QUALITY ASSESSMENT OF BOREHOLE WATERS IN ENUGU URBAN

CHAPTER ONE

1.0INTRODUCTION 

The use of water by man is as old as the existence of human beings since water, which is a natural

resource, is indispensable to life. 

Water is a common chemical substance that is essential for the survival of all known forms of life. It is used in vast quantities for drinking purposes, and even in greater quantities for washing, bleaching, dyeing, cooling, raising steam to drive engines or turbines to generate  electricity and in other industrial processes far too numerous to mention [1,2]. 

As a result of industrialisation and urbanisation, people migrate to townships and the population in these cities become too high; so is the need for water. Although surface water such as lakes, rivers, streams and springs are easily accessible, there is a great quest for people to drill borehole ground waters which are thought to be of better quality[3]. It is pertinent to observe that there are several human activities, which have indirect and devastating effects on ground water quality. Such activities include accidental or unauthorized release of chemical substances, discharge of untreated effluents, leaching of noxious liquids from solid waste deposits, surface runoff, untreated sewage, from population around the area [4,5]. This is because these pollutants or contaminants are carried by water and water moves easily through the soil and underlying rocks. This occurs particularly where the soil is sandy, gravelley or shallow or over porous limestone bedrock [6].

It is therefore the concern of scientists to ensure that the supply of water is maintained at sufficient purity for the masses to use. All the water from the borehole to the consumption level ought to meet the standards laid down by World Health Organization for drinking water to make the water potable. Substandard water samples can lead to diseases such as typhoid fever, dysentery, cholera and other types of gastrointestinal disturbances[7].For drinking water to be safe, the concentration of undesirable substances should not exceed the levels established by World Health Organization[8]  as shown in

Table 1below

Table 1: WHO Permissible Values

 This was focused on the quality of borehole waters in Enugu urban in relation to World Health Organization standards, to ascertain their potability. 

1.1. BACKGROUND OF THE STUDY 

 Nigeria is located in West Africa and has variable terrain. The climate ranges from equatorial in the south to tropical in the centre and arid in the north. Climatic variations influence the vegetations, ranging from mangrove swamps in the south, tropical rainforest in the centre, Savannah in the north and Sahel Savannah in the north-east. The annual rainfall varies from 4000mm in the south and 250mm in the north, with a national average of 1180mm [9]. Geological reports gave rock types as Precambrian basement in the southwest, southeast and north-central. The rocks include gneisses, schists, migmatites, pegmatite, charnockitic and quartzschist [10]. The study area Enugu urban is found in

Enugu State, southeast Nigeria, situated on longitude 7⁰30¹ 0E and latitude 6⁰30¹ 0N and has tropical vegetation. The major climatic seasons are wet or rainy season, which begins in March or April, and ends in October and the dry season, which begins in November and ends in March or April.

 Groundwater is an important water resource in both the urban and rural areas of Nigeria. Enugu which was previously mined for coal produced acid wastes that were  rich in metal elements like Pb, Cu, Zn, As, Mn and Fe. Most of these are toxic at fairly low concentrations. The coal mining at Enugu especially, has the potential of posing an acid mine drainage[11]. Though groundwater is considered to be aesthetically acceptable for domestic use, presence of poorly designed pit latrines, poor solid waste management as well as poor and inadequate water protection, may lead to contamination of groundwater with pathogenic bacteria. 

                               Also there is a growing fear of environmental

pollution by Lead (Pb) in the state generally due to the littering of the streets with storage batteries and to a lesser degree from gasoline burning engines and smokes from other fuels.

1.2. SCOPE OF STUDY 

Analysis of samples of borehole waters hand dug-wells and control (distilled) water to find temperature, color, pH electrical conductivity, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), total hardness, calcium hardness, magnesium hardness, alkalinity,

                                                         2-                                       2+

chloride, SO4  , NO3-  , PO₄3–,  Pb,    Cu, 2+  Zn, 2+  Cd, 2+  Fe2+ 

contents, total coliform (TC) counts and  Langelier Satuation Index (LSI) using some of the parameters in accordance to the standard method. 

1.3. AIMS 

–      To improve man’s health, through the taking of potable water

–      To determine the extent of contamination of the waters 

1.4 OBJECTIVES OF STUDY 

 The objectives of the study were to examine the physico-chemical and bacteriological quality of water from ten boreholes in Enugu urban, and to determine the corrosion potential of the water.