CHAPTER ONE

INTRODUCTION

1. BACKGROUND OF THE STUDY

Human civilization prospered in the vicinity of water sources and especially along river banks. We often heard tales pertaining to their quality and quantity for years, either for potable or agricultural use. However, settlements in due course and indiscriminate exploitations made groundwater suffer in maintaining its basic characteristics. Reasons might not be limited but vigilance in time might restore or reduce the onslaught and thus safeguard futuristic needs. Often, assessments of groundwater involve multiple approaches base on the type of interpretation and thus status leading to management strategies. It seems wise that an understanding of the quantitative and qualitative changes in groundwater system because of existing and proposed hydrologic stresses is a pre-requisite for their proper management. The idea of weathered, fractured, and freshwater basements along with local environment would enhance these chances in any given area. The demand for groundwater use will continue to increase, and further problems are likely to become evident because of land use and climate changes. This will involve ongoing evaluation of groundwater’s sustainable yields and management regimes including the use of entitlements in the light of changing knowledge about climate, hydrogeology, and other factors influencing water scarcity, as well as continuing policy adjustment in the light of improving knowledge and an increase in experience (Andrew et al. 2005).

In general, groundwater assessments often involve geophysical, geological, or chemical data in the assessment of its various characteristics. Respective data interpretation reveals either geomorphology or geology or geo-hydrochemistry of those areas. Now-a-days, modeling, remote sensing, and computed assessments are being widely used with the above conventional methods of assessments. River and reservoir basin studies follow a close trend in their assessments using the above approaches. According to Lewis Brent (2001), it is possible to take an image of the subsurface quickly and inexpensively through application of various nonintrusive surface geophysical methods. Electrical resistivity studies have extensively been used in groundwater geophysical investigations because of the correlation that often exist between electrical properties, geologic formations, and their fluid content (Zohdy and Jackson 1969; Fitterman and Stewart 1986). Schwartz and McClymont (1977) and Stoller and Roux (1975) had reported that the variations in the apparent resistivity in the given area can often be related qualitatively to geological features, and for delineation of aquifers, these are the pre-requisites for the assessment of regional/local groundwater potential.

Delineation of aquifers and subsequently their groundwater potential assessment were carried out in different parts of India, using different geophysical, geological, geochemical, remote sensing, and geographic information system (GIS) methods depending on the local hydro-geological conditions (Rai 2009), while isotope and GIS integration studies have been reported by Elias and Ierotheos (2006). A new hydro-chemical technique based on electrical conductivity logs was developed for the delineation of water-bearing fractures in hard rock areas and tested in the Maheshwaram watershed (Saxena et al. 2005). An integrated study was carried out in Bairasagara watershed in Karnataka, India to investigate the subsurface conditions in hard rock environment with the aim of identifying zones with groundwater potential (Chandra et al. 2006). The geochemical studies on the Dankar, Thinam, and Gete lakes in the Spiti valley of higher Himalaya have been carried out to understand the nature of lithology and the type of weathering at the source (Das and Dhiman 2003). However, the geochemistry and quality assessment of Dhanbad, India has been reported by Singh et al. (2007) and hydro-geological and hydrochemical study on Kali-Ganga, India was also reported by Umar et al. (2001). In an integrated approach of weathering, chemisorptions and trace metal fluxes to the oceans have been reported by Dowling et al. (2003) along the Bengal basin’s groundwater. The quality assessment and determination of pollution sources of interactive study in southern Europe has been reported on Axios-Varda River by Milovanovic (2007), while integration of thematic maps and GIS for the identification of groundwater zones has been reported by Murthy et al. (2003).

The studies on the groundwater involving integrated approach that have been reported are mainly based on the geophysical dominance assessments relating to areas in and around the present study, including mathematical modeling based on resistivity (Vinoda Rao and Gurunadha Rao 2006) and integration of geo-electrical and pumping data (Rao 2003). The electrical resistivity survey was applied by Kshirasagar and Rao (1989) in Varaha River basin, India while Sarma and Swamy (1981) applied this on Visakhapatnam basin, India to study the pollution status. In assessment, development, and management of surface/groundwater resources to meet the demands of water supply from available water resources, a novel approach of integrated assessment was carried out by us and is reported in the present paper. In this present investigation, the resistivity survey was carried out in 50 locations along the Thandava Reservoir during June 2012 along with soil sample collection and their analysis for the comprehensive assessment of the groundwater’s characteristics. It was aimed that the integrated approach of the various parameters would reveal realistic conclusions rather than speculative assumptions based on single parameter assessments.

1. STATEMENT OF THE PROBLEM

Hydro geochemistry of groundwater is determined by its chemical and biogeochemical constituents. The exploration and exploitation of groundwater as a major resource to meet the growing population in some urban cities located in the basement complex rocks around Ondo cityarea South Western Nigeria has been a subject of discussion (Odukoya and Abimbola 2010; Nagard 2010; Obiefuna and Sheriff 2011; Olorunfemi 1990).

The quality of water is now the concern of experts in all countries of the world. Eighty percentage of the diseases and deaths in the developing countries are related to water contamination UNESCO (2007), UNDP (1971). It has been generally agreed that the water delivered to the populace should meet the high requirement of modem hygiene and should at least be free from pathogenic organisms and toxic substance. It is therefore important to carry out water quality assessment for sustainable management of water bodies.

Additionally, intense agricultural and urban developments have placed a high demand on groundwater resources worldwide and also directly or indirectly play a major role in regulating groundwater chemistry (Lowrance et al. 1997; Fakir et al. 2002; Cardona et al. 2004).

Groundwater contamination can cause intense agricultural activities is usually expressed increasing salinity and increasing nutrient concentration (Dash et al. 2006; Perez et al. 2003; Chae et al. 2004). Uncontrolled applications of fertilizers and manure, as well as indiscriminate disposal of domestic wastes and sewage, could further contribute to the degradation of groundwater quality, especially in the developing countries (Oladeji et al. 2012). Similarly, urban development also causes deterioration in groundwater quality (Nkotagu 1996; Stigter et al. 1998; Zilberbrand et al. 2001). In the light of the above, the study will try to investigate the relationship effect between geochemical and ground water in Ondo city area of south western Nigeria.

1. AIM AND OBJECTIVES

The aim of this study is to investigate the relationship effect between geochemical and ground water. Specifically, the study will seek to:

1. Examine whether Hydro geochemistry of groundwater is determined by its chemical and biogeochemical constituents
2. Examine whether urban development  causes deterioration in groundwater quality
3. Examine the role of geochemical experts on quality of groundwater
4.  Examine whether indiscriminate disposal of domestic wastes and sewage, contributes to the degradation of groundwater quality
   1. RESEARCH QUESTIONS

Arising from the research objectives, the following research questions will be presented and addressed in the study:

1. Does Hydro geochemistry of groundwater is determined by its chemical and biogeochemical constituents
2. Does urban development  causes deterioration in groundwater quality
3. What is the role of geochemical experts on quality of groundwater
4.  Does  indiscriminate disposal of domestic wastes and sewage, contributes to the degradation of groundwater quality

1. RESEARCH HYPOTHESIS

H0 there is no relationship effect between geochemical and groundwater

H1 there is relationship effect between geochemical and groundwater

1. SIGNIFICANCE OF THE STUDY

Groundwater is an important medium for geochemical exploration of many different styles of mineralization, including porphyry copper, volcanogenic massive sulphide (VMS), sandstone uranium, and gold.

The study finding will be very useful to plumbers and groundwater diggers on the indiscriminate disposal of domestic wastes and sewage affecting the degradation of groundwater quality.

Ultimately, the study will be eye opener to the policy makers of the State on control measures for quality groundwater consumption.

1. SCOPE OF THE STUDY

The study is limited to geochemical investigation of groundwater around Ondo city area of south western Nigeria.

The study focuses on whether Hydro geochemistry of groundwater is determined by its chemical and biogeochemical constituents; it examine whether urban development causes deterioration in groundwater quality; it examine the role of geochemical experts on quality of groundwater; and lastly examine whether indiscriminate disposal of domestic wastes and sewage, contributes to the degradation of groundwater quality.

1. LIMITATION OF THE STUDY

TIME CONSTRAINTS: One the challenges experienced by the researcher is the issue of time; the research will simultaneously engage in departmental activities like seminars and attendance to lectures. But the researcher was able to meet up with the deadline for the submission of the project.

FINANCIAL CONSTRAINTS: Every research work needs funding; however lack of adequate funds might affect the speed of the researcher in getting materials for completion of the project.

1.9 DEFINITION OF TERMS

Groundwater 

Is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells.

Geochemistry 

Is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the entire Solar System, and has made important contributions to the understanding of a number of processes including mantle convection, the formation of planets and the origins of granite and basalt. It is an integrated field of chemistry and geology.

Hydrology

Study of water and its properties, including its distribution and movement in and through the land hydrologic cycle consists of the passage of water from the oceans into the atmosphere by evaporation and transpiration (or evapotranspiration), onto the lands, over and under the lands as runoff and infiltration, and back to the oceans.areas of the earth.