation processes. The mineral dissolution of silicates and evaporites was an important source of chemical ions in the groundwater. Furthermore, the chemical weathering of evaporites combined with the processes of evaporation and cation exchange had a significant influence on the salinization of multi-layered unconfined and confined groundwater in alluvial-proluvial plain areas. In addition, synthetic fertilizers were the main pollution sources of NO3- in groundwater in the intensive agricultural zones.

Optimization and Removal of Heavy Metals from Groundwater Using Moringa Extracts and Coconut Shell Carbon Powder


 
 
 
 Abstract: This study focuses on enhancing the efficacy and elimination of heavy metals from groundwater by employing bio-absorbents generated from Moringa extracts and Coconut shell carbon powder. The green synthesis technique was utilized to produce cost-effective absorbents, including powdered Moringa seeds, leaves and carbon from coconut shells. The study examines the effectiveness of synthetic bio-absorbents in removing heavy metals, including Copper (Cu), Cadmium (Cd), Iron (Fe), Lead (Pb), Chromium (Cr), and Zinc (Zn), from groundwater. Identifying functional groups such as Hydroxyl (OH), C-H of alkenes, C=C of alkenes, and C-O from carboxylic acids have been determined to be essential for removing metals in groundwater. The method of FT-IR spectroscopy was used to characterize these functional groups. The examination of the morphology of Moringa seeds indicated the presence of consistent spherical network sheets, but Moringa leaves had a hexagonal network structure like a flower. The coconut shell photos revealed the presence of irregular, small-sized flakes that were clustered together to create a sheet. In light of the escalating deterioration of groundwater quality in Vijayawada as a result of industrial expansion, urban development, and significant infrastructure initiatives, the primary objective of the study was to ascertain the primary contaminants present in the groundwater. Subsequently, adsorption methods utilizing natural bio-absorbents were employed. Water samples were gathered and exposed to bio-absorption utilizing powdered Moringa olifera leaves, powdered Moringa olifera seeds, and powdered carbon derived from coconut shells. The technique of Atomic Absorption Spectroscopy was utilized to examine the decrease in concentrations of heavy metals. The findings demonstrated that the bio-absorption of heavy metals was more prominent in Moringa olifera seed powder than in Moringa olifera leaf powder and coconut shell carbon powder. The highest levels of adsorption for copper, cadmium, and lead were achieved at 98.5%, 99.5% and 99.4%, respectively. This work offers useful insights into the potential of bio-absorbents manufactured using green methods for effectively eliminating heavy metals from groundwater. It addresses the crucial problem of water quality in metropolitan areas.
 
 
 

RETRACTED: Exploring Groundwater Quality Assessment: A Geostatistical and Integrated Water Quality Indices Perspective

Groundwater is an important source of freshwater. At the same time, anthropogenic activities, in particular, industrialization, urbanization, population growth, and excessive application of fertilizers, are some of the major reasons for groundwater quality deterioration. Therefore, the present study is conducted to evaluate groundwater quality by using integrated water quality indices and a geospatial approach to identify the different water quality zones and propose management strategies for the improvement of groundwater quality. Groundwater quality was evaluated through the physicochemical parameters (pH, chloride (Cl−), fluoride(F−), iron (Fe−2), nitrate (NO3−1), nitrite (NO2), arsenic (As), total hardness, bicarbonate (HCO3−), calcium (Ca+2), magnesium (Mg+2), color, taste, turbidity, total dissolved solids (TDS)) and microbiological parameters including total coliforms, fecal coliforms, and Escherichia coli of samples collected from the water and sanitation agency (WASA) and urban units. Irrigation parameters crucial to the assessment, including (electrical conductivity (EC), residual sodium carbonates (RSC), and sodium adsorption ratio (SAR)), were also collected at more than 1100 sites within the study area of upper and central Punjab. After collecting the data of physicochemical parameters, the analysis of data was initiated to compute the water quality index for groundwater quality, a four-step protocol in which the Analytical Hierarchy Process (AHP) was used to determine the weights of selected parameters by generating a pairwise matrix, on the relative importance of parameters using the Satty scale. The index was then classified into five classes for quality assessment of drinking water (excellent, good, medium, bad, and very bad) and four classes for irrigation water quality assessment (excellent, good, permissible, and unsuitable). After computing the index values for drinking as well as irrigation purposes, the values were interpolated, and various maps were developed to identify the status of groundwater quality in different zones of the study area. Mitigation strategies for water pollution involve source control, such as monitoring industrial discharge points and managing waste properly. Additionally, treating wastewater through primary, secondary, or tertiary stages significantly improves water quality, reducing contaminants like heavy metals, microbiological agents, and chemical ions, safeguarding water resources. The findings highlight significant regional variations in water quality issues, with heavy metal concerns concentrated notably in Lahore and widespread emerging microbiological contamination across all studied divisions. This suggests a systemic problem linked to untreated industrial effluents and poorly managed sewerage systems. The computed indices for the Lahore, Sargodha, and Rawalpindi divisions indicate water quality ranging from marginal to unfit, underscoring the urgency for remediation. Conversely, other divisions fall within a medium class, potentially suitable for drinking purposes. Notably, microbiological contamination at 27% poses a major challenge for water supply agencies, emphasizing the critical need for pre-disposal primary, secondary, and tertiary treatments. These treatments could potentially rehabilitate 9%, 35%, and 41% of the study area, respectively, pointing toward tangible, scalable solutions critical for safeguarding broader water resources and public health. With the current pace of water quality deterioration, access to drinking water is a major problem for the public. The government should prioritize implementing strict monitoring mechanisms for industrial effluent discharge, emphasizing proper waste management to curb groundwater contamination. Establishing comprehensive pre-disposal treatments, especially primary, secondary, and tertiary stages, is imperative to address the prevalent heavy metal and microbiological issues, potentially rehabilitating up to 41% of affected areas. Additionally, creating proactive policies and allocating resources for sustainable groundwater management are crucial steps for ensuring broader water resource security and public health in the face of deteriorating water quality. Therefore, urgent regional action is needed to address escalating anthropogenic threats to groundwater, emphasizing the crucial need for proactive measures to safeguard public health and ensure sustainable water resources.

Assessment of groundwater suitability for drinking and irrigation purpose using statistical and geospatial techniques

Water is a vital source for all living individuals on earth. The consumption of fresh water has increased rapidly in recent years. Industrialization, urbanization, and population growth have resulted in deterioration of surface and groundwater quality. It is very important to manage groundwater resources and protect them from anthropogenic activities in order to sustain life on earth. This paper discusses methods for assessing the quality of groundwater using statistical and geospatial techniques. In addition, geographic information system (GIS)-integrated statistical methods are also discussed. Statistical methods, including quality indices, irrigation water quality parameter, and geospatial methods, including inverse distance weighted (IDW) and kriging strategies for evaluating groundwater quality and assessing aquifer susceptibility are also explained. In addition, the paper provides an overview of key groundwater quality indices (GWQI) and irrigation water quality indices (IWQI) that have developed over time and used for groundwater quality evaluation around the world. It is revealed that the use of GIS-integrated advanced statistical approaches is not common in assessments of groundwater quality. The constraints and research gaps of previous studies, as well as the prospects for future research needs have been examined.

Environmental implications of salinity and flooding induced changes in porewater nitrogen and phosphorous dynamics

ABSTRACT This study aimed to investigate the effects of fresh water and seawater flooding on phosphorous (P) and nitrogen (N) dynamics in two calcareous soils (Biscayne and Krome) of South Florida using a 28-day greenhouse flooding experiment. Porewater samples were collected at three depths over four periods (1, 7, 14, and 28 days) of flooding and analyzed for selected water quality parameters. Results showed that seawater-flooded Biscayne soil had a 4.4 fold higher porewater soluble reactive phosphorus (SRP) concentration than freshwater. Additionally, porewater SRP concentration and total phosphorus (TP) in Biscayne soil increased with prolonged flooding duration and column depth. Furthermore, both freshwater and seawater flooding increased porewater NH4 + - N concentration; however, the increase was more pronounced in seawater flooded samples. NH4 + - N concentration also increased with flooding duration. Overall, the study highlights the risks of nutrient leaching from seawater flooded coastal soils that could contribute to the deterioration of surface and groundwater quality.