Samuel Y. Ganyaglo

Investigation of the possible sources of heavy metal contamination in lagoon and canal water in the tannery industrial area in Dhaka, Bangladesh

This study evaluated the heavy metal pollution level of tannery effluent-affected lagoon and canal water in the southwestern Dhaka, Bangladesh. The measured physicochemical parameters (electrical conductivity, chemical oxygen demand, pH, SO

Reconnaissance on the suitability of the available water resources for irrigation in Thakurgaon District of northwestern Bangladesh

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Preliminary groundwater quality assessment in the central region of Ghana

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Application of geochemical and stable isotopic tracers to investigate groundwater salinity in the Ochi-Narkwa Basin, Ghana

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Application of Water Quality Index (WQI) and Multivariate Analysis for Groundwater Quality Assessment of the Birimian and Cape Coast Granitoid Complex: Densu River Basin of Ghana

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Surface water quality assessment in the central part of Bangladesh using multivariate analysis

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Water quality assessment of groundwater in some rock types in parts of the eastern region of Ghana

) and metals (As, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, and Zn) were subjected to principal component (PCA) and hierarchical cluster analyses, and examining correlation matrix as well in order to explain the behavior and sources of the parameters/metals. The mean concentrations of the heavy metals in the lagoon and canal water were very high and, in most cases, exceeded the standard limits recommended by the Bangladesh Government. The following elemental associations were obtained from PCA and CA: Ca–Cd–Cr–Fe–K–Mn–Pb–Zn, Co–Cu–Ni, and As, which could be linked to anthropogenic sources (i.e., processes of the tannery and paint industries with some contributions from the municipal waste system). Potassium, Ca, Cr, Mn, Fe, Zn, As, and Cd occurred as important anthropogenic markers in the lagoons and lower part of the canal. Copper, Co, and Ni were importantly distributed in the lower part of the canal, which also received metal inputs from the municipal waste and other industrial sources, including paint industry. GIS-based factor score maps, generated to show the spatial controls of the major processes affecting surface water hydrochemistry, suggest that the activities of paint and tannery industries and municipal sewage are pervasive processes in the area, whereas the contribution from pesticides (used for tanning and disinfecting hides) has localized effects. This study has provided the evidence that effluents discharged from the tannery and auxiliary industries and urban sewage system are the main sources of heavy metal pollution in the lagoon and canal water systems in the Hazaribagh area of southwestern Dhaka. The high mean concentrations (in mg/l) of Cr (5.27), Pb (0.81), As (0.59), and Cd (0.13) observed in the water samples may have serious public health and potential environmental hazard implications.

Origin of Dissolve Ions in Groundwaters in the Northern Densu River Basin of Ghana Using Stable Isotopes of 18O and 2H

Reconnaissance on the suitability of the available groundwater resources for irrigation in Thakurgaon District of northwestern Bangladesh was done by determining pH, TDS, EC, hardness, alkalinity, major cations and anions. The pH values suggest that the water is slightly acidic to strongly basic. The dominant cation and anion in the study area are Ca2+, Mg2+ and HCO3−, respectively. Calcium bicarbonate, calcium–magnesium–bicarbonate and calcium carbonate are the dominant hydrochemical facies among the water samples. The groundwater system in the study area may be recharged through infiltration of rain. The above statement is further supported by Gibbs plot where most of the samples fall within the rock-dominance zone. The evolution of these waters may be controlled by precipitation and dissolution of carbonate minerals. The USSL, SAR–EC classification schemes and Wilcox plot confirm that the groundwater samples are good to excellent as irrigation water. However, the groundwater evolution in this study is mainly the result of weathering of carbonate minerals and cation exchange within the aquifer materials, confirming the shallow porous groundwater hydrochemistry characteristics.

The hydrochemistry of groundwater in the Densu River Basin, Ghana

Insufficient knowledge of the hydrogeochemistry of aquifers in the Central Region of Ghana has necessitated a preliminary water quality assessment in some parts of the region. Major and minor ions, and trace metal compositions of groundwater have been studied with the aim of evaluating hydrogeochemical processes that are likely to impair the quality of water in the study area. The results show that groundwater in the area is weakly acidic with mean acidity being 5.83 pH units. The dominant cation in the area is Na, followed by K, Ca, and Mg, and the dominant anion is Cl−, followed by HCO3− and SO42−. Two major hydrochemical facies have been identified as Na–Cl and Na–HCO3, water types. Multivariate statistical techniques such as cluster analysis (CA) and factor analysis/principal component analysis (PCA), in R mode, were employed to examine the chemical compositions of groundwater and to identify factors that influenced each. Q-mode CA analysis resulted in two distinct water types as established by the hydrochemical facies. Cluster 1 waters contain predominantly Na–Cl. Cluster 2 waters contain Na–HCO3 and Na–Cl. Cluster 2 waters are fresher and of good quality than cluster 1. Factor analysis yielded five significant factors, explaining 86.56% of the total variance. PC1 explains 41.95% of the variance and is contributed by temperature, electrical conductivity, TDS, turbidity, SO42−, Cl−, Na, K, Ca, Mg, and Mn and influenced by geochemical processes such as weathering, mineral dissolution, cation exchange, and oxidation–reduction reactions. PC2 explains 16.43% of the total variance and is characterized by high positive loadings of pH and HCO3−. This results from biogenic activities taking place to generate gaseous carbon dioxide that reacts with infiltrating water to generate HCO3−, which intend affect the pH. PC3 explains 11.17% of the total variance and is negatively loaded on PO43− and NO3− indicating anthropogenic influence. The R-mode PCA, supported by R-mode CA, have revealed hydrogeochemical processes as the major sources of ions in the groundwater. Factor score plot revealed a possible flow direction from the northern sections of the study area, marked by higher topography, to the south. Compositional relations confirmed the predominant geochemical process responsible for the various ions in the groundwater as mineral dissolution and thus agree with the multivariate analysis.

Hydrogeochemical and Groundwater Quality Studies in the Northern Part of the Densu River Basin of Ghana

ABSTRACT Rainwater, groundwater and soil-water samples were analysed to assess groundwater geochemistry and the origin of salinity in the Ochi-Narkwa basin of the Central Region of Ghana. The samples were measured for major ions and stable isotopes (δ18O, δ2H and δ13C). The Cl− content in rainwater decreased with distance from the coast. The major hydrochemical facies were Na-Cl for the shallow groundwaters and Ca-Mg-HCO3, Na-Cl and Ca-Mg-Cl-SO4 for the deep groundwaters. Groundwater salinization is caused largely by halite dissolution and to a minor extent by silicate weathering and seawater intrusion. Stable isotope composition of the groundwaters followed a slope of 3.44, suggesting a mixing line. Chloride profiles in the soil zone revealed the existence of salt crusts, which support halite dissolution in the study area. A conceptual flow model developed to explain the mechanism of salinization showed principal groundwater flow in the NW–SE direction. EDITOR D. Koutsoyiannis ASSOCIATE EDITOR K. Heal