Groundwater Samples Research Articles

Groundwater Quality Assessment for Drinking and Irrigation Purposes in Khartoum Area-Between the two Niles-Sudan

The Nile and groundwater waters are the two sources for drinking and irrigation water in Khartoum corridors. The assessment of groundwater quality is of high priority for safe uses of water. The suitability of groundwater for drinking purpose was made by applying water quality index (WQI). For irrigation purpose the assessment was based on the Percentage of sodium, Sodium adsorption ratio (SAR), Permeability index (PI), Residual sodium carbonate (RSC), Kelly’s ratio (KR), Magnesium adsorption ratio (MAR) and Chloro-alkaline indices (CAI). The water quality index (WQI) reveals that all groundwater samples are found between excellent and good category of water and appropriate for drinking purposes. It is indicated that 95% and 96% of groundwater samples are grouped as excellent water for Gezira and Sandstone aquifers respectively, the remaining samples grouped as Good water. Most of the characteristics of irrigation water which calculated for the groundwater of Sandstone aquifers are more suitable for irrigation than the groundwater for Gezira aquifers (%Na, SAR, PI %, RCS, MAR%, KR and CAI). In the Sandstone aquifers the water quality adjacent to the Blue Nile is of higher quality standers than groundwater quality adjacent to the White Nile.

Spatial Variation of Physico-chemical and Microbial Parameters in Groundwater of Selected LGAs of Akwa-Ibom State, Nigeria

Physico-chemical and microbial parameters of groundwater are useful indicators in monitoring the progress of Goal 6.3 of Sustainable Development Goals (SDGs). The study evaluated the spatial variation of physico-chemical and microbial parameters in groundwater of selected LGAs of Akwa-Ibom State, Nigeria in line with SDGs. A total of twenty (20) groundwater samples were collected from boreholes at different locations within Uyo, Itu, Ibiono Ibom and Ibesikpo Asutan Local Government Areas of Akwa-Ibom State. The boreholes were selected at random. Sterilized and pre-labelled water sampling bottles were used in collecting representative water samples to prevent contamination. Physico-chemical parameters sensitive to environmental changes such as temperature, pH and electrical conductivity were measured in-situ. Sampling and analysis followed guidelines specified by the American Public Health Association, (2012). Chemical analysis was carried out at the Geospectra Laboratory in Port Harcourt, Rivers State of Nigeria. Results showed that the groundwater condition ranged from acidic and slightly weakly acidic in Uyo and Ibiono Ibom but slightly alkaline in Itu. All the heavy metals analysed were within the permissible limits specified by WHO (2018) and NSDWQ (2015) in drinking water. The average values of total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), faecal coliform and total coliform in Uyo, Itu, Ibiono and Ibesikpo were 57.4 mg/L, 40.1 mg/L, 97.0 mg/L, 1032 and 1542.3 MPN/100ml, 54.3 mg/L, 51.6 mg/L, 110 and 47, 20.5 mg/L, 35.7 mg/L, 78.5 mg/L, 28.8 and 82.5 MPN/100ml, and 184 mg/L, 42.8 mg/L, 94.3 mg/L, 130 and 280 MPN/100ml respectively. The values of pH, BOD, COD, faecal and total coliforms were found to be above the permissible limits. Faecal and total coliforms, which indicate recent contamination, are high in Uyo and could be attributed to urbanisation with its consequent sewage management issues and increased animal droppings. There is a need for proper sewage management within the city.

Application of Geographical Information System –Water Quality Index Techniques for Evaluating the Groundwater Quality in Kaniqirzhala Landfill, Kurdistan Region, Iraq

The aim of the current study through uses the Water Quality Index for drinking and irrigation purposes and Heavy Metal Pollution Index to determine quality groundwater in 25 wells spread throughout Kaniqirzhala landfill within the Erbil governorate during 2022. Groundwater samples from various wells have been gathered for chemical and physical analysis in order to determine the water quality. Turbidity, pH, electrical conductivity, total dissolved solids, total alkalinity, total hardness, major anions (SO4-2, Cl-1, Hco3-1, NO3-2, PO4-3) and major cations (Ca+2, Mg+2, Na+1, K+1) are all included in the analysis. In addition to heavy metals investigations were conducted on a variety of metals, including manganese (Mn), nickel (Ni), zinc (Zn), arsenic (As), barium (Ba), boron (B), cadmium (Cd), copper (Cu), iron (Fe), and lead (Pb). Results indicated that higher values of nitrate were calculated in sites 10 to 17. But, in all wells higher concentrations of alkalinity and total hardness were recorded .The concentrations of heavy metals in wells water ranged from low to high according to WHO guidelines for drinking purposes. Drinking water quality index ranged from 52.20 (good quality) at site 9 to 137.01 (poor quality) at site 14. The value of the irrigation water quality index, which is low at site 15, which indicates low restriction for irrigation uses, while the value of 50.01 recorded at site 4 indicates high restriction for irrigation purposes. In all groundwater sites under study, a heavy metal pollution index of greater than 100 indicates extremely poor water quality unsuitable for human consumption. This study concluded all examined wells were deemed to be of extremely poor to good quality for to use in for drinking water based on the water quality index, while extremely low quality based on the heavy metals pollution index .

Assessment of Groundwater Quality and Hydrochemistry using Water Quality Index in District Mirpur Khas, Sindh, Pakistan

Groundwater is a major source of drinking water in the rural areas of Sindh province, including District Mirpur Khas of Pakistan. This study was undertaken to evaluate the suitability of groundwater in Mirpur Khas for drinking purposes. In October and November 2018, the groundwater samples were collected from 50 bore wells and analyzed 17 physico-chemical parameters. The pH ranged from 7.8 to 8.8, indicating the slightly alkaline nature of the water. The mean abundance of major cations is Na+ > Ca2+ > Mg2+ > K+ and for major anions, it is SO42– > Cl– > HCO3– > NO3– > F–. The hydrochemical facies of groundwater samples show that 29 have a mixed composition, Na+-K+-Cl– characterized by 17 and the remaining 4 fall into the Ca2+-Mg2+-HCO3– category. The water quality index (WQI) was calculated based on WHO standards for drinking water using 16 physico-chemical parameters. The computed WQI values range from 20.4 to 503.1. Out of the 50 samples, 9 are classified as ‘excellent,’ 21 as ‘good,’ 13 as ‘poor,’ 4 as ‘very poor,’ and 3 as ‘unsuitable for drinking.’ The average WQI value is 118.7 for 50 samples, which falls under the ‘good’ category. Turbidity and EC exhibited the highest mean effective weight values, indicating their significant influence on the WQI values.

Geochemical Correlation of Volcanic Rocks and Groundwater Quality in the Todoko-Ranu Complex, Sahu District, West Halmahera, North Maluku, Indonesia

The research area is located in the Mount Todoko-ranu complex and its surroundings, Sahu District, West Halmahera Regency, North Maluku, Indonesia. This area geologically consists of Quaternary volcanic rocks with various petrochemical composition. On the other hand, natural water found in the research area generally physically appears turbid, while people who take water from this sites actually need clean water. As it is known, groundwater quality is influenced by the geochemistry of the aquifer through which it flows, therefore it is important to conduct a study on the geochemical correlation of volcanic rocks and groundwater quality in the research area. Thus, the aim of this research is to examine the geochemical characteristics of Mount Todoko-Ranu complex volcanic rocks, to analyze groundwater quality, and to study the correlation between the geochemical characteristics of rocks and the quality of groundwater in this volcanic complex. Methodology applied in this study was geological mapping, rock samples testing to determine the mineralogy chemical composition, groundwater, and surface water samples testing to identify their quality, and then correlation analysis. The results show that andesitic and basaltic-andesite of calc-alcaline volcanic rock complex is correlative to no dominant cation, but bicarbonate anion, or mixing type of natural water.

Validating a portable device for groundwater iron measurement in Bangladesh

The mineral iron is essential for health at an optimum level. In Bangladesh iron is obtained from the drinking source groundwater, attributing largely to the good iron status in population. This groundwater iron poses two scenarios—predominantly high in many areas and predominantly low in other areas. Despite good iron status, burden of anemia in population is high. To control anemia, iron supplementation programs are operational against the backdrop of high iron status. This often leads to iron-associated side effects, plausibly due to excess iron, especially among the individuals exposed to high amount of iron from the drinking water. This geological phenomenon warrants the supplementation program to deliver different doses depending on the groundwater iron level. To enable that, the country needs an area-representative “mapping” of groundwater iron. However, such a mapping using the gold standard laboratory methods is expensive and logistically intensive. The aim of the study is to validate Handheld Colorimeter (HI721 Checker® HC), a portable device (“spot kit” device) to measure iron concentration in the drinking groundwater. The study was carried out in the rural Belkuchi upazila of the Sirajganj district in the Rajshahi division. In the study 25 tubewells were selected and categorized into five groups. Among them, four were categorized based on their iron concentration, low iron conc. (0-<1 mg/L), medium iron conc. (1-2 mg/L), high iron conc. (2-10 mg/L), very high iron conc. (>10 mg/L). One additional group was included for tubewell water that was used after filtering. The study compared the iron estimates measured in groundwater samples of the selected tube wells by the spot kit device and the same samples measured by atomic absorption spectrophotometry (AAS). There was a high agreement between the estimates by the spot kit and AAS (Kappa coefficient= 0.72, p <0.001; Lin’s concordance = 0.829, p < 0.001). Pitman's test of difference in variance exhibited that the two methods produced equally precise results (r=0.227, p=0.275). The study concluded that the Handheld Colorimeter (HI721 Checker® HC) was valid to measure the iron concentration of groundwater under field conditions. This device can facilitate testing processes, particularly in remote or resource-constrained areas where sophisticated testing methods (i.e: AAS) are unavailable and thus may help the re-design of the anemia control program in settings like Bangladesh with high and variable level of iron in the drinking groundwater.

Hydrochemical Characteristics and Spatial Variability in Coastal Aquifers Southern IraqUtilizing a GIS Technique

The present study investigates water quality regarding drinking and irrigation supplies by gathering and analyzing twelve groundwater samples south of Basrah, south Iraq. Many wells in the area concerned are exploited mainly for various industrial and agricultural activities, impacting the ground water quality. The standard guidelines recommended by the Iraqi Quality Standard limits and the World Health Organization have been used to determine the suitability of drinking. The physicochemica analyses showed that all sampled waters are unsuitable for the drinking supply due to high total dissolved solids (TDS) levels reaching 12925 mg/L. Four valuable indices have been applied for estimating the irrigated water quality, namely, the sodium adsorption ratio (SAR), the soluble sodium percentage (SSP%), the magnesium hazard (MH%), and Kelly’s ratio (KR%). The results of water class as regards the percent of samples showed: SAR results, 25% excellent water, 41.7% good water, and 33.3% doubtful water; SSP% results, 16.7 % good water, 75% permissible water, and 8.3 % doubtful water; MH% results, 100% suitable irrigated water; and KR% results show 41.7% suitable water and 58.3 % unsuitable water. The USSL salinity diagram (Wilcox) result revealed 83.3 % of samples fall in very high salinity-very high sodium hazard class C4S4, and 16.7 % of samples fall in very high salinity-high sodium hazard class C4S3 and very high salinity-medium sodium hazard class C4S2, respectively. Increasing salinity of coastal aquifers has impacted sources such as seawater intrusion and intensive irrigation, and usages of excessive fertilizers and herbicides can largely pollute the groundwater quality.

Delineation of the Hydrogeological Functioning of a Karst Aquifer System Using a Combination of Environmental Isotopes and Artificial Tracers: The Case of the Sierra Seca Range (Andalucía, Spain)

The Sierra Seca aquifer system is located in the northeast (NE) of the province of Granada, in the Prebetic Domain (Betic Cordillera). It is composed of different aquifer units hosted in the Lower Cretaceous and Upper Cretaceous limestones. The two aquifers are separated by a low permeability marl layer, which effectively acts as a barrier between them. To outline the behavior of the hydrogeological system, 407 samples of precipitation and 67 samples of groundwater were obtained from May 2020 to Oct. 2022 and isotopically (δ18O and δ2H) analyzed. For the estimation of the recharge elevation, a new methodology has been applied to estimate the isotopic content of recharge as a function of precipitation. This allowed the evaluation of the vertical gradient of both precipitation (∇Zδ18OP=−2.9 ‰/km) and aquifer recharge (−4.4 ‰/km≤∇Zδ18OR≤−2.9 ‰/km). Therefore, estimating (1) the recharge zone elevation associated with the aquifer system, which is comprised between 1500 and 1700 m a.s.l., and (2) the transit time of recharge to reach the outflow point of the aquifer system, which varies between 4 and 5 months, is possible. Additionally, three tracer tests were conducted to outline the hydrologic connection between the recharge and discharge zones of the aquifer system. The results show that the Fuente Alta spring drains the limestones of the Lower Cretaceous, while La Natividad spring does the same with the limestones of the Upper Cretaceous. In the case of the Enmedio spring, groundwater discharge is related to infiltration through the streambed of the watercourse fed by the Fuente Alta spring.

Antifungal resistance profile and genetic relatedness of moulds from rural groundwater sources

Antifungal resistance remains a significant public health threat, yet poorly investigated. This study for the first time investigated the antifungal profile of moulds isolated from groundwaters in a rural community of Osun State, Southwest Nigeria. Groundwater samples were collected during dry and rainy seasons, and processed for mould isolation using standard methods. The isolates were presumptively identified and screened for in vitro susceptibility using 4 antifungals conventionally employed in clinical cases. Multiple antifungal resistance phenotypes and indices were equally evaluated. Representative of each putatively identified species were confirmed using molecular techniques. A total of 29 and 27 moulds were obtained during the dry and rainy seasons, respectively. Genus Aspergillus was the most prevalent (30.4%). Of the 56 isolates subjected to antifungal susceptibility testing, 55(98%) were resistant to fluconazole, followed by flucytosine 49(88%), ketoconazole 45(80%) and amphotericin B 31(55%). Exactly 46 isolates were multidrug-resistant, 23(50%) each, to 3 and 4 drugs, respectively. The multiple antifungal resistance index (MARI) evaluated was 1 in all the samples A-Q, except C (0.75), transcending the threshold limit of 0.2, indicating the isolates to be of high antifungal usage origin. The molecularly identified species had 99–100% similarity with reference strains from GenBank and evolutionary relationship of taxa revealed 10 distinct clades. The outcome of this study reveals a rise in the frequency of antifungal resistance in moulds towards standard drugs, thus, advocating for adequate investigations targeted at monitoring antifungal resistance in groundwater milieus.

Radiogenic 32P as a new dating tool to determine groundwater ages of 50–1000 years

Groundwater age has significant hydrogeological implication for groundwater renewal and solute transport. The period between 50 to 1000 years, marked by increased human activity, which is also a gap of groundwater dating. Cosmogenic 32Si with a half-life of 144±11 a, is the only viable dating tool for this range but is seldom used due to complex pretreatment and time-consuming and expensive detection. Radiogenic 32P, as a daughter isotope of 32Si, decays by emitting high-energy β- particles and is easily detected. 32Si and 32P reaches radioactive equilibrium within 3 months, meaning they maintain consistent activity levels in groundwater aged between 50 and 1000 years. Therefore, 32P can be used to date groundwater in the range of 50–1000 a. 32P is enriched and extracted using Mg(OH)2 co-precipitation method. The 32P solution is then mixed with a solvent mixture containing Triton X-100 and Permafluor and detected using an ultra-low background liquid scintillation spectrometer. The counting time ranges from 2500 to 3000 min with an efficiency of 65 %, and the 32P count peak surface is observed between channels 600 and 900. Comparing the 32P ages with the 14C and 32Si ages of groundwater samples from the Jianghan Plain, Central China, reveals that 32P ages and 14C ages exhibit similar trends, and the 32P ages and 32Si ages are approximately consistent in the range of 50–1000 a. Therefore, radiogenic 32P dating groundwater in the range of 50–1000 a is feasible, convenient and reliable.

Hydrogeochemical evolution and heavy metal characterization of groundwater from southwestern, Nigeria: An integrated assessment using spatial, indexical, irrigation, chemometric, and health risk models

This study examines the hydrogeochemical and heavy metal parameters of groundwater in Ojo District to determine its suitability for use, potential sources, and human health implications. Ten groundwater samples were assessed, and hydrogeochemical modelling was performed via the Aquachem software. The chemical ions were in the following order: EC > (107.78–448.65 μS/cm) > TDS (182.02–320.77 mg/l) > TH (46.22–182.45 mg/l) > pH (5.55–6.35); HCO3− (64.13–125.82 mg/l) > Na+ (36.87–96.49 mg/l) > Ca2+ (47.65–58.88 mg/l) > SO42− (19.94–53.67) > NO3− (15.55–44.25 mg/l) > Cl− (20.43–27.16 mg/l) > Mg2+ (11.09–16.87 mg/l) and K+ (2.55–7.86 mg/l). The concentrations of heavy metals in groundwater were in the range of: Fe (0.11–0.27 mg/l) > Mn (0.003–0.16 mg/l) > Ni (0.05–0.12 mg/l) > Zn (0.003–0.05 mg/l) > Pb (0.001–0.03 mg/l) > As (0.001–0.005 mg/l) > Cr (0.002–0.005 mg/l) > Cd (0.001–0.003 mg/l) and Cu (0.001–0.0002 mg/l), with Pb, Mn, and Ni exceeding their allowable limits. The Schoeller and Gibbs plots revealed that the major mechanisms controlling the aquifer groundwater in Ojo region are geological rock weathering and mineralization, with a minimal influence of saltwater intrusion. The piper trilinear diagram also revealed that none of the cation was dominant while the anions were strongly dominated by HCO3− (weak acids). The hydrogeochemical facies which describes the geochemical characteristics of the groundwater were classified into 3 types; “Ca2+–Mg+–HCO3– (65 %)”, “mixing zones (30 %)”, and “Na+–K+–Cl––HCO3– (5 %)”. The hydrogeochemical modelling revealed that the groundwater is characterized by forward cation exchange, while rock–water interactions (silicate dissolution) were heavily involved in the geochemical processes. The single pollution index showed that Pb, Ni, and Mn contributed significantly to contamination, and the multi–pollution indices showed that the groundwater was slightly-moderately polluted. The integrated groundwater quality index revealed that only 10 % were clean, 50 % were poor or moderately unclean, 30 % were highly unclean, and only 10 % were extremely unclean (unfit for utilization). The water pollution index showed that 70 % of the groundwater was good. The irrigation indices suggest that the groundwater would enhance soil quality and support plant growth. Multivariate analysis revealed that the groundwater is being influenced by geogenic factors and anthropogenic activities. The health risk assessment (Hazard Quotient and Hazard Index) showed that exposure of adults to the investigated groundwaters could result in noncarcinogenic adverse effects. The cancer risk values also exceeded the minimum limit (1.0 x 10−6) and thresholds (1.0 x 10−4) for adults, indicating the carcinogenic potential of the groundwater.

Isotope characterisation of groundwater resources in uranium impacted Fazilka, Punjab

AbstractGroundwater is the most reliable source for freshwater supplies in India and abroad. Population rise has affected the groundwater resources both in terms of quality and quantity. Punjab, being an agrarian state, is highly dependent on groundwater resources for both irrigation and drinking purposes. Recent studies have indicated presence of uranium in groundwater especially in southwestern parts of Punjab. In this research, water samples were collected from Fazilka district of Punjab for evaluating the water quality focussing uranium and identifying source and recharge processes of groundwater. Uranium concentration was found in both shallow and deep groundwater samples. Inter-ionic correlations signify that alkalinity and electrical conductivity of the water samples control the uranium mobilization from the aquifer matrix. Isotopic systematics demonstrate that groundwater recharge is mainly through rainwater infiltration.

Groundwater quality assessment using revised classical diagrams and compositional data analysis (CoDa): Case study of Wadi Ranyah, Saudi Arabia

This research aims to assess the status and chemical properties of groundwater in the shallow aquifer of the Wadi Ranyah region, Saudi Arabia, using robust statistical methods (CoDA) that take into account the unique characteristics of chemical analysis data from forty-five (45) groundwater samples collected in the Wadi Ranyah valley. A centered logarithmic transformation (clr) approach and isometric logarithmic transformation (ilr) plots for compositional data were utilized to determine the different water types and to understand the hydrogeochemical processes influencing groundwater chemistry in the region. The results of principal component analysis and K-means clustering reveal the existence of three groundwater groupings: (i) The first group occupies the recharge region with a relationship between trace metal elements (F, Pb, Mn, Zn), pH, and TDS, indicating the effect of alteration of igneous and metamorphic rock minerals. (ii) The second group characterizes the downstream part of the Al-Hujrah area with a relationship between calcium and nitrates, indicating the influence of agricultural activities. (iii) The third group, located in the Ranyah area, shows a relationship between major ions (Na+, SO42−, Mg2+, HCO3–, Cl−, K+), which explains water mineralization influenced by silicate weathering and evaporation phenomena. According to the modified Piper diagram (ilr Piper), two hydrochemical facies are identified. The upstream region is categorized as Ca-HCO3– while the downstream region is classified as Na-K-HCO3–. Calculated water quality index (WQI) values indicate that all Wadi Ranyah groundwater samples are of very poor quality (WQI > 300). This is due to higher concentrations of polluting elements (Pb, Mn and F), in particular the high lead concentrations which vary between 0.24 and 0.4 mg/L, and are well above the WHO limit (0.01 mg/L) for consumption of drinking water. The application of CoDA for the first time in the study region has provided a more detailed and reliable assessment of the mechanisms governing groundwater quality, permitting suggestions for the management of groundwater resources and defining future research needs.

Assessment of Uranium Pollution in Ground Water and Human Health in Balod District, Chhattisgarh

A laser fluorimetric technique was used to measure the amount of uranium present in samples of groundwater from the Balod district, Chhattisgarh, central India. For this purpose, we collected twenty-nine water samples from different villages in the Balod district, Chhattisgarh from September 2022 to June 2023. Here, the concentration of uranium in the sample of water ranges from 0.10 to 66.7(µg/l). A maximum number of samples had uranium contamination levels below the acceptable limit (30 µg/l), except for Siwani village (66.7µg/l), as approved by the WHO. The USEPA recommendations were used to determine the chemical risk ( Non-carcinogenic) and excess lifetime carcinogenic risk (ECR) caused by groundwater consumption. The allowed excess lifetime cancer risk ( ELCR) value of 1.0´10-4was found to be exceeded in a few water samples by the risk of cancer resulting from drinking water. The LADD value of 18 % and HQ value of 24% of the water sample exceed the permissible limit indicating a high risk of chemical poisoning. In this analysis, we found that the area's uranium's chemical toxicity may be the cause of non-carcinogenic health problems, but eventually, there is no Carcinogenic (radiological) risk to people.

Assessing the Heavy Metal Contamination Prevailing in Groundwater at Rishipur Village, West Bengal, India

The recent surge in interest surrounding water contamination has prompted a study to evaluate the water quality of groundwater in Rishipur village, Malda District, West Bengal, India. The area's groundwater is crucial for drinking, residential, and irrigation purposes due to its proximity to agricultural fields, where most local residents live. The intended purpose of the study is to comprehensively appraise the groundwater quality of a dug well, specifically analysing the intensities of different heavy-metals existing in the water, resulting in valuable insights into its quality. The native residents rely on the usage of this groundwater for drinking and domestic purposes without any purification. However, potential contamination may be present due to nearby agricultural activities. Thus, the study will enable us to make recommendations for mitigating any identified contamination. Exemplary samples of water from a well were consistently collected near the agricultural region over the course of a year, from April 2021 to March 2022. The groundwater samples were analysed for the presence of heavy elements: iron; zinc; copper; manganese; nickel; chromium; cobalt and lead to evaluate the water excellence. To ascertain the overall water eminence status, the Heavy-Metal-Pollution-Index; (HPI), was calculated, which is considered an efficient and reliable technique for water eminence assessment. In this study, the value of HPI; 101.66 in January, indicates high heavy-metal pollution, although it remained within the desired range for the rest of the months. In the analysis of the descriptive statistical data, both substantial positive and negative relations were observed, which were illustrated in a correlation coefficient matrix. Furthermore, the interaction of heavy-metal variables was also explored by utilising the R-Square values derived from the multiple linear regression analysis, which allowed to gain insights into how these variables interplayed with one another. The investigation conclusively established that the eminence of water is deemed appropriate for consumption alongside other domiciliary purposes, with the exception of January.

Hydrochemical insights, water quality, and human health risk assessment of groundwater in a coastal area of southeastern China.

Groundwater is a vital water supply worldwide, but its quality has gradually deteriorated with the development of society. In this study, a total of 40 groundwater samples were collected during the pre- and post-monsoon to analyze the hydrochemical process and assess the groundwater quality and human health risks in a coastal area of southeastern China. The results showed that the concentrations of major ions were in the order of Ca2+> Mg2+ > Na+ > K+ and HCO3- > SO42- > Cl- > NO3- > F- during the pre- and post-monsoon periods. A slight increase was observed during the post-monsoon period. The Piper diagram suggested that the hydrochemical type of groundwater was predominantly HCO3-Ca. Principal component analysis (PCA), ionic ratios, and saturation index (SI) determined that the water-rock interactions involving silicate and carbonate minerals played a significant role in the hydrochemical process. The results of the entropy-weighted water quality index (EWQI) and irrigation water quality index (IWQI) evaluations revealed that the general qualities of groundwater were suitable for both drinking and irrigation purposes. However, the excesses of NO3- and SO42- were observed locally. Human health risk assessment concluded that groundwater posed a low risk to human health, and infants faced higher risk compared with adults. The study would provide valuable information for groundwater environmental protection.

Antimicrobial resistance profiling of bacteria isolated from wastewater and samples of pharmaceutical industries in South India

The study was aimed to determine the phenotypic and genotypic antimicrobial resistance in the isolated bacteria from the influent (25), effluent (15), surface and ground water samples (15) surrounding the pharmaceutical industries located in south India. From 55 samples, 48 isolates of 10 different bacteria were obtained. The identified bacterial isolates were viz. Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogenes, Corynebacterium sp., Acinetobacter sp., Aeromonas punctata, Ralstonia picketti, Staphylococcus aureus, Stenotrophomonas maltophillia, and Citrobacter freundii. The phenotypic profile of resistance through antibiotic susceptibility test was carried out against sixteen different antibiotics. Standard PCR technique was used for the detection of 12 resistance genes encoding carbapenems, quinoline, aminoglycoside, β-lactam belonging blaOXA-58,blaOXA-22,qnrA, qnrB, aac(6)-Ib-cr, aac (3)-XI, mec A, qepA, aadB, blaVIM, blaOXA-48 and blaNDM. Pseudomonas aeruginosa (1: TN/I/2020) showed presence of 3 resistance genes. qnrB (489 bp) gene was present in maximum of 7 isolates while blaVIM (196 bp) gene was present in 6 isolates. The resistance genes blaNDM (621 bp) was present in three different isolates; aac (X):6)-lb-cr (482 bp), qepA (495 bp), aadB (500 bp), blaOXA-58 (843 bp) resistant genes were present in two different isolates each among the bacterial isolates obtained in this study. In phenotypic resistance profiling by AST method, out of 16 antibiotics tested, 14 showed resistance. Similarly, in genotypic resistance profiling, among 12 resistance genes tested, a maximum of three resistance genes were noticed in Pseudomonas aeruginosa. There were positive and negative correlations observed between phenotypic and genotypic resistance among different antibiotics and their resistance genes indicating the variations in the resistance gene expression.

Linking recharge water sources to groundwater composition in the Hindon subbasin of the Ganges River, India

Groundwater resources of the densely populated Indo-Gangetic Basin are under increasing pressure, not only from extensive groundwater abstraction, but also from contamination. In this study we aim to better understand how different recharge sources affect the hydrochemical and isotope composition of groundwater. We used the Hindon subbasin in Northern India as a case study. Recharge water sources and groundwater were analysed for hydrochemical variables and stable isotopes along a 50 km transect between the Yamuna and Ganges rivers. Groundwater samples were statistically clustered based on hydrochemical variables, and the spatial variation of the groundwater clusters was compared with recharge sources.Groundwater quality could be linked to both recharge from irrigation canal water as well as recharge from polluted river water of the Hindon and its tributaries. We could not directly link groundwater outside these related zones to their recharge source. However, we suspect that shallow polluted groundwater (< 40 m depth) is affected by recharge from agricultural areas and infiltration of municipal wastewater, whereas deeper unpolluted groundwater (40–80 m depth) originates from recharge by rain and river water under more pristine conditions. Our findings show that human activities significantly impact the quality of groundwater, as we found vertical recharge of clean irrigation canal water and polluted municipal, agricultural and river surface water (up to 40 m depth). At one location, groundwater at 75 m depth shows increased Cl, NO3 and SO4 concentrations, suggesting accelerated downward displacement of polluted shallow groundwater by pumping. Limited horizontal displacement was found. We present a conceptual model demonstrating the evolution from a previously unpolluted groundwater system discharging to the river, to a contemporary system with infiltration dominance of polluted river, municipal and agricultural water and local clean irrigation canal water. This model may be relevant for large parts of the Indo-Gangetic Basin.

Revealing the impact of wildfires on groundwater quality: Insights from Sierra de la Culebra (Spain)

Wildfires induce changes in soil and vegetation composition, significantly impacting the hydrological cycle and altering future runoff and infiltration patterns. Ash residue on the ground can infiltrate the subsoil along with water, leading to modifications in groundwater hydrochemistry. Climate change and summer heatwaves can create favourable conditions for severe wildfires, such as the one that occurred in Zamora, Spain, in 2022. Fourteen simultaneous points of origin across various locations in Zamora triggered the worst environmental disaster in this province, as well as the largest fire recorded in the history of Spain. Following the severe wildfires in Sierra de la Culebra, Zamora, groundwater samples were obtained to compare the hydrochemistry with pre-fire background data spanning several years. A general decline in pH across all sampling points was observed, most notably at Z1, likely due to its very high permeability and leaching of organic acids from burned vegetation. Increases in major ions such as SO42− and NO3− were detected at Z1-2, while HCO3− levels decreased, indicating possible oxidation of soil organic matter and the introduction of wildfire-derived organic acids into the groundwater system. Elevated concentrations of Na+, K+, Mg2+, and Ca2+ were observed at Z3, suggesting possible ash residue infiltration. Despite the severity of the wildfires, the results indicate that there were no significant long-lasting impacts on groundwater quality overall. This finding suggests that the groundwater systems in the study area are resilient to such environmental catastrophes.

Pollution source characterization and evaluation of groundwater quality utilizing an integrated approach of Water Quality Index, GIS and multivariate statistical analysis

ABSTRACT The Mid-Gangetic Plain, a vital farmland in India, faces increasing groundwater quality deterioration due to anthropogenic activities. This study aimed to assess groundwater quality and contamination sources in the region utilizing statistical methods. A total of 78 groundwater samples were collected and analyzed using standard methods. The hydrochemistry analysis of samples revealed that several parameters such as Ca2+, Mg2+, HCO3−, NO3−, F− and PO43− surpassed the limits prescribed by the Bureau of Indian Standards (BIS). The principal component analysis yielded three significant factors, explaining 68.96% variation, highlighting geogenic and anthropogenic influences on groundwater chemistry. Hierarchical cluster analysis categorized groundwater into three clusters based on the parameters with similar trends of variation. Furthermore, Discriminant analysis identified four significant variables (Mg2+, F−, Cl− and NO3−) responsible for creating the distinction among the identified clusters. Hydrogeochemical categorization and multivariate statistical analyses indicated that rock–water interaction, weathering, leaching and anthropogenic activities collectively influenced groundwater quality throughout the studied region. The Water Quality Index reveals that 59% of samples have good water quality, while 41% exhibit poor quality predominantly concentrated in the south-western, south-eastern and central regions. This study demonstrates the efficacy of statistical techniques to interpret complex datasets and grasp water quality dynamics, enhancing groundwater management.