Groundwater Irrigation Research Articles

Compliance of Legal Restrictions in Potable Water Abstraction in Rajshahi WASA Area: An Overview

The ground water level in Barind area Rajshahi rise and falls continuously with the advance of wet and dry season. A growing population, urbanization, increasing pressure on land and water resources by different competing usage and degradation of scarce resources challenge the extraction, management and protection of the water resources of Rajshahi as well as all over the Bangladesh. Agriculture is the major water using sector for ground water irrigation with rice cultivation, the single most important activity in the economy. Industry is also liable for large scale water withdrawal. Due to water level depletion ‘deep tube well’ especially submersible pump is randomly used in many of the houses in Rajsahi WASA area. Apart from agriculture, presently uncontrolled water abstraction for domestic or household purposes causes serious threats to sustainable ground water management. Due to this excessive stress upon the ground water resource, the yield capacity is being reduced and the need to conserve them is now generally recognized. Some of the legislations have clear guidelines and restrictions on personal source of ground water abstractions. National water policy, 1999 stressed the need for the protection of surface water and groundwater resources. WASA Act, 1996; Water Act, 2013; Local Govt. Act 2009 are the major instruments in this respect. This study has been an attempt to review the relevant laws regarding restrictions on domestic water abstraction and to examine through field survey the real scenario how far these are being complied with.

Nanobubble transport in porous media: Towards agro- and environmental applications

Nanobubbles have been increasingly used in various applications involving porous media, such as groundwater remediation and irrigation. However, the fundamental scientific knowledge regarding the interactions between nanobubbles and the media is still limited. The interactions can be repulsive, attractive, or inert, and can involve reversible or irreversible attachment as well as destructive mechanisms. Specifically, the stability and mobility of nanobubbles in porous media is expected to be dependent on the dynamic conditions and the physicochemical properties of the porous media, solutions, and nanobubbles themselves. In this study, we investigated how changes in solution chemistry (pH, ionic strength, and valence) and media characteristics (size and wettability) affect the size and concentration of nanobubbles under dynamic conditions using column experiments. Quartz crystal microbalance with dissipation monitoring provided a deeper understanding of irreversible and elastic nanobubbles’ interactions with silica-coated surfaces. Our findings suggest that nanobubbles are less mobile in solutions of higher ionic strength and valence, acidic pH and smaller porous media sizes, while the wettability of porous media has a negligible influence on the retention of nanobubbles. Overall, our findings provide insights into the underlying mechanisms of nanobubble interactions and suggest potential strategies to optimize their delivery in various applications.

Comprehensive Analysis of Groundwater Suitability for Irrigation in Rural Hyderabad, Sindh, Pakistan

An irrigation quality assessment for rural Hyderabad was made by determining the pH, EC, TDS and TH beside major cations and anions. This study employed various parameters to determine the suitability of groundwater for irrigation and its hydrochemistry. Permissible limits of major cations and anions revealed that approximately 26% of samples exceeded acceptable levels for Electrical Conductivity (EC), 87% for Ca2+, 89% for Mg2+, and 60% for Na+, while none exceeded the limits for K+. Conversely, 47% of samples for HCO3−, 91% for Cl−, and 100% for SO42−, NO3−, and CO32− proved suitability for irrigation. Notably, irrigation indices highlighted favorable results, with 100% conformity for SAR, SSP, RSP, and PI values, and substantial percentages of 78% and 85% for MH and KR values, respectively, affirming their suitability for irrigation practices. Employing the USSL diagram, 22%, 65%, and 11% of samples fall into the C2S1, C3S1, and C4S1 categories. According to the Wilcox diagram, 25%, 43%, 30%, and 2% are classified under C1, C2, C3, and C4 categories, respectively. The Gibbs ratio shows a concentration within the evaporation dominance, and CAI values showed positive ion exchange. Overall, Hyderabad’s rural areas are generally suitable for irrigation, apart from certain areas where water quality may not be acceptable for plants lacking high salt tolerance.

Geochemical characteristics, mechanisms, and suitability of groundwater resource for sustainable water supply in Quetta valley

ABSTRACT Groundwater is a crucial water resource for various usages worldwide. The Quetta Valley of Pakistan was investigated regarding its groundwater quality sustainability based on integrated approaches of hydrochemistry, geographic information system, and multivariate statistics. A total of 29 groundwater samples were collected from monitoring wells to get insights into the hydrochemical suitability of groundwater for sustainable irrigation and drinking utilization. The results indicate groundwater is mainly featured by the hydrochemical facies of HCO3·Cl-Ca. Groundwater hydrochemical composition is dominantly governed by the dissolution of carbonates and silicate minerals in combination with positive cation exchange in the valley. Principal component analysis reveals a significant influence of geogenic factors on groundwater chemistry, further supported by PHREEQC simulation that detects a supersaturation of calcite, dolomite, and sulphate minerals in the aquifer. The irrigation water quality index divides groundwater in the study area into three zones, which signify low restriction and no restriction, except for a severe restriction in the southwestern part of the valley. Groundwater is generally suitable for irrigation across the valley. The entropy-weighted water quality index classifies groundwater as excellent and good quality for drinking. This study can provide crucial insights for authorities on groundwater suitability in Quetta Valley and similar regions worldwide.

Groundwater assessment for sustainable development in the Wadi Al-Hamd Basin, Al-Madinah Al-Munawarah, KSA

This study relied on well monitoring many drilled wells data in the Wadi Al-Hamd Basin to determine water level and chemical properties from field measurements. The characteristics of groundwater must be assessed in terms of present and future eases and stresses to ensure sustainable development. Hydrogeological, hydrochemical, groundwater quality indices and Geographic Information Systems (GIS) data sets have been integrated to assess the groundwater aquifer in the study area. To implement this work, we measured the depth to the water table from eighty-eight drilled wells. Also, the major ions were determined from 82 water samples to evaluate the physicochemical properties, groundwater facies, and controlling mechanisms using diagrams such as the modified Piper proposed by Chadha, Total Ionic Salinity (TIS), and Gibbs. In this study, five irrigation water quality indicators (IWQI), including total dissolved solids (TDS), sodium adsorption ratio (SAR), potential salinity (PS), magnesium hazard (MH), and residual sodium carbonate (RSC) have been determined to assess the suitability of groundwater for irrigation. Based on the findings of this study, groundwater flows from the southeast and northwest to the west and south, respectively. In this basin, 56% of water samples have TDS greater than 2000 mg/L, while 62% of water points are categorised as Na–Cl water type, which indicates that evaporation and rock–groundwater interaction influenced groundwater quality evolution. Almost 87% of samples were rated good to excellent for irrigation use with respect to SAR. On the other hand, all water points are suitable for irrigation based on RSC. Likewise, groundwater is suitable for irrigation purposes despite the relatively high PS levels (>5 meq/L in about 49% of samples) and some small spots with high levels of MH (>50% in about 12% of samples), especially in the southern and central portions of the studied basin.

Shallow groundwater quality and health risk assessment of fluoride and arsenic in Northwestern Jiangsu Province, China

Assessing groundwater quality is critical to regional water resource conservation and human health safety, especially in areas with co-existence of toxic constituents fluoride (F−) and arsenic (As). In this study, fourteen groundwater samples were collected in Feng County, Northwestern Jiangsu Province to identify dominant contaminants and their spatial distribution and health risk. The composition and variation characteristics of major ions (K+, Na+, Ca2+, Mg2+, Cl−, SO42−, HCO3−, and NO3−) and trace elements (F−, As, and Mn) were analyzed. The hydrochemical results revealed that high F− groundwater was mainly distributed in the northern areas whereas As-riched groundwater was primarily distributed in southern areas. Notably, over 85.7% and 21.4% of the shallow groundwater samples exceeded the drinking water quality standard of 1.5 mg/L for F− and 10 µg/L for As, respectively. Based on the water quality index (WQI) appraisal result, 71.4% of the groundwater in the study area is classified as “poor”, and thus unsuitable for drinking directly. We assessed the human non-carcinogenic health risk of F− (HQFluoride) and As (HQArsenic) and the carcinogenic health risk of As (CRArsenic). The calculated hazard quotient (HQ) for F− indicated nearly all groundwater samples have an unacceptable risk (HQ > 1) for each age group. However, HQArsenic values revealed that 28.6%, 21.4%, 21.4%, and 21.4% of groundwater samples posed potential non-carcinogenic health risks for infants, children, females, and males, respectively. The calculated results of CRArsenic showed that 0%, 21.4%, 28.6%, and 28.6% of groundwater samples posed unacceptable health risks (CR > 1.0 × 10−4) to infants, children, females, and males, respectively. The groundwater irrigation suitability assessment results showed that 21.4% of samples were doubtful to unsuitable for irrigation, and 85.7% owed magnesium hazards. The findings of this study will assist policymakers in formulating proper remedial policies and mitigation strategies to ensure the safety of drinking and irrigation water.

Reconstruction of the Subsurface of Al-Hassa Oasis Using Gravity Geophysical Data

Al-Hassa city, located in Eastern Saudi Arabia, boasts the world’s largest oasis and the most expansive naturally irrigated lands. Historically, a total of 280 natural springs facilitated significant groundwater discharge and irrigation of agricultural land. Furthermore, the water in certain springs formerly had a high temperature. The spatial variability of the water quality was evident. At the same time, Al-Hassa Oasis is situated on the northeastern side of the Ghawar field, which is the largest conventional onshore oil field in the world in terms of both reserves and daily output (approximately 3.8 mmb/d). The aforementioned traits suggest an intricate subsurface that has not yet been publicly and thoroughly characterized. Due to the presence of significant cultural noise caused by agricultural and nearby industrial activities, a robust, easy-to-use, and accurate geophysical method (gravity) was used to cover an area of 350 km2, producing the 3D subsurface model of the study area. A total of 571 gravity stations were collected, covering the whole Al-Hassa Oasis and parts of the nearby semi-urban areas. The gravity data were corrected and processed, and a 3D inversion was applied. The resulting 3D geophysical subsurface modeling unveiled an intricate subterranean configuration and revealed lateral variations in density, indicating the presence of a potential salt dome structure, as well as fracture zones that serve as conduits or obstacles to the flow of the subsurface fluids. This comprehensive modeling approach offers valuable insights into the subsurface dynamics of the broader study area, enhancing our understanding of its qualitative tectonic and hydraulic features and their impacts on the area’s natural resources, such as groundwater and hydrocarbons.

Prediction of groundwater level changes based on machine learning technique in highly groundwater irrigated alluvial aquifers of south-central Punjab, India

Groundwater serves as a vital resource for all living organisms. In regions extensively reliant on groundwater irrigation, hydro-climatic factors, groundwater extraction, and the flow of surface water exhibit an indirect interdependence. This study primarily aims to anticipate GWL in such highly irrigated zones using the Machine Learning (ML) approach. To achieve this, the widely employed Random Forest (RF), Bagging-Reduce Error Pruning Tree (Bagging-REPTree), and Bagging-Decision Stump Tree (Bagging-DSTree) models have been employed for the accurate forecasting of groundwater levels. The long-term pre-monsoon and post-monsoon (fourteen locations) data set of South-Central Punjab state has been applied for the model calibration/training and validation/testing. Seven statistical indices were used such as percent bias (PBIAS), root mean square error (RMSE), normalized root mean square error (nRMSE), RMSE-observation standard deviation ratio (RSR), mean absolute error (MAE), Nash Sutcliffe efficiency (NSE) and correlation coefficient (CC) for the model performance analysis. The results revealed that the RF model outperformed in pre-monsoon (testing phase) (RMSE = 0.682, NSE = 0.958) as well as the post-monsoon (testing phase) (RMSE = 0.150, NSE = 0.997) compared to the other two models in the station Ahmadapur and the similar trend is observed in all the stations. Overall, the RF model demonstrates superior performance in predicting groundwater levels during both pre-monsoon and post-monsoon seasons, particularly in highly groundwater-irrigated alluvial aquifers of the southern region.

Saving farm subsidies with smart climate interventions: the case of transition to a millet-based agriculture

PurposeThe study attempts to estimate farm subsidies the governments can save by transitioning to a millet-based production system, replacing GHG emission-intensive crops.Design/methodology/approachIt updates a 131 × 131 commodity input–output (IO) table of the year 2015–16 into 2021–22 using the RAS procedure and simulates the economy-wide impacts of replacing rice and wheat with pearl millet and sorghum using consumption and production approaches. It then quantifies fertilizer, electricity and credit subsidy expenses the government can save through this intervention. It also estimates the potential reduction in GHG emissions that the transition could bring about. India is taken as a case.FindingsResults show pearl millet expansion brings greater benefits to the government. It is estimated that when households return to their pearl millet consumption rates that prevailed in the early-reform period, this could save the Indian government Rs. 622 crores (USD 75 m). The savings shall be reinvested in agriculture to finance climate adaptation/mitigation efforts, contributing to a sustainable food system. Net GHG emissions also decline by 3.3–3.6 MMT CO2e.Practical implicationsIndian government has been actively aiming to bring down paddy areas since 2013–14 through the Crop Diversification Program and promoting millets (and pulses and oilseeds) on these farms. The prime reason is to check rapidly declining groundwater irrigation in Green Revolution states. Regulations in the past in these states have not brought the intended results. Meanwhile, electricity and fertilizers are heavily subsidized for agriculture. A slight shift in the cropping system can help conserve these resources. Meanwhile, GHG emissions could also be brought down and subsidies could well be saved. The results of the study indicate the same.Social implicationsA less warm society is what governments and nongovernment organizations across the world are aiming for at present. Financial implications affect actions against climate change to a greater extent, apart from technological innovations. The effects of policy strategies discussed in the study, taking a large country as a case, when implemented appropriately around the regions, could help move a step closer to action against climate change.Originality/valueThe paper addresses a key but rarely explored research issue – that how a climate-sensitive crop choice will help reduce the government’s fiscal burden to finance climate adaption/mitigation. It also offers a mechanism to estimate the benefits within an economy-wide framework.

Impact of sand media continuous drying and rewetting cyclic on nutrients transformation performance from reclaimed wastewater effluent at soil aquifer treatment

Reusing reclaimed wastewater became a practical resource for water utilization in groundwater recharge and irrigation activities. However, the quality of reclaimed wastewater needs improvement to meet the environmental regulations and reduce contamination risks. A laboratory-scale study simulated a soil aquifer treatment (SAT) system, exploring the synergistic effects of wet and dry cycles alongside key physicochemical parameters on pollutant removal efficiency using a glass column filled with quartz sand as the filtration medium. The investigation focused on the cyclic wetting and drying phases to unravel their impact on removing NH4+, NO3−, and PO43−. The synthetic wastewater introduced into the system exhibited varying pollutant concentrations during wet and dry periods, influenced by dynamic soil water content (WC%), pH, dissolved oxygen (DO), and oxidation–reduction potential (ORP). The high removal rates of 93% for PO43− and 43% for Total N2 demonstrate the system’s capability to reduce concentrations significantly under dynamic alternating between wet and dry conditions. Results unveiled that the wet period consistently yielded higher removal rates for N2 species. Interestingly, for PO43−, the dry periods demonstrated a higher removal efficiency. Moreover, the study identified an average NO3− production during the experimental phases as a byproduct of nitrification. The average NO3− production in wet periods was 2.5 mg/L, whereas it slightly decreased to 2.2 mg/L in dry periods. These findings underscore the nuanced influence of wet and dry conditions on specific pollutants within SAT systems. Applying the logistic regression model and principal component analysis demonstrated the statistical significance of WC, pH, DO, and ORP in predicting wet/dry conditions, providing quantitative insights into their influential roles on the nutrient dynamic concentrations. This study contributes valuable data to our understanding of SAT systems, offering practical implications for designing and implementing sustainable wastewater treatment practices and pollution management across diverse environmental contexts.

Spatial Prediction of Groundwater Potential of Upper Tigris Basin Mapping in the Turkey with GIS-Based Multicriteria Decision Making (MCDM) Method

The Upper Tigris region in the Middle East is in Turkey and this study shows it to be an area with significant water resources that enable agricultural activities in the region. Since the GAP irrigation project has not been completed yet, there is an extensive use of groundwater for irrigation. This situation threatens the groundwater potential of the basin in a negative manner. Therefore, determination of groundwater potential should be evaluated properly instead of approving the groundwater potential of the region with observation wells, which is a more costly method. In this study, the groundwater potential of the basin was calculated by the GIS-based Multi-Criteria Decision Making (MCDM) method via main elements affecting groundwater formation. The GIS-based-AHP method is used for identifying the groundwater potential zones of the Upper Tigris Basin as an alternative to expensive and time-consuming method of well drilling. There are 8 key criteria taken into account; Geomorphology (GM), Geology(G), Line Density (LD), Slope (SL), Drainage Density (DD), Land Use (LU), Rainfall (R), and Soil Type (ST) and the individual weight of each criterion was evaluated by the AHP technique and utilized by the “Spatial Analysis Overlay Weighted Method” obtaining the “Groundwater Potential Index (GWPI)”. The GWPI values obtained is used to classify the Upper Tigris Basin into five categories as follows: 319 km2 of the basin has very poor potential (3.8%); 2217 km2 has poor potential (26.7%); 2800 km2 has moderate potential (33.7%); 2200 km2 has good potential (26.5%); and finally, 763 km2 has very good potential (9.2%).

In situ arsenic immobilization by natural iron (oxyhydr)oxide precipitates in As–contaminated groundwater irrigation canals

Arsenic-contaminated groundwater is widely used in agriculture. To meet the increasing demand for safe water in agriculture, an efficient and cost-effective method for As removal from groundwater is urgently needed. We hypothesized that Fe (oxyhydr)oxide (FeOOH) minerals precipitated in situ from indigenous Fe in groundwater may immobilize As, providing a solution for safely using As-contaminated groundwater in irrigation. To confirm this hypothesis and identify the controlling mechanisms, we comprehensively evaluated the transport, speciation changes, and immobilization of As and Fe in agricultural canals irrigated using As-contaminated groundwater. The efficiently removed As and Fe in the canals accumulated in shallow sediment rather than subsurface sediment. Linear combination fitting (LCF) analysis of X–ray absorption near edge spectroscopy (XANES) indicated that As(V) was the dominant As species, followed by As(III), and there was no FeAsO4 precipitate. Sequential extraction revealed higher contents of amorphous FeOOH and associated As in shallower sediment than in the subsurface layer. Stoichiometric molar ratio calculations, SEM‒EDS, FTIR, and fluorescence spectroscopy collectively demonstrated that the microbial reductive dissolution of amorphous FeOOH proceeded via reactive dissolved organic matter (DOM) consumption in subsurface anoxic porewater environment facilitating high labile As, whereas in surface sediment, the in situ-generated amorphous FeOOH was stable and strongly inhibited As release via adsorption. In summary, groundwater Fe2+ can efficiently precipitate in benthic surface sediment as abundant amorphous FeOOH, which immobilizes most of the dissolved As, protecting agricultural soil from contamination. This field research supports the critical roles of the phase and reactivity of in situ-generated FeOOH in As immobilization and provides new insight into the sustainable use of contaminated water.

High resolution prediction and explanation of groundwater depletion across India

Food production in much of the world relies on groundwater resources. In many regions, groundwater levels are declining due to a combination of anthropogenic extraction, localized meteorological and geological characteristics, and climate change. Groundwater in India is characteristic of this global trend, with an agricultural sector that is highly dependent on groundwater and increasingly threatened by extraction far in excess of recharge. The complexity of inputs makes groundwater depletion highly heterogeneous across space and time. However, modeling this heterogeneity has thus far proven difficult. Using two ensemble tree-based regression models, we predict district level seasonal groundwater dynamics to an accuracy of R 2 = 0.4–0.6 and Pearson correlations between 0.6 and 0.8. Further using two high-resolution feature importance methods, we demonstrate that atmospheric humidity, groundwater groundwater-based irrigation, and crop cultivation are the most important predictors of seasonal groundwater dynamics at the district level in India. We further demonstrate a shift in the predictors of groundwater depletion over 1998–2014 that is robustly found between the two feature importance methods, namely increasing importance of deep-well irrigation in Central and Eastern India. These areas coincide with districts where groundwater depletion is most severe. Further analysis shows decreases in crop yields per unit of irrigation over those regions, suggesting decreasing marginal returns for largely increasing quantities of groundwater irrigation used. This analysis demonstrates the public policy value of machine learning models for providing high spatiotemporal accuracy in predicting groundwater depletion, while also highlighting how anthropogenic activity impacts groundwater in India, with consequent implications for productivity and well-being.

Facile fabrication of polymeric-inorganic hybrid coated membrane with super-hydrophilic and underwater super-oleophobic properties for highly efficient crude oil-in-water emulsion separation

The oily wastewater is a huge wastewater stream that can potentially serve as an enormous source of clean water for water reuse applications such as groundwater recharge or irrigation. Given the huge potential of cleaning oily wastewater, we have developed an amino-functionalized nickel oxide nanoparticles coated inorganic-polymeric hybrid membrane with superhydrophilic and underwater superoleophobic properties for excellent crude oil-in-water (O/W) emulsion separation potential using a cross-flow filtration system. The use of ceramic alumina (Al2O3) support offers increased chemical, thermal, and mechanical stability while nickel oxide (NiO) decoration equips the membrane with special surface wettability to avoid membrane fouling. Moreover, the amino-functionalized NiO-coated polyamide network (F-NiO/PA) offers an active layer dense enough to separate the oil from water when the surfactant-stabilized crude oil-in-water emulsion was used as feed during separation experiments. Hence fabricated F-NiO/PA@Alumina membrane was studied by using different membrane characterization techniques to explore the features and understand the structure of F-NiO/PA@Alumina membrane. The F-NiO/PA@Alumina membrane possessed a superhydrophilic (water contact angle; θW, A = 0°) and underwater superoleophobic (oil contact angle; θO, W = 161°) surface wettability which is an ideal feature required for O/W emulsion separation. The F-NiO/PA@Alumina membrane demonstrated a high O/W emulsion separation efficiency of >99 % even with crude oil concentrations as high as 200 ppm using a cross-flow filtration system. The stability test of the separation performance of the F-NiO/PA@Alumina membrane also revealed a separation performance of >99 % for the duration of the test using a cross-flow filtration system.

The physical and chemical properties of the technosols in the pot experiment with waste and groundwater irrigation


 
 
 Mediterranean areas are characterized by a strong spatial variability that makes the soil hydrogeological logical response highly complicated. Some seasons provoke dramatic changes in soil properties determining the runoff rates, such as soil water content or soil water repellency. In recent years, important progress has been made in adapting water needs to local conditions through the use of various parameters to assess soil water status. Estimation of the water status of the soil has been widely used in soil science as a tool for quantitative analysis. The main objective of this case study was to analyze technosol and irrigation water physical and chemical properties in the pot experiment with lysimeters. A pot experiment with Avocado rootstocks was equipped with lysimeters in the facilites of the «La Mayora Experimental Field site» of the Higher Council for Scientific Research (Spain). The scheme of the pot experiment included three sources of irrigation: a) groundwater; b) regenerated municipal wastewater (100%); c) a mix of ground and regenerated municipal wastewater (50 / 50%). Chemical analysis data indicate that the reclaimed wastewater does not meet irrigation requirements in terms of pH, EC and due to the significant content of sodium and chlorine. Even groundwater satisfies irrigation water qualitative requirements partially. The suitability of irrigation water on pH level can be characterized mainly as unsuitable and doubtful. Diluting regenerated wastewater with groundwater following the 50% principle led to a decrease in the potential risks for salinization of groundwater connected with leaching of the leachate. The dynamics of the change in the volume of leachate are related to precipitation, the frequency of irrigation, and different manifestations of the physical, mineralogical, and chemical properties of technosols.
 
 

A Study on Groundwater Irrigation Expansion in Bihar, India

Water use has increased by more than twice the rate of population growth over the past century. Although, there is worldwide water scarcity, an increasing number of areas are chronically short of water. There has been a substantial increase in irrigated areas in the last thirty -five years. The Net Irrigated Area (NIA) in Bihar has increased from 2808 thousand hectares in 1985 to 3083 thousand hectares in 2021. The total annual replenishable groundwater potential of Bihar has been estimated as 33.15 billion cubic meters (bcm) with an annual extraction of 13.50 bcm. The share of surface water is declining while groundwater is increasingly being used in crop production. A total of 11754 thousand hectares have been estimated as the ultimate irrigation potential in the state, including major, medium and minor irrigation schemes, utilizing both surface and groundwater. If the available potential is fully exploited, it can cover more than the total cultivated area of the state. Considering the interests of both present and future generations attention needs to be directed towards the sustainable use of groundwater and promoting various sources of surface water.

Characterization of groundwater potability and irrigation potential in Uttar Pradesh, India using water quality index and multivariate statistics

Abstract This study includes groundwater quality data from 290 monitoring sites from 69 districts of Uttar Pradesh, India. The analysis of the data showed that 1.3, 75.52, 47.93, and 31.03% of groundwater samples had concentrations of electrical conductivity (EC), total hardness (TH), Mg2+, and HCO3−, respectively, higher than the maximum permissible limit. Groundwater quality index (GWQI) was calculated for these 290 monitoring sites which revealed that 21 sites (7.24%) had inappropriate GWQI for drinking water, and 18 sites (7.24%) had an unsuitable index for irrigation. Most of the sampling sites (98.97%) showed high EC contents in groundwater with a mean value of 999.33 μS/cm. Fluoride content was found within the permissible limits in 95.52% of the samples, while 4.48% had high concentrations. The use of hierarchical cluster analysis differentiated all the sites into two clusters: one with high pollution and the other with low pollution. Significant correlations exist between physicochemical and irrigation indicators in the correlation matrix. High loadings of EC, TH, Ca2+, Mg2+, Na+, Cl−, and SO42− were identified in the first principal component, which are thought to be pollution-controlled processes from anthropogenic sources. According to the Chadha diagram, CaHCO3 and Ca–Mg–HCl were the two most prevalent chemicals in the water.

Appraisal of non-carcinogenic health risks posed by fluoride and iron in groundwater of a rural semi-arid part of India

ABSTRACT The study was initiated to evaluate groundwater quality in the post-monsoon season (2021) vis a vis chemistry and hydrochemical facies, assessment of probabilistic health risks posed by F− and Fe and quality appraisal of regional groundwater for irrigation in Kumarganj community development block. As per potable water quality standards of Bureau of Indian Standards (BIS), 50% and 13.3% of water samples were found to be unsafe due to F− and Fe, respectively. Fluoride concentration ranged from 0.1 to 3.62 mg l−1 (mean, 1.22 mg l−1). The northern, north-western and south-eastern parts of the block were found to have F− concentrations above the permissible safe limit of 1.0 mg F l−1 while a small area within southern region had >1 mg l−1 Fe. Factor analysis showed that four factors contributed to 38.21%, 19.67%, 10.62%, and 8.45%, respectively, to water quality. According to the human health risk assessment by Total Hazard Index, all age groups in the study area were at risk of exposure, in the order of THIchildren > THIinfant > THIadult due to consumption of excessive F− and Fe. This assessment was consistent with the results of probabilistic health risk assessment undertaken by Monte Carlo simulation (5000 trials) wherein maximum risk of 4.14 and 0.17 at 95th percentile to children was attributable to F− and Fe, respectively.

Deep groundwater irrigation altered microbial community and increased anammox and methane oxidation in paddy wetlands of Sanjiang Plain, China.

The over-utilizing of nitrogen fertilizers in paddy wetlands potentially threatens to the surrounding waterbody, and a deep understanding of the community and function of microorganisms is crucial for paddy non-point source pollution control. In this study, top soil samples (0-15 cm) of paddy wetlands under groundwater's irrigation at different depths (H1: 6.8 m, H2: 13.7 m, H3: 14.8 m, H4: 15.6 m, H5: 17.0 m, and H6: 17.8 m) were collected to investigate microbial community and function differences and their interrelation with soil properties. Results suggested some soil factor differences for groundwater's irrigation at different depths. Deep-groundwater's irrigation (H2-H6) was beneficial to the accumulation of various electron acceptors. Nitrifying-bacteria Ellin6067 had high abundance under deep groundwater irrigation, which was consistent with its diverse metabolic capacity. Meanwhile, denitrifying bacteria had diverse distribution patterns. Iron-reducing bacteria Geobacter was abundant in H1, and Anaeromyxobacter was abundant under deep groundwater irrigation; both species could participate in Fe-anammox. Furthermore, Geobacter could perform dissimilatory nitrate reduction to ammonia using divalent iron and provide substrate supply for anammox. Intrasporangium and norank_f_Gemmatimonadacea had good chromium- and vanadium-reducting potentials and could promote the occurrence of anammox. Low abundances of methanotrophs Methylocystis and norank_f_Methyloligellaceae were associated with the relatively anoxic environment of paddy wetlands, and the presence of aerobic methane oxidation was favorable for in-situ methane abatement. Moisture, pH, and TP had crucial effects on microbial community under phylum- and genus-levels. Microorganisms under shallow groundwater irrigation were highly sensitive to environmental changes, and Fe-anammox, nitrification, and methane oxidation were favorable under deep groundwater irrigation. This study highlights the importance of comprehensively revealing the microbial community and function of paddy wetlands under groundwater's irrigation and reveals the underlying function of indigenous microorganisms in agricultural non-point pollution control and greenhouse gas abatement.

From subsistence to market-oriented farming: The role of groundwater irrigation in smallholder agriculture in eastern India

Empowering smallholder farmers in low and middle-income countries (LMICs) and improving their livelihood is a critical goal for poverty reduction. To achieve this, agricultural commercialization can play an important role. However, a prerequisite to achieving agricultural commercialization is access and control of stable irrigation. This study revisits empirically the relationship between groundwater irrigation and crop commercialization. It also analyses the underlying mechanisms of how groundwater affects crop commercialization through on-farm production diversity. Studying the effects of groundwater irrigation on crop commercialization is essential for comprehending the trade-off between agricultural benefits and the environmental costs of groundwater irrigation. Geospatial and remote sensing information, combined with primary household data from small-scale farmers in eastern India, are employed in conjunction with an instrumental variable technique and a 3SLS simultaneous equation model for the analysis. The results suggest that small-scale farmers in eastern India experience enhanced crop commercialization when they have access to groundwater irrigation. Furthermore, the study suggests that the utilization of groundwater irrigation indirectly promotes crop commercialization by incentivizing farmers to diversify their production system.