HYDROGEOCHEMICAL ANALYSIS OF GROUNDWATER QUALITY OKITIPUPA SOUTHWESTERN NIGERIA

Water is an essential requirement of life which has been considered more as an economic resource rather than a social good. Despite the fact that fresh water storage in the environment remains constant, demand for freshwater such as groundwater has experience increase due to population explosion, urbanization, irrigation and domestic activities (MacDonald et al. 2014). However, the quantity and qual- ity of this economic resource are equally important factors in the context of modern water management (Kumar et al. 2013; Anudu et al. 2008). Factors such as nature of surface runoffs, weathered products and mineralogical composition of the underlying lithology/rock types usually plays a vital role in the chemistry of groundwater hence they affect the groundwater quality. The hydrochemical studies of major dissolved ions of groundwater have been used to understand the evolution of groundwater, identification of the predominant geochemical processes and determination of the effects of anthropogenic activities on groundwater in several parts of the world. Several processes such as climate changes, soil/ rock interactions, dissolution and/or precipitation of mineral species, exchange reactions, degree of chemical weathering of the various rock types, groundwater resources and agriculture actvities, prolonged storage in the aquifer and so forth (Mat- thess 1982; Hem 1985; Appelo and Postma 2005; Subramani et al. 2005; Kumar et al. 2009; Garcia-Ruiz et al. 2011; Ako et al. 2012; Gomo et al. 2012; Rajesh et al. 2012; Bozdag and Gocmez 2013; Daniele et al. 2013, Su et al. 2013; Garcia- Garizabal et al. 2014; Montcoudiol et al. 2014; Varol and Davraz 2014; Abrahao et al. 2015; Ghesquiere et al. 2015; Puntoriero et al. 2015; Redwan and Abdel Moneim 2015) also affect the chemistry of groundwater. However, the chemistry of groundwater evolution is an important factor before determine its use for overall groundwater quality usage such as domestic, irrigation and industrial purposes (SarathPrasanth et al. 2012; Subba Rao et al. 2002; Kumar et al. 2014). The knowledge accrued from hydrochemistry (hydrochemical evaluation) is very important to assess the groundwater quality in any area in which the groundwater is used for both irrigation and irrigation needs (Srinivas et al. 2013; Kumar et al. 2014). The study area Okitipupa is located in Ondo State southwestern Nigeria and made up of two contrasting geological terrains (basement and sedimentary terrains). Inadequate access to portable water supply in these areas has been reported due to short fall in water supply by the Ondo State Water Corporation. The shortage in water supply has led to random digging of shallow hand-dug wells and boreholes without systematic pre-drilling groundwater investigation. These groundwater sources have also been found to be highly susceptible to pollution in some locations due proximity to polluted surface water bodies and other human activities. This accounted for the increased rate of water borne diseases such as dysentery, diarrhea, guinea worm, skin infection and typhoid in some locations of the study area especially in Ore area (Olotu et al. 2009). In this respect, this study is fundamental and can serve as a reference for the authorities (local governments) to improve and sustain the development and management of water resources in the future. It is upon this background that this study was aimed at investigating the hydrogeochemical processes and its contribution to the overall groundwater quality in both Ore and Okitipupa areas. This comparative investigation also ascertains the major controlling factors influencing the distributions of dissolved ions in these waters and to determine the processes affecting the chemistry of groundwater. 1.2 Objectives of Study The objective of the present study is to assess the physicochemical parameters of groundwater in Okitipupa Township and compare MI values to ascertain its suitability for human consumption. The objective of the study on hydrogeochemical analysis of groundwater in Okitipupa, SW Nigeria, is to evaluate the extent of cations and anions in the region's groundwater. This includes: 1. Assessment of Water Quality Parameters: Evaluate the concentrations of key hydrogeochemical parameters such as pH, electrical conductivity, major ions (e.g., Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄²⁻, HCO₃⁻), and trace elements (e.g., Fe, Mn, Cu, Zn) in groundwater samples from Okitipupa. 2. Identification of Water Quality Issues: Identify potential water quality issues such as salinity, contamination by anthropogenic activities, and natural sources of pollutants affecting groundwater in the study area.