Groundwater quality in the vicinity of a dumpsite in Lagos metropolis,Nigeria

Inappropriate management of municipal solid waste dumpsites is a major cause of groundwater contamination in developing countries,but the extent of the problem is not known.This study investigated groundwater quality in the vicinity of Olusosun dumpsite in Lagos,Nigeria,the most populous city in sub-Saharan Africa.During 2020,monthly groundwater samples were collected in 17 wells and boreholes used as drinking water sources,and analysed for 20 physico-chemical parameters.Differences between sites and seasons were statistically assessed,together with changes in water quality index(WQI).The results indicated that heavy metals(Pb^(2+),Ni^(+),Mn^(2+),Fe^(2+),Cr^(6+)),cations(Ca^(2+),Mg^(2+),K^(+)),total hardness and pH were the main parameters impairing water quality.Drinking water quality standards from both the World Health Organization and Nigeria government were exceeded more often in the wet season than in the dry season.Some groundwater properties were negatively correlated with distance to dumpsite(e.g.,Fe^(2+),Pb^(2+),NO_(3)^(−)).Significant differences between sites were identified,but with no clear spatial trend.WQI varied from excellent(6%-24%of the sites over the study period)to unsuitable for drinking water purposes(12%-18%),with good quality prevailing at most sites(35%-47%).Although groundwater quality declined at 24%of the sites over 2020,the results indicated improvements compared with previous decades.Remediation strategies must be implemented to safeguard public health and the sustainability of water resources.

Groundwater Quality Surroundings Mining Activities Areas in Arlit Region(Tim MersoïBasin,North Niger)

The study area is a semi-arid area located in the Arlit region.This area contains significant uranium deposits that have been mined by two mining companies since 1968.The objective of this study is to determine the impact of these activities on existing aquifers,in particular Izegouande aquifer.A methodological approach based on hydrochemical methods focusing on the analysis of nitrates and sulfates showed that waters of Izegouande aquifer have high nitrate concentrations ranging from 16 mg/L to 60 mg/L,higher than WHO(World Health Organization)standards drinking water.In addition,these waters show elevated sulfate levels ranging from 16 mg/L to 57 mg/L,therefore acceptable.These high concentrations of nitrates and sulfates are located mainly near wastewater treatment of Arlit city and near industrial zone,which are potential areas for transfer of these elements such as nitrates and sulfates.It is therefore urgent to carry out periodic and regular checks on groundwater in these areas.

Groundwater quality modeling using self-organizing map(SOM) and geographic information system(GIS) on the Caspian southern coasts

Groundwater is the main source for water provision in the arid and semi-arid areas such as Iran.The groundwater quality was simulated by using a hybrid model integrating a Self-Organizing Map(SOM)and geographic information system(GIS).SOM and GIS were used as pre-processing and postprocessing tools in the Mazandaran Plain.Further,the Ground Water Quality Index(GWQI)and its effective factors were estimated by using digital maps and the secondary data.Neuro Solutions software was used for simulating the groundwater quality.To do this,a model was trained and optimized in the SOM and then the optimized model was tested.In the next step,the performance of SOM in groundwater quality simulation was confirmed(test stage,Rsqr=0.8,and MSE=0.008).Then,the digital maps of the SOM inputs were converted to raster format in GIS.In the last step,a raster layer was generated by combining the model input layers which comprised the model inputs values.The tested SOM was used to simulate GWQI in the sites without the secondary data of the groundwater quality.Finally,the groundwater quality map was generated by coupling the results of SOM estimations and GIS capabilities.The results revealed that the coupling of SOM and GIS has high performance in the simulation of the groundwater quality.According to the results,a limited area of the studied plain has groundwater resources with low quality(GWQI>0.04).Therefore,that will be a threat to the life of humans,animals,and vegetative species.Therefore,it is necessary to plan for managing the groundwater quality in the Mazandaran plain.

Compilation of Groundwater Quality Map and study of hydrogeochemical characteristics of groundwater in Asia

The groundwater quality map is among a series of Asian groundwater environment maps, which has been compiled and is about to be published. The article introduces the central theme and main content of the map, evaluates the method applied for groundwater quality gradation, and discusses hydrogeochemical characteristics of Asian groundwater. The distribution of water quality is investigated through the data collection of selected elements; hydrogeochemical characteristics are demonstrated via the analysis of elements’ allocation in horizontal and vertical zones; whilst the groundwater quality is evaluated by the Analytic Hierarchy Process(AHP).

Hydrogeochemical processes and multivariate analysis for groundwater quality in the arid Maadher region of Hodna,northern Algeria

This study focused on water quality and hydrogeochemical processes(evolution,origin)in the Maadher region,central Hodna in Algeria.In recent decades,the excessive exploitation of this resource due to urbanization,irrigation,and the effect of climate change reaching the countries of northern Africa have caused a decline in water levels and hydrochemical changes in the aquifer.The sampling campaign in 2019 based on 13 physicochemical parameters was carried out on the water from 32 boreholes in the study area,compared to data archives of both sampling campaigns in 1967 and 1996.The result revealed that the groundwater as a whole has moderate freshwater quality,due to its total dissolved solids(TDS)content and other dissolved ions of concern(nitrate NO),which exceed WHO standards.In addition,Piper diagram indicates that the hydrochemical facies of sulfate–chloride–nitrate–calcium(SO–Cl–NO–Catype),which globally characterizes the study area and these elements are the dominant dissolved ions.Principal component analysis and hierarchical cluster analysis(HCA)methodologies are applied in order to define the major control factors that affect the hydrochemistry of Maadher plain.Three distinct water groups were found,illustrating a different evolution of salinity(EC and TDS).The HCA indicated an interesting cluster with a distinct contamination signature and most likely with significantly higher sulfate,chloride,and nitrate concentrations.Anthropogenic processes also play an important role in the study area.The water resource comes from Bousaada Wadi,the exchange at the aquifer depth and the agricultural practices contribute to the deterioration of the quality.

Assessment of Groundwater Quality for Domestic and Irrigation Purposes in Northern Bamenda (Cameroon)

Safe and reliable drinking water availability constitutes a nightmare in many towns of developing countries and is usually appreciated from its physical appearance without prior knowledge of its chemical and biological properties. This study investigates the suitability of groundwater for domestic and irrigational purposes through physico-chemical and bacteriological analyses in the Northern part of Bamenda Town (Cameroon). Thus, 20 groundwater samples were collected from hand-dug wells and spring sources in September 2018 (rainy season) and February 2019 (dry season) and physico-chemical and bacteriological characteristics were determined. The results revealed that pH ranged from 5.5 to 6.6, thus enabling the classification of the water as slightly acidic. Electrical conductivity varied between 0.01 - 0.06 μS/cm. The relative abundance of ions was such that Ca2+ > K+ > Mg2+ > Na+ for cations and HCO-3 > Cl- > NO-3 > SO-4 for anions. The water types were Ca-Mg-NO3 in both dry and rainy seasons. The results revealed that the mechanisms controlling groundwater chemistry are rock weathering and atmospheric precipitation. Indicator bacteria such as E. coli, Shigella, Enterobacteria, Vibrio, Streptococcus and Staphylococcus were detected in the studied groundwater samples, thus the water sources may pose a threat to public health.

Evaluation of Groundwater Quality in the Deep Maastrichtian Aquifer of Senegal Using Multivariate Statistics and Water Quality Index-Based GIS

A regional groundwater quality evaluation was conducted in the deep Maastrichtian aquifer of Senegal through multivariate statistical analysis and a GIS-based water quality index using physicochemical data from 232 boreholes distributed over the whole country. The aim was to 1) identify the water types and likely factors influencing the hydrochemistry, and 2) determine the suitability of groundwater for drinking and irrigation. Results showed that sodium, chloride, and fluoride are highly correlated with electrical conductivity (EC) reflecting the significant contribution of these elements to groundwater mineralization. The principal component analysis evidenced: 1) salinization processes (loaded by Na+, K+, EC, Cl-, F- and HCO3-) controlled by water/rock interaction, seawater intrusion and cation exchange reactions;2) dolomite dissolution loaded by the couple Ca2+ and Mg2+ and 3) localized mixing with upper aquifers and gypsum dissolution respectively loaded by NO3- and SO42-. The hierarchical clustering analysis distinguished four clusters: 1) freshwater (EC = 594 μs/cm) with mixed-HCO3 water type and ionic contents below WHO standard;2) brackish (Na-mixed) water type with moderate mineralization content (1310 μs/cm), 3) brackish (Na-Cl) water type depicted by high EC values (3292 μs/cm) and ionic contents above WHO and 4) saline water with Na-Cl water type and very high mineralization contents (5953 μs/cm). The mapping of the groundwater quality index indicated suitable zones for drinking accounting for 54% of the entire area. The occurrence of a central brackish band and its vicinity, which were characterized by high mineralization, yielded unsuitable groundwater for drinking and agricultural uses. The approach used in this study was valuable for assessing groundwater quality for drinking and irrigation, and it can be used for regional studies in other locations, particularly in shallow and vulnerable aquifers.

Groundwater Quality for Irrigation Purposes and Classification for Hydrochemical Facies in Parts of Southern Ijaw Local Government Area, Bayelsa State, Nigeria

As a result of economic development and rapid growth of the population in Southern Ijaw Local Government Area of Bayelsa State, Nigeria, there have been clear changes in the use of land, resulting in increased demand for water for various uses including agricultural activities. This study examined groundwater quality and classification of hydrochemical facies of communities in the study area. Fifteen (15) communities within the LGA were selected and groundwater from hand-dug well (HDW-15 samples) and borehole (BH-15 samples) was sourced during the wet season (July) and dry season (March) and analyzed for seasonal variation, irrigation purposes and hydrochemical facies classification using a standard method. Based on Sodium Adsorption Ratio (SAR) classification scheme, all groundwater sources in the area are excellent for irrigation purposes because they all have SAR values <3. This implies that SAR values of <3 will not threaten vegetation. The value of sodium percentage (Na%) ranges from 29.81% to 66.13% and 23.30% to 71.89% for hand dug wells in both wet and dry seasons. Similarly, the value of Na% ranged from 3.57% to 16.32% and 3.38% to 19.60% for borehole water in both wet and dry seasons. The groundwater hydrochemistry facies analysis indicated that there was an adjustment in groundwater chemistry during dry season while HDW and BH are linked to different sources. Groundwater in the communities are contaminated for both sources and season;however, showed potential for irrigational purpose. There is a need for continuous monitoring of the water quality, improvement in environmental and sanitation practices while treatment of water is strongly advised.

Sustainability Assessment of the Groundwater Quality in the Khoyrasole Block, Birbhum District, West Bengal to Achieve Rural Water Security

In order to attain the water security goal, specifically in highly developingareas, delineation of pure and sustainable water resources is of utmostpriority. In the present study, a preliminary investigation of the groundwaterchemistry was carried out. This was followed by assessing the suitabilityof groundwater to be used as an alternative and reliable resource for publicuse in the Khoyrasole block, Birbhum district, India. Altogether 15(fifteen)samples of groundwater, were collected from bore wells spread well overthe Khoyrasole block have been considered. After completing the chemicalanalysis of the groundwater samples, the study revealed the quality ofgroundwater. The spatial distribution of groundwater quality parameterssuch as pH, Total Dissolved solids (TDS), Hardness, Calcium, Magnesium,Sodium, Potassium, Iron, Chloride, Carbonate, Bicarbonate, Sulphate,Nitrate and Fluoride have also been studied. High to very high levels ofiron and fluoride have been observed to be present in 67% and53% of thesamples respectively. Based upon the calculated parameters like SAR,MAR, PI and Chloro Alkaline Indices, groundwater of Khoyrasole blockis majorly suitable for the purpose of agriculture and irrigation. Plotting ofionic scatter plots and geochemical facies also indicate the water samplesto be of “fresh water” category, with no dominant cation or anion playing aselectively dominant role in influencing the groundwater chemistry in thestudy area.

The Influence of Fertilizers on Groundwater Quality in Gaza Strip—Free Settlements on Khan Younis—Case Study

The Palestinian Ministry of Agriculture started the agricultural investment in some free settlements in Gaza strip since 2008. The proposed areas to be planted and the proposed crops were chosen randomly without any researches to study the expected adverse impacts of these agricultural projects on the environmental components. This research aimed at the groundwater aquifer in the proposed region physically and chemically by taking five water samples from water wells in the place. Represented groundwater samples taken from observation wells in the study area were tested in term of total dissolved solids (TDS), electric conductivity (EC), and (N-P-K) concentrations to be compared with the regulated groundwater standards. As a result of testing two fertilizers, it is found that the announced concentrations of (N-P-K) don’t match the real results. The real results are less than the announced concentrations, especially for the phosphorus concentration which had a real result about half of the announced concentration for both fertilizers. Although the real concentrations of (N-P-K) in the used fertilizers are less the announced concentrations, slightly pollution is found in the groundwater aquifer. The groundwater testing results in five observation wells showed that the groundwater tends to be basic, high salinity ranged between 550 and 3500 μS/cm, and Total Dissolved Solids (TDS) results ranged between 330 and 2300. Nitrate results ranged between 65 and 160 ppm, whereas phosphorus and potassium results showed that all groundwater samples met the standards and didn’t exceed them.

The Influence of Weather and Climate Variability on Groundwater Quality in Zanzibar

Climate change and variability have been inducing a broad spectrum of impacts on the environment and natural resources including groundwater resources. The study aimed at assessing the influence of weather, climate variability, and changes on the quality of groundwater resources in Zanzibar. The study used the climate datasets including rainfall (RF), Maximum and Minimum Temperature (Tmax and Tmin), the records acquired from Tanzania Meteorological Authority (TMA) Zanzibar office for 30 (1989-2019) and 10 (2010-2019) years periods. Also, the Zanzibar Water Authority (ZAWA) monthly records of Total Dissolved Solids (TDS), Electrical Conductivity (EC), and Ground Water Temperature (GWT) were used. Interpolation techniques were used for controlling outliers and missing datasets. Indeed, correlation, trend, and time series analyses were used to show the relationship between climate and water quality parameters. However, simple statistical analyses including mean, percentage changes, and contributions to the annual and seasonal mean were calculated. Moreover, t and paired t-tests were used to show the significant changes in the mean of the variables for two defined periods of 2011-2015 and 2016-2020 at p ≤ 0.05. Results revealed that seasonal variability of groundwater quality from March to May (MAM) has shown a significant change in trends ranging from 0.1 to 2.8 mm/L/yr, 0.1 to 2.8 μS/cm/yr, and 0.1 to 2.0℃/yr for TDS, EC, and GWT, respectively. The changes in climate parameters were 0.1 to 2.4 mm/yr, 0.2 to 1.3℃/yr and 0.1 to 2.5℃/yr in RF, Tmax, and Tmin, respectively. From October to December (OND) changes in groundwater parameters ranged from 0.2 to 2.5 mm/L/yr 0.1 to 2.9 μS/cm/yr, and 0.1 to 2.1℃/yr for TDS, EC, and GWT, whereas RF, Tmax, and Tmin changed from 0.3 to 1.8 mm/yr, 0.2 to 1.9℃/yr and 0.2 to 2.0℃/yr, respectively. Moreover, the study has shown strong correlations between climate and water quality parameters in MAM and OND. Besides, the paired correlation has shown significant changes in all parameters except the rainfall. Conclusively, the study has shown a strong influence of climate variability on the quality of groundwater in Zanzibar, and calls for more studies to extrapolate these results throughout Tanzania.

Investigation of Groundwater Quality with Borehole Depth in the Basin Granitoids of the Ashanti Region of Ghana

The dependence of groundwater quality on borehole depth is usually debatable in groundwater studies, especially in complex geological formations where aquifer characteristics vary spatially with depth. This study therefore seeks to investigate the relationship between borehole depth and groundwater quality across the granitoid aquifers within the Birimian Supergroup in the Ashanti Region. Physicochemical analysis records of groundwater quality data were collected from 23 boreholes of public and private institutions in the Ashanti Region of Ghana, and the parametric values of iron, fluoride, total hardness, pH, nitrate, and nitrite were used to study the groundwater quality-depth relationship. The results showed that the depth-to-groundwater quality indicated a marginal increase in water quality in the range of 30 to 50 m, which is mathematically represented by the low-value correlation coefficient (r2 = 0.026). A relatively significant increase occurs in the depth range of 50 to 80 m, which is given by a correlation coefficient of r2 = 0.298. The mean percent parameter compatibility was 74%, 82%, 89%, and 97% at 50, 60, 70, and 80 m depths, respectively. The variations in groundwater quality per depth ratio ranged from 1.48, 1.37, 1.27, and 1.21 for 50, 60, 70, and 80 m depth, respectively. The recommended minimum borehole depth for excellent groundwater quality is suggested with a compatibility per meter depth ratio of 1.37. This results in a range between 50 and 70 m as the most desirable drilling depth for excellent groundwater quality within the granitoids of the Birimian Supergroup of the Ashanti Region in Ghana.

Evaluation of groundwater quality in the Xinjiang Plain Area

Groundwater is the main source of drinking water for the urban and rural residents in the plain area of the Xinjiang Uygur Autonomous Region,China.The quality of groundwater has a direct relationship with human health.Thus,386 groundwater samples collected from April to August in 2003 were analyzed.The samples were collected in basic evaluation units which are determined on the basis of watersheds.Total dissolved solids,total hardness,pH value,NH3–N,C6H5OH,Chemiluminescence detection of permanganate index(CODMn)and intestinal germ group were evaluated according to the guidelines of Groundwater Quality Standard(GB/T14848-93).The quality of the groundwater in each evaluation unit was classified by using the One Veto Method(a unified approach stipulated by the Ministry of Water Resources).The results indicate that the groundwater in the mainstream area of the Tarim Basin and the Yerqiang River Sub-basin belongs to Category V;the groundwater in the Wulungu River Sub-basin,the KaiduKongque River Sub-basin,the Kashgar River Sub-basin,the Cherchen River Sub-basin and the Hotan River Subbasin belongs to Category IV;the groundwater in the Aibi Lake System belongs to Category II,and the groundwater of other evaluation units belongs to Category III.The causes of water quality formation were concisely analyzed.The results can be useful for the evaluation and management of water resources in the Xinjiang Plain Area.

Hydrogeochemical characterization and quality assessment of groundwater using self-organizing maps in the Hangjinqi gasfield area,Ordos Basin,NW China

Water resources are scarce in arid or semiarid areas,which not only limits economic development,but also threatens the survival of mankind.The local communities around the Hangjinqi gasfield depend on groundwater sources for water supply.A clear understanding of the groundwater hydrogeochemical characteristics and the groundwater quality and its seasonal cycle is invaluable and indispensable for groundwater protection and management.In this study,self-organizing maps were used in combination with the quantization and topographic errors and K-means clustering method to investigate groundwater chemistry datasets.The Piper and Gibbs diagrams and saturation index were systematically applied to investigate the hydrogeochemical characteristics of groundwater from both rainy and dry seasons.Further,the entropy-weighted theory was used to characterize groundwater quality and assess its seasonal variability and suitability for drinking purposes.Our hydrochemical groundwater dataset,consisting of 10 parameters measured during both dry and rainy seasons,was classified into 6 clusters,and the Piper diagram revealed three hydrochemical facies:Cl-Na type(clusters 1,2 and 3),mixed type(clusters 4 and 5),and HCO3-Ca type(cluster 6).The Gibbs diagram and saturation index suggested thatweathering of rock-forming mineralswere the primary process controlling groundwater chemical composition and validated the credibility and practicality of the clustering results.Two-thirds of 45 groundwater samples were categorized as excellent-or good-quality and were suitable as drinking water.Cluster changes within the same and different clusters from the dry season to the rainy season were detected in approximately 78%of the collected samples.The main factors affecting the groundwater quality were hydrogeochemical characteristics,and dry season groundwater quality was better than rainy season groundwater quality.Based on this work,such results can be used to investigate the seasonal variation of hydrogeochemical characteristics and assess water quality accurately in the others similar area.

Research on quality changes and influencing factors of groundwater in the Guanzhong Basin

This paper studies the distribution features, the chemical elements beyond standards and the influencing factors of shallow groundwater quality in the Guanzhong Basin through the data monitored in the last twenty years. The final purpose is to comprehensively evaluate the divisions of groundwater quality in the Guanzhong Basin. Results show that, the groundwater quality is in good shape, and suitable for drinking. Drinking accounts for 16.02% of the total, most of which are distributed in the lubotan of Weibei. Some come from loess plateau of Qian-Liquan County and some are generated by the industrial pollution of Xingping City. Materials exceeding standards include chloride, sulfate, three nitrogen, fluoride, manganese, iron, hexavalent chromium and so on. The main factors influencing the quality of shallow groundwater include groundwater exploitation, natural background value of special components and precipitation, among which the groundwater exploitation poses the greatest impact. The depth of water is positively correlated with the concentration of sulfate, nitrate and total hardness.

Quality evaluation of groundwater in the North China Plain

This paper presents a method combining single-indicator comprehensive evaluation and influence factor identification to measure groundwater quality. This method not only reflects groundwater quality classification with clear physical significance, but also divides the possibilities of man-made pollution in regional groundwater. The paper selects 6 063 representative groundwater wells in the North China Plain to evaluate 49 groundwater inorganic and organic index and comes to a conclusion: Controlled by geological environment and hydrogeological conditions, the groundwater quality in the North China Plain deteriorates from the bottom of maintain to coastal area, with Class I to III groundwater decreasing from 49% to 3.9% while Class V groundwater increasing from 21% to 86.9%; the quality of deep groundwater is better than that of shallow groundwater; the contribution rate of manganese, total hardness, total dissolved solids and iodide in shallow groundwater to over-III type water exceeds 50%; the contribution rate of nitrite in pollution index reaches 20%; while heavy metal and organic indexes have limited impact on regional groundwater quality. The North China Plain is an important economic area in China. Over decades, it has witnessed intense human activities, and water resource quantity demanded has been far greater than quantity supplied. Due to scarce surface water resource, groundwater becomes the pillar supporting regional economic development. This has led to increasing groundwater exploitation and development. According to statistics, the exploitation degree of shallow groundwater reaches 105% in the North China Plain and 118% in the Hebei Plain; the exploitation degree of deep groundwater reaches 143% in the North China Plain and 163% in the Hebei Plain. The serious over-exploitation of groundwater brings various geological environmental problems, with the worsening of groundwater quality being a typical one. Besides impact brought by human activities, the poor quality of natural water in the North China Plain is also an important factor. Therefore, to understand the current regional groundwater quality situation and to master influence factors and influence degree can provide reliable scientific protection for regional economic development.