Groundwater Samples Research Articles

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.

Enrichment mechanism of groundwater fluoride and its hydrogeological indications in the Badain Jaran Desert, northwest China

Fluoride (F−) enrichment in groundwater poses significant risks to drinking water safety; however, reports of high F− concentrations in groundwater in a vast desert and its hydrogeological indications are limited. In this study, we collected 275 groundwater samples from various depths in the Badain Jaran Desert (BJD) to investigate the distribution characteristics and enrichment mechanisms of F− in desert groundwater, utilizing hydrochemistry, environmental isotopes, and statistical methods. The results indicate that (1) the groundwater F− concentrations in the mountainous areas, desert areas, and downstream wetland areas are 0.10–9.45 mg/L (average of 3.05), 0.19–58.00 mg/L (average of 4.32), and 0.62–9.91 mg/L (average of 1.99), respectively, with corresponding exceedance rates (>1 mg/L) of 83%, 71%, and 80%. (2) In mountainous areas, F− enrichment mechanisms are attributed to ion exchange, evaporative concentration, and the dissolution of fluoride minerals. In desert areas, F− enrichment mechanisms involves multiple hydrogeochemical processes, with the dissolution of fluoride minerals being the most significant, followed by evaporative concentration and desorption. And evaporative concentration is particularly pronounced in shallow groundwater (depth <4 m). In wetland areas, F− enrichment mechanisms are mainly ion exchange and desorption. (3) The F− concentration characteristics (<2 mg/L) and the significant correlation between F− and HCO3− (R = 0.55, P < 0.01) in the deep groundwater of the desert suggest that groundwater does not originate from deep geothermal sources. (4) Based on the significant differences in groundwater F− concentrations, there is a weak hydrodynamic connection between the groundwater in the Quaternary aquifer and that in the underlying Cretaceous bedrock in desert areas. These findings not only facilitate the safe use of groundwater in desert environments but also provide new insights into the formation, circulation, and evolution of desert groundwater.

Regional characteristics of groundwater sulfate source and evolution in the multi-layer aquifer system of the northern Shaanxi coal mine base, northwestern China: Evidence from geochemical and isotopic fingerprints

Groundwater sulfate contamination in mining areas has attracted widespread attention. However, deciphering the source and evolution of sulfate in large-scale mining areas remains a challenge due to intense anthropogenic influences and complex hydrogeological conditions. In this study, 94 groundwater samples were analyzed by a combination of self-organizing maps, MixSiar model, multi-isotope analyses (δ34S, δ18OSO4, δD and δ18Owater) and hydrogeochemical methods to investigate the regional characteristics of groundwater sulfate source and evolution in China's largest coalfield (the Shenfuyu Coalfield). The results showed that the source and evolution of groundwater sulfate were controlled by human activities (mining and agricultural activities) and hydrogeological conditions. The groundwater sulfate primarily originated from pyrite oxidation, gypsum dissolution and human inputs. For the mining districts with shallow mining depths, pyrite oxidation and fertilizer contributed to groundwater sulfate. In addition, the ground cracks and abandoned mines controlled the BSR and pyrite oxidation processes. In contrast, the gypsum dissolution and cation exchange dominated the sulfate evolution in the mining districts with deep mining depths due to slow groundwater circulation. This study provided new insights into the source and evolution of groundwater sulfate in large coalfields, as well as references for regional water resource utilization and protection.

Land use & land cover dynamics and its relationship with nitrate pollution in groundwater around inactive mine areas using geospatial techniques, SW part of Cuddapah basin, Southern India

Geospatial maps can show how the ineffective operations of inactive mines affect water and aquifer quality. As such, the purpose of this study is to assess the impact of mining and irrigation on the aquifer ecosystem through the evaluation of LULC and slope maps through the application of Landsat 8 OLI/TIRS and DEM data. A total of 50 groundwater samples were prepared from villages in the close proximity to inactive mines during pre and post monsoon periods in 2021. The results of the analysis revealed alarming statistics, that 14% of groundwater samples exceeded the WHO nitrate limit in pre & post monsoon season, indicating a high-risk in the study area. According to guidelines (USEPA, 2014), 34% in pre-monsoon and 26% post-monsoon of samples exceeded the THI levels for adults and children respectively, indicating non-carcinogenic health risks. In addition, 80% of the samples in both seasons exhibited high NPI values, indicating nitrate contamination associated with blue baby syndrome. From the Geospatial analysis the findings from the LULC classification indicate that there has been a significant increase in cropland area from 2016 to 2021 due to changes in forest land, fallow land, and water resources. These problems have been exacerbated by the expansion of cultivated land, which has increased from 71.1 square kilometers in 2016 to 118 square kilometers in 2021, accounting for 13.1% of the total area. This expansion, coupled with elevated water body resource availability, has compounded the nitrate pollution including in intensely irrigated regions. The slope map analysis revealed that the inactive mines occur at low slope, high rainfall areas and these are compounded by runoff from other sources such as domestic and agricultural wastes. For these matters, sealing and remediating these inactive mines is essential so as to prevent further nitrate leakage.

Applying the water quality indices and geographic information system approach to assessing the suitability of groundwater quality for drinking and irrigation purposes in the semi-arid region of Tebessa-Ain Chabro, Northeastern Algeria

Assessing the groundwater quality is important for the efficient exploitation of water resources in semi-arid areas. The study area in northeast Algeria mostly depends on groundwater as its main source of water, and the quality of groundwater is becoming important due to the increasing need for freshwater. The hydrochemical characteristics and water quality of groundwater in the Tebessa-Ain Chabro were assessed using water quality indices, geochemical modeling, and multivariate statistical approaches. The study discovered that the groundwater samples could be classified into four distinct water groups using hierarchical cluster analysis in Q mode (HCA) based on their electrical conductivity. We identified three forms of water: mixed (Ca2+–Mg2+–Cl−), Na+–K+–HCO3−, and Ca2+–Cl−. According to the water quality assessment, only 38% of the samples were deemed suitable for human consumption, while 34% were categorized as poor water, 10% as extremely poor, and 17% as unsafe for drinking. The irrigation water quality index identified four classifications: low, moderate, high, and severe restriction, with corresponding percentages of 31%, 31%, 7%, and 31%. The nitrate pollution index (NPI) showed that 48% of samples fell into the moderate pollution class. Human activity, such as sewage infiltration and waste disposal in open areas, was the cause of this nitrate contamination. The saturation index values showed that groundwater was less saturated in halite and sylvite and more saturated in aragonite, calcite, dolomite, anhydrite, gypsum, and hydroxyapatite. The Tebessa region’s groundwater’s hydrochemical properties and water quality have been assessed using multivariate statistical techniques, geochemical modeling, and water quality indexes. The study’s conclusions can provide a foundation for upcoming research evaluating the region’s groundwater quality.

Evaluation of environmental geochemical signatures due to RO rejects on arid agricultural farms and tangible solutions

The impact of reverse osmosis (RO) rejects in the groundwater presents a significant challenge in arid regions. This study collected groundwater samples, product water, and reverse osmosis brine (ROB) from evaporation ponds and analyzed them for major ions and trace elements. Test boreholes were drilled near the ROB site along the flow direction, and borehole sediment samples were collected. The samples were predominantly gravelly sand, and the depth to water level fluctuated around 30 m below ground level (bgl), with minerals mainly consisting of calcite, gypsum, and Quartz. Data loggers reflected a rise in water level (<22 m bgl) corresponding to higher electrical conductivity (>16 mS/Cm) during the cropping period in many locations, confirming the impact of ROB in groundwater. The results were further supported by enriched signatures of δ18O (∼ +1.5‰) and δ2H (∼ +15‰). The saturation index of the minerals reflected that carbonate minerals (Calcite > Dolomite) were saturated in the ROB relative to the groundwater. The vertical variation of mineral assemblages in the boreholes indicated gypsum precipitation in the capillary zone along with calcite and dolomite. The assemblage varies as the groundwater moves from the disposal site. The speciation of different compounds along the groundwater path indicated higher carbonate and sulfate species (CaCO3 > CaHCO3> CaSO4 > NaSO4 > MgSO4) near the disposal site, with variations along the flow direction. Considering the significant variation in temperature in the region (5 to 50 ℃), the water sample composition was modeled using PHREEQC, suggesting that the increase in temperature led to supersaturation of Epsomite and Gypsum compositions. The ROB was theoretically mixed with groundwater and product water in different proportions, and an optimum composition (10:90) for safe disposal was derived and tested fit for reuse in agriculture.

3D-printed thermally expanded monolithic foam for solid-phase extraction of multiple trace metals.

Digital light processing (DLP) 3DP, commercial acrylate-based photocurable resins, and thermally expandable microspheres-incorporated flexible photocurable resins were employedto fabricate an SPE column with athermally expanded monolithic foam for extracting Mn, Co, Ni, Cu, Zn, Cd, and Pb ions prior to the determination using inductively coupled plasma mass spectrometry. After optimizationofthe thermally activated foaming, the design and fabrication of the SPE column, and the automatic analytical system, the DLP 3D-printed SPE column with the thermally expanded monolithic foam extracted the metal ions with up to 14.8-fold enhancement (relative to that without incorporating the microspheres), with absolute extraction efficiencies all higher than 95.6%, and method detection limits in the range from 0.5 to 5.2ng L-1. We validated the reliability and applicability of this method by determination ofthe metal ions in several reference materials (CASS-4, SLRS-5, 1643f, and Seronorm Trace Elements Urine L-2) and spikedseawater, river water, ground water, and human urine samples. Theresults illustrated that to incorporate the thermally expandable microspheres into the photocurable resins with a post-printing heating treatment enabled the DLP 3D-printed thermally expanded monolithic foam to substantially improve the extraction of the metal ions, thereby extending the applicability of SPE devices fabricated by vat photopolymerization 3DP techniques.

Glutathione engineered gold nanoparticles-based electrochemical aptasensor for determination of arsenic ions in water, food, and soil samples

Arsenic, As(III) is one of the highly toxic metalloid ions present in the earth's crust. Its availability especially in groundwater, soil, and plant products can impose significant environmental and health risks. In order to examine aforementioned matrices for the presence of As(III), we have fabricated a sensitive electrochemical bionanoprobe using As(III) specific aptamer modified glutathione (GSH)-capped gold nanoparticles. The developed probe demonstrated remarkable sensing performance for a wide concentration range of As(III) (e.g., 0.1–1000 mg/L) with extremely high sensitivity of 0.0875 µA/(mg/L.mm2). Moreover, we have achieved an exceptionally low limit of detection (0.13 µg/L) for As(III) using the developed bionanoprobe. Furthermore, it displayed excellent performance in monitoring As(III) in groundwater, soil, and rice samples.

Geochemical fingerprinting of Norway spruce from the Eastern Carpathians: Sr isotopic and multi-elemental signatures

Ensuring efficient wood traceability within procurement chains is essential for establishing sustainable forest management and minimizing environmental damage in countries that produce and export timber. While some progress has been made with key legislative reforms to tackle this issue, the effectiveness of law enforcement still relies on the availability of appropriate analytical tools to determine the provenance of wood. This study documents the Sr isotopic and multi-elemental signatures of Norway spruce trees in the Eastern Carpathians, Romania – an area known for intensive forest logging. The research focused on trees from Rodna, Rarău, and Călimani, analyzing tree rings from 1970 to 2020 to assess temporal variability and develop site-specific geochemical fingerprints. In conjunction with tree samples, corresponding soil, groundwater, and river samples were analyzed, providing a comprehensive view of the bioavailable 87Sr/86Sr ratios in these ecosystems. The study found a strong correlation between the Sr isotope ratios in the wood and those in corresponding water and soil samples, confirming that the wood accurately mirrors local geochemical signatures. The Sr isotope ratios were consistent across most of the cores from trees within the same site but varied among sites within the same region. Principal Component Analysis of the Sr isotopic and multi-elemental data highlighted closer clustering of samples from the Călimani area, though distinguishing the samples from the Rodna and Rarău regions proved more difficult due to overlapping data points. This study broadens our understanding of geochemical variability and its implications. The insights gained provide a valuable foundation for future research aimed at enhancing wood traceability methods.

Unveiling nitrate contamination and health risks: Insights from groundwater quality assessment and Monte Carlo simulation along the Southern Caspian Sea Coasts

Groundwater resources are at great risk of contamination due to increased industrial and agricultural activities, population growth and urban expansion. This study investigated factors controlling spatio-temporal variability in groundwater quality and nitrate concentration at the southern coast of Caspian Sea, Iran to provide public health risk assessment. Na-Cl (44.8%) and Ca-HCO3 (58.6%) types water were the dominant hydrogeochemical facies in dry and wet seasons, respectively. Most of the examined groundwater samples were found unfit for drinking but appropriate for agricultural irrigation. The chemistry of groundwater predominantly influenced by combination of local lithology and ion exchange in aquifer as well as seawater intrsuin. Nitrate concentration varied from 0.05 to 200 mg/L with a mean value of 33.1 mg/L in which 13.7% and 27.5% of samples showed concentration higher than WHO's recommended value in dry and wet seasons, respectively. The highest nitrate concentrations were observed at locations in proximity to human settlements including cities, villages as well as agricultural lands. The identified pollution hotspots confirm nitrate contributions from un-treated wastewater effluents and agricultural practices with minimum contribution from industrial activities. The result of Monte Carlo simulation revealed that children were at highest risk from drinking of groundwater containing nitrate. This study highlights the urgent need for action to address the growing threat to groundwater quality and public health posed by contamination from various sources in the southern coasts of Caspian Sea.

Hydrochemical Characteristics, Controlling Factors and Groundwater Sources of Zaozigou Gold Mine

The Zaozigou gold deposit is recognized as one of the largest and most significant independent gold deposits in northwest China, representing a colossal orogenic gold-antimony deposit. It is imperative to delve into the hydrochemical characteristics and controlling factors within the mining area to unveil the groundwater circulation evolution process and enhance water resource management. In 2018, a comprehensive collection of 50 groups of groundwater samples was conducted, alongside 17 groups of surface water and underground mine water samples in 2023. Compositional descriptive analysis, correlation analysis, Piper three-plot, Gibbs map, ion ratio method, hydrogeochemical simulation and PCA methods were employed to reveal the chemical characteristics and evolution process of groundwater in the Zaozigou gold mine. Furthermore, employing water isotopes theory allowed for the identification of recharge sources and circulation conditions within the Zaozigou Gold Mine. The findings indicated a transition from HCO3-Na·Ca type polluted water in 2018 to primarily the SO4-Ca·Mg type and HCO3·SO4-Na·Ca·Mg type groundwater hydrochemistry types by 2023. The hydrochemical characteristics of the study area are closely related to the mining depth and time. The chemical characteristics are influenced by various factors such as rock weathering, mineral dissolution, cation exchange processes, atmospheric precipitation as well as human activities related to pollution from industrial mining activities.