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Antioxidant enzymes in plants are critical for protection against oxidative stress and for the overall health and resilience of plant systems. However, antioxidant responses of plants grown in shallow and saline groundwater are poorly understood. Therefore, understanding the biochemical responses of plants to shallow groundwater significantly affects food security and environmental conservation. With this aim, the present work was carried out for 2 years in drainable lysimeters to assess the effects of four different groundwater salinities (0.38, 2.0, 4.0 and 8.0 dS m−1) on the temporal changes in antioxidant enzymatic activity in wheat plants under three different groundwater depths (30, 55 and 80 cm). Superoxide dismutase (SOD), glutathione S‐transferase (GST) and catalase (CAT) activities varied significantly based on groundwater depth and salinity. CAT and GST enzyme levels increased curvilinearly with rising groundwater depth and salinity. Conversely, the GR enzyme activity showed no significant change with groundwater depths but increased linearly with higher salinity. SOD enzyme activity notably increased at a groundwater depth of 30 cm but decreased at a depth of 80 cm. Moreover, the peak activity of the GR enzyme was observed at a 6 dS m−1 groundwater salinity under groundwater depths. Additionally, the GST and CAT enzyme activities were inhibited more when the groundwater depth was <55 cm and the groundwater salinity was >4.20 dS m−1. Finally, identifying the peak levels of antioxidant enzymes could potentially serve as an indicator for determining the optimal timing for applying stress mitigation methods in areas with shallow and saline groundwater. [ABSTRACT FROM AUTHOR]

An investigation of the distribution and control factors of groundwater is significant for the rational exploitation and utilization of groundwater resources. This study analyzes the hydrogeochemical processes and control factors of shallow groundwater in the Guohe River Basin. A hydrogeological survey was conducted, and hydrochemical and hydrogen–oxygen isotopic data of 125 samples of surface water and groundwater were analyzed. The results showed that the total dissolved solid (TDS) content in shallow groundwater was 138–2967 mg/L, with an average of 831 mg/L. A decline in the TDS was observed from the upper to the lower reaches. The contents of the anions and cations in the shallow groundwater were in the order HCO3− > Cl− > SO42− and Na+ and K+ > Mg2+ > Ca2+, respectively. The cation exchange increased the aqueous concentrations of Na+ and K+, and the TDS content was highly correlated with the contents of Na+, Cl−, and SO42− ions. The δD and δ18O values in shallow groundwater increased from the upper to the lower reaches, with the mean δD values being −59.72‰, −53.58‰, and −47.17‰ and the mean δ18O values being −8.33‰, −7.37‰, and −6.43‰. The contribution rates of the recharge source, evaporation, and water–rock interaction to the groundwater TDS concentration were 20.4%, 29.5%, and 50.1%, respectively. The water–rock interaction dominated the formation of shallow groundwater in the Guohe River Basin. The dissolution of salt rock and gypsum contributed to ion formation in shallow groundwater. The research findings can be used to improve the groundwater quality in the Guohe River Basin. [ABSTRACT FROM AUTHOR]

This study investigates the chemical characteristics, formation, and sources of inorganic nitrogen (IN) of shallow groundwater across the Sanjiang Plain, aiming to enhance drinking water safety management and pollution control. A total of 167 groundwater and 27 surface water samples were collected for constituents and isotopes (H2 and O18). The hydrogeochemical characteristics showed that the major type is HCO3‐ Ca·Mg, with low total dissolved solids and a neutral to weak alkaline nature. Rock weathering processes govern the hydrochemical composition of groundwater. Hydrogen and oxygen stable isotopes analyses revealed that precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO3‐N concentrations, with sewage, manure, and fertilizers being the primary IN sources. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes, causing the loss of NO3‐N and leaving NH4‐N as the dominant IN form. Organic matter mineralization is likely a more significant contributor to NH4‐N concentrations than ammonium fertilizers. These findings provide valuable information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions. Practitioner Points: Rock weathering processes govern the hydrochemical composition of groundwater, and precipitation serves as the main water source.In alluvial areas, oxidative conditions lead to the enrichment of NO3‐N. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes.Organic matter mineralization is likely a more significant contributor to NH4‐N concentrations than ammonium fertilizers.These findings provide references for water management and information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions. [ABSTRACT FROM AUTHOR]

Groundwater is the main source of water for more than 2 billion people worldwide. In southern Brazil, the Crystalline Basement Aquifer System is composed of strategic groundwater reservoirs. Groundwater is mostly taken from shallow wells, and it is often used without any treatment, which poses a risk to public health. The present study aims to evaluate shallow groundwater quality and the geochemistry of shallow and deep groundwater located in the municipality of Canguçu, southern Brazil. The physicochemical and microbiological parameters of groundwater samples collected from shallow wells were monitored and analyzed using ANOVA variance analysis and water quality index (CCME WQI) approaches. Also, the results were compared with secondary data from deep wells. The monitored shallow wells had thermotolerant coliforms, Escherichia coli, pH, potassium, manganese, iron, and nitrate in disagreement with the guidelines of the World Health Organization. Moreover, variance analysis showed that the parameters temperature, dissolved oxygen, pH, chloride, and magnesium were the most influenced by seasonal variations. According to the CCME WQI, most samples had good quality (60%), 28% had fair quality, and 12% had poor quality. In addition, the field campaigns with higher precipitation rates also presented fair quality. Therefore, most of the shallow groundwater quality is affected by surface pollutants from the urban area, aggravated in rainy periods. Whereas deep groundwater is influenced by geochemistry mechanisms. The results revealed the risk of water consumption for public health and the urgent need for better maintenance of these wells and water treatment implementation. [ABSTRACT FROM AUTHOR]

Groundwater near a sulfuric acid plant in Xingyang, Henan, China was sampled from seven distinct sites to explore the prevalence of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs). Results showed that genes aadA, blaCTX-M, tetA, qnrA, and sul1 were detected with 100% frequency followed by aac(6')-Ib (85.71%), ermB (85.71%), and tetX (71.42%). Most abundant ARGs were sul1 in LSA2 (1.15 × 1011 copies/mL), tetA in LSA6 (4.95 × 1010 copies/mL), aadA in LSA2 (4.56 × 109 copies/mL), blaCTX-M in LSA4 (1.19 × 109 copies/mL), and ermB in LSA5 (1.07 × 109 copies/mL). Moreover, in LSA2, intl1 as a marker of class 1 integron emerged as the most abundant gene as part of MGE (2.25 × 1011 copies/mL), trailed by ISCR1 (1.57 × 109 copies/mL). Environmental factors explained 81.34% of ARG variations, with a strong positive correlation between the intl2 and blaCTX-M genes, as well as the ISCR1 gene and qnrA, tetA, intl2, and blaCTX-M. Furthermore, the intI1 gene had a strong positive connection with the aadA, tetA, and sul1 genes. Moreover, the aac(6')-Ib gene was associated with As, Pb, Mg, Ca, and HCO3-. The intl2 gene was also shown to be strongly associated with Cd. Notably, network analysis highlighted blaCTX-M as the most frequently appearing gene across networks of at least five genera. Particularly, Lactobacillus, Plesiomonas, and Ligilactobacillus demonstrated correlations with aadA, qnrA, blaCTX-M, intI2, and ISCR1. Based on 16S rRNA sequencing, the dominant phyla were Proteobacteria, Firmicutes, Bacteroidota, Acidobacteriota, and Actinobacteriota, with dominant genera including Pseudomonas, Ligilactobacillus, Azoarcus, Vogesella, Streptococcus, Plesiomonas, and Ferritrophicum. These findings enhance our understanding of ARG distribution in groundwater, signaling substantial contamination by ARGs and potential risks to public health. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There is no doubt that hypoxia and seawater mixture are profoundly affecting the global nitrogen (N) cycle. However, their mechanisms for altering N cycling patterns in shallow coastal groundwater are largely unknown. Here, we examined shallow groundwater N transformation characteristics (dissolved inorganic N and related chemical properties) in the coastal area of east and west Shenzhen City. Results showed that common hypoxic conditions exist in this study area. Ions/Cl− ratios indicated varying levels of saltwater mixture and sulfide formation across this study area. Dissolved oxygen (DO) affects the N cycle process by controlling the conditions of nitrification and the formation of sulfides. Salinity affects nitrification and denitrification processes by physiological effects, while sulfide impacts nitrification, denitrification, and dissimilatory nitrate reduction to ammonium (DNRA) processes through its own toxicity mechanism and the provision of electron donors for DNRA organisms. Redundancy analysis (RDA) results indicate that the influence magnitude is in the following order: DO > sulfide > salinity. Seawater mixture weakened the nitrification and denitrification of groundwater by changing salinity, while hypoxia and its controlled sulfide formation not only weaken nitrification and denitrification but also stimulated the DNRA process and promotes N regeneration. In this study area, hypoxia is considered to exert greater impacts on N cycling in the coastal shallow groundwater than seawater mixture. These findings greatly improve our understanding of the consequences of hypoxia and seawater mixture on coastal groundwater N cycling. [ABSTRACT FROM AUTHOR]

Nanling County, situated on the southern bank of the Yangtze River's middle and lower reaches in China, and has not yet carried out hydrogeochemical geological surveys. This study is pivotal in ensuring the reliability of the drinking water supply, particularly during emergencies. Utilizing an array of analytical methods—statistical analysis, Shularev classification, Piper trilinear diagram, Gibbs diagram, ion ratio method, and mineral saturation index—this research elucidates the hydrogeochemical characteristics and principal water–salt interactions in Nanling's shallow groundwater. Our findings, derived from the Shularev classification and Piper trilinear diagram, reveal that, in the southern mountainous and river valley plain regions, the primary hydrogeochemical type of groundwater is HCO3-Ca. Conversely, in the northern area of Sanli Town and the adjoining plain, groundwater predominantly falls under the HCO3-Na•Ca category, with some regions showing the characteristics of HCO3•Cl-Ca, HCO3•Cl-Na•Ca, and, occasionally, HCO3•SO4-Na•Ca. According to the Gibbs diagram analysis, the predominant source of groundwater in this region is attributed to water–rock dissolution processes occurring during groundwater runoff. The increase in Na+, Ca2+, Cl−, HCO3−, and SO42− concentrations in the water–rock interaction in the study area is mainly due to the dissolution of rock salt, gypsum, calcite, and dolomite, and the alternating cation adsorption occurs during the reaction. Finally, the mineral saturation index points to the ongoing dissolution of gypsum, calcite, and dolomite, until a state of precipitation–dissolution equilibrium is reached. This comprehensive study provides vital insights into the hydrogeochemical dynamics of Nanling County's groundwater, contributing significantly to our understanding of regional water quality and its management. [ABSTRACT FROM AUTHOR]

Shallow groundwater is a critical water resource for sustaining vegetation growth in arid and semi-arid environments and affects stand transpiration (T) dynamics. However, it is still difficult to quantify the impact of groundwater on T. Here, we introduced a novel groundwater response function in the Jarvis-type model (referred to as MJSG) and tested its performance using Populus popularis sapflow data over two main growing seasons (2018–2019). The results showed that the performance of the MJSG model depended on groundwater level. Specifically, when groundwater table depth was within 1.2–2.0 m, the precision of daily T simulation by the MJSG model was higher than that by the MJS model without groundwater response function over two years, with an increase in Nash-Sutcliffe Efficiency (NSE) from 0.787 to 0.825. Furthermore, in contrast to the MJS model, the MJSG model could better capture the diurnal course of T in 10:00–16:00, with a significant increase in NSE from 0.592 to 0.706. The improvement allows a more accurately estimate of tree water use under shallow groundwater fluctuations, which will help broaden the ecohydrological application of the Jarvis-type model to similar areas.

In order to identify and effectively control the impact of NO3− pollution on human health, on the basis of investigation, sampling, analysis and testing, statistical analysis software (SPSS19), groundwater pollution analysis software, Nemera comprehensive index method, correlation analysis method and human health risk assessment model are applied for analysis and research. The results indicate that the groundwater in the study area is mainly Class II water, with overall good water quality. The main influencing factors for producing Class IV are NO3−, Fe, F− and SO42−. The use of agricultural fertilizers is the main source of NO3− exceeding standards in groundwater in this area. There are significant differences in the health hazards caused by NO3− pollution in groundwater among different populations, and infants and young children are more susceptible to nitrate pollution. The division of pollution areas and high-risk groups plays an important guiding role in preventing health risks. The new achievements will help people improve their awareness of risk prevention, caring for the environment, respecting nature and implementing precise policies, promoting society to step onto the track of scientific and healthy development. HIGHLIGHTS Scientific evaluation of groundwater quality was conducted and the main factors affecting water quality were analyzed.; Scientific evaluation was conducted on NO3− pollution in the research area and the main sources of NO3− were identified.; The significant differences in the health hazards of NO3− pollution were identified.; The research results have an important guiding role in preventing health risks.;

Precipitation patterns, water flow direction, and local land-use practices affect surface water (SW) and shallow groundwater (SGW) nutrient concentrations in riparian wetlands. Given physical process complexities, spatiotemporal quantification of nutrients and physical factors influencing nutrient concentrations are needed to advance wetland water resource management. To address these needs, a study was conducted in riparian wetlands of a mixed land-use catchment in West Virginia (WV), USA. Observed data included SW–SGW levels and nutrient concentrations, including nitrate (NO3-N), nitrite (NO2-N), ammonium (NH4-N), orthophosphate (PO43-P), total nitrogen (total_N), and total phosphorus (total_P) from January 2020 to December 2021. Water samples were collected monthly from stream gauge sites (n = 4) and co-located piezometers (n = 13). Results showed that, on average, gaining stream conditions were observed in upstream sites, and losing stream conditions were observed in downstream sites. Observed nutrient profiles between SW and SGW included SW exhibiting a higher average NO3-N concentration (0.42 mg/L), while SGW displayed an elevated NH4-N concentration (1.55 mg/L) relative to other nitrogen species. Significantly high (p < 0.05) SW NO3- concentrations in summer and fall were attributed to increased precipitation and corresponding water level and, therefore, pressure head and transport fluctuations. Principal Component Analysis (PCA) showed differences in nutrient concentrations based on the water source type and catchment land use, explaining 65% of data variability. Spearman correlation analysis illustrated the correlation among nutrient concentrations, land use, and water level changes in SW and SGW environments. This study provides needed baseline data on nutrient dynamics for a riparian wetland in a mixed land-use catchment, supplying science-based information to advance land and water management practices in the study watershed and similar physiographic watersheds globally. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The sustainability of shallow groundwater systems, pivotal to maintaining ecosystem equilibrium and facilitating the sustainable development of mine sites, is the core of various dynamic indicators in response to mining activity and mining area planning. This study quantitatively evaluates the impact of mining activities on shallow groundwater systems at the orefield scale, taking the equivalent permeability coefficient (EPC) of "Soil–Rock" composite water-resisting strata and the response mechanism of shallow groundwater in multi-mine mining as the entry points. A modified six-step evaluation method for the response mechanism of shallow groundwater in multi-mine mining is proposed using mathematical statistics, numerical simulation, and theoretical analysis methods. The method is used to evaluate the sustainability of the shallow water system in the Yushen mining area, to study the distribution characteristics of the water resource carrying capacity (WRCC) in different mining areas of the Yushen area, and to analyze the number of mines allowed to be mined under geological conditions with a WRCC of more than moderate bearing capacity. The results show that when the mining area of a mine in the Yushen area is set to 1 × 108, 7.5 × 107, 5 × 107, and 2.5 × 107 m2, as the mining area of the designed mine decreases, the area bearing surplus gradually increases, with values of 1.70 × 109, 1.98 × 109, 2.28 × 109, and 2.58 × 109 m2. The number of mines allowed to be mined under geological conditions with a WRCC above moderate capacity is 20, 31, 51, and 112, respectively. [ABSTRACT FROM AUTHOR]

Soil salt accumulation is a widespread problem leading to diminished crop yield and threatening food security in many regions of the world. The soil salinization problem is particularly acute in areas that lack adequate soil water drainage and where a saline shallow water table (WT) is present. In this study, we present laboratory‐scale column experiments, extending over a period of more than 400 days that focus on the processes contributing to soil salinization. We specifically examine the combined impact of soil compaction, surface water application model and water quality on salt dynamics in the presence of a saline shallow WT. The soil columns (60 cm height and 16 cm diameter) were packed with an agricultural soil with bulk densities of 1.15 and 1.34 g/cm−3 for uncompacted and compacted layers, respectively, and automatically monitored for water content, salinity and pressure. Two surface water compositions are considered: fresh (deionized, DI) and saline water (~3.4 mS/cm). To assess the sensitivity of compaction on salt dynamics, the experiments were numerically modelled with the HYDRUS‐1D computer program. The results show that the saline WT led to rapid salinization of the soil column due to capillarity, with the salinity reaching levels much higher than that at the WT. However, compaction layer provided a barrier that limited the downwards moisture percolation and solute transport. Furthermore, the numerical simulations showed that the application of freshwater can temporarily reverse the accumulation of salts in agricultural soils. This irrigation strategy can help, in the short‐term, alleviate soil salinization problem. The soil hydraulic properties, WT depth, water quality, evaporation demand and the availability of freshwater all play a role in the practicability of such short‐term solutions. The presence of a saline shallow WT would, however, rapidly reverse these temporary measures, leading to the recurrence of topsoil salinization. [ABSTRACT FROM AUTHOR]

In this work, a method of simultaneously analyzing pesticide concentration and assessing its risks was developed. Assessments were conducted to evaluate the distribution characteristics and risks to human health of pesticides in shallow groundwater in agricultural areas. We developed multi-residue analytical methods using liquid chromatography (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) to analyze 57 pesticides in groundwater. In addition, risk assessments were performed by setting scenarios considering the routes of pesticide infiltration into groundwater. For the simultaneous analysis of 57 pesticides, the liquid–liquid extraction method was applied twice using dichloromethane under acidic and alkaline conditions. The extract was concentrated and analyzed using LC-MS/MS (41 pesticides) and GC-MS/MS (16 pesticides). The precision and accuracy ranges of the analytical methods were 0.1~12.9% (within ±15%) and 80.3~113.6% (within ±20%), respectively. The limit of quantification was found to range from 0.0004 to 0.0677 μg/L. In total, 57 pesticides were monitored in 200 groundwater wells from 2019 to 2020. Twenty-six pesticides, including metolachlor and imidacloprid, were detected, with an average concentration of 0.0008 μg/L in groundwater. The pesticide types and detection levels differed depending on the survey period and surrounding land. When the risks associated with alachlor, metolachlor, and carbofuran were assessed, their health risks when found in groundwater were evaluated to be negligible (non-carcinogenic risk: less than 10−3, carcinogenic risk: less than 10−6). [ABSTRACT FROM AUTHOR]

Groundwater is considered an important source of water aid for human consumption. However, this water can be contaminated by impurities, such contamination spots that might reach the water tables. The aim of this study was to investigate the quality of shallow groundwater in Flores neighborhood, located in the municipality of Benevides, within Belém metropolitan region, State of Pará, Brazil. Recommendations described in Standard Methods for Examination of Water and Wastewater were followed at the time to determine physical-chemical parameters such as potential hydrogen (pH), electrical conductivity (EC), total dissolved solids (TDS), apparent color, turbidity, total hardness (TH), ions and trace elements. Multivariate statistical analysis has shown that most predictive water-quality parameters set for human consumption are associated with natural events involving weathering and leaching processes. Nevertheless, parameters of nitrate, phosphate, EC, TDS and pH are also influenced by anthropic conditions in the surroundings, mainly phosphate and nitrate ions. Therefore, it can be concluded that shallow groundwaters in Flores neighborhood are unsuitable for human consumption, making it necessary for municipal public authorities to take action to solve the problem of water shortage in the borough, thus preventing the population from use those shallow groundwaters, as their consumption can bring health problems.

【Objective】 Many arid and semiarid regions in North and Northwest of China are poor in freshwater but have saline groundwater. Efficient utilization of these saline waters is crucial for agricultural sustainability. This study seeks to experimentally identify the optimal alternation of freshwater and saline water for irrigating arable crops in areas with shallow groundwater. 【Method】 The experiment was conducted at a maize field from May to October in 2022 at an experimental site in Darat Banner, Erdos. It compared four irrigations: irrigating with saline water only (T1), irrigating with saline water twice followed by a freshwater irrigation (T2), irrigating with saline water once followed by one freshwater irrigation (T3), irrigating with freshwater only (CK). In each treatment, we measured water and salt distribution in the soil, as well as yield of the maize. 【Result】 Alternate irrigation significantly influenced soil moisture and salinity. T3 considerably increased root water uptake during the critical growth stage of the crop, manifested by the 0.75% to 1.3% reduction in water content in the 0~40 cm soil layer, and 2.02% to 3.71% increase in water content in the 40~100 cm soil layer. During the irrigation period, there were 58.45% and 63.98% of soils salinized in T2 and T3, respectively. Compared to CK, alternate irrigation reduced crop yield by 10% to 13%, but saved 33% to 50% of freshwater. Grain yield and water use efficiency of T3 were 90.26% and 23.2% higher than that of T1, respectively, despite its 7.2% reduction in grain yield compared to CK. Groundwater recharge during the reproductive period accounted for 21.74% to 25.55% of the water consumed by the maize. 【Conclusion】 Considering the effect of alternate irrigation on distribution of water and salt in soil, as well as the growth and water consumption of the maize, the most suitable irrigation method for maize in the saline soil is alternating saline water and freshwater(T3).

Odor emission from the soil of pesticide-contaminated sites is a prominent environmental problem in China, but there are very few researches about the component and spatial distribution of odorous substances in the soil of contaminated sites. In this paper, to investigate the odor pollution condition of an organophosphorus pesticide production site in a city of South China, the odor pollutants in the soil and soil gas were analyzed and the key odor–contributing substances were identified. Besides, the correlation between the concentrations of odorous substances in soil and soil gas was analyzed, and the measured results were compared with the predicted results by the linear model and DED model. An off-line soil gas sampling device was designed to collect the gas emitted from soil because the groundwater level in the site was too shallow to build a soil gas well. The key odor substances were screened from the detection results of soil gas via odor activity value (OAV) analysis, which revealed that the key odorous substances included benzene, ethylbenzene, ammonia, toluene, m,p-xylene, methyl sulfide, dimethyl disulfide, and formaldehyde. Furthermore, the spatial distribution of the odor substances in the soil of the pesticide-contaminated site was closely related to the layout and geologic structure of the site. The odor pollutants in soil were mainly distributed near the phosmet production workshop and the drainage ditch network. As for the deep distribution, the odorous substances were mainly enriched in the silty clay or clay layer (5.6–11 m), followed by the sludge layer (1–3.6 m). Finally, the predicted model (linear model and DED model) analysis suggested that the linear model was more suitable for predicting the concentration of odorous substances in the soil gas with the detection data of soil in this pesticide-contaminated site. [ABSTRACT FROM AUTHOR]

The piedmont area in the north of Hangjinhouqi of Hetao Plain is the main water source for residents of the Yellow River Basin. The groundwater is characterized by high arsenic, but the distribution pattern of arsenic is unknown, which poses a threat to water safety for the residents. In this study, 295 groups of shallow groundwater samples and 8 groups of sediment samples were collected to find out the pattern and origin of arsenic enrichment in groundwater in this area. Combined with the results of two holes and seven layers of hydrological monitoring boreholes and geophysical exploration, the hydrogeological structure, distribution and hydrochemical characteristics of the shallow water-bearing system in the north of the piedmountain alluvial and diluvial incline plain and the Yellow River alluvial plain were analyzed, and the distribution and enrichment environment of arsenic in the groundwater were discussed. The results show that the arsenic content of groundwater exhibits a clear strip-shaped distribution. Horizontally, from the top of alluvial fan to the plain area, the arsenic content increases from <10. 0 μg / L to >400. 0 μg / L, and the sediment particles gradually become finer, from oxidation environment to reduction environment, which promotes the release and enrichment of arsenic. Vertically, arsenic-rich groundwater is distributed in three depth of 20-23 m, 40-50 m and 60-70 m. The hydrochemical characteristics show that it is a weak alkali reduction environment, and the chemical type of groundwater is mainly Cl·HCO3 -Na·Ca. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Our research is aimed at exploring quality differences in different water sources,and the quality influence from precipitation,shallow groundwater depth,and other factors in an agricultural ecosystem.Samples of flowing surface water and shallow groundwater were collected from four and five locations near the National Agro-ecological System Observation and Research Station of Shangqiu in Henan Province to monitor water quality from 2010 to 2020.Quality of these two water sources was studied as a dynamic process to identify influencing factors using descriptive statistics and a time series analysis method.Ca2+,Mg2+,Na+,HCO3-,SO42-and Cl-content and electrical conductivity were usually higher in poorly renewed shallow groundwater than in flowing surface water.Rises in the underground water table caused by increased precipitation could promote salt ion migration from top soil to groundwater,thereby amplifying discrepancies between these two kinds of water.Spanning 10 years of monitoring,peak values were observed for all ions,during which Na+,Ca2+and SO42-in flowing surface water and K+in shallow groundwater reached their maxima in March 2012 and September 2011 respectively.The hydrochemical types of these two waters were consistently similar over time.Although seasonal variation exerted less influence on periodical ion content changes,the long-term dynamic interaction between precipitation and the groundwater table notably regulated the hydrochemical type and ion flux in the waters.In the scenario in which increased precipitation raised the water table,shallow groundwater SO42-,and Cl-levels could easily exceed the threshold for agricultural production suggested by Standard for Groundwater Quality（GB/T14848—2017）,rendering it unsuitable for irrigation.This study confirmed that long-term quality in flowing surface water and shallow groundwater was dynamically influenced by long-term changes in precipitation and groundwater depth in a typical agricultural ecosystem in eastern Henan,which can provide a reference for water quality risk management in farmland environments and water source selection in local agriculture production. [ABSTRACT FROM AUTHOR]

The present study aims at evaluating the quality of shallow groundwater (SGW) and its suitability for irrigation purpose in the most urbanised part of Johannesburg city, South Africa. The SGW samples were collected in three consecutive years and analysed for 20 selected physicochemical parameters, and heavy metals. The results were compared with the South African water quality, and Food and Agricultural Organization irrigation water quality guidelines, and standard indices derived from laboratory outputs. The results of the study show that all physiochemical parameters and heavy metals were within the limits set by both guidelines for irrigation purposes, except for potassium (3.58 mg∙dm –3) and manganese levels (3.152 mg∙dm –3). The calculated irrigation parameter values of sodium adsorption ratio ( SAR), sodium percentage (Na%), residual sodium carbonate ( RSC), magnesium hazard ( MH), Kelly’s ratio ( KR) and permeability index ( PI) were within the permissible range of irrigation water quality standards. The findings of this study provide helpful information for decision-makers such as utilisation of the studied groundwater for irrigation uses.

Simulating shallow groundwater (SGW) flow dynamics and stream–SGW interactions using numerical modeling tools is necessary to develop a mechanistic understanding of water flow systems and improve confidence in water resource management practices. A three-dimensional (3D) SGW flow model was developed for a riparian wetland in a mixed forest and agricultural catchment in West Virginia (WV), Appalachia, USA, using a Modular 3D Groundwater Model (MODFLOW). The MODFLOW simulation was calibrated in steady (R2 = 0.98, ME = −0.21, and RMSE = 0.77), transient state (R2 = 0.97, ME = −0.41, and RMSE = 1.28) and validated (R2 = 0.97, ME = −0.28, and RMSE = 1.05) using observed SGW levels from thirteen nested piezometers under steady and transient states. An experimental MT3D transport scenario was developed to show the lateral transport of NO₃-N from the aquifer to stream cells. Relatively stable SGW head distribution was observed. In the downstream reach, SGW discharge varied from 948 m3/day to 907 m3/day in 2020, with creek seepage ranging from 802 m3/day to 790 m3/day. Similarly, SGW input to the stream ranged from 891 m3/day to 978 m3/day, while creek seepage ranged from 796 m3/day to 800 m3/day in 2021. In upstream reaches, losing stream conditions were observed in January, June, and September 2020 and January to April 2021, while gaining stream conditions prevailed during other months. Thus, an approximately monthly alternating gaining–losing stream condition was observed in the upstream area. An experimental MT3D transport scenario resulted in an advection–dispersion scenario, showing a cumulative loss of 947 g of NO3-N from SGW to the stream. Denitrification accounted for the cumulative loss of 1406 g of NO3-N from SGW, surpassing 639 g of nitrate from the SGW to the stream during the study period. Additionally, particle tracking using MODPATH indicated a long residence time for SGW nutrients, affirming the efficiency of nitrogen transformation through denitrification. This study is among the first to simulate hydrologic and nutrient interactions in riparian wetlands of a mixed land use catchment in the Appalachian region of the northeastern United States. The results better inform water resource management decisions and modeling efforts in the Appalachian region and similar physiographic regions globally.

Nanling County, situated on the southern bank of the Yangtze River’s middle and lower reaches in China, and has not yet carried out hydrogeochemical geological surveys. This study is pivotal in ensuring the reliability of the drinking water supply, particularly during emergencies. Utilizing an array of analytical methods—statistical analysis, Shularev classification, Piper trilinear diagram, Gibbs diagram, ion ratio method, and mineral saturation index—this research elucidates the hydrogeochemical characteristics and principal water–salt interactions in Nanling’s shallow groundwater. Our findings, derived from the Shularev classification and Piper trilinear diagram, reveal that, in the southern mountainous and river valley plain regions, the primary hydrogeochemical type of groundwater is HCO3-Ca. Conversely, in the northern area of Sanli Town and the adjoining plain, groundwater predominantly falls under the HCO3-Na•Ca category, with some regions showing the characteristics of HCO3•Cl-Ca, HCO3•Cl-Na•Ca, and, occasionally, HCO3•SO4-Na•Ca. According to the Gibbs diagram analysis, the predominant source of groundwater in this region is attributed to water–rock dissolution processes occurring during groundwater runoff. The increase in Na+, Ca2+, Cl−, HCO3−, and SO42− concentrations in the water–rock interaction in the study area is mainly due to the dissolution of rock salt, gypsum, calcite, and dolomite, and the alternating cation adsorption occurs during the reaction. Finally, the mineral saturation index points to the ongoing dissolution of gypsum, calcite, and dolomite, until a state of precipitation–dissolution equilibrium is reached. This comprehensive study provides vital insights into the hydrogeochemical dynamics of Nanling County’s groundwater, contributing significantly to our understanding of regional water quality and its management.

【Objective】 Predicting change in groundwater table in response to natural and anthropogenic influence is a prerequisite in groundwater resource management. This paper compares several methods commonly used in studying groundwater dynamics based on the shallow groundwater exploration in plain areas in central China. 【Method】 The study was based on shallow groundwater resources in Puyang City in Henan province. We analyzed the groundwater dynamics in the region using three methods: water balance method, dewatering-volume method, and time series method. 【Result】 The time series method is applicable only to areas where groundwater development and utilization do not show considerable change with time. In contrast, the water balance method and dewatering volume method are more mechanistic, providing more accurate results as they consider potential changes in groundwater usage and management. As the dewatering volume method divides the studied region into subunits based on administrative regions rather than hydrogeological conditions, it could lead to significant differences when compared to measurements from monitoring boreholes. The water balance method considers factors such as current groundwater development, hydrogeological conditions and groundwater management measures, and it is hence more accurate for analyzing groundwater dynamics. 【Conclusion】 Results calculated by the improved groundwater balance method proposed in this paper are consistent with ground-truth data. It is more reliable for evaluating the response of shallow groundwater table to change in management and usages in plain areas.

In recent years, the degradation of palm groves due to the rise of hypersaline groundwater has increased. This research aims to assess the hydraulic connectivity status between the Oued Righ channel and the adjacent aquifer. For this purpose, a piezometric network with 20 monitoring wells was installed, and the channel's water and bottom levels were measured in April and September of 2019 at 12 gauging stations, then the soil samples of the banks and the bottom were collected from the channel. The results showed the predominance of silty loam formation, which has reflected the weakly values of hydraulic conductivity of the clogging layer, with values ranging from 5.51 x 10-5 to 6.74 x 10-6 m/s, and according to the results of the hydraulic head differences between the channel and phreatic water for both periods, we found two types of water return statuses: hydraulically connected in the sections (22.5-25.5 km and 36-42.5 km), and hydraulically disconnected in the sections (23.5-24.5 km and 38.5-42 km). The study's findings are critical for water resources management, in order to preserve palm groves' wealth, which is the most important economic resource for the population. [ABSTRACT FROM AUTHOR]

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Copyright of East China Geology / Huadong dizhi is the property of Editorial Department of East China Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of East China Geology / Huadong dizhi is the property of Editorial Department of East China Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil moisture is a key variable that contributes for flux partitioning into sensible and latent heat components. There is a pressing need to study the impacts of shallow groundwater table dynamics on antecedent soil moisture and corresponding feedbacks to atmosphere. In this study, we evaluate WRF‐NoahMP simulated soil moisture using two experimental configurations: one with the default, free drainage approach (CTL) and with Miguez‐Macho groundwater scheme (GW). Results are presented for the study conducted over Ganga River basin, India between the years 2008 and 2014 for all the three seasons (pre‐monsoon, monsoon, post‐monsoon). It was observed that the GW model runs, improve soil moisture in topmost and bottom‐most layers. We discovered that the simulations improved temporal negative bias of seasonal accumulation during monsoon by around 91 mm. In addition, the average negative bias in latent heat flux improved by around 28 W/m2. Compared to CTL, GW was found to contribute additional atmospheric moisture content ranging between 3% and 5%. Comparison with in‐situ ground water showed that model overestimates the ground water table depth. This can be attributed to the ability of the model to only simulate natural occurring variabilities and lack of inclusion of anthropogenic factors such as ground water pumping in the model. The groundwater trend in Ganga is declining at alarming rate. In addition, if over exploitation of groundwater is not monitored properly, water and food scarcity is an imminent threat to the country's economy. To the best of authors knowledge, this is the first study of its kind to be implemented over Ganga basin, which evaluates the role of shallow ground water table on regional climate using coupled atmosphere‐land surface‐groundwater model. In summary, we highlight that the groundwater component along with WRF‐NoahMP coupled model improves soil moisture and precipitation representation over the Ganga basin. [ABSTRACT FROM AUTHOR]

The sustainability of shallow groundwater systems, pivotal to maintaining ecosystem equilibrium and facilitating the sustainable development of mine sites, is the core of various dynamic indicators in response to mining activity and mining area planning. This study quantitatively evaluates the impact of mining activities on shallow groundwater systems at the orefield scale, taking the equivalent permeability coefficient (EPC) of “Soil–Rock” composite water-resisting strata and the response mechanism of shallow groundwater in multi-mine mining as the entry points. A modified six-step evaluation method for the response mechanism of shallow groundwater in multi-mine mining is proposed using mathematical statistics, numerical simulation, and theoretical analysis methods. The method is used to evaluate the sustainability of the shallow water system in the Yushen mining area, to study the distribution characteristics of the water resource carrying capacity (WRCC) in different mining areas of the Yushen area, and to analyze the number of mines allowed to be mined under geological conditions with a WRCC of more than moderate bearing capacity. The results show that when the mining area of a mine in the Yushen area is set to 1 × 108, 7.5 × 107, 5 × 107, and 2.5 × 107 m2, as the mining area of the designed mine decreases, the area bearing surplus gradually increases, with values of 1.70 × 109, 1.98 × 109, 2.28 × 109, and 2.58 × 109 m2. The number of mines allowed to be mined under geological conditions with a WRCC above moderate capacity is 20, 31, 51, and 112, respectively.

In this work, a method of simultaneously analyzing pesticide concentration and assessing its risks was developed. Assessments were conducted to evaluate the distribution characteristics and risks to human health of pesticides in shallow groundwater in agricultural areas. We developed multi-residue analytical methods using liquid chromatography (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) to analyze 57 pesticides in groundwater. In addition, risk assessments were performed by setting scenarios considering the routes of pesticide infiltration into groundwater. For the simultaneous analysis of 57 pesticides, the liquid–liquid extraction method was applied twice using dichloromethane under acidic and alkaline conditions. The extract was concentrated and analyzed using LC-MS/MS (41 pesticides) and GC-MS/MS (16 pesticides). The precision and accuracy ranges of the analytical methods were 0.1~12.9% (within ±15%) and 80.3~113.6% (within ±20%), respectively. The limit of quantification was found to range from 0.0004 to 0.0677 μg/L. In total, 57 pesticides were monitored in 200 groundwater wells from 2019 to 2020. Twenty-six pesticides, including metolachlor and imidacloprid, were detected, with an average concentration of 0.0008 μg/L in groundwater. The pesticide types and detection levels differed depending on the survey period and surrounding land. When the risks associated with alachlor, metolachlor, and carbofuran were assessed, their health risks when found in groundwater were evaluated to be negligible (non-carcinogenic risk: less than 10−3, carcinogenic risk: less than 10−6).

Groundwater resources strongly support crop water requirement and economic yield improvement in semi-arid and arid areas. Water resources management require more investigation in the response of evapotranspiration (ET) partitioning and water use efficiency to groundwater change. Observational data collected over a three-year period, including water and carbon flux, vegetable sap flow, meteorological factors, soil water content, and groundwater depth, were employed in this study. Additionally, an improved Shuttleworth-Wallace model was used for partitioning plant transpiration and bare soil evaporation (E) in a sunflower cropland with shallow groundwater. The ET of the sunflower was founded to be 353.5 ± 15.0 mm, and approximately 48.3 ± 7.4% derived from the groundwater evaporation. E amounted approximately 145.6 ± 6.1 mm over the growth season, and around 47.2% of which was lost during the seeding stage. Furthermore, its dynamics depended on crop growth and groundwater table depth (WTD). These large amounts of non-productive soil E had a negative impact on the water-carbon coupling. The presence of E had resulted in a lower ecosystem water use efficiency (WUEe), measured at 1.02 ± 0.33 g C kg−1 H2O, compared to canopy water use efficiency (WUEc) of 1.68 ± 0.41 g C kg−1 H2O. These results demonstrated that regulating WTD could improve WUEe by increasing WUEc and reducing soil E. To achieve the higher WUEe, an optimum WTD was range of 1.5–2.0 m for border-irrigated sunflower field grown on sandy loam, identified by an analysis of normalized evaporation difference at the varying WTD. This finding highlights the significance of maintaining specified WTD, providing valuable insights into the complex interplay between crop evapotranspiration components and shallow groundwater. Moreover, it offers guidance for precision agriculture irrigation practices.

The vicinity of the proposed site ol Hekui NPP in Jiangxi Province was taken as the study area, and the shallow groundwater was chosen as the research object. Five surlace water and thirty-seven shallow groundwater samples, including spring and well water, were collected lor hydro chemical and isotopic analysis. The major results obtained Irom this study were as follows: the surlace water in the study area was fresh water and weakly alkaline, and the major anions and cations were HCO, and Ca2+; The spring water was weakly acidic, and the major anions and cations were HCO孑 and Na+; The well water was weakly alkaline, and the major anions and cations were HCOr, Cl-, SO4-, and Ca, 十 and Na+. Water-rock interaction and atmospheric precipitation were the dominant factors allecting the chemical characteristics ol shallow groundwater in this area. Na+ and K十 came Irom halite and silicate dissolution. Ca2+ came Irom carbonate and gypsum dissolution. HCO孑, Cl-, and SO4-were Irom carbonate, halite, and gypsum dissolution, respectively. The saturation index results showed that major components ol shallow groundwater were Irom the weathering and dissolution of silicate and carbonate. Stable hydrogen and oxygen isotope compositions showed that well water was mainly recharged by atmospheric precipitation and allected by mixing reactions. Groundwater exchanged with hydrocarbon and silicate minerals, CO2, wall rocks, and clay. Unlike spring water and well water, surface water was signilicantly allected by evaporation. Tritium concentration was between 2. 1 3. 6 TU, and it was speculated that the age ol shallow groundwater was over 50 years. This study provides not only the natural environment background value lor the proposed site ol Hekui Inland NPP but also a theoretical basis for the development and utilization ol groundwater resources, as well as environmental protection and the optimization ol the design scheme lor the construction ol the NPP. Meanwhile, this study has relerence signilicance for water pollution in emergencies. [ABSTRACT FROM AUTHOR]

To study distribution characteristics and potential health risks ol natural radionuclides in the nearby water body belore the construction ol Hekui Nuclear Power Plant (NPP) in Jiangxi province, live surlace water, twenty-nine well water and eight spring water samples were collected Irom the proposed site ol Hekui NPP, and activity concentrations ol 238 U, 232 Th, 226 Ra and 40 K were analyzed. The internal radiation dose coellicient method recommended by the International Commission on Radiological Protection (ICRP) and the U. S. Environmental Protection Agency (U S EP A) was used to assess the carcinogenic risk ol ingesting nuclides t hrough drinking water in people ol dilierent ages. Results showed that activity concentrations ol 2x8 U, 2x2Th and 226 Ra in the water body ol the study area were lower than the World Health Organization (WHO) standards for potable water. Compared with research at home and abroad, activity concentrations ol natural radionuclides in the water body ol the study area was 吐 a low level. The risk ol cancer caused by radionuclides in surface water in the descending order was as follows: children group(l. 71 X 10-8 a-1) > adult group(3. 99 X 10-9 a-1) > juvenile group(3. 21 X 10-9 a-1)・ The order in shallow groundwater was: children group〉juvenile group > adult group. All the risk values ol carcinogenesis were lower than 1 X 10-6 a-1 (US EPA standard), but the risk children was highest. This study provides background data for radiative environment monitoring alter NPP is built, and provides a scientilic basis and theoretical relerence lor the safety of the water environment near NPPs. [ABSTRACT FROM AUTHOR]

The present study aims at evaluating the quality of shallow groundwater (SGW) and its suitability for irrigation purpose in the most urbanised part of Johannesburg city, South Africa. The SGW samples were collected in three consecutive years and analysed for 20 selected physicochemical parameters, and heavy metals. The results were compared with the South African water quality, and Food and Agricultural Organization irrigation water quality guidelines, and standard indices derived from laboratory outputs. The results of the study show that all physiochemical parameters and heavy metals were within the limits set by both guidelines for irrigation purposes, except for potassium (3.58 mg·dm-3) and manganese levels (3.152 mg·dm-3). The calculated irrigation parameter values of sodium adsorption ratio (SAR), sodium percentage (Na%), residual sodium carbonate (RSC), magnesium hazard (MH), Kelly's ratio (KR) and permeability index (PI) were within the permissible range of irrigation water quality standards. The findings of this study provide helpful information for decision-makers such as utilisation of the studied groundwater for irrigation uses. [ABSTRACT FROM AUTHOR]

The contribution of groundwater to evapotranspiration in crop irrigation scheduling is gaining importance worldwide. A two consecutive year wheat experiment was conducted in drainable lysimeters to evaluate the response of grain yield and quality, spike traits, water use efficiency, evapotranspiration and thousand kernel weight of wheat plants under twelve different shallow and saline groundwater conditions. The treatments included three groundwater depths (GWD) (D1: 30 cm, D2: 55 cm and D3: 80 cm) and four groundwater salinities (GWS) (S1: 0.38, S2: 2, S3: 4 and S4: 8 dSm−1). The results show that the average decrease in grain yield for D2 and D1 compared to D3 was 20.9% and 30.7%, respectively, while the decrease for S2, S3 and S4 compared to S1 was 11.8%, 18.0% and 25.1%. The highest evapotranspiration was found in the D3S1 treatment (630.1 and 550.1 mm in 2017–2018 and 2018–2019, respectively), which increased by 48.0% and 30.2% in the first and second seasons, respectively, compared to the D1S4 treatment. Thus, a GWD at 80 cm with 0.38 dSm−1 GWS was able to meet 72% of the total water requirement of wheat under loam soil conditions. Water use efficiency values ranged from 1.49 to 1.65 kg m−3 in the first season and from 1.18 to 1.73 kg m−3 in the second season, with the highest water use efficiency values found at 80 cm GWD. Regression analysis showed that GWS had a greater effect on water use efficiency than GWD. On average, thousand kernel and hectolitre weights were highest under D3S1, reaching 49.6 g and 77.8 kg hl−1, respectively. Soil salinity increased steadily with increasing GWS at all GWD conditions, and higher soil salinity values were observed at 30 cm GWD. In addition, controlling a groundwater depth at 80 cm with 8.0 dSm−1 GWS did not significantly increase soil salinity, which did not result in high grain yield losses. Finally, it is recommended to control groundwater at a constant depth of 80 cm with 0.38 dSm−1 GWS after the tillering period of winter wheat to save more irrigation water, control soil salinity and improve yield and grain quality in the region with shallow‐saline groundwater. [ABSTRACT FROM AUTHOR]

Groundwater is the main water source for humans and plays an important role in health and food production. To understand the hydrogeochemical characteristics and quality of shallow groundwater in rural areas of Suzhou, Anhui Province, China, 32 groups of shallow groundwater samples were collected. The results of the study showed that the nature of the groundwater is slightly alkaline. The order of abundance of cations is Ca2+ > K+ + Na+ > Mg2+, whereas that of anions is HCO3− > Cl− > SO42−. The main hydrochemical types are HCO3-Ca, HCO3-Mg, and HCO3-Na. Hydrogen and oxygen isotope abundances indicated that shallow groundwater recharge in the study area is due to precipitation and is affected by evaporation. The ion ratio analysis suggested that the ions in the shallow groundwater originate from the weathering of silicate minerals and the dissolution of carbonate and sulphate minerals, accompanied by different degrees of ion exchange. Water quality evaluation indicated that the water is good and can be used directly as agricultural irrigation water. [ABSTRACT FROM AUTHOR]

Copyright of Multidiszciplináris Tudományok is the property of University of Miskolc and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this work is to demonstrate for the first time the results of hydrogeochmical studies carried out in the Steinvik River catchment, in order to provide detailed information regarding the chemical composition of groundwater in the Hornsund region, SW Spitsbergen. The water chemistry in the non-glaciated Steinvik River catchment is largely controlled by hydrological processes related to thaw of the near surface permafrost. Groundwater runoff is generated from the fast flow through well-permeable active layer. Recharge from melting snow, permafrost and rain, together with short residence time of groundwater, favors the forming of low-mineralized water, reaching 41 and 50 μS/cm for surface and groundwater, respectively, with the dominance of HCO3−, Cl−, Mg2+, Ca2+ and Na+ ions. In some water samples, increased concentrations of aluminum (up to 268 μg/L ) were found. The highest concentrations of phosphate, nitrite and ammonium in water seem to be related to the presence of bird colonies. Groundwater of active layer in the studied catchment belongs to young meteoric water with the age limited to one summer season.

Investigation presented is devoted to the problem of ecological and geochemical assessing of surface and near-surface waters of Kyiv (on the example of Sunny Lake, Lower Telbin Lake and shallow groundwater of Vodnykiv Island). As part of an ongoing assessment of the ecological-hygienic and medico-biological state of Kyiv, a set of surface water and shallow groundwater samples was collected and analysed (ICP-MS) for major and trace-element concentrations. Surface-water samples included two lakes that are popular recreation sites. Although all waters had near-neutral pH, concentrations of several trace elements were found to be above the maximum permissible concentrations (MPC) in Sunny Lake (Sb to 63 mg/dm3, Mn to mg/dm3) and Lower Telbin Lake (Al to 4,0 mg/dm3, Fe to 1,4 mg/dm3, As to 50 mg/dm3). Shallow groundwater samples had highly elevated concentrations of Fe (to 16,3 mg/dm3) and Mn (to 2,6 mg/dm3), as well as dissolved organic acids (to 25 mg/dm3). Two primary controls were established to explain the observed peculiarities in water quality: 1) water residence time coupled with the underlying geology; and 2) proximity to industrial effluent, including incineration and wastewater treatment facilities. In addition, lake-bed sediment was locally contaminated (e.g., lead up to 100 times the MPC). Preliminary data on the metal content of aquatic vegetation suggests a potential threat to human health and the environment. As a whole, our data show that the sampled water bodies fail to meet minimum requirements for category II (cultural, household, recreational) use. Although other water bodies in the area meet category II standards, continued loading of bio-organic and man-made inorganic pollutants may degrade water quality in the future. This situation can only be avoided by the introduction of scientifically sound and administratively supported reclamation measures which are at the moment slowly implementing in Ukraine.

The operation of the nuclear fuel complex is constantly accompanied by contamination of liquid industrial discharges with tritium. The problem of preventing such pollution is complicated by the fact that the pollutant component (tritium) is an integral part of the aqueous transport substance. Equally important is the need to purify deuterium water used in the nuclear industry from tritium and to increase the efficiency of tritium concentration technologies for further use. The use of the process of electroosmotic fractionation of hydrogen isotopes is proposed for purification of NPP process waters from tritium. In the isotopic molecule of tritiated or deuterium water (“HTO”, “DTO”), the covalent bond D – O and T – O is stronger than H – O, so it is possible to separate the hydrogen isotops by using the electroosmostic method in aqueous solution on composite mineral proton-conducting membranes. Such conductors can provide fractionation of hydrogen isotopes by proton exchange by tunneling or forwarding transport of ions in the process of electroosmosis under the influence of the applied electric field. In order to determine the possibility and efficiency of the electroosmotic process for fractionation of hydrogen isotopes in aqueous solution, we used a three-chamber electroosmotic cell with variable proton-conducting membranes made of mixtures of montmorillonite clay and zeolite (MCZ), montmorillonite and quartz sand (MQS), montmorillonit (MC) and saponite (SC) clays. The anode chambers were filled with electrolyte in the amount of 450–550 cm3, prepared from tritiated water, with a specific activity of 5,950 Bq·dm– 3 with the addition of anhydrous Na2CO3 salt. Under the influence of the electric field, electroosmotic filtration of the dissociated tritiated electrolyte through weakly permeable clay and composite membranes from the anode chamber to the cathode chamber was happening. At the same time, due to the proton conductivity of electroosmotic membranes with increasing strength and voltage of electric current, the alkalinity of the aqueous solution in the cathode chamber increased and the specific activity of tritium in the filtrate (catholyte) decreased by 14–26%. The method is protected by the Patent of Ukraine for a utility model.

The hydrochemical characteristics of shallow groundwater and the factors affecting them were analyzed using descriptive statistical analysis, Piper trilinear charts, Gibbs charts, and ion ratios, to help improve the groundwater quality of the Poyang Lake Plain. The results showed that the groundwater was weakly acidic, with an average pH of 6.27. was the main ion component, with high stability in the study area. The chemical ions in groundwater were mainly controlled by rock weathering, and Ca2+ and Mg2+ originated from the dissolution of carbonate, silicate, or evaporite. Cation exchange was an important driving factor in the formation of groundwater chemical components in the study area. The shallow groundwater and surface water in the region around Poyang Lake are replenished by precipitation, but both are more affected by evaporation. The large d-excess value indicated that the groundwater was greatly affected by water–rock interactions. The main source of is chemical fertilizer and levels were less affected by domestic sewage, which may be because the study area is a traditional agricultural area. Rock weathering, leaching, and human activities were the main driving factors for the evolution of the chemical characteristics of the groundwater in the study area. These results provide a technical reference and the basis for regional collaborative efforts to control groundwater and surface water pollution. HIGHLIGHTS The release of metal ions is accelerated in weakly acidic groundwater.; Both natural and human activities influence the hydrochemical characteristics of groundwater.; Nitrate comes from chemical fertilizer and domestic sewage in groundwater.; The driving factors for the evolution of hydrochemical characteristics are rock weathering and human activities.;

Perfluoroalkyl substances (PFASs) in shallow groundwater are increasingly being studied due to the global occurrence, environment persistence, bioaccumulation, and potential human health risk. In this research, 16 PFAS (11 perfluorinated carboxylic acids and 5 perfluorinated sulfonic acids) concentrations in groundwater were quantified to obtain information on geographical distribution and PFAS detection pattern for 4 years in South Korea. In the results, groundwater PFAS concentration ranged from non-detectable to average 45.2 ng/L (sum of PFASs). The major PFAS compounds were perfluorooctanoic acid (PFOA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS). The short chain (C < 8) PFASs were more prevalent than long chain (C > 8) PFASs in shallow groundwater. However, the detection patterns of 15 PFASs were different for each aquifer. Subsequently, through a health risk assessment, a non-carcinogenic risk level through ingestion, inhalation, and dermal contact for PFOA and PFOS was determined at 10−1, and it presents the need for PFAS management of groundwater. [ABSTRACT FROM AUTHOR]

The objective of this work is to demonstrate the results of hydrogeochmical studies carried out in the Steinvik River catchment for the first time, in order to provide detailed information regarding the chemical composition of groundwater in the Hornsund region, SW Spitsbergen. The water chemistry in the non-glaciated Steinvik River catchment is largely controlled by hydrological processes related to thaw of the near surface permafrost. Groundwater runoff is generated from the fast flow through well-permeable active layer. Recharge from melting snow, permafrost and rain, together with short residence time of groundwater, favors the forming of low-mineralized water, reaching 41 and 50 µS/cm for surface and groundwater, respectively, with the dominance of HCO3-, Cl-, Mg2+, Ca2+ and Na+ ions. In some water samples, increased concentrations of aluminum (up to 268 µg/L) were found. The highest concentrations of phosphate, nitrite and ammonium in water seem to be related to the presence of bird colonies. Groundwater of active layer in the studied catchment belongs to young meteoric water with the age limited to one summer season. [ABSTRACT FROM AUTHOR]

Shallow groundwater is an important water source for Haloxylon ammodendron (H. ammodendron). The accurate estimation of evapotranspiration (ETg) from groundwater is of great significance for the water cycle and the maintenance of ecological stability. Using a combination of the water balance method and the groundwater level fluctuation method (WTF), the water balance components (precipitation, soil moisture, groundwater depth, and Bowen ratio meteorological data) in the desert–oasis transition zone were continuously monitored from 2015 to 2018 and the ETg was estimated The results showed that the closed degree of Bowen specific energy after data screening was higher, and the annual actual evapotranspiration (ETa) value could be reliably calculated at 260.87 mm. As the main contributor to water consumption in the growing season, latent heat accounted for 70.16~91.86% of the energy balance. Precipitation had no significant impact on water consumption for H. ammodendron vegetation growth, and the precipitation in the main growing season accounted for 59.44% of the ETa. The groundwater depth in the study area decreased yearly and had a significant impact on the growth of H. ammodendron vegetation. Although the groundwater depth in the study area was greater than 9 m, the ETg, as an important part of the water balance, was found to participate in the evapotranspiration process brought about by H. ammodendron due to the strong root system and supporting capillary water in the soil. The actual evapotranspiration ETa for H. ammodendron in the main growing season was 244.32 mm, and the contribution rate for ETg was as high as 74.78% or approximately 182.35 mm. After the ETg was verified using the water balance method and WTF, R was greater than 0.96, the RMSE range was 1.5931~4.5706, the bias range was −0.15~0.11, and the IOA value was greater than 0.95. The accuracy of the estimation model was high, and the results were relatively accurate. The model can be applied in the desert–oasis transition zone to obtain accurate ETg estimations and provide theoretical guidance and a scientific basis for local water resource management and ecological protection. [ABSTRACT FROM AUTHOR]

Binhai New Area (BHNA), as one of the most economically and industrially regions in the Haihe River Basin, China, is seriously affected by seawater intrusion and groundwater over-exploitation. Groundwater vulnerability assessment (GVA) is an effective tool to protect the groundwater resources from being polluted. In this study, vertical and horizontal groundwater conditional factors were first assessed separately by two different models. The AHP-DRASTIC model was used to evaluate the intrinsic groundwater vulnerability and the AHP-GALDIT model was used to evaluate the specific groundwater vulnerability to seawater intrusion. Then, a GIS-based overlaying approach was used to get the comprehensive shallow groundwater vulnerability. The results of the comprehensive model showed that the vulnerability areas of very low, low, medium, and high account for 1.37%, 11.36%, 60.56%, and 26.71%, respectively. Finally, to effectively manage the groundwater in the study area, two remediation areas, two control areas, and one protected area were determined based on the comprehensive groundwater vulnerability maps. This study can not only promote the development of rational exploitation of shallow groundwater and prevention of groundwater pollution in BHNA but also provide a framework for future research in the GVA on the coast. [ABSTRACT FROM AUTHOR]

To reveal the effect of interlayer on the temperature of freeze-thaw soil and the transformation between phreatic water and soil water in shallow groundwater areas, a freeze-thaw test was conducted with a groundwater table depth of 0.5 m under laboratory freeze-thaw action. The soil temperature and the transformation between phreatic water and soil water of sand columns under constant freezing temperature at −20°C lasted for 20 days, and the thawing process lasted for 15 days were monitored. The interlayers with a particle size of 0.1–0.5 mm (d50 = 0.3 mm) and a thickness of 5 cm were set at 5, 15, 20, and 25 cm away from the surface and these sand columns were marked as D5, D15, D20, and D25, which were compared with a homogeneous sand column (Ch) with a particle size of 0.5–1.5 mm (d50 = 1.0 mm). The results showed that the fine particle interlayer had thermal insulation on the soil profile and that it effectively inhibited upward migration of phreatic water to soil water during the freezing process. A sand column that had a near-surface interlayer had a better thermal insulation, a stronger inhibition effect on upward migration amount of phreatic water to soil water (UMA) and a larger cumulative downward movement amount of soil water to phreatic water (DMA). The cumulative UMA of D5, D15, D20, and D25 was 61%–84% of Ch during the freezing stage, and the cumulative DMA of D5, D15, D20, and D25 was 29%–57% of Ch during the thawing stage. The inefficient loss of groundwater increased exponentially with the depth of interlayer, the sand column with an interlayer that was farther away from the surface consumed more groundwater and stored more water in the unsaturated zone, and its DMA reached almost zero earlier. These research results were significant for the scientific evaluation of water resources in shallow groundwater areas.