Hydrogeochemical Investigation of Elevated Arsenic Based on Entropy Modeling, in the Aquifers of District Sanghar, Sindh, Pakistan

Arsenic (As) contamination in drinking groundwater is a common environmental problem in Pakistan. Therefore, sixty-one groundwater samples were collected from various groundwater sources in District Sanghar, Sindh province, Pakistan, to understand the geochemical behavior of elevated As in groundwater. Statistical summary showed the cations and anions abundance in decreasing order of Na+ > Ca2+ > Mg2+ > K+, and HCO3− > Cl− > SO42− > NO3−. Arsenic was found with low to high concentration levels ranging from 5 µg to 25 µg/L with a mean value of 12.9 µg/L. A major water type of groundwater samples was mixed with NaCl and CaHCO3 type, interpreting the hydrochemical behavior of rock–water interaction. Principal component analysis (PCA) showed the mixed anthropogenic and natural sources of contamination in the study area. Moreover, rock weathering and exchange of ions controlled the hydrochemistry. Chloro-alkaline indices revealed the dominance of the reverse ion exchange mechanism in the region. The entropy water quality index (EWQI) exposed that 17 samples represent poor water, and 11 samples are not suitable for drinking.

Integrated Geophysical and Hydrogeochemical Characterization and Assessment of Groundwater Studies in Adum West Area of Benue State,Nigeria

Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization. Subsurface geoelectric parameters such as resistivity and thickness obtained from geophysical method (Vertical Electrical Sounding VES) was used to determine aquifers vulnerability, longitudinal resistance (ρL) and transverse unit resistance (Rt). Thirty four water samples were collected from groundwater sources for physicochemical analysis.Estimated results from longitudinal conductance (S), (Rt) and (ρL) showed that the values ranges from 0.03 to 2.5mhos, 103.64 to 1964417.8 Ω/m2 and 215.41 to 65731.68 Ω-m respectively. Result from S suggested that 50 % of groundwater is considered to be vulnerable to contamination from the earth surface, while the remaining 50 % is considered to be slightly vulnerable to surface contamination. Further findings obtained from hydrogeochemical analysis such as Gibb’s and Chadba plots revealed that groundwater is highly influenced by rock water interaction,groundwater is classified to be Na+ + HCO3¯, Ca2+ + Mg2++ HCO3¯ , Na+ + Cl¯ and Ca2+ + Mg2+ + Cl¯ water type. Deduction from Soltan classification suggested that groundwater is classified to be of Na+ ˗ HCO3¯ and Na+ ˗ SO4 2¯ water type. Results obtained from Ec and pH suggested that the values were below WHO permissible limit, while result obtained from TDS showed that at some sampling points TDS values were above WHO limit. Based on pH value obtained groundwater within the study area fell within slightly basic to acidic.

Use of GIS in Hydrogeochemical Study and Quality Status From Pudukkottai District, Tamil Nadu, India

This study focused on hydrogeochemical characterisation and groundwater quality deterioration based on drinking, irrigation purposes in Pudukottai district. Eighty-seven groundwater samples were collected from the bore and dug wells during pre and post monsoon seasons in the year 2019. The order of mean abundance of ions is followed as C l > HCO3 > Na > SO4 > Mg > Ca > K (325.5 > 182.2 > 181.4 > 83.2 > 51.1 > 35.8> 9.1 > 8.6 > o.9 > 0.3) and Cl > Na > HCO3 > SO4 > Mg > Ca > K (415.7 > 230.3 > 198.2 > 82.9 > 53.8 > 43.4 > 14.9) in both seasons. Analytical results are used in Piper, Gibbs, Na% vs. EC, USSL, and PI to evaluate the hydrogeochemical processes. Rock water interaction and evaporation processes causing variations in hydrogeochemistry of the study area during pre and postmonsoon. Nearly 15 % of the groundwater samples were not permissible for drinking based on the standard, which is distributed in south eastern region of the study area. It is revealed from Na%, SAR, RSC, MgC and KR results that majority of the groundwater samples are fit for irrigation uses. The higher concentration of EC, TDS, Cl and Na values noted in south region due to the sea water intrusion that attributed by excess pumping in the coastal regions. The drinking water quality index (DWQI) and irrigation water quality index (IRWQI) are calculated to identify the suitability of groundwater for drinking and irrigation purposes. However, this research concludes that the groundwater quality of maximum part in the district is appropriate for drinking as well as agriculture which can be used for the sustainable growth. It is also recommended implementing the artificial recharge techniques to improve the groundwater quality.

A Review of Water Resources in Delta State, Nigeria With Emphasis on Hydrogeochemical and Microbial Assessment

This research presents a review on water resources in Delta state, southern part of Nigeria, with emphasis on hydrogeochemical and microbial assessment. It also evaluate factors responsible for water contamination, and their resulting health problems within the study area. To achieve the objective of this study, related articles were downloaded from Google, published article on influence of hydrogeochemical and microbial activities on water resources, these articles were thoroughly studied. Findings from this study revealed that groundwater was more studied than surface water. It was observed that groundwater within the riverine communities are much more prone to pollution when compared to groundwater in upland area. From reviewed article, it was observed that, larger percentage of groundwater showed presence of coliform. Study from reviewed article further suggested that hydrogeochemical processes such as rock water interaction, saltwater intrusion and precipitation influences groundwater quality within the study area especially within Sombreiro-Warri Deltaic Plain Deposit.

Hydrogeochemical Features and Genesis of Confined Groundwater and Health Perspectives for Sustainable Development in Urban Hengshui, North China Plain

Groundwater in confined aquifers is the preferred water resource worldwide, and its hydrochemical quality is the premise for sustainable development. A systematic hydrogeochemical research was conducted to get insight into the hydrochemical characteristics, genesis, and potential health threats of confined groundwater, based on analytical data of 45 groundwater samples collected from the urban area of Hengshui, Central North China Plain (NCP). The results showed most groundwater had desirable hydrochemical quality with a nearly neutral to slightly alkaline nature and dominantly soft-fresh Cl-Na face. Solute chemistry was governed by rock-water interaction including minerals dissolution and ion exchange, but out of the anthropogenic influences. All nitrogen pollutants and Zn were within the desirable limit, while F−, Mn, and Fe were beyond the desirable limit recommended by WHO in 28.9%, 15.6%, and 68.9% of samples. Overall chronic health risk from these toxic elements was identified in terms of various populations and mainly contributed by F−. Infants were more prone to the health risks of aqueous pollutants. Differential water supplies based on hydrochemical quality are recommended, and water improvement measures are suggested to be conducted aiming at the harmful fluoride in confined groundwater. The present research could provide valuable references for the health sustainability of confined groundwater utilization in sedimentary plains like NCP worldwide.

Study of water salinity in the Chtouka plain (Morocco) using TEM geophysical method, chemical and isotopes tracers

<p>The Chtouka plain in Morocco suffers from groundwater overexploitation and a significant increase in water salinity. In this study, a multidisciplinary approach combining water chemistry, stable isotopes of water (18O, 2H) and Transient Electromagnetic (TEM) method was used. The main objective was to identify the water salinity sources and the extension of the marine intrusion. Water samples were collected from wells and boreholes, springs, the Massa river and the main source of freshwater in the region, the Youssef Ibn Tachfine Dam. Geophysical (TEM) measurements (12 profiles comprising 83 measurement points) were carried out along the coastal zone and around the northern bank of the Massa river. The results show a spatial variability of water salinity, indicating rock-water interaction, seawater intrusion and anthropogenic influence. The interpretation of the TEM soundings allow to draw the front line of the marine intrusion in the aquifer. The results, compared to previous numerical simulations, show a significant progress of the marine intrusion into the coastal aquifer. The intrusion indeed reaches a distance of 2.5 km from the coast, far beyond models’ predictions. The local water authorities can use these results to improve their monitoring network and better assess the progress of the seawater intrusion.<br>Keywords: Water salinity, TEM geophysical method, chemical and isotopes tracers, marine intrusion</p>

Statistical analysis of hydrochemistry and isotopic characterization of groundwater from the Parecis Basin

ABSTRACT Knowledge of mechanism controlling the hydrochemistry of groundwater are crucial requirement to understand the hydrochemical evolution and evaluate the water quality of subsurficial water resources. Thus, to understand the process governing the hydrochemistry variability and flow dynamics of the Parecis and Ronuro Aquifers, the use of statistical analysis and isotopic characterization were combined. In the correlation matrix it was found that the highest correlation coefficient was observed for HCO3-, Ca2+, Mg2+, Sr2+, SO42-, and F-, which suggested that these parameters are derived from the same source, most likely from rock–water interactions. Additionally, we noticed moderate to high correlation among NO3-, Cl-, Na+, K+, and Ba2+, which collectively are indicative of domestic sewage contamination. Finally, a principal component analysis (PCA) identified that the most variance in hydrochemistry from the evaluated samples was controlled by HCO3-, Ca2+ and Mg2+, which is associated with rock–water interaction. Regarding the 18O and 2H isotope values, it could be observed that the aquifer recharges were of meteoric origin and that the Ronuro Aquifer samples were more enriched than the PAS samples. This work reinforces the capability of multivariate statistics to discern the main process that controls the variability of groundwater hydrochemistry.

Assessment of Groundwater Quality in parts of Jalna district of Maharashtra, India using Water Quality Index

In the present study, fifty-five groundwater samples were collected from the parts of the Jalna district of Maharashtra, India. The water samples were analyzed to determine various physic-chemical parameters like pH, electrical conductivity, total dissolved solids, total hardness, alkalinity, chloride, sulphate, calcium, magnesium, sodium and potassium. The groundwater’s geochemical control and hydrogeochemistry were evaluated using the Piper plots and water quality index (WQI). The hydrochemical analysis reveals that the groundwater is predominantly of CaNaHCO3 type, Water quality index (WQI) indicates that 33% and 2% of groundwater samples fall in poor and very poor categories for drinking purposes. This study reveals that groundwater quality is unfit for drinking purposes at a few places. The effective leaching, dissolution process and rock-water interaction process are the main sources for degrading the groundwater quality.

Deep Groundwater Recharge Mechanism in the Sedimentary and Crystalline Terrains of Sri Lanka: A Study Based on Environmental Isotopic and Chemical Signatures of Spring Water

In many instances, dynamic, potential status and geochemical characteristics of groundwater discharging through natural springs are not well known. Present study has assessed the deep groundwater in the form of thermal and non-thermal spring in artesian condition in the selected zones in Sri Lanka, using isotope and geochemical characteristics. The results revealed that evaporation-fractional crystallization and cation-exchange in the sedimentary aquifers while rock-water interaction in crystalline deep aquifers, are the significant mechanism that control the groundwater chemistry. All the deep groundwater recharged from meteoric water at different elevations and further influenced by either evaporation or rock-water interaction during the subsurface flow. Artesian aquifers in the sedimentary terrain in the north-western coastal zones showed the recharging elevation as from 100 to 200 m amsl. They are not mixed with sea water and slightly impacted by the locally evaporated surface waters. Almost all these waters are comparatively old; indicating slow movement along the regional flow paths. Considering the recharge and discharge conditions of artesian non-thermal waters in the Southern lowlands of crystalline terrain can be classified as non-mixed, non-evaporated and young groundwater with higher elevation recharge. The artesian non-thermal waters in the East North Central lowlands, have shown the same characteristics but with evaporated conditions. All artesian thermal waters are tritium free, hence they are older and deep percolated. Intensive rock-water interaction and higher altitude origin were observed in some thermal springs. Some spring clusters in the weathered overburden have shown significant mixing with recent local rains. Non-mixed, non-evaporated and less rock-water interacted nature is a significant in two thermal springs that emerges through (chemically inert) quartzite bed rock. Both thermal and non-thermal water with artesian condition have clearly indicated that they are originated from a common recharge source but with different flow paths in different penetration depths and travel distances, resulting different chemical characteristics. Fresh water springs are mostly young and recharged from local rains followed with shallow percolation.

Assessment of Groundwater Geochemistry of Vel River basin, Western Maharashtra, India

To study the chemistry of major ion in groundwater from Vel (Velu) River basin, sixty (60) samples of dug wells and bore wells were collected and analyzed using standard techniques given by APHA. It shows order of dominance for cations, Na+ > Ca2+ > Mg2+ > K+ and in anionic concentration as HCO3- > Cl- > SO42- in groundwater. The pH of groundwater is slightly alkaline (range: pH 7.0 - 8.1), while average values of Electrical Conductivity (EC) is about 2641 µS/cm indicating high mineralization of groundwater. In general, the cationic concentration (Na+, K+, Ca2+ and Mg2+) of the groundwater increase in the downstream side (from Northwest to South east), suggesting geological control on the composition of groundwater while highest concentration is in lower part of the basin are generally associated with the high salinity. In the major anions, bicarbonate (HCO3-) is higher due to rock-water interaction. Average value of chloride is about of 235 mg/L due to discharge zones along with anthropogenic activities. The geochemical data plotted on Piper Trilinear Diagram is showing dominant hydro-chemical facies: Ca2++Mg2+, Na++ K+, Cl-+ SO42- -HCO3- found in 83.3 % samples indicating the alkaline earth exceeding the alkalis and the strong acids exceeds the weak acids. The pH, Total Hardness (TH) and Magnesium (Mg2+) of the samples show more proportion of samples falling above desirable limit. Otherwise the quality of groundwater is good for drinking. The irrigation indices like SAR, KR and SSP were considered to evaluate groundwater suitability for irrigation. Comparing with SAR parameter all samples are excellent to good for irrigation. In SSP, 33.3 % samples are within permissible, while 66.6% samples are doubtful for irrigation purpose. In KR almost all samples (excluding 04 samples in lower side of basin) are suitable for irrigation. So, variations in climate, geology with anthropogenic activities are modifying the groundwater geochemistry of Vel River Basin.