Abstract
The quality assessment of borehole and well waters from ten
locations in Enugu urban area were studied and compared
with World Health Organisation standards. The parameters
measured include temperature, color, pH, electrical
conductivity, total hardness, calcium hardness, magnesium
hardness, total solids, total dissolved solids, total suspended
solids, alkalinity, chloride, sulphate, phosphate, nitrate,
copper, cadmium, zinc, lead, iron, and total coliform. Langelier
Saturation and Ryznar Stability Indices were also calculated
for some of these parameters. The results obtained at daily
intervals were plotted and they showed pollution of seven of
the boreholes. Concentrations of Cadmium were high above
the limit in six of the boreholes while concentrations of lead
and phosphates were high in only two of the boreholes, with
respect to the WHO permissible limits for potable water. All
the waters show presence of coliform and corrosion potentials.
Consequently, these groun
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 500
Sulphate (mgl–1
) 400
Nitrate (mgl–1
) 50
Phosphate (mgl–1
) 1.0
Chloride (mg-1
) 250
Iron (mgl–1
) 0.3
Manganese (mgl–1
) 0.05
Lead (mgl–1
) 0.05
Copper (mgl–1
) 1.0
Zinc (mgl–1
) 5.0
Cadmium (mgl–1
) 0.05
Fecal coliform count/100ml 0
Total coliform count/100ml 0
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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
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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.
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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.
Fig 1: Map of Nigeria
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Fig. 1: Map of Nigeria
Fig. 2: Map of Enugu showing study Area
Population
Industries
Borehole
Main road
Market
Airport
KEY
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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,
chloride, SO4 , NO3 , PO4 , Pb, Cu, Zn, Cd, Fe
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.