Groundwater Sources Research Articles

Feasibility study on the optimal design method of ground-water source hybrid heat pump system applied to office buildings

In order to reduce the energy consumption of buildings, a ground source heat pump (GSHP) system was introduced to reduce the building energy consumption. However, general GSHP systems are not as popular as photovoltaic and thermal systems owing to soil imbalances and performance degradation during long-term operation. To solve this problem, we propose a ground-water source hybrid heat pump (GWHP) system. GWHP systems can simultaneously use ground and water sources to avoid soil imbalance and degradation. In this study, we proposed a GWHP system and investigated its feasibility as a replacement for a GSHP system in terms of performance and heat source temperature. In addition, an optimal capacity design method for the GWHP system is presented to evaluate its economic feasibility. The performance and economic analysis show that the cooling and heating performance of the proposed GWHP was 15 % and 3 % better, respectively, compared to the existing GSHP system. Our results also showed that the proposed design method was approximately 5.3 % less expensive than the existing GSHP systems. The GWHP system could be a suitable alternative to the GSHP system, as confirmed by both the energy simulation and cost analysis.

Groundwater hydrochemistry, source identification and health assessment based on self-organizing map in an intensive mining area in Shanxi, China

The Changzhi Basin in Shanxi is renowned for its extensive mining activities. It's crucial to comprehend the spatial distribution and geochemical factors influencing its water quality to uphold water security and safeguard the ecosystem. However, the complexity inherent in hydrogeochemical data presents challenges for linear data analysis methods. This study utilizes a combined approach of self-organizing maps (SOM) and K-means clustering to investigate the hydrogeochemical sources of shallow groundwater in the Changzhi Basin and the associated human health risks. The results showed that the groundwater chemical characteristics were categorized into 48 neurons grouped into six clusters (C1–C6) representing different groundwater types with different contamination characteristics. C1, C3, and C5 represent uncontaminated or minimally contaminated groundwater (Ca–HCO3 type), while C2 signifies mixed-contaminated groundwater (HCO3–Ca type, Mixed Cl–Mg–Ca type, and CaSO4 type). C4 samples exhibit impacts from agricultural activities (Mixed Cl–Mg–Ca), and C6 reflects high Ca and NO3− groundwater. Anthropogenic activities, especially agriculture, have resulted in elevated NO3− levels in shallow groundwater. Notably, heightened non-carcinogenic risks linked to NO3−, Pb, F−, and Mn exposure through drinking water, particularly impacting children, warrant significant attention. This research contributes valuable insights into sustainable groundwater resource development, pollution mitigation strategies, and effective ecosystem protection within intensive mining regions like the Changzhi Basin. It serves as a vital reference for similar areas worldwide, offering guidance for groundwater management, pollution prevention, and control.

Variation in water uptake pattern of the constructive species Pinus koraiensis: Evidence from water stable isotopes

Plant water uptake plays a crucial role in regulating the water balance for the stability of ecosystems. Previous studies on plant water uptake, focused on arid and semi-arid regions due to water scarcity in these areas, leaving gaps in understanding the strategies and factors affecting plant water uptake in temperate semi-humid regions, where there is a high sensitivity to climate change To assess water uptake patterns through stable isotopes (δD and δ18O), we chose Pinus koraiensis, a dominant species in the broadleaf Korean pine forest, poplar–birch forest and spruce–fir forest of the Changbai Mountain. Our findings indicated that soil water served as the direct water source for Pinus koraiensis, while precipitation, river water, and groundwater indirectly contributed via replenishing soil moisture and subsequently supporting plant water uptake. Within the broadleaf Korean pine forest and poplar–birch forest, Pinus koraiensis primarily extracted soil water from depths of 0–10 cm, accounting for approximately 49.6 % and 54.5 % of its total water uptake, respectively. In contrast, within the spruce–fir forest, Pinus koraiensis primarily extracted soil water from depths 40–50 cm, representing approximately 31.9 % of its total water uptake. In addition, through the partial correlations and variation partitioning analyses, the results revealed that sand content was the driver of the plant water uptake pattern, which affected the fine root distribution by determining the field capacity and bulk density to drive the plant water uptake. Future forest conservation management endeavours will primarily concentrate on protecting soil integrity, reducing soil erosion, maintaining regional water balance, and preserving plant diversity in the Changbai Mountain region.

Arsenic contamination of groundwater sources and a comparative study of its remediation by various conventional and recent approaches in Nepal

AbstractGroundwater is a major source of drinking water for millions of people across the globe. Most of these sources are reported to contain elevated levels of arsenic. Human health and ecosystems are adversely affected by arsenic‐contaminated drinking water. So, arsenic‐contaminated groundwater has become a major global health concern. This paper reviews groundwater contamination sources and gives an outline of arsenic contamination in different places in Nepal. It also critically reviews the health hazards associated with arsenic poisoning. A comparative study has been made regarding different aspects of conventional and recent technologies, and the one that is the most suitable for remediation of contaminated water has been recommended.

Evaluate the groundwater quality and human health risks for sustainable drinking and irrigation purposes in mountainous region of Chongqing, Southwest China

Groundwater is crucial for agriculture and domestic consumption. This research investigated the hydrogeochemical properties and contaminant sources of groundwater within the mountainous terrain of northern Chongqing, with the objective of evaluating its appropriateness for irrigation and potable use. The hydrochemical type of the groundwater was HCO3 − Ca, dominated by silicate and calcite dissolutions. High NO3− (29.03% exceeds 10 mg/L) were attributed to the overuse of agricultural fertilizers. A comprehensive evaluation was conducted to determine the groundwater suitability for agricultural and potable uses. The results showed that groundwater in the southwestern region, particularly within the Yangtze River mainstem watershed, exhibited less suitability for irrigation owing to its lower mineralization, in contrast to the northeastern region near the Daning River watershed. But this trend is reversed for drinking purposes. Overall, the groundwater was appropriate for both drinking (93.55% were classified as excellent) and irrigation (70.98% were classified as low restriction) purposes in the study area. Deterministic and probabilistic noncarcinogenic health risk analyses centered on nitrate exposure revealed that infants (with 13.79% of samples >1) were at greater risk than children (8.58%), adult males (6.98%), and adult females (5.24%). This underscores the urgency to reduce nitrogen fertilizer usage and improve water management in the region. This research will provide guidance for the sustainable groundwater management in mountainous regions.

Bacteriological Evaluation of Surface and Groundwater used for Domestic Purposes in Ibadan

The right to safe and clean drinking water is a human right, unfortunately many communities rely on unsafe and contaminated water for drinking and domestic purposes. Through improper sewage and hospital waste disposal, pathogenic and antibiotic resistant bacteria have found their way to natural water sources used by humans. In this study we aim to profile pathogenic bacteria and resistant Escherichia coli (E. coli) from surface and ground water sources in three local government areas of Oyo state. 30 water samples were collected randomly from the selected local government areas. Bacteriological, biochemical and antibiotic-resistant analysis was carried out on the isolated bacteria from the water samples. E. coli (28.30%) and Kleb pneumoniae (23.77%) were the predominant bacteria isolates, while Shigella (16.22%) and Salmonella (16.22%) also had substantial percentages. Nineteen E. coli was isolated and identified, with high antibiotic resistance rates observed in nalidixic Acid (100%), augmentin (100%), ampiclox (94.74%) and third-generation cephalosporins. Conversely, moderate levels of resistance were observed in nitrofurantoin (55.55%), cefepime (57.89%), and second-generation fluoroquinolones. This study reveals substantial pathogenic bacteria and antibiotic resistant E. coli in water samples which endangers the health of communities’ dependent on these water sources and exposes the inhabitants to antibiotic-resistant organisms from contaminated water used for domestic purposes. It is crucial to put in place water treatment measures and quality monitoring programmes in order to guarantee that the populace has access to clean and safe drinking water.

Functional analysis, diversity, and distribution of the ean cluster responsible for 17β-estradiol degradation in sphingomonads.

17β-estradiol (E2) is a natural endocrine disruptor that is frequently detected in surface and groundwater sources, thereby threatening ecosystems and human health. The newly isolated E2-degrading strain Sphingomonas colocasiae C3-2 can degrade E2 through both the 4,5-seco pathway and the 9,10-seco pathway; the former is the primary pathway supporting the growth of this strain and the latter is a branching pathway. The novel gene cluster ean was found to be responsible for E2 degradation through the 4,5-seco pathway, where E2 is converted to estrone (E1) by EanA, which belongs to the short-chain dehydrogenases/reductases (SDR) superfamily. A three-component oxygenase system (including the P450 monooxygenase EanB1, the small iron-sulfur protein ferredoxin EanB2, and the ferredoxin reductase EanB3) was responsible for hydroxylating E1 to 4-hydroxyestrone (4-OH-E1). The enzymatic assay showed that the proportion of the three components is critical for its function. The dioxygenase EanC catalyzes ring A cleavage of 4-OH-E1, and the oxidoreductase EanD is responsible for the decarboxylation of the ring A-cleavage product of 4-OH-E1. EanR, a TetR family transcriptional regulator, acts as a transcriptional repressor of the ean cluster. The ean cluster was also found in other reported E2-degrading sphingomonads. In addition, the novel two-component monooxygenase EanE1E2 can open ring B of 4-OH-E1 via the 9,10-seco pathway, but its encoding genes are not located within the ean cluster. These results refine research on genes involved in E2 degradation and enrich the understanding of the cleavages of ring A and ring B of E2.IMPORTANCESteroid estrogens have been detected in diverse environments, ranging from oceans and rivers to soils and groundwater, posing serious risks to both human health and ecological safety. The United States National Toxicology Program and the World Health Organization have both classified estrogens as Group 1 carcinogens. Several model organisms (proteobacteria) have established the 4,5-seco pathway for estrogen degradation. In this study, the newly isolated Sphingomonas colocasiae C3-2 could degrade E2 through both the 4,5-seco pathway and the 9,10-seco pathway. The novel gene cluster ean (including eanA, eanB1, eanC, and eanD) responsible for E2 degradation by the 4,5-seco pathway was identified; the novel two-component monooxygenase EanE1E2 can open ring B of 4-OH-E1 through the 9,10-seco pathway. The TetR family transcriptional regulator EanR acts as a transcriptional repressor of the ean cluster. The cluster ean was also found to be present in other reported E2-degrading sphingomonads, indicating the ubiquity of the E2 metabolism in the environment.

Integrated Exploitation of Rainwater and Groundwater: A Strategy for Water Self-Sufficiency in Ca Mau Province of the Mekong Delta

Groundwater sources have been exploited excessively for numerous purposes worldwide, leading to increasingly severe depletion. However, the replenishment of groundwater sources has not usually been a focus in economically and socially underdeveloped countries and regions. In coastal provinces of the Vietnamese Mekong Delta (VMD), rural areas are facing difficulties in accessing fresh water due to shortages from the water supply plant and excessive use of groundwater, highlighting an urgent need for sustainable development solutions. Our study first conducted interviews with 200 households in Ca Mau Province of the VMD to identify the current situation and the challenges and obstacles of rainwater harvesting and to find sustainable and proactive solutions. We then analyzed daily rainfall data from 10 meteorological stations to construct four scenarios of the water balance method: (i) potential rainwater harvesting based on existing roof area; (ii) optimal scale of storage tank and catchments for different levels of water usage; (iii) tank scale utilizing rainwater entirely during the rainy season and basic needs during the dry season; and (iv) integrated water supply between rain and groundwater. The results showed that using rainwater entirely for domestic water supply requires large storage tank capacities, making these scenarios difficult to achieve in the near future. Our research introduces a novel integrated water supply approach to storing rain and groundwater that has demonstrated high effectiveness and sustainability. With existing tank capacities (0.8 m3 per person), rainwater could only meet over 48% (14 m3 per year) of the water demand while requiring 14.8 m3 of additional groundwater extraction. With a tank capacity of 2.4 m3 per person, ensuring rainwater harvesting meets basic demand, harvested rainwater could satisfy 64% of the demand, with artificial groundwater supplementation exceeding 1.79 times the required extraction, while excess rainwater discharge into the environment would be minimal. Our research results not only provide potential solutions for rainwater and groundwater collection to supplement sustainable domestic water sources for Ca Mau but also serve as an example for similar regions globally.

Global energy use and carbon emissions from irrigated agriculture

Irrigation is a land management practice with major environmental impacts. However, global energy consumption and carbon emissions resulting from irrigation remain unknown. We assess the worldwide energy consumption and carbon emissions associated with irrigation, while also measuring the potential energy and carbon reductions achievable through the adoption of efficient and low-carbon irrigation practices. Currently, irrigation contributes 216 million metric tons of CO2 emissions and consumes 1896 petajoules of energy annually, representing 15% of greenhouse gas emissions and energy utilized in agricultural operations. Despite only 40% of irrigated agriculture relies on groundwater sources, groundwater pumping accounts for 89% of the total energy consumption in irrigation. Projections indicate that future expansion of irrigation could lead to a 28% increase in energy usage. Embracing highly efficient, low-carbon irrigation methods has the potential to cut energy consumption in half and reduce CO2 emissions by 90%. However, considering country-specific feasibility of mitigation options, global CO2 emissions may only see a 55% reduction. Our research offers comprehensive insights into the energy consumption and carbon emissions associated with irrigation, contributing valuable information that can guide assessments of the viability of irrigation in enhancing adaptive capacity within the agricultural sector.

Groundwater hydrochemical signatures, nitrate sources, and potential health risks in a typical karst catchment of North China using hydrochemistry and multiple stable isotopes.

Nitrate pollution in aquatic ecosystems has received growing concern, particularly in fragile karst basins. In this study, hydrochemical compositions, multiple stable isotopes (δ2H-H2O, δ18Ο-Η2Ο, δ15Ν-ΝΟ3-, and δ18Ο-ΝΟ3-), and Bayesian stable isotope mixing model (MixSIAR) were applied to elucidate nitrate pollution sources in groundwater of the Yangzhuang Basin. The Durov diagram identified the dominant groundwater chemical face as Ca-HCO3 type. The NO3- concentration ranged from 10.89 to 90.45mg/L (average 47.34mg/L), showing an increasing trend from the upstream forest and grassland to the downstream agricultural dominant area. It is worth noting that 47.2% of groundwater samples exceeded the NO3- threshold value of 50mg/L for drinking water recommended by the World Health Organization. The relationship between NO3-/Cl- and Cl- ratios suggested that most groundwater samples were located in nitrate mixed endmember from agricultural input, soil organic nitrogen, and manure & sewage. The Self-Organizing Map (SOM) and Pearson correlations analysis further indicated that the application of calcium fertilizer, sodium fertilizer, and livestock and poultry excrement in farmland elevated NO3- level in groundwater. The output results of the MixSIAR model showed that the primary sources of NO3- in groundwater were soil organic nitrogen (55.3%), followed by chemical fertilizers (28.5%), sewage & manure (12.7%), and atmospheric deposition (3.4%). Microbial nitrification was a dominant nitrogen conversion pathway elevating NO3- levels in groundwater, while the denitrification can be neglectable across the study area. The human health risk assessment (HHRA) model identified that about 88.9%, 77.8%, 72.2%, and 50.0% of groundwater samples posing nitrate's non-carcinogenic health hazards (HQ > 1) through oral intake for infants, children, females, and males, respectively. The findings of this study can offer useful biogeochemical information on nitrogen pollution in karst groundwater to support sustainable groundwater management in similar human-affected karst regions.

Ensuring water security by reviving selected springs in Kangra region, Himachal Himalaya, India

ABSTRACT In the Himalaya, availability of fresh water is a need of mankind, but due to numerous unsustainable developments, hill peoplesare witnessing scarcity of potable water. Hence, there is an imperative need for continuous monitoring of different water sources of Himalaya along with sustainable groundwater management practices in the highlands. The present study is based on extensive field visits investigating natural and other anthropogenic influences on mountain springs, locally known as “boweris”. In the undertaken study, eleven boweris were identified in the Salol region of Kangra, out of which two were exclusively selected as representative boweris, for their detailed studies and revival during the year 2021–2022. The physio-chemical characteristics (pH, TDS, and Electrical Conductivity) of the collected water samples from the boweris and hand pumps were found to be within the acceptable limits as prescribed by Bureau of Indian standards. The correlation between the pairs of TDS-EC depicted a strong positive relationship in both post-monsoon and pre-monsoon seasons and was found to be 0.94 and 0.99, respectively. Results of the t-test show a statistically significant difference in the mean concentrations of TDS (p = 0.02) and EC (p = 0.01) compared to pH (p = 0.39) with no significant difference at 5% significance level during both the seasons in the studied area. It was evident from the field investigations that the recharge structures constructed are facilitating the local boweris in maintaining the water level during the dry seasons. In the Bhatlahru region, the water level in the boweris rose from 127 to 159 cm, whereas in the Salol region, a rise from 119 to 142 cm was observed. The obtained results support the effectiveness and suitability of the proposed structures for the sustainable water resource management in the lower Himalaya. However, regular and long-term hydrological monitoring of the existing groundwater sources of the Himalaya is required for a better understanding of groundwater dynamics.

Groundwater Potential Zones Using Multi – Criteria Decision Making for Mirzapur, District, U.P, India

Groundwater is one of the most prominent fresh water sources and is under significant threat due to numerous factors such as growing population, rapid urbanization, multiple cropping practices and utilizing by the major water intensive industries. The quality and quantity of groundwater sources are both affected by climate change. Climate variability also has a significant impact on the parameters that influence groundwater recharge. The fall in groundwater levels is worsened by erratic monsoon with deficit amount of rainfall occurring in combination with high heat-flow and over-exploitation of groundwater which contributes stress on the water resources. This study was conducted for Mirzapur district where the groundwater serves as the main source for domestic and agricultural purposes rather than the other sources of water. To delineate the potential groundwater zones, the following parameters were used i.e. geology, drainage density, slope, geomorphology, soil, land use and land cover and lineament density (an area can indirectly reveal the groundwater potential) are constructed as separate layers in the GIS (Geographic Information System) background. Thereafter, a weighted overlay analysis was carried out to achieve the graded potential zones using the weights computed for each layer by AHP (Analytical Hierarchy Process) method. In addition, the GWP map has been divided into four categories using multi criteria decision analysis (MCDA): excellent, good, moderate, and poor. The results of the study revealed that the excellent potential zone comprises of 24.4 % (1101 km2), good 40.07% (1840 km2), moderate 29.8% (1347 km2), and poor 5.1% (228 km2) of the total geographical area. Future management plans, including natural and artificial recharge practices, may be made effectively in these locations because the approach used yielded reliable data.

Water Quality Assessment using different Indices for Irrigation Purpose at Wardha District

With the help of multiple indices (SAR, LI, RI, SSP, and RSC) for irrigation, the current study set out to determine the level of groundwater pollution in the Wardha region. The research involved 15 villages in the Wardha District, five from each of Wardha, Seloo, and Hinganghat. Over the course of two years, 90 samples were taken from fifteen groundwater structures. 13 physicochemical factors and 5 indices were evaluated using analysis. The study discovered that the groundwater sources in each of the 15 villages in the Wardha District are contaminated, making the water unfit for human consumption and necessitating some sort of filtration before usage for domestic or agricultural purposes. The findings of Langlier that practically all groundwater samples exhibit factors that cause scaling are supported by the Ryznar index values, which range from 5 to 7. SAR data indicates that around 60% of the groundwater being examined had low levels (10.0).

Assessment of modern irrigation versus flood irrigation on groundwater potentiality in old clayey lands

Groundwater management in semiarid and arid regions, like northern Egypt, is essential for the sustainability of scarce resources through monitoring groundwater status and sources of recharge to the aquifer. In the Qalyubia Governorate, Nile Delta, Egypt, the study examined the recharge of groundwater in lands subject to flood irrigation and compared it with water-saving irrigation methods to detect how irrigation practices influence the potentiality of groundwater. A simulation of the two irrigation techniques, flood irrigation, and water-saving irrigation, was performed. Using GMS, simulations are done to calculate the water balance in the main 8 districts of Qalyubia Governorate. In comparison to flood irrigation, it was found that water-saving irrigation has less recharge intensity, which in turn causes a lowering in groundwater levels. The decline in groundwater table ranges between 10 and 50 cm. Modern irrigation influences the potentiality of the Nile Delta aquifer, which can’t be underestimated.

Оценка уязвимости карстовых подземных вод к загрязнению на основных массивах Горного Крыма с использованием региональной методики

Introduction. Assessment of groundwater vulnerability to contamination is an effective tool for scientific substantiation of the sanitary protection zones for drinking water sources. Karst ground waters of the Mountain Crimea form the main resources for water supply in the Crimean Peninsula. This study has a purpose to perform the assessme nt and mapping of karst ground waters resource vulnerability to contamination on such representative massifs of the Crimean Mountains as Chatyrdag, Dolgorukovsky, Karabi and Ay-Petri . Materials and methods. Assessment of karst ground waters vulnerability is conducted by use of Mountain -Crimean method. It has been developed on the base of some wide-tested European methods (COP-method and Slovene approach) with methodological modification and adaptation to regional conditions of the Mountain Crimea. The input data for assessment is spatial information about ground waters vulnerability factors: protective layers in vadose zone, flow concentration by streams, sinkholes and caves, precipitation regime etc. The collected spatial information was converted into attributed geo data layers, which were subsequently subjected to overlay operations in Arc GIS 10 software according to assessment scheme. Results. According to the assessment results, approximately 34 and 14% of the Chatyrdag massif area gained the category of high and very high vulnerability, on the Karabi massif – 14 and 17%, on the Dolgorukovsky massif – 14 and 2%, on the Ay-Petri massif – 19 and 7% of total area respectively. The result ing vulnerability maps demonstrate significant mosaics and contrast, which is associated with discrete distribution of protective covers and high differentiation of ground water recharge conditions within the catchments of karst massifs. Discussion. Analysis of the resulting vulnerability maps have revealed that the leading factors determining areas of high and very high vulner ability of karst waters are runoff concentration factors, while the factors of protective cover mainly determine the areas with low vulnerability. The zones of high vulnerability on the Chatyrdag and Karabi massifs are mainly coincide with areas of high density of karst forms (sinkholes and caves), while high vulnerability zones of the Ay-Petri and Dolgorukovsky massifs are predominantly associated with areas near permanent and temporary watercourses. In general, the obtained maps of groundwater vulnerability are quite consistent with the known data on the hydro-geological conditions of the assessed massifs. Conclusions. The identified differences in the area ratio and spatial distribution of ground waters vulnerability categories between the assessed massifs are a consequence of local geological, geo-morphological and hydrological features. The obtained results confirm high applicability of the Mountain-Crimean regional method for groundwater vulnerability assessment, at least for the karst massifs of the Mountain Crimea. Suggestions for practical application and direction for future research. The produced groundwater vulnerability maps create a scientific basis for delineation of water protection zones, assessing the risks of groundwater pollution and developing the territorial planning schemes within studied areas. The next stage of study is an assessment of groundwater source vulnerability for individual karst springs used in water supply.

Подземные источники балки Пещерная озера Баскунчак: гидрохимические особенности и эмиссия парниковых газов

For the first time, full-scale measurements of methane and carbon dioxide emissions by the chamber method were carried out in summer for groundwater sources discharged in the valley of the Peshernaya Gulch creek, located in the north-west of Lake Baskunchak. pH values, concentrations of CH4, basic ions, gross Fe and Mn were determined in the water of the sources; concentrations of CH4, H2S, organic matter, Eh and pH values, density and humidity were determined in various layers of bottom sediments (up to 27 cm). A detailed description of the identified groundwater sources was carried out, their primary morphometric and morphological characteristics were measured, as well as the flow rate. It was found that more than 10 ascending karst sources of groundwater are discharged in the Peshchernaya beam, 5 of which were active during the research period and mainly confined to the left screw of the beam. The active sources of the left screw of the beam are characterized by a small flow rate and are sodium chloride brines with a mineralization of 93.9–107.1 g/l. The bottom sediments accumulating in the sinkholes of underground sources are characterized by a neutral acid-base environment and restorative conditions. The concentrations of CH4 and ∑H2S in the sediments of the sources varied, respectively, in the range of 0.08–0.77 µg/g vl.o. and 0.023–2.63 mg/g vl.o. with minimal values for both gases in the lower less reduced layer with a low content of Sorg. The concentration of methane in the water of active sources varied from 26.3 up to 38.4 µl/l and was on average 2 times higher than in the waters of a stream fed by them and an inactive source. The specific methane flux from the water surface of active sources varied in the range of 0.6–1.5 mg/(m2∙h), which is 2 orders of magnitude lower than the specific CO2 flux of 46.4–106.1 mg/(m2∙h). The isotopic composition of carbon (δ13C) CH4 and CO2 measured in gas bubbles rising from the bottom of one of the ascending sources indicates the modern biochemical genesis of these greenhouse gases.

Study on Hydrochemical Characteristics and Interactions between Groundwater and Surface Water in the Dongting Lake Plain

The Dongting Lake Plain is a major ecological reserve for river and lake wetlands in the Yangtze River Basin, with complex river and lake relationships and frequent water flow exchange. Studies on the hydrochemical characteristics and the mechanism of interaction between groundwater and surface water will actively promote the scientific management, utilization of water resources, and protection of the ecological environment in the Dongting Lake Plain. Based on hydrogeochemical statistics, Gibbs diagrams, ion ratios, rock weathering end-element diagrams, hydrogen–oxygen isotope relationship diagrams, and other technical methods, the chemical characteristics, ion sources, and the distribution of hydrogen–oxygen isotopes of groundwater and surface water in “the Three Inlets” and “the Four Rivers” water system areas as well as the Dongting Lake water were analyzed. Additionally, the interactions between groundwater and surface water and the proportions of these contributions were discussed. The results show that both groundwater and surface water in the Dongting Lake Plain are weakly acidic or alkaline, and the anions are mainly HCO3−, the cations are mainly Ca2+and Mg2+, with the hydrochemical types being mainly HCO3−Ca−Mg and HCO3−Ca. The chemical characteristics of groundwater and surface water are mainly affected by the interaction between water and rock; the ions in surface water mainly come from the weathered dissolution of carbonate and silicate rocks, while the ions in groundwater mainly come from the weathered dissolution of carbonate and silicate rocks, with the dissolution of evaporite rocks locally. Groundwater and surface water are mainly distributed near the local meteoric water line (LMWL), and the slope of the local evaporation line is less than that of the LMWL, which indicates that atmospheric rainfall is an important recharge source for groundwater and surface water and that at the same time, it is affected by evaporation to a certain extent. Part of the groundwater in the Dongting Lake Plain is discharged into the surface rivers in “the Three Inlets” and “the Four Rivers” water system areas, and the other part is directly discharged into Dongting Lake. According to the mass balance relationship of isotopes, the proportions of surface water in “the Three Inlets” and “the Four Rivers” water system areas contributing to Dongting Lake’s water are 18.48% and 60.38%, respectively, and the proportion of groundwater in the lake plain contributing to Dongting Lake water is 21.14%.

Evaluating hydrogeochemistry and heavy metal contamination of groundwater at Ranipet environs: employing multivariate statistics, agricultural indices, and health risk assessment.

Water plays an essential role in sustaining life on Earth as an indispensable natural resource. In recent decades, dependence on groundwater for domestic and industrial purposes has become inevitable. The Ranipet industrial environs (RIE) has many tanneries and chemical industries, which affects the groundwater quality. This study assessed groundwater quality and its suitability for domestic, agricultural, and human health risk assessments. 40 groundwater samples (28 open wells and 12 bore wells) were collected during pre-monsoon 2022 and analyzed by employing multivariate statistics, standard scatter plots, irrigation indices, and health risk assessment. The results of hydrogeochemical analysis and multivariate statistics affirmed that electrical conductivity (EC), total dissolved solids (TDS), calcium (Ca2+), and magnesium (Mg2+) have controlled the hydrochemistry of RIE. Cadmium (Cd) at 46% and chromium (Cr) at 33% have contaminated the groundwater in the study area, making it unsuitable for human consumption and irrigation. The agricultural indices analysis results show groundwater quality ranging from very poor to unsuitable making it unsuitable and also affects crop productivity. Hazard index (HI) results infer that Cr and Cd severely contaminated the RIE's groundwater, encompassing 14 villages, making the groundwater unfit for drinking, domestic use, and irrigation. Hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) analysis revealed that 2 in 100 infants and 3 in 1000 people over the age of 63 are likely to develop cancer due to Cr and Cd in the REI. This is a need-of-the-hour problem, addressing this issue with preventive measures to ensure the protection of groundwater sources will lead to achieving the Sustainable Development Goal 6 (Clean Water and Sanitation).

Occurrence of forever chemicals in Chennai waters, India

BackgroundPer- and polyfluoroalkyl substances (PFAS) are considered ‘contaminants of emerging concern’ due to their environmental persistence, bio-accumulative potential, and adverse effects on human health. They are widely employed in producing various goods used in daily life, such as non-stick cookware, cleaning agents, and many industrial applications in aerospace, automotive, construction, electronics, and military, all of which ultimately end up in different environmental matrices. India’s rapid economic growth necessitates a comprehensive understanding of its PFAS contamination levels and potential human and ecological exposure.ResultsThe present study reports the quantification of one long-chain and two short-chain perfluoroalkyl acids and three long-chain and two short-chain perfluorosulfonic acids and qualitative analysis using suspect screening in the waters of Chennai, Tamil Nadu, India. Samples were collected from surface and groundwater sources, including the Adyar river, Buckingham canal, Chembarambakkam lake, and the water treatment plant. The concentrations analyzed in all the samples ranged from 0.10 ng/L to 136.27 ng/L. Groundwater had some of the highest concentrations of PFAS. L-PFBS (up to 136.27 ng/L) and PFOA (up to 77.61 ng/L) are present in all the samples. The concentrations of all the target PFAS increased in the 5 to 103% range in the final treated water compared to the raw water of the water treatment plant. This treated water is distributed as a source of drinking water for the residents of Chennai. Additionally, the dominance of short-chain compounds (4–7 carbons) over long-chain compounds (> 7 carbons) was observed. Suspect screening revealed numerous precursors and other fluorinated compounds abundantly present in the samples.ConclusionsOur study revealed PFAS levels up to 136.27 ng/L in both surface and groundwater samples from Chennai. These findings raise concerns about potential risks to ecosystems and human well-being. The dominance of short-chain PFAS coupled with abundant precursors and unidentified fluorinated compounds indicates an ongoing shift toward alternatives. Conventional water treatment is ineffective in eliminating these chemicals from the water system; rather, increasing the PFAS concentrations from raw water to treated water necessitates advanced polishing steps. Industrial emissions, untreated domestic wastewater discharge, and open dump sites have been suspected as the significant sources of contamination, highlighting the need for further investigation to fully assess the extent of PFAS contamination in Chennai.Graphical

Groundwater development and management constraints in drought prone Chiredzi and Zvishavane Districts, Zimbabwe

Communities in drought-prone areas continued to fall into new vulnerability traps due to increasing water demand and stress. The study assessed groundwater development and management constraints in the Chiredzi and Zvishavane districts of Zimbabwe. Groundwater development and management activities implemented in the study area were supported by the Government of Zimbabwe, development partners, humanitarian agencies, private sector corporate social responsibility, and individual households. Interpretivism and realism philosophical positionalities were employed in the study. Whilst interpretivism’s inductive approach enabled an in-depth qualitative methodology and understanding of the groundwater constraints, the direct realism provided quantitatively driven scientific and statistical data to answer the research questions exhaustively. Quantitative data was gathered through a household questionnaire administered to randomly selected respondents. Qualitative data was gathered using focus group discussions, key informant interviews, direct field observations and measurements. Respondents to the key informant interview were drawn from district-level government officials, local authorities, traditional leaders, village pump minders and water point committee members.Due to climate change, communities have experienced an increase in the decline in groundwater levels during the dry season evidenced by demand surpassing supply. Temperature increase and rainfall decline experienced by 97%, and 73% of respondents from Chiredzi and Zvishavane districts, respectively, resulted in increased withdrawal and reduced groundwater recharge. Participants revealed that groundwater withdrawal is on the increase while recharge is declining as evidenced by the increase in conflicts at waterpoints. The 85% coverage by low groundwater-yielding basement hydrogeological formation suggested a slight reduction in groundwater recharge due to reduced rainfall and increased community vulnerability to drought. Village Pump Minders and Water Point Committees experienced operational challenges that affected the maintenance of groundwater sources. This was mainly due to the incapacitation of local institutions in terms of financial resources, equipment, and skills. The study recommends a groundwater replenishment model to improve groundwater aquifer recharge. Strengthening of local institutions improves the management of groundwater using integrated water resources management (IWRM) framework that promotes coordination between competing uses.