CHAPTER ONE

1.0     INTRODUCTION

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

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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

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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

Parameters

WHO LIMIT

Color

5 – 25 units

Taste and odor

Unobjectionable

Turbidity

5 units

pH

6.0 – 8.5

Electrical conductivity (µmhoscm–1)

50

Alkalinity (mg–1) CaCO3

100

Total solids (mg-1)

1000

Total dissolved solids (mgl–1)

1000

Total suspended solid (mgl–1)

500

Total hardness (mgl–1) CaCO3

500

Calcium hardness (mg-1) CaCO3

500

Magnesium (mg-1) CaCO3