Groundwater quality in high-sulfur coal mining region of India: Spatial distribution, source control, and health risk assessment.

The groundwater quality in the vicinity of the Makum coalfield, renowned for its high-sulfur coal deposits, was investigated. The oxidation of sulfur in the coal generates acid mine drainage (AMD), a global environmental challenge that contaminates natural resources. The region's high sulfur coal content intensifies AMD formation, necessitating a comprehensive assessment of its impact on human health and the environment. This study analyzes the water quality parameters such as pH, EC, TDS, Na+, Ca+2, Mg+2, K+, HCO3-, SO4-2, F-, Cl -, and NO3- in groundwater, findings concerning low pH levels (5.8) and fluoride concentration (0.15 mg/L) compared to standards. Groundwater chemistry was analyzed to identify the sources controlling water composition through Gibbs diagrams, Piper diagrams, and saturation indices. The Gibbs diagram shows that rock weathering is the crucial factor controlling groundwater chemistry, while the Piper diagram indicates Ca-Cl as the Principal water type. Additionally, an in-depth analysis of groundwater chemistry reveals that carbonate dissolution primarily occurs due to minerals like calcite, dolomite, and gypsum, findings supported by saturation indices. The present study yielded an average water quality index of 40.19, indicating excellent to good water quality in 51 out of 52 samples analyzed. The average hazard index values for adults and children were 0.60 and 0.58, respectively, indicating that 49 of 52 samples pose negative non-carcinogenic risks associated with nitrate and fluoride contamination. The irrigation indices, graphical representations such as the Wilcox and Doneen classification, and the USSL diagram elucidate the suitability for irrigation purposes. Moreover, the Principal Component Analysis identified the sources of ions as originating from geogenic processes and mining activities. The study stresses environmental assessments, health risk management, and sustainable practices for groundwater in high-sulfur coal mining areas.

Hydrogeochemical characterization and evaluation of groundwater quality in Kangayam taluk, Tirupur district, Tamil Nadu, India, using GIS techniques.

The main objective of the present study is to evaluate the hydrogeochemical characteristics of groundwater and its suitability for drinking water supply in Kangayam taluk, Tirupur district, Tamil Nadu, India. To achieve this objective, seventy-eight groundwater samples were collected from the wells spread over the study area during December 2016. The collected groundwater samples were tested in the laboratory for various hydrogeochemical parameters such as hydrogen ion concentration (pH), electrical conductivity, total dissolved solids, total hardness, calcium, magnesium, sodium, potassium, chloride, bicarbonate, carbonate, nitrate, sulphate and fluoride. The analytical results were compared with WHO drinking water standards to assess the suitability of groundwater for drinking purposes. To understand the spatial variation of hydrogeochemical parameters over the study area, choropleth (zonation) maps were prepared using geographical information system (GIS). Overall groundwater quality zones were demarcated by overlaying and integrating all the spatial plots using GIS. Three groundwater quality zones such as (1) most desirable, (2) maximum allowable and (3) not permissible were demarcated based on the limits prescribed by the WHO for drinking purposes. This study indicates that 49% of the study area does not possess potable groundwater. About 21% of the area represents "most desirable" category, and the remaining 30% area represents "maximum allowable" category for drinking purposes. The Piper's trilinear diagram indicates that groundwater of this region is Mixed CaMgCl type. As the groundwater quality is poor nearly 49% of the total area, it is necessary to go for treatment before drinking water supply. It is also essential to recharge the aquifer artificially to improve the quantity and quality of groundwater.

GIS based geostatistical modelling and trends analysis of groundwater quality for suitable uses in Dhaka division.

Preserving the quality of groundwater has become Bangladesh's primary challenge in recent years. This study explores temporal trend variations in groundwater quality on a broader scale across 18 stations within the Dhaka division over 35 years. The data set encompasses an analysis of 15 distinct water quality parameters. Modified Mann-Kendal, Sens Slope and Mann-Kendal tests were performed to determine the trend's variation and slope. In addition, the spatial-temporal changes in the quality of groundwater are studied through Geographic Information System (GIS) mapping and Piper diagram was applied to identify the unique hydrochemical properties. This is the first study conducted on this area using various trends analysis and no in-depth study is available highlighting the trends analysis of groundwater quality on a larger magnitude. In contrast, the correlation matrix reveals a high association between Mg2+ and SO42-, Na+ and Cl- that affects salinity and overall hardness at the majority of sites. The Piper diagram also demonstrates that the groundwater in Madaripur Sadar has major salinity issues. The analysis reveals a distinctive dominance of bicarbonate (HCO3-) ions across all sampling stations, with (HCO3-) equivalent fractions consistently ranging from 0.70 to 0.99 which can cause a significant impact on groundwater uses. This extensive analysis of long-term groundwater quality trends in the Dhaka Division enables researchers to comprehend the overall transition of groundwater quality for hardness related complications in future. Moreover, it can be a baseline study considering the valuable implications and future steps for sustainable water resource management in this region.

Application of fuzzy C-means clustering and fuzzy EDAS to assess groundwater irrigation suitability and prioritization for agricultural development in a complex hydrogeological basin.

The current research is focused on detecting a river basin suitable for agriculture and priority for management using a new clustering tool of groundwater quality with fuzzy logic technique in R and Geographical Information System. A new fuzzy clustering-soft computing technique has been executed to determine the different hydrochemical zones considering 13 essential parameters such as electrical conductivity, hardness, chloride, sodium adsorption ratio, residual sodium carbonate, soluble sodium percent, magnesium hazard, permeability index, potential salinity, residual sodium bicarbonate, Kelly's ratio, synthetic harmful coefficient, and exchangeable sodium percentage. The derived fuzzy C-mean clustering (FCM) outperformed other available hard computing techniques like hierarchical clustering, K-means clustering, and agglomerative clustering. It divided the sampling sites into 2 clustering groups (FCM I and FCM II) which has been validated using fuzzy silhouette index (0.85), the partition coefficient (0.76), the partial entropy (0.68), and the modified partition coefficient (0.52). The hydrogeochemical analysis confirmed that the rock-water interaction, chemical weathering, and ion exchange process are predominant in the aquifer system of the study area. According to the correlation plots, the studied groundwater samples largely evolved from [Formula: see text], mixed [Formula: see text] types, and [Formula: see text] types. The spatial distribution map and the hydrochemical analysis also gives a clear depiction of the fluoride (> 1.0 mg/l) and high iron (> 0.3 mg/l) contamination in groundwater quality, making it unsuitable for both drinking and irrigation. A fuzzy EDAS priority map has been prepared based on all the irrigation suitability parameters which concludes that the groundwater at the upstream and downstream section of the basin requires the most attention. Based on the highest priority for management, five zones have been delineated: very high (5.98%), high (22.31%), medium (16.39%), low (32.30%), and very low (23.02). The findings of this study will be beneficial to planners and policymakers as they can develop schemes to solve similar problems across the country.

[Source Analysis and Composition Characteristics of Water-soluble Ions During Spring Festival in Ningbo].

Water-soluble ions and some trace gases during the Spring Festival in Ningbo were observed using an ion online gas composition and aerosol monitoring system. Combined with meteorological elements data, the source analysis and composition characteristics of water-soluble ions and trace gases were analyzed. The average concentration of ρ(PM2.5) during the observation period was 33.1 µg·m-3, and there was light pollution. The order of concentration of water-soluble ions was NO3->SO42->NH4+>K+>Cl->Na+>Ca2+>Mg2+. The secondary inorganic ions ρ(NO3-), ρ(SO42-), and ρ(NH4+) were the most water-soluble ions, which were 12.5, 10.5, and 7.2 µg·m-3, respectively. According to the PMF source analysis, firecracker combustion, secondary generation (background, industrial source), and dust sources were the major sources of fine particles during the observation period, and their contribution rates of PM2.5 were 21.9%, 64.5%, and 13.6%, respectively. When the secondary generation was the main pollution, NH4+ accounted for 92.2% of the cations. When firecracker combustion was the main pollution from New Year's Eve to the second day, the proportion of K+ions significantly increased. Dust sources were affected by regional transport from the northwest direction. When the dust source was the main pollution, the proportion of K++Ca2+and Na++Mg2+ increased.

[Chemical Characteristics and Causes of Groups Water in Niangziguan Spring].

Discharge in Niangziguan Spring is 7.19 m3·s-1, which is the main water supply source for Yangquan City and Pingding County. Every year, Yangquan municipal government take water from the mouth of Niangziguan Spring to supply drinking water to urban residents at a rate of approximately 1.7 m3·s-1. It is of great significance to determine the characteristics and causes of variations in spring water flow conditions for the appropriate utilization of water resources and pollution prevention. Here, sample collection and hydrochemical isotope analyses were undertaken for the Niangziguan Spring area to chemically characterize the water environment and genesis. The pH of the karst spring is 7.2-7.5 with an average of 7.36; the calcium content of the water is 112.1-135.2 mg·L-1 with a mean value of 131.4 mg·L-1; the concentration of magnesium ions is 34.8-42.3 mg·L-1 with an average of 40.8 mg·L-1; the concentration of K++Na- ions is 41.6-46.7 mg·L-1 with an average of 45.2 mg·L-1; and the sulfate ion concentration is 185.6-271.8 mg·L-1 with a mean value of 255.4 mg·L-1. The hydrochemical type of the aquifer is classified as HCO3·SO4-Ca·Mg. The spring water is characterized by high Ca2+, Mg2+, and SO42- concentrations, and low Na+, K+, and Cl- concentrations. The supply path of Chengxi Spring is shortest followed by Wulong Spring. The supply paths of the remaining five spring are much longer. The Niangziguan Spring water environment is characterized by increasing pollution from coal mine acid drainage alongside decreasing inputs from domestic sewage. Environmental isotope tracing shows that sulfate in Chengxi Spring mainly derives from precipitation and gypsum dissolution, and the concentrations of sulfate in Wulong Spring are increasing. These changes are mainly driven by the amount of coal mine acid water pollution in the area.

The characteristics and mixing states of PM2.5 during a winter dust storm in Ningbo of the Yangtze River Delta, China.

Dust particulates play an essential role for the nucleation, hygroscopicity and also contribute to aerosol mass. We investigated the chemical composition, size distribution and mixing states of PM2.5 using a single-particle aerosol mass spectrometer (SPAMS), Monitor for AeRosols and Gases (MARGA), and off-line membrane sampling from 2018.1.24 to 2018.2.20 at a coastal supersite in Ningbo, a port city in Yangtze River Delta, China. During the study campaign, the eastern part of China had experienced a wide range of cooling, sandstorm, and snowfall processes. The entire sampling campaign was categorized into five sub-periods based on the levels of PM2.5 and the ratios of PM2.5/PM10, namely clean (T1), heavy pollution (T2), light pollution (T3), dust (sandstorm) (T4) and cleaning pollution (T5) period. After comparing the average mass spectrum for each period, it shows that the primary ions, such as Ca2+and SiO3-, rarely coexist with each other within a single particle, but secondary ions generally coexist with these primary ions. Furthermore, the coexistence of each two different ions within a particle does not show distinct variation for the whole study periods. All these suggest that the absorption and partitioning of gaseous contaminants into the surface of primary aerosol through heterogeneous reactions are the major pathways of aging and growth of aerosol; and the merging of particles through collisions usually is insignificant. Although the absolute concentrations of nitrate and sulfate all increased with the PM2.5 concentrations, the relative equivalent concentrations of NO3- and SO42- displayed opposite trends; the relative contribution of sulfate decreased and that of nitrate increased as the increase of pollution. During the dust period, the relative equivalent concentrations of calcium and/or potassium ions in PM2.5 are significantly higher. This study provided deep insights about the mixing states and characteristics of particulate after long-range transport and a visualization tool for aerosol study.

Human health risk assessment of some bottled waters from Romania.

The paper presents the quality status of 14 brands of bottled water, with sources of groundwaters from different mountain areas alongside the Carpathian Mountains from Romania. A number of 12 physico-chemical parameters (ammonium, bicarbonate, electrical conductivity, carbonate, chemical oxygen demand, chloride, nitrate, nitrite, pH, sulphate, total hardness, turbidity), 9 metals and metalloids (Li, B, Na, Mg, Al, K, Ca, Sr, Ba) and 17 heavy metals (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Mo, Ag, Cd, In, Tl, Pb, Bi) were determined and studied. The quality status, the potential contamination and the health risk assessment of bottled waters were assessed, by using the drinking water quality index, the heavy metal pollution index, the heavy metal evaluation index, the degree of contamination and the human health risk indices. Hierarchical cluster analysis was applied, indicating similarities among the studied bottled waters based on their metal content. The Piper diagram reveals that the majority of bottled water samples fall into the Ca, Mg, Na, K, Cl-, SO42-, CO32-, HCO3- categories. The quality of bottled waters based on the indices results indicated marginal, poor and very-poor quality status of the studied water samples, while the health risk assessment indices presented potential risks at aluminium, chloride and nitrate for the inhabitants who used those water samples with the purpose of drinking. The pollution indices with respect to metals generally reflected a low pollution status. This study represents the first attempt in assessing the overall quality of some bottled water collected from the mountain area, Romania, likewise assessing the comprehensive human health risk due to several chemical elements determined in water in amounts around and exceeding the maximum allowable concentrations. This research can be useful for development of potential strategies for risk control and management in the field of drinking water.

Geospatial Distributions of Groundwater Quality in Gedaref State Using Geographic Information System (GIS) and Drinking Water Quality Index (DWQI).

The observation of groundwater quality elements is essential for understanding the classification and distribution of drinking water. Geographic Information System (GIS) and remote sensing (RS), are intensive tools for the performance and analysis of spatial datum associated with groundwater sources control. In this study, groundwater quality parameters were observed in three different aquifers including: sandstone, alluvium and basalt. These aquifers are the primary source of national drinking water and partly for agricultural activity in El Faw, El Raha (Fw-Rh), El Qalabat and El Quresha (Qa-Qu) localities in the southern part of Gedaref State in eastern Sudan. The aquifers have been overworked intensively as the main source of indigenous water supply in the study area. The interpolation methods were used to demonstrate the facies pattern and Drinking Water Quality Index (DWQI) of the groundwater in the research area. The GIS interpolation tool was used to obtain the spatial distribution of groundwater quality parameters and DWQI in the area. Forty samples were assembled and investigated for the analysis of major cations and anions. The groundwater in this research is controlled by sodium and bicarbonate ions that defined the composition of the water type to be Na HCO3. However, from the plots of piper diagram; the samples result revealed (40%) Na-Mg-HCO3 and (35%) Na-HCO3 water types. The outcome of the analysis reveals that several groundwater samples have been found to be suitable for drinking purposes in Fa-Rh and Qa-Qu areas.

[Hydrochemical Characteristics of Groundwater and the Origin in Alluvial-proluvial Fan of Qinhe River].

To study the hydrochemical characteristics of groundwater and the factors controlling the alluvial-proluvial fan of the Qinhe River, 60 samples were collected including 9 surface water samples and 51 groundwater samples. The distribution characteristics of the hydrochemistry and major controlling factors of hydrochemical evolution processes of surface water and groundwater in the study area were analyzed by using mathematical statistics, the Schakerev classification, Piper diagrams, Schoeller diagrams, Gibbs plots, and ion ratios. The results show that:① the major anions and cations of surface water and groundwater in the study area are Ca2+, Mg2+, SO42-, and HCO3-. The recharge sources of surface water and groundwater are closely related; ② the major hydrochemical types of the groundwater are HCO3-Ca, HCO3-Ca·Mg, and HCO3·SO4-Ca·Mg, while the major hydrochemical type of surface water is HCO3·SO4-Ca·Mg; and ③ the major ions of surface water and groundwater are affected by carbonate mineral weathering and dissolution, ion exchange, and evaporation. Sulfuric acid and carbonic acid were involved in carbonate mineral weathering and dissolution.

Factors controlling groundwater quality in the Yeonjegu District of Busan City, Korea, using the hydrogeochemical processes and fuzzy GIS.

The hydrogeochemical processes and fuzzy GIS techniques were used to evaluate the groundwater quality in the Yeonjegu district of Busan Metropolitan City, Korea. The highest concentrations of major ions were mainly related to the local geology. The seawater intrusion into the river water and municipal contaminants were secondary contamination sources of groundwater in the study area. Factor analysis represented the contamination sources of the mineral dissolution of the host rocks and domestic influences. The Gibbs plot exhibited that the major ions were derived from the rock weathering condition. Piper's trilinear diagram showed that the groundwater quality was classified into five types of CaHCO3, NaHCO3, NaCl, CaCl2, and CaSO4 types in that order. The ionic relationship and the saturation mineral index of the ions indicated that the evaporation, dissolution, and precipitation processes controlled the groundwater chemistry. The fuzzy GIS map showed that highly contaminated groundwater occurred in the northeastern and the central parts and that the groundwater of medium quality appeared in most parts of the study area. It suggested that the groundwater quality of the study area was influenced by local geology, seawater intrusion, and municipal contaminants. This research clearly demonstrated that the geochemical analyses and fuzzy GIS method were very useful to identify the contaminant sources and the location of good groundwater quality.

Caracterização hidrogeoquímica de águas subterrâneas utilizadas para abastecimento público na porção nordeste do Sistema Aquífero Guarani / Hydrogeochemical characterization of groundwater for public supply in the Northeastern portion of the Guarani Aquifer System

RESUMO O Sistema Aquífero Guarani (SAG) compreende um dos mais importantes aquíferos do mundo, tanto pela grande reserva quanto pela qualidade de suas águas subterrâneas. Entretanto, nem todas as regiões, nas quais o SAG é utilizado no abastecimento público, possuem estudos a respeito do quimismo de suas águas e de sua associação com a geologia. Este trabalho apresenta a caracterização hidrogeoquímica das águas subterrâneas do SAG utilizadas no abastecimento público em São Carlos, São Paulo, região nordeste do SAG, por meio de amostras provenientes de 27 poços tubulares profundos. A captação de água subterrânea é proveniente principalmente do SAG. Entretanto, também é possível verificar a presença das formações Botucatu, Piramboia, Serra Geral, Itaqueri, Adamantina e sedimentos cenozoicos. Apesar de pouco mineralizadas, verifica-se variabilidade iônica na composição das águas subterrâneas, evidenciada na distribuição espacial da condutividade elétrica na área de estudo. Os resultados hidroquímicos apontam para a existência de quatro fácies hidroquímicas: bicarbonatadas mistas, bicarbonatadas cálcicas, bicarbonatadas sódicas e sódica fluoretada, em ordem decrescente de representatividade. A heterogeneidade geológica interfere na concentração de íons na água, por meio da dissolução mineral, e possibilita a mistura das águas subterrâneas. A análise de componentes principais constatou que 62,7% da variabilidade total do conjunto amostral é explicada, principalmente, por dois fatores. O primeiro grupo de variáveis representa 38,7% da variabilidade, atribuída principalmente aos íons provenientes da dissolução de minerais (HCO3−, Ca2+, Na+, Mg2+) e aos parâmetros relacionados a esse processo (pH e condutividade elétrica). O segundo revelou 24% da variabilidade total, que pode estar associado a origens antrópicas, como a presença dos íons Cl−, N-NO3−, SO42-, F− e K+.

ABSTRACT The Guarani Aquifer System (GAS) comprises one of the most important aquifers in the world due to its large water reserve and its groundwater quality. However, some regions that comprise the GAS groundwater for human supply are not thoroughly characterized on water chemistry and its relation with the local geology. This work presents the hydrogeochemical characterization of groundwater from the northeast region of the GAS used for human public supply in São Carlos (São Paulo, Brazil) based on samples from 27 deep boreholes. The groundwater exploration occurs mainly from GAS. However, it is also possible to verify the presence of the Botucatu, Piramboia, Serra Geral, Itaqueri, Adamantina, and Cenozoic sediments. Although little mineralized, there is a large ionic variability in the groundwater composition, also evidenced by spatial distribution of the electrical conductivity in the research area. These results explain four hydrochemical water types: mixed bicarbonate; calcium bicarbonate; sodium bicarbonate; and sodium fluoride, in decreasing order of representativeness. The concentration of ions in groundwater reflects the geological heterogeneity, through mineral dissolution and possible groundwater mixing. A Principal Component Analysis demonstrated that 62.7% of the total sample set variability is explained by two main factors. The first one represents 38.7% of the variability; mainly attributed to ions from minerals dissolution (HCO3−, Ca2+, Na+, Mg2+) and parameters related to this process (pH and electrical conductivity). The second group showed 24.0% of the total variability, which may be associated with anthropic activities origins, such as the presence of Cl−, N-NO3−, SO42-, F−, and K+.