Assessing water quality using water quality index and multivariate analysis

Abstract

Groundwater is increasingly gaining significance as the main solution to the water supply problems in Ghana, especially in the rural areas. This study was conducted to determine which factors play significant roles in the hydrochemistry of groundwater from the southern Voltaian formation. Conventional graphical and multivariate statistical methods were used. The study reveals three main factors controlling the hydrochemistry. Silicate mineral weathering and reverse cation exchange are the most important processes affecting the hydrochemistry of groundwater at this part of the formation. Interpolation maps created from factor scores suggest that these processes are the most pervasive, recording high scores almost everywhere in the study area. Carbonate mineral weathering is the second most important process in the hydrochemistry. This study finds that carbonate mineral weathering in the area is probably facilitated by carbonic acid rather than sulfuric acid. Chemicals from agricultural activities constitute the third most important process influencing groundwater quality in the area. Eighty samples were used to calculate water quality indices, WQI, which were in turn used to classify groundwater from the study area. Over 98% of the samples fall within the ''Excellent'' and ''Good'' categories, suggesting that groundwater from the southern Voltaian formation is generally acceptable for drinking purposes.Keywords Factor scores Á Cation exchange Á Water quality index Á Silicate Á Carbonate InroductionGroundwater plays a very pivotal role in the domestic water delivery system in Ghana. It is particularly the main water supply for the rural population, which forms about 74% (Ghana Statistical Services 2000) of the total population of the country. There are a number of reasons why groundwater is attractive for most domestic uses: the resource is generally protected from most surface polluting activities and does not need bacteriological treatment prior to consumption; aquifers underlie most of the rural communities and can be tapped at relatively shallow depths; surface water resources are virtually nonexistent in most of these communities and where surface water resources exist, they are often so much polluted that the cost of tapping groundwater is modest compared to the cost of treating surface water resources before usage. In addition to meeting the domestic water needs of the rural population, it has been envisaged that groundwater has the potential of being phased in sufficient quantities to meet irrigation needs to raise the living standards of the communities whose main stay over the years has been rain fed peasant farming.The Voltaian system covers about 45% of the total landmass of Ghana and underlies most of the very deprived communities where the poverty level is worse than the national average. In light of the all important role of groundwater resources in most of the poverty alleviation strategies adopted by the government and many a non

Groundwater Chemistry Regulated by Hydrochemical Processes and Geological Structures: A Case Study in Tongchuan, China

“…In order to assess the possible role of ion exchange in the hydrochemistry of groundwater, (Ca 2+ + Mg 2+ ) − (HCO 3 − + SO 4 2− ) in meq/L was plotted against (Na + + K + ) − Cl − in meq/L. The (Ca 2+ + Mg 2+ ) − (HCO 3 − + SO 4 2− ) equation means that the cations Ca and Mg were corrected by omitting the influences by other processes (e.g., carbonate or silicate weathering), whereas the (Na + + K + ) − Cl − equation means that the cations K and Na were from sources other than their respective chlorides [49]. If ion exchange is the dominant process in the system, the samples should form a line with a slope of −1 [16,20,42,49].…”

“…The (Ca 2+ + Mg 2+ ) − (HCO 3 − + SO 4 2− ) equation means that the cations Ca and Mg were corrected by omitting the influences by other processes (e.g., carbonate or silicate weathering), whereas the (Na + + K + ) − Cl − equation means that the cations K and Na were from sources other than their respective chlorides [49]. If ion exchange is the dominant process in the system, the samples should form a line with a slope of −1 [16,20,42,49]. Figure 6e shows that cluster 1 and cluster 2 samples have a slope of −1, indicating cation exchange influences the groundwater chemistry of these samples, and cluster 3 has a slope of −0.6, indicating that cation exchange shows less influence on the water chemistry in cluster 3 than it does in the other clusters.…”

“…Figure 6e shows that cluster 1 and cluster 2 samples have a slope of −1, indicating cation exchange influences the groundwater chemistry of these samples, and cluster 3 has a slope of −0.6, indicating that cation exchange shows less influence on the water chemistry in cluster 3 than it does in the other clusters. Chloro alkaline indices (CAI) [37,49], calculated using Equations (3) and (4), were further used to identify the specific ion exchange between the groundwater and its host environment.…”

Removal of Iron and Manganese from Aqueous Solution Using Hydroxyapatite Prepared from Cow Bone

“…But in the case of final concentration of iron, the final concentration was 2.012 mg/l which is still not safe for drinking. Therefore, there is need for undergoing another cycle of adsorption by contacting with the hydroxyapatite adsorbent [46][47][48][49][50][51] . …”

Geospatial modelling for groundwater quality mapping: a case study of Rupnagar district, Punjab, India

“…The occurrence and movement of groundwater in an area is governed by several factors, such as topography, hydro-geomorphology, geology, drainage pattern, land use, climatic conditions and inter relationships among these factors. The quality of groundwater is equally important as its quantity owing to the suitability of water for various purposes (Yidana and Yidana, 2010). It refers variation of groundwater quality in an area is a function of physical and chemical parameters that are greatly influenced by geological formations and anthropogenic activities (Subramani et al, 2005;Vijith and Satheesh, 2007;Nas and Berktay, 2010).…”