The drinking of contaminated water is potentially hazardous to the well-being of humanity. Effective groundwater management depends on detecting groundwater contamination before it hits a critical ...point. The DRASTIC framework, modified globally to include land use (L), is utilized to evaluate groundwater vulnerability in various regions. In this study, an assessment of groundwater's susceptibility to contamination and a water quality index map to determine its fitness for Edo State have been done using the DRASTIC, DRASTIC-AHP, and DRASTIC-L-AHP models. The distinction of potential-risk water zones in Edo State, Nigeria, was made possible by the GIS that was used to create and combine several attribute maps. Results established that in the study area, very low (1,741.683 km2; 45%), low (1,741.683 km2; 10%), moderate (3,483.366 km2; 20%), and high (4,354.2075 km2; 25%) risk zones of groundwater contamination were identified on the overall DRASTIC-L-AHP map. The study found a significant pollution risk in one-fourth of the area, primarily in the Edo north and south regions of the study area. The significance of each factor for groundwater susceptibility and contamination risk was evaluated through a sensitivity analysis (SA). The SA indicated that the impact of the vadose zone is the most efficient variable in the DRASTIC-L-AHP model, with an effective weight value of 33.45% that is much larger than the theoretical value of 21.51%. The DRASTIC-L-AHP model, validated through hydrochemical analysis, is the least inaccurate and suitable for the current study area, serving as a useful pre-decisional tool for managing and preserving groundwater.
•It is critical to assess groundwater risk based on land use intensification.•For an area with profound agriculture, the DRASTIC-L approach is essential.•Observed data gathered from boreholes in various zones was used to corroborate the results.•A mechanism for establishing priorities regarding the management of water in communities.
Dehdan village lies downstream of Hattar Industrial Estate (HIE) that dumps industrial effluents into the nearby stream in Haripur Basin, Pakistan. In this paper, an integrated methodology such as ...borehole drilling, 1D and 2D geoelectrical measurements and hydrochemical anaylysis is suggested for assessing groundwater dynamics of the Dhedan area. A total of six boreholes were drilled to analyze aquifer sediments and to establish regional water table within the study area. Geoelectrical investigation emerges as an effective complementary technique that improved the data coverage and reduces the cost of borehole drilling, especially in the developing country. The geoelectrical datasets that consist of 1D and 2D sounding sites were acquired using the composite Wenner-Schlumberger configuration across the study area. The 1D-vertical electrical sounding (VES) data is utilized to infer subsurface rocks and to estimate hydraulic conductivity (S). The 2D-electrical resistivity tomographs (ERTs) each about 300 m long were also acquired across the highly contaminated Dehdan stream. Physicochemical and heavy metal analyses of twenty-three water samples collected from the stream water and the aquifer sediments were carried out to suggest potable water-quality in the region. A good correlation between the 1D resistivity data and borehole logs is established to investigate subsurface rocks down to 175 m depth. The results show presence of a shallow aquifer unit at about 17 m thick and relatively a deep aquifer layer at about 50 m depth. The hydraulic conductivity (S) identified moderate to good protective zones for contamination. The ERTs imaged contaminated highly conductive layer overlain by relatively resistive layers. Resistivity value for the highly conductive zone, about 25 m thick, is <11 Ωm. The ERT shows a localized shallow aquifer unit that is recharged by the contaminated stream water especially during rainy seasons. The 3D model based on the ERTs demonstrates that the resistivities within the low-resistivity anomaly remain unchanged and gradually increased downward. It was considered that these spatial changes in resistivities were related to dilution of stream highly-contaminated water with shallow aquifer sediments and the contamination migration downward to next aquifer unit across the stream. The hydrochemical analysis shows that four out of six analysed samples were highly polluted and the contamination level decreased at greater depths and as distance from the highly contaminated stream increases. A semi-confined to confined aquifer unit present at about 50 m depth contains relatively good quality water. This aquifer unit is highly encouraged for groundwater exploitation for human consumption.
•An integrated approach to assess groundwater contamination, attributed to effluents of the Hattar Industrial Estate.•Borehole logs and geoelectrical data delineated groundwater aquifer units.•2D ERT tomographs imaged contaminated aquifer unit.•Physiochemical and elemental analysis of water samples suggest majority samples are highly polluted.
•High SNR induced polarization data successfully locate landfill leachate plume.•Strong IP signals from infrastructures is captured in conductive leachate plume.•Integrated data improves the spatial ...resolution of leachate plume.
Landfills have been identified as a significant concern to the surrounding surface and groundwater ecosystem because of the discharge of leachate. To tackle the uncertain localization of the contamination plume due to low sampling densities, a combination of hydrochemical analysis and induced polarization survey (IP) is employed to characterize the leachate in a municipal landfill. The polarization effect in the contaminated area is significantly higher than expected for landfill sites, but relatively low chargeability zones (<100 mV/V) indicating the distribution of leachate are observed inside high conductivity (>600 mS/m) areas. With reliable geophysical results confirmed by similar formation factors from both field and laboratory data, the abnormal high polarization effect is influenced by installed steel sheet piles next to the survey cable. In addition, we successfully identify linear relationship between the geophysical responses and dominant inorganic conservative compounds (Cl- and Na+) from the leachate plume. The gentle variations of borehole chemical parameters show that the plume is not affected by a continuous contamination source any more, indicating that the steel sheet pile effectively cut off the contamination from the leachate tanks. In conclusion, the integration of IP and hydrochemical data is an excellent way to locate contaminated zones and monitor the behaviors of leachate plume in the landfill.
Groundwater in the Rania basin, Iraqi Kurdistan region, has been under intensive exploitation in the last two decades, where quantity and quality are both affected. Hence, any attempt to protect the ...aquifers has become an urgent need. Saruchawa, Qulai Rania, and Qulai Kanimaran are the three large springs, among dozens of others in the area, that are heavily relied on as the sole or main source of water supply. Hydrochemical analysis, the first and most practical step to evaluating the water quality, was carried out through 60 water samples collected from 13 springs and 17 wells in both dry and wet seasons (October 2018 and May 2019). Laboratory results show a high calcium bicarbonate concentration with weak acids’ dominance. Protection zones are delineated for these springs using aquifer susceptibility to contamination and analysis of the recession part of the spring curves. The equivalent relationship between the protection factor (Fp) produced by the Epikarst, protective cover, infiltration condition, and Karst network development mapping method and the groundwater protection zone (S) is considered. Qulai Rania and Kanimaran Springs are mapped to be in S2 (a highly vulnerable area), whereas Saruchawa Spring is located in S1 (very highly vulnerable). Based on the second method results (recession curve analyses), all three selected springs fall under the (D-type) vulnerability category. As a result, the immediate protection zone was going to be surrounded by the inner protection zone, and both are enclosed within the outer protection zone, which covers the remainder of the catchment area.
Groundwater resources play the single most important role in the delivery of potable water to rural communities in northern Ghana, especially during the long dry season and where surface water ...sources are polluted or non-existent. This study sought to assess the quality and main controls on groundwater chemistry in parts of Sawla-Tuna-Kalba District in the Savannah Region of Ghana. Multivariate statistical analysis and conventional hydrochemical plots were employed in the analysis of 112 groundwater samples from the study area. Conventional graphical methods, R-mode Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) identified dissolution of silicates and the influence of agrochemicals and domestic wastewaters as the main sources of variations in the hydrochemistry in the study area. Q-mode HCA coupled with Stiff diagrams identified Ca–HCO3 water type in recharge areas, and Mg–Ca–HCO3 water type, which evolves into a Ca–Na–K–HCO3 water type in discharge areas in the groundwater flow regime. Mineral stability diagrams indicate the groundwater is stable in kaolinite, which suggests little or no restricted groundwater flow conditions. Groundwater quality for domestic purposes was assessed using the weighted arithmetic index approach. The computed water quality indices (WQIs) from the data suggest that 94% of the sampled boreholes provide groundwater of “excellent” quality for drinking purposes, whereas 5% and 1% present water of “good” and “poor” quality respectively. Spatial interpolation of the estimated WQIs suggests the quality of the groundwater in the study area is suitable for domestic purposes. The assessment of the groundwater quality for irrigation purposes suggests the water is of “excellent” to “permissible” quality and may be used for irrigation without prior treatment.
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•The quality and main controls on groundwater hydrochemistry have been assessed using multivariate statistical analysis and conventional hydrochemical plots.•Silicate mineral dissolution and the influence of agrochemicals and domestic wastewaters are the main controls on groundwater hydrochemistry.•Ca–HCO3 water type in recharge areas, and Mg–Ca–HCO3 water type, which evolves into a Ca–Na–K–HCO3 water type in discharge areas in the groundwater flow regime has been identified.•Water quality indices (WQIs) suggests 94% of the sampled boreholes provide groundwater of “excellent” quality for drinking purposes.•Groundwater quality for irrigation is of “excellent” to “permissible” quality and maybe used for irrigation without prior treatment.
The current research integrates vertical electrical sounding (VES) and hydrochemical analysis to delineate water bearing zones, assess their vulnerability to surficial contamination, and implications ...on water quality of District Bagh, Azad Jammu and Kashmir. In order to achieve the desired results, a total of 45 VES points and 25 water samples were collected from springs, open and bore wells in the study area. The VES data was acquired using ABEM Terrameter SAS 4000. The interpretation of VES data revealed confined to unconfined aquifer systems, furthermore, the aquifer thickness ranges between 5–95 m with the resistivity values of 10–70 Ohm m. Darzarouk parameters were utilized to demarcate the protective capacity of the aquifer system based on a vul nerability map. This map classified the surficial protective capacity from moderate to very good associated with good clay cover that will restrict the surficial infiltration from contaminating the groundwater. The hydrochemical analysis of the area further justified the vulnerability assess ment as only 2 samples (9 and 24) out of 24 were found not feasible for drinking. The study will prove useful for the local administration as the population has been drastically increasing in the Bagh District and provision of safe drinking water will be difficult in the future.
The valley plain of Lhasa City is located on the Qinghai-Tibetan Plateau, which is one of the most developed and densely populated areas in Tibet. Groundwater is an important water supply source and ...plays an irreplaceable role in the social and economic development of Lhasa City. This study has investigated the dynamic characteristics of groundwater in the valley plain of Lhasa City through the methods of mathematical statistics and hydrochemical analysis. The results showed that local topography, climate, and urbanization substantially influenced the groundwater dynamics. Under the combined influences from urbanization and climate, the groundwater level decreased over three time periods, but the groundwater-level configuration has not shown significant changes in over 15 years. From 1997 to 2015, the hydrochemical type of groundwater has changed from HCO
3
–Ca to HCO
3
·SO
4
–Ca·Mg and HCO
3
·SO
4
–Ca. The concentrations of Cl
−
, Mg
2+
, and SO
4
2−
in groundwater increased, but the concentrations of other ions were relatively stable. Water–rock interaction was the main mechanism controlling the groundwater chemistry in the study area, and it was mainly associated with the dissolution of silicate, carbonate, and halite.
Groundwater chemistry of the two different seasons collected between 2020–2021 from the coastal areas of Nagapattinam, Mayiladuthurai and Karaikal in Tamil Nadu state of southeast India were ...evaluated for seawater intrusion into coastal aquifers. Groundwater types, its classification was evaluated to know the extension of seawater intrusions into coastal aquifers using the Groundwater Quality Indices (GQI) such as GQIPiper(mix), GQIPiper(dom), fsea, GQIfsea and GQISWI. Piper diagram grouped most samples (GQIPiper(mix) and GQIPiper(dom)) in domain-II, representing Na-Cl water type, followed by domain-IV, indicating mixed Ca-Mg-Cl water for both the seasons. As measured by the saltwater Intrusion as Groundwater Quality Index (GQISWI), about 62.5 % and 37.5 % of the pre-monsoon samples showed low saltwater intrusion and moderate seawater intrusion, respectively. In the post-monsoon samples, the low saltwater intrusion increased to around 82.5 % and the moderate seawater intrusion decreased to 17.5 % of the groundwater samples. The GIS framework was used to display the geographical distribution of groundwater types as well as the delineation of vulnerable zones from seawater intrusion.
As an important component of the exploration and evaluation of geothermal resources, the formation model has unique formation and distribution rule in different regions. Reliable geological models ...need to be established to help in temperature prediction, favorable area selection, and drilling design studies prior to the development of geothermal resources. This paper provides an integrated approach for analyzing the formation models of geothermal resources by combining geological studies and the wide-field electromagnetic method. The resistivity profile is converted into a geologic profile by analyzing the fault distribution, stratigraphic lithology, magmatic rock development, and signal changes of the profile. Comprehensively analyzing the geological elements including the heat sources, water sources, thermal reservoirs, transport conditions, cap rock, and preservation conditions, we investigate the matching relationship of the geological elements on the geologic profile and establish a formation model of the geothermal resources. This approach avoids the respective limitations of geological and geophysical methods, and the formation model established by this approach is comprehensive, intuitive, and accurate and can provide support for the development of geothermal resources.
Since the Quaternary Period, paleo-seawater intrusions have been suggested
to explain the observed saline groundwater that extends far inland in
coastal zones. The Luanhe River delta (northwest coast ...of the Bohai Sea, China)
is characterized by the distribution of saline, brine, brackish, and fresh
groundwater from the coastline inland. The groundwater in this region exhibits a wide range of total dissolved
solids (TDS): 0.38–125.9 g L−1. Meanwhile, previous studies have
revealed that this area was significantly affected by Holocene marine
transgression. This study used hydrochemical, isotopic, and sedimentological
methods to investigate groundwater salinization processes in the Luanhe
River delta and its links to paleo-environmental settings. Isotopic
results (2H, 18O, 14C) allowed old groundwater recharge to be distinguished from
new groundwater recharge. Hydrochemical analysis using the PHREEQC code
indicated that the salt in saline and brine groundwater originates from a
marine source. The 18O–Cl relationship diagram yields three-end-member
groundwater mixing, and two mixing scenarios are suggested to explain the
freshening and salinization processes in the study area. When this was interpreted
along with data from paleo-environmental sediments, we found that groundwater
salinization may have occurred since the Holocene marine transgression. The
brine is characterized by radiocarbon activities of ∼ 50–85 pMC and relatively depleted stable isotopes, which are associated with
seawater evaporation in the ancient lagoon during delta progradation and
mixing with deeper fresh groundwater, which was probably recharged in the cold
Late Pleistocene. The brackish and fresh groundwaters are
characterized by river-like stable isotope values, where high radiocarbon
activities (74.3–105.9 pMC) were formed after the washing out of the salinized
aquifer by surface water in the delta plain. This study presents an approach
that utilizes geochemical indicator analysis with paleo-geographic
reconstruction to better assess groundwater evolutionary patterns in coastal
aquifers.
