Geochemistry of groundwater

Groundwater quality assessment using pollution index of groundwater (PIG), ecological risk index (ERI) and hierarchical cluster analysis (HCA): A case study

Exposure to heavy metals pollutions in water predisposes consumers to human and environmental health deterioration. In this study, the extent of heavy metals contamination, water quality index, ecological and human health risk assessments of groundwater resources in Ajao industrial area of Lagos, Nigeria were carried out. Results revealed that Cu is the most prevalent heavy metal, contaminating 85.71% of the analyzed water samples. Based on the groundwater quality index, 76.19% of the samples are of excellent water quality and suitable for drinking, domestic and industrial purposes. However, the quality of 23.81% variedly deteriorated. Ecological risk assessment revealed that 85.71% and 14.29% of the samples pose low and moderate ecological risks, respectively. This assessment also showed that Cu was the major heavy metal posing ecological risk in the industrial area. Based on hazard quotients, Cu impacted the potentiality of chronic diseases than other heavy metals. Health hazard index analysis revealed that children are more exposed to non-carcinogenic chronic health risks due to ingestion of contaminated groundwater than the adult population. Probability of cancer risk (PCR) revealed that 19.05% of the samples pose high Cr cancer risk for both adult and children, while 14.29% pose high Cd and Ni cancer risks. Correlation and factor analyses indicated that the origin of the heavy metals in water is majorly attributed to anthropogenic inputs rather than natural, geogenic processes. Awareness programs towards protecting the groundwater in this area should be launched and encouraged. Moreover, contaminated water should be treated before use.

Extent of heavy metals pollution and health risk assessment of groundwater in a densely populated industrial area, Lagos, Nigeria

The present study region comprises granite and granite gneisses aquifer system constituted by Precambrian rocks. Groundwater is the primary source for drinking and other domestic purposes. Many developing regions in the world suffer from lack of safe drinking water. A rural part of Wanaparthy District in Telangana State, India, is one of them. For this reason, the groundwater samples collected from the study region were analyzed for pH, TDS, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, NO3− and F− and evaluated groundwater quality criteria, using ionic spatial distribution (ISD), entropy water quality index (EWQI) and principal component analysis (PCA). The ISD maps show that some locations are not suitable for drinking purpose due to exceeding concentrations of TDS, Mg2+, Na+, K+, HCO3−, Cl−, NO3−and F−, compared to those with national drinking water quality standards. According to the EWQI, about 3%, 47%, 43% and 7% of the total area come under the excellent, good, medium and extremely poor water quality types for drinking purpose, respectively. Chadha’s diagram classified the area as carbonate hardness (63%), non-carbonate alkali (17%), carbonates alkali (13%) and non-carbonate hardness (7%) zones. The binary diagrams (Na+ + K+ vs TC, Na+ vs Ca2+ and HCO3− vs TC) indicate that the quality of groundwater is controlled by influences of water–rock interactions, mineral weathering and dissolution, ion exchange and evaporation as well as the impact of anthropogenic sources. The PCA transferred the chemical variables into three principal components accounts for about 81% of the total variance. The high positive loadings of PC1 (Cl−, TDS, SO42−, Na+, NO3−, Mg2+ and HCO3−) stand for processes of silicate weathering and dissolution, ion exchange and evaporation, and the influence of domestic waste waters, irrigation return flows and chemical fertilizers on the groundwater system, the PC2 (F− and pH) signifies the alkaline nature of groundwater, which causes fluorosis, and the PC3 (K+) is a result of potassium fertilizers. The study helps to take remediate measures at a specific site and hence suggests the treatment of water before its drinking and also the recharge of the aquifer artificially to improve the groundwater quality.

Quality criteria for groundwater use from a rural part of Wanaparthy District, Telangana State, India, through ionic spatial distribution (ISD), entropy water quality index (EWQI) and principal component analysis (PCA)

This paper assessed the degree of heavy metals pollution, the possible pollution sources, and the human health risks of groundwater from shallow Eocene Aquifer in selected urban centers of Onitsha,...

Heavy Metals Pollution Source Identification and Probabilistic Health Risk Assessment of Shallow Groundwater in Onitsha, Nigeria

The hydrogeochemical characteristics, water quality and health risk statuses of waters in Umunya district, southeastern Nigeria were studied, in attempt to evaluate their suitability for drinking and domestic purposes. Twelve groundwater and 3 surface water samples were analyzed for 26 physicochemical and hydrogeochemical parameters, using standard techniques. Results show that dominance of cations and anions is in the order Ca2+ > Na+ > K+ > Mg2+ and HCO3– > Cl– > NO3– > SO4–, respectively. Order of dominance of the heavy metals is Pb > Zn > Fe > Ni > Mn > Cr > Ba. Eight water types were identified, with Ca–Na–HCO3 (26.66%) and Na–Cl–HCO3 (20%) dominating the study area. All the water types characterize five major facies. Further, the result revealed that the physical properties and chemical ionic concentrations in the waters are well below standard maximum permissible limits, although majority of the samples have pH values off the allowable limits of 6.5–8.5, classing the waters as slightly acidic. Generally, the water quality in the study area is deteriorated due to the presence of high levels of heavy metals. Water quality index results show that 46.67% of the water samples are in excellent and good categories. 13.33% are in poor water category, whereas 40% are in category unsuitable for drinking purposes. A good percentage of the waters predispose users to health risks. Stoichiometric and statistical analyses revealed that the variations in chemistry and quality of the waters are due to combined influence of human activities and geogenic processes (silicate weathering and ionic exchanges). Treatment of contaminated waters before use is, therefore, recommended.

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The hydrogeochemical signatures, quality indices and health risk assessment of water resources in Umunya district, southeast Nigeria

In an attempt to determine their suitability for consumption and irrigation uses, the prevailing hydrogeochemical processes and quality of both surface and groundwaters in Ojoto province, southeastern Nigeria were studied. Classical scientific methods and indicators such as hydrogeochemistry, stoichiometry, water quality index (WQI), and multivariate statistical analyses were integrated to achieve the research objectives. pH results classified most of the waters as slightly acidic. The order of dominance of the major cations and anions is Na+ > Ca2+ > K+ > Mg2+ and SO42– > Cl– > NO3– > HCO3–, respectively. The dominant water type is Na–Ca–SO4, and the dominant water facies in the area is sodium sulphate (Na–SO4), constituting about 54% of the total samples. Several hydrogeochemical, stoichiometric, and multivariate statistical analyses revealed that both anthropogenic inputs and geogenic processes (such as precipitation, silicate weathering, oxidation, and ionic exchange) influence the chemistry and quality of the waters. WQI of the waters showed that only 17.86% of the analyzed samples are of good quality for drinking purposes, whereas the quality of 53.57, 17.86, and 10.71% of the samples is poor, very poor, and unfit for use, respectively. Various irrigation suitability assessments (including salinity hazard, sodium absorption ratio, sodium percentage, residual sodium carbonate, chloro-alkaline indices, magnesium hazard, Kelly’s ratio, permeability index, and potential salinity) conducted revealed that majority of the analyzed waters have poor irrigation quality.

Investigating the hydrogeochemical processes and quality of water resources in Ojoto and environs using integrated classical methods

This paper quantified the level of heavy metals contamination, identified possible sources of pollution, and assessed the human health risks associated with drinking water resources in Ojoto Province, Nigeria. The study’s gross findings revealed that the suitability of some water sources for consumption purposes in this province is questionable. Based on water quality index, 57.14% of the total samples are within acceptable limits, while 42.86% are unsuitable for drinking. It was observed that the northwestern and southern parts of the study area have more of deteriorated water quality. The health hazard index revealed that 25% of the samples predispose their consumers (both adult and children populations) to high chronic health risks. Moreover, heavy metal pollution index, contamination index, and probability of cancer risk (CR) revealed that about 25% of the total samples were unsuitable and off the CR standard acceptable range of ≤ 1 × 10−6–1 × 10−4. Correlation and component factor analyses linked the origin of major ions to geogenic processes and that of the heavy metals to both natural and anthropogenic processes. Cluster analysis divided the samples into two equal classes (50% each): poor and excellent quality waters. This study indicated that Pb is the priority pollutant impacting the water quality. The various assessments revealed that waters from hand-dug wells and deeper boreholes are the least contaminated and hence best suited for drinking than waters from springs, streams, and shallow wells.

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Chemometric analysis for pollution source identification and human health risk assessment of water resources in Ojoto Province, southeast Nigeria

Groundwater samples from five rural agricultural villages within the Anambra basin of southeastern Nigeria were selected for the determination of their drinking quality, hydrogeochemical characteri...

Multidimensional Analysis of the Contamination Status, Corrosivity and Hydrogeochemistry of Groundwater from Parts of the Anambra Basin, Nigeria

In developing regions that engage in agricultural and industrial activities, access to high-quality water for drinking, domestic, irrigation and industrial purposes is limited. In this study, compr...

Chukwuma N. Mgbenu

Papers

The hydrogeochemical signatures, quality indices and health risk assessment of water resources in Umunya district, southeast Nigeria

Investigating the hydrogeochemical processes and quality of water resources in Ojoto and environs using integrated classical methods

Chemometric analysis for pollution source identification and human health risk assessment of water resources in Ojoto Province, southeast Nigeria

Multidimensional Analysis of the Contamination Status, Corrosivity and Hydrogeochemistry of Groundwater from Parts of the Anambra Basin, Nigeria

A multi-criteria water quality evaluation for human consumption, irrigation and industrial purposes in Umunya area, southeastern Nigeria