1
IMPACT OF WASTE DISPOSAL PRACTICES ON SURFACE AND
GROUNDWATER: A CASE STUDY OF UYO AREA,
SOUTHEASTERN, NIGERIA
BY
ASUQUO, MARY JOSEPH
(PG/M.Sc./07/43231)
DEPARTMENT OF GEOLOGY
FACULTY OF PHYSICAL SCIENCES
UNIVERSITY OF NIGERIA
NSUKKA
JULY, 2010
2
IMPACT OF WASTE DISPOSAL PRACTICES ON SURFACE AND GROUNDWATER:
A CASE STUDY OF UYO AREA, SOUTHEASTERN, NIGERIA
BY
ASUQUO, MARY JOSEPH
(PG/M.Sc./07/43231)
A RESEARCH PROJECT SUBMITTED TO THE DEPARTMENT OF GEOLOGY
FACULTY OF PHYSICAL SCIENCES UNIVERSITY OF NIGERIA, NSUKKA
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF A MASTER
OF SCIENCE IN HYDROGEOLOGY
JULY, 2010
3
CERTIFICATION
Asuquo, Mary Joseph is a postgraduate student in the Department of Geology
with the registration number PG/M.Sc./07/43231 has satisfactorily completed the
requirements for the course and research work for the degree of Master of
Science in Hydrogeology. The work embodied in this project report is original and
has not been submitted in part or full for any degree or diploma of this or any
other university.
________________________ ____________
Prof C.O. Okogbue Date
Project Supervisor
__________________________ ____________
Dr. A.W. Mode Date
Ag. Head of Department
_________________________________ ________________
External Examiner Date
4
DEDICATION
This work is dedicated to the ALMIGHTY GOD, my helper, JESUS CHRIST, the hope
of my salvation and to the HOLY SPIRIT, my comforter.
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ACKNOWLEDGEMENT
I am expressing my sincere thanks to the Almighty God who is my hope,
and the helper of my destiny. I also wish to thank my supervisor Prof.C.O.
Okogube for taking time out of his tight schedule to supervise this work.
I am particularly grateful to my late supervisor late Prof. H. I. Ezeigbo with
whom I initiated this work. My heartfelt gratitude goes to Mr. O.S. Onuwuka of
the department of Geology, University of Nigeria, Nsukka, for his suggestions and
other lecturers for their contributions.
Dr Nganje and Mr ukpong for their words of advice. Mr. Ugbaja and Mr
chinjinju who ran the statistical analyses at no cost. Profound gratitude goes to
my father Mr Joseph Asuquo Akpan, Emmanuel Okon my friend, my classmates
Omonona Olufemi Victor, Ayuba Rufai, Isreal Godwin, Mfon Esu and Chinenye
Uwom.
Special thanks go to Mr Esuene Sampson for all the Journals he provided
towards this work and Nsikan Imeh Etuk for being there at all times. I appreciate
and love you all.
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ABSTRACT
Impacts of waste disposal on surface and groundwater in Uyo metropolis was
carried out with the intent of determining surface and groundwater sources that
have been polluted by the city dumps. Water samples from Uyo, were collected
and analyzed for physical, chemical and biological constituents to identify the
geogenic (hydro geochemical) and anthropogenic processes that control the
water quality. The data analyses were carried out using analysis of variance and
principal component analysis. The analysis of variance was used to differentiate
between the concentrations of physical, biological and chemical parameters of
surface and groundwater. Principal component analysis was made on the
physical, chemical and biological variables, and four components were chosen.
The graphical interpretations were done using stiff and piper diagrams. The
groundwater is acidic and soft and most of the samples are not fit for drinking. All
the parameters show significant differences in concentrations between surface
and groundwater except the trace elements, nitrate, bicarbonate and bacteria.
The first principal component is characterized by conductivity ,TDS, total solid,
total hardness, calcium hardness, Ca 2 , Na , K , Cl parameters; The second
turbidity, total suspended solids Fe2+; The third magnesium hardness, Mg 2 ; and
the fourth NO 3 .These components are interpreted to be controlled by geogenic
processes (hydro geochemical) : cation exchange and dissolution processes,
weathering of ferromagnesian minerals and silicate minerals and anthropogenic
processes: sewage waste and leachate from the solid refuse disposal sites. The
principal component sample location plot clearly explained the spatial distribution
of water sample locations and the various processes affecting them. The water
samples located in the vicinity of four town dump site are strongly affected by the
geo-genic process while those in the vicinity of Barracks road dumpsite are
strongly affected by the anthropogenic activities. Principal component analysis in
the present study assisted the assemblage of water quality results, from different
sources by explaining the processes (hydro-geochemical and anthropogenic
processes) affecting them. The stiff pattern shows that surface water has higher
ionic strength than groundwater. The predominant water type in the study is
calcium magnesium sulphate chloride type as revealed by the piper diagram.
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TABLE OF CONTENTS
TITLE PAGE i
CERTIFICATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
TABLE OF CONTENTS vi
LIST OF TABLES viii
LIST OF FIGURES ix
LIST OF PLATES x
CHAPTER ONE: INTRODUCTION
1.1 Background information 1
1.2 Study Area 1
1.3 Climate and vegetation 3
1.4 Relief and Drainage 3
1.5 Aims and Objective 3
CHAPTER TWO: REGIONAL GEOLOGICAL SETTING
2.1 Regional Geological Setting 5
2.2 Local Geology and Hydrogeology 5
2.3 Literature review 9
8
CHAPTER THREE: METHODS OF STUDY
3.1 Geochemical Methods 12
3.2 Statistical Method 14
3.3 Determination of groundwater flow direction 15
CHAPTER FOUR: RESULTS AND DISSCUSSION
4.1 Hydro-geochemistry and Water quality 17
4.2 Comparison between Surface water and Groundwater 21
4.3 Sources and Controlling Processes of Elements in Water 21
4.4 Impact of Wastes on Surface and Groundwater Sources 29
4.5 Stiff Plots 35
4.6 Piper Trilinear Diagram 35
CHAPTER FIVE: CONCLUSIONS 42
REFERENCES 44
APPENDICES 48
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LIST OF TABLES
Table 1: Stratigraphic and Hydrostratigraphic Units in Akwa Ibom State 8
Table 2: Physiochemical Parameters 18
Table 3: Classification of Water based on salinity 19
Table 4: Classification of water based hardness 19
Table 5: Analysis of Variance 22
Table 6: Rotated Component Matrix of Chemical Data of Water Samples 23
Table 7: The Processes Controlling each Principal Components 27
Table 8: Distribution of clusters of water samples 29
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LIST OF FIGURES
Figure 1: Accessibility Map of the Study Area 2
Figure 2: Drainage Map of the Study Area 4
Figure 3: Paleogeography of the Tertiary Niger-Delta 6
Figure 4: Base map of the study area showing the sampling points in relation
to the pollution sources. 13
Figure 5: Water Table Contour Map 16
Figure 6: The Principal Components Plots of Variables in Rotated Space 24
Figure 7: The Component Plots of Water Samples Locations in Rotated Space 28
Figure 8: Areal Distribution of Water Sample Locations Affected by
Cation Exchange and Dissolution Processes 31
Figure 9: Areal Distribution of Water Sample Locations Affected by
Weathering of Ferromagnesium Minerals 32
Figure 10: Areal Distribution of Water Sample Locations Affected by
Weathering of Silicate Minerals 33
Figure 11: Areal Distribution of Water Sample Locations Affected by
Anthropogenic Activities 34
Figure 12: Stiff Diagrams Showing the Relative Concentrations
of Major Cations and Anions in Waters in the Study Area 36
Figure 13: Piper Tri-linear Diagram 38
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APPENDICES
Appendix 1: Physical and bacteriological parameters analyzed for
Quality assessment of water samples from Uyo 48
Appendix 2: Chemical parameters analyzed for quality
assessment of water samples from Uyo 49
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CHAPTER ONE
INTRODUCTION
1.1 Background Information
Geochemical processes that control the quality of surface and groundwater
are currently a topic of increasing concern everywhere because water is a blue
gold of vital economic and social importance. Its quality has an effect on the
health of human beings as well as the growth of crops. Minerals of bedrock are
subjected to weathering and leaching, and so contribute dissolved constituents to
both surface and groundwater. Also anthropogenic activities affect water
chemistry. An understanding of these processes is thus essential for the
sustainable development of the water resources of an area.
Many interrelated processes control the chemical composition of water and
the understanding of these processes is needed before one can act intelligently
towards groundwater quality control and improvement (Hem, 1991). Principal
component analyses are thus used for identifying the geogenic and anthropogenic
processes which result in the variations in the chemical composition of both
surface and groundwater that may have adverse effects on human beings. This
will aid in implementing the appropriate remedial management measures in time
for the development of water resources of an area.
1.2 Study Area
The study area lies between latitude 5000
'and 5
054
'N and longitude 7
o54
and 8o
00' (Figure 1). It belongs to the tropical rainforest zone and is part of the
low lying coastal / deltaic plains of southern Nigeria. The water sources in the
area are subsurface (boreholes) and surface (stream) sources. The principal refuse
disposal methods in the area are open dumps. The area is accessible through a
network of motorable roads such as the Ikot Ekpene road, Calabar Itu road etc.
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Ikot Obo ng
Ikot Obio
Ikot Ekpu k
Aba k-I biaku U ru an
Iba Oku
UYO
Barracks
Priso n
Ewe t
Ikot Nt ue m
Ibiaku U fo t
Fo ur Tow nsAtan
Oku
Ibo ko Of fo t
Effia t Of ot
Etoi
Aka
Itiam Oko pe di
Itiam Eb ia
Itiam Et oi
Ifa Ikot Oku n
Use Of ot
Ikot Anyang
N
EW
S
5°00' 5°0
0'
5°2' 5°2
'
5°4' 5°4
'
7°54'
7°54'
7°56'
7°56'
7°58'
7°58'
5
5
Road River
LEGEND
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#
KAN0MAIDUGURI
ENUGU
Study
Area
3 0 3 6 Kilometers
Figure 1: Accessibility Map of the Study Area.
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1.3 Climate and Vegetation
Climate can be defined as the total observation of weather elements in a
place or region over a long period of time as (Illoeje, 1981). The study area
belongs to the tropical rainforest zone and has a mean annual rainfall of 1250mm,
with a relative humidity greater than 80%, an annual temperature of less than 27 O C (Offodile, 2002), and an annual evaporation of 1680mm (Edet et al. 2001).The
vegetation is typically rainforest and swamp. It is made up of perennial trees such
as Obeche, Opepe, Epiphytes climbers, shrubs etc.
1.4 Relief and Drainage
The study area is characterized by low relief with elevations ranging from
less than 10m to 50m above mean sea level and increasing in the northward
direction (Ugbaja et al. 2004).The area is drained by Idim Uyo and its tributaries
and the dominant drainage pattern is dendritic (Figure 2).
1.5 Aims and Objectives
This study is aimed at:
i. Evaluating the level of contamination in the surface and groundwater resources
of Uyo, and
ii. Evaluating the heavy metal concentrations and distributions in the water and
explaining such in relation to hydro-geochemical processes and other factors, and
to compare their concentrations with WHO standards.
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Ikot Obong
Ikot Obio
Ikot Ekpuk
Abak-Ibiaku Uruan
Iba Oku
UYO
Barracks
Prison
Ewet
Ikot Ntuem
Ibiaku U fot
Four TownsAtan
Oku
Iboko Off ot
Effiat Of ot
Etoi
Aka
Itiam Okopedi
Itiam Ebia
Itiam Etoi
Ifa Ikot Okun
Use Ofot
Ikot Anyang
N
EW
S
5°00' 5°00
'
5°2' 5°2
'
5°4' 5°4
'
7°54'
7°54'
7°56'
7°56'
7°58'
7°58'
5
5
Rive r
LEGEND
3 0 3 6 Kilometers
Figure 2: Drainage Map of the Study Area
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CHAPTER TWO
GEOLOGY AND HYDROGEOLOGY
2.1 Regional Geological Setting
The study area belongs to the southeastern part of the Niger Delta
Sedimentary Basin described by Reyment, 1965; Short and Stauble, 1967; Murat,
1972; Kogbe, 1989; Wright et al., 1985; Esu et al., 1997. The Niger Delta
Sedimentary Basin is located in the southern part of Nigeria, and is bounded by
the Atlantic Ocean to the South. The Northwest rim of the delta shares boundary
with the Benin flank. The Eastern side on the other hand is bordered by the
Calabar flank while the Senonian Abakiliki Uplift and Anambra Basin lie to the
North (Kogbe, 1989).There are three subsurface Stratigraphic units in the modern
Niger Delta. These Formations range from Miocene to Recent in age with
sediment thickness of about 6000ft (Kogbe, 1989).The geomorphic units
identifiable within the Formations include Point Bars, Channel Fills , Natural
Levees, Back Swamp Deposit, Oxbow Fill etc.
The Protodelta developed in the northern part of the basin started during the
Campanian transgression and ended with the Paleocene transgression. Formation
of the modern delta began during the Eocene (Figure 3). It has been suggested
that the basin which enhanced and controlled the development of the present
pday Niger delta developed by rift faulting during the three major depositional
environments typical the Precambrian (Weber, 1971).These major depositional
environments which Short and Stauble recognized as the three subsurface
stratigrahic units in the morden Niger Delta include; Benin, Akata and Agbada
Formations.
2.2 Local Geology and Hydrogeology
Four main hydro-stratigraphic units have been delineated in the study area.
These include three aquiferious units named upper, middle and lower sand
aquifers and the Imo Shale Aquitard (Esu et al., 1997).The upper sand aquifers
consist of coastal plain sands of Benin Formation and the recent alluvium. These
k o p e d i I t i a m
E b i a I t i a m
E t o i I f a
I k o t
O k u n
U s e O f o t
I k o t A n y a n g
2 0 2 4 K i l o m e t e r s
N
E W
S
5 ° 0 0 ' 5 ° 0 0 '
5 ° 2 ' 5 ° 2 '
5 ° 4 ' 5 ° 4 '
7 ° 5 4 '
7 ° 5 4 '
7 ° 5 6 '
7 ° 5 6 '
7 ° 5 8 '
7 ° 5 8 '
5 5
C o n t o u r 1 5 1 5
-
3 0
3 0
- 4 5
k o p e d i I t i a m
E b i a I t i a m
E t o i I f a
I k o t
O k u n
U s e O f o t
I k o t A n y a n g
2 0 2 4 K i l o m e t e r s
N
E W
S
5 ° 0 0 ' 5 ° 0 0 '
5 ° 2 ' 5 ° 2 '
5 ° 4 ' 5 ° 4 '
7 ° 5 4 '
7 ° 5 4 '
7 ° 5 6 '
7 ° 5 6 '
7 ° 5 8 '
7 ° 5 8 '
5 5
C o
t o u r 1 5 1 5
-
3 0
3 0
- 4 5
E
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Figure 3: Paleogeography of the Tertiary Niger Delta – Stages of Delta Growth
(Short and Stauble, 1967)
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Coastal plain sands are mostly made up of unconsolidated sands and gravelly
sands with clay intercalations. The Recent Alluvium comprises gravels, lateritic
sands, fine to medium grained and carbonaceous sand (Esu et al., 1997).The
sediments of the Benin Formation are more permeable and discharge more
copiously than those of the Recent Deltaic Alluvium. This is due to the more
arenaceous character of their aquifers (Offodile, 2002) (Table 1).
Edet (1993b) stated that the upper sand aquifer has the following
characteristics: thickness 20m – 200m, saturated thickness of aquifer 39m– 100m,
static water level 1 -55m, yield 316 – 530m3/d, transmisssivity 200 – 8300m2/d,
hydraulic conductivity 2 – 28m/d, drawdown 1.2 - -42.5m and storage coefficient
0.10 – 0.30. The recharge of this aquifer is from precipitation and its groundwater
is being exploited through bored wells.
The middle sand aquifer comprises the Bende-Ameki Group and Ogwashi
Asaba Formation of Middle Eocene to Miocene (Esu et al., 1997). Lithologically,
the aquifer is composed of yellow reddish, greyish and whitish sands, gravels and
semi consolidated sandstones with intercalations of clayey layers. These sands are
generally fine to coarse grained and moderately well sorted. The thickness of the
middle sand aquifer ranges from about 70m to 2400m, average saturated
thickness is 100mm, well yield is 20 – 352m2/h, drawdown is 2.7 -32.6, hydraulic
gradient 5.0 ×10 , transmissivity is 147.5 – 2013.3m2/d, storage coefficient 2.0 ×
10 to 3.6 × 10 2 and static water level in the range 1.23 to 41.50 (Esu et al., 1997).
Recharge in the middle sand aquifer is by direct infiltration and deep percolation
from precipitation and discharge is through abstraction wells and effluents
streams.
The Imo Shale Aquitard consists of blush grey calcareous shale and
siltstones with intercalations of thin sandstones and bands of clayey ironstones or
fossilferous limestone. Evidences of groundwater circulation in this unit are
provided by numerous springs in the outcrop area (Esu et al., 1997).
Lower sand aquifer comprises Maastrichian sediments of the Nsukka
Formation and Ajali Sandstone (False Bedded Sandstone). Lithologically, this unit
19
Table 1: Stratigraphic and Hydrostratigraphic units in Akwa Ibom State. Nigeria.
Age Groups(s)/ Formations
Lithology Aquifer
QUATERNARY
Recent Pliocene Pleistocene
Alluvium Ridges Benin formation (coastal plain sands)
Gravel, lateritic sand, fine to medium grained and carbonaceous sand Unconsolidated sand and gravelly sand with clayey intercalations
Upper sand
TERTIARY Oligocene Miocene Middle Eocene Paleocene Early Eocene
Ogwashi-Asaba Ameki formation Imo Shale
Grit and sand with intercalations of clay band lignite seams Semi – consolidated sandstone and siltstone plus minor shale Shale with thinner sandstone and band of fossilferous limestone
Middle sand Aquitard
Cretaceous Maastrichtian Nsukka Ajali sanstone
Lateritic sandstone and minor shale
Lower sand
Adapted from Esu et al., 1997.
20
is made up of pebbly to coarse lateritic sandstones, siltstones and minor shales
(Esu et al., 1997). Vertical electrical soundings suggest thickness of about 150m
for the Nsukka and Ajali Formation (Edet, 1993a).Water level ranges between
43.20 and 47.0m.Drawdown varies from 0.25 – 4.45m while yield ranges from
480 – 760m3/d. The transmissivity of this aquiferious unit is in the range of 198.8-
379.5m2/d (Esu et al., 1997; Onuoha and Mbazi, 1988).
2.3 Literature Review
The literature review presented herein contains review of previous works
that relate to surface and groundwater pollution, contaminant sources and their
effects on the water resources.
ASTM (1969) states that turbidity in water is usually caused by particulate
matter in suspension which results from land surface erosion, while colour results
from the presence of organic matter. Feachem et al. (1978) reported that hazards
from microbial pollution of water in the tropics were on a higher scale than from
chemical pollutants. De Fetters (1980) listed some chemical and biological
contaminants responsible for ground water contamination which include groups
of metals, non metals and organisms. He further reported that water from
recharging source can leach chemicals from buried solid wastes.
Sykes et al. (1982) stated that the contaminant plume created from a
dump site is capable of persisting in groundwater environment several years after
the sources must have been eliminated as was the case with the Canadian force
base sanitary landfill at Borden, Onatario. Azamatullah and Ekwere (1985) posited
that the enhanced metal concentrations in stream sediments of Cross River
Esturary were due to anthropogenic and lithogenic inputs. They also stated that
factors such as organic matter and grain size of sediments control natural metal
concentrations in water bodies. Hem (1985) stated that causes of anomalous
concentrations of E. coli bacteria in groundwater may be due to the nearness of
the static water levels to the surface in areas where the porous and permeable
layers overlie the water table. Kashef (1986) reported that changes in
21
groundwater quality are due to the following: varying concentrations of the
infiltrated precipitation, the reaction of groundwater to its environments, the
length of the flow path, the residence times of water, vegetative type and human
activities. He presented changes in chemical quality to be more intense in shallow
aquifers than deeper ones because shallow aquifers are more easily affected by
seasonal variations and human activities.
Ezeigbo (1988) identified sources of water degradation in coastal and
inland areas to include dissolution of constituents in water during its movements,
poor waste disposal methods and salt water intrusion due to poor groundwater
abstraction in coastal areas and inland areas of evaporite deposits.Okufarasin
(1991) stated that in areas where the underlying geology is of uncompacted
coarse sands, the polluting effluent from a waste dump is capable of infiltrating
into the subsurface to contaminate the groundwater in the aquifer and form a
pollution plume that can extend for several hundreds of metres. Edet and Ntekim
(1996) observed that pockets of enhanced heavy metals concentrations in the
hinterlands of Akwa Ibom State (with reference to Uyo) are probably due to the
local geochemical processes increase in agricultural activities, domestic wastes
and corrosion products.
Domenico and Schwartz (1998) stated that trace elements in surface and
groundwater are capable of being toxic or lethal to humans at relatively low
concentrations because of their tendency to accumulate in the body. Esu and
Amah (1997) reported that surface and groundwater in Uyo are acidic to slightly
alkaline; they have low pH and high carbondioxide content and as such the water
in these areas is corrosive to iron and steel and could attack carbonate minerals.
Ogunbajo (2004) discovered that most of the water sources in Ibadan and its
environs are fresh waters with alkali and alkaline earth characteristics. He also
discovered that the contamination of the subsurface water is most likely from
dissolution of bedrocks through which they flow.
Ogunbajo and Kolajo (2004) used trace metals (iron, copper and lead) as
indices for their investigation for water quality. They concluded that both the
surface and groundwater sources in Ibadan and its environs have been
22
contaminated and polluted due to the objectionably high concentrations of trace
metals. Tijani et al. (2002) concluded that the leaching of waste materials from
dump sites into the subsurface water have significant effects on groundwater
quality, most especially the shallow aquifers in the weathered zone. Subba et al.
(2006) used principal component analysis to facilitate the determination of
different assemblages of water quality results in the Anantapur District of India.
Amah, et al. (2007) stated that the occurrence of faecal coliform in the coastal
areas of Akwa Ibom State is greater in surface water than in groundwater. In
addition, the causes of the anomalous occurrence of Escherichia coli in these
waters is due to poor waste disposal systems, increase in industrialization and
ingress of contaminated surface water into wells, and shallow boreholes which
have not been properly constructed.
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CHAPTER THREE
METHODS OF STUDY
3.1 Geochemical Methods
A total of twenty three water samples consisting of twenty groundwater
and three surface water sources were collected. The sample locations were
selected based on their proximity to septic tank, pit latrine (human waste disposal
system) and waste dump site (Figure 4).
The water samples were collected in 2 litres plastic bottles. Such
information as sample source, sample location (longitude and latitude), time, date
of collection and weather condition were carefully recorded. The water bottles
were stored in an ice- packed cooler kit and sent for analysis within twenty four
(24) hours. pH ,conductivity and temperature were determined in the field using
WTW pH meter, conductivity meter and mercury -in- glass thermometers
respectively. Colour and turbidity were determined in the laboratory using Hach
DR/2000Spectrophotometer.Total suspended solid (TSS) was determined with
Hach DR/200 Spectrophotometer. Total hardness was determined for each
sample by titrating the water sample with 0.02m EDTA solution.
Chloride was determined by colorimetric method, with the use of mercury
thiocyanate/ferric ion reagents on the HACH DR/2000 Spectrophotometer.
Alkalinity was determined by titrimetric analytical method employing standard
HCl solution. 100ml of each sample was titrated with standard HCl using
phenolphthalein and Bromo cresol green indicator. Acidity was determined by
titrimetric method using standard NaOH solution with bromo phenol indicator.
Lead, chromium, cadmium and manganese were determined with digital bulk
model 2005 atomic absorption spectrophotometer (AAS). Sulphate, nitrate iron
and phosphate were determined with Hach DR/ 2000 Spectrophotometer.
Total heterotrophic bacteria and total feacal coliform was determined by
Millipore membrane filtration method.
24
Figure 4: Base Map of the Study Area Showing the Sampling Points in Relation to
their Pollution Source.
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; ;
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% a % a
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% a
% a
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I k o t O b o n g
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I k o t E k p u k
A b a k - I b i a k u U r u a n
I b a O k u
U Y O
B a r r a c k s
P r i s o n
E w e t
I k o t N t u e m
I b i a k u U f o t
F o u r T o w n s A t a n
O k u
I b o k o O f f o t
E f f i a t O f o t
E t o i A k a
I t i a m O k o p e d i
I t i a m E b i a
I t i a m E t o i
I f a I k o t
O k u n
U s e O f o t
I k o t A n y a n g
L 1 L 2 L 3 L 4
L 5
L 6
L 7
L 8
L 9 L 1 0
L 1 1
L 1 3
L 1 4
L 1 6
L 1 7
L 1 8
L 1 9
L 2 0
L 2 1
L 1 5 L 2 3
1 0 1 2 K i l o m e t e r s
N
E W
S
5 ° 0 0 ' 5 ° 0 0 '
5 ° 2 '
5 ° 2 '
5 ° 4 '
5 ° 4 '
7 ° 5 4 '
7 ° 5 4 '
7 ° 5 6 '
7 ° 5 6 '
7 ° 5 8 '
7 ° 5 8 '
8 ° 0 0 '
8 ° 0 0 ' 8
8
5 5
W a s t e d u m p s þ
S e p t i c t a n k s
% a
P i t l a t r i n e s
;
S t r e a m Ê Ú B o r e h o l e s . Ë R i v e r
L E G E N D
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3.2 Statistical Method
The analysis of variance and principal component analysis of all the
measured geochemical data were carried out with computer software packages.
A computer package, GENSTAT, was used for the analysis of variance of the
geochemical data. The principal component analysis was carried out using
computer software, SPSS. The analysis of variance tests the difference between
geochemical analysis result of surface and groundwater. The result of the analysis
of variance was grouped into Two (2) namely Surface water samples which differ
in composition from groundwater samples and surface water samples which have
no significant difference from groundwater. The principal component analysis
quantifies the relationship between the variables by computing the matrix of
correlations for the entire data set and summarizes the data set without losing
much information (Subba et al., 2006).Varimax rotation, an orthogonal rotation
method that minimizes the number of variables that have high loading on each
component was used. The matrix of the correlations, employing varimax rotation,
was decomposed into component plots of variables and water samples locations.
The component plots provided a means by which mutually independent axes
termed principal components which describe the data set can be derived.
The principal component plot of variables presented a graphical
representation of spatial similarity between the variable in each principal
component, whereas the principal component plot of water sample locations
presented a graphical representation of similarity between the locations in each
component and the processes affecting them. The basis for selection of four
components was to choose a number of components that reach a certain
preselected variance greater than eight percent.
3.3 Determination of Groundwater Flow Direction
The water table contour map (Figure 5) digitized during the course of this
study reveals a dominant northeast southwest groundwater flow pattern. Similar
observation was made by (Esu et al., 1997).The dominant southeasterly trend
26
more or less parallels the main surface divide between the Qua Iboe and the
Cross River systems (Esu et al., 1997 ).The water level contours (Figure 5)
Illustrate the direction of movement of groundwater to be mainly towards the sea
and the major rivers with an average hydraulic gradient of 5.0 × 10 -4. (Esu et al.,
1997). From the static water level data collected during this study, it was
observed that the water table in the study area is at a level of 14.3m – 36m below
the ground surface. This is similar to the observation of Offodile (2002).
Groundwater flow directions were one of the bases for selection of water sample
locations.
27
Figure 5: Water Table Contour Map Showing the Direction of Groundwater Flow
in the Study Area with Scale of Depth to Water Table in Metres.
28
CHAPTER FOUR
RESULTS AND DISCUSSION
4.1 Hydro-geochemistry and Water Quality
Detailed results of analysis of surface and groundwater samples are
presented in Appendices I and II. The mean, standard deviation, maximum and
minimum values, and range for the physical, chemical and biological parameters
are presented in Table 2. The pH of the groundwater ranges from 3.78 to 4.68
while that of surface water ranges from 6.03 to 7.53.These ranges indicate that
the groundwater in the study area is acidic while the surface water is slightly
acidic to neutral. The acidic nature of the groundwater is due to the presences of
shale intercalations in the Benin Formation (Edet et al., 2003). TDS is in the range
of 14.00 – 282.75 mg/l, Classification of water type based on TDS shows that the
water sources in the area are fresh water (Table 3). The total hardness (TH) of the
water samples is in the range of 5.00 – 62.0 mg/l indicating soft to moderately
hard waters for both surface and groundwater (Table 4). Conductivity values
range from 200 – 435µScm 1 with mean of 108.77 µScm 1 ; these values are far
below the WHO (2006) maximum allowable concentration of 1500µScm 1 for
drinking water. From the cations and anions analyzed, it is observed (Table 2) that
the concentration of Calcium (Ca 2 ) is between 1.6 and 23.2mg/l with mean 10.03
and standard deviation 6.29. These values fall within the WHO (2006) limits of
200mg/l for Calcium (Table 4) .Sodium (Na ) concentration in the water samples
is between 6.8 and 55.9 mg/l with a mean of 18.03 mg/l. This concentration range
is within the WHO (2006) maximum permissible limit of 200mg/l (Table 4).
Magnesium (Mg 2 ) in the study area ranged from 0.0 to 5.86mg/l, with a mean of
0.755 and standard deviation of 1.19mg/l. These values fall within the WHO
(2006) limit of 150mg/l for magnesium exceed the Nigerian standards of 0.2mg/l
for drinking water (Table 4). Magnesium in the study area may be derived from
the dissolution of carbonates of the adjoining Mfamosing Limestone. Potassium
(k ) ranged from 0 to 23.9 mg/l, with a mean of 1.04 and standard deviation of
0.09 mg/l. The value of potassium in some of the samples exceeds the WHO
(1993) limits of 10mg/l.
29
Table 2: Physiochemical Parameters
Parameter Mean mg/l
Range mg/l
Standard Deviation
WHO (2006)
SON (2007)
% Exceeding WHO and SON Safety limits
Calcium 10.03 1.6 – 23.2 6.29 - -
Magnesium 0.75 0.0 – 5.86 1.19 150 0.2 65%
Sodium 18.03 6.8 – 55.9 10.43 200 200 Within the range
Iron 0.06 0.01 – 0.26 0.06 - 0.3 Within the range
Potassium 7.72 0.00 – 23.9 4.93 10 - 34.7%
Chloride 18.79 4.1 – 20.1 19.47 250 250 Within the range
Phosphate 0.47 0.006 – 3.32 0.78 - -
Nitrate 32.05 16.28 – 63.36 13.48 50 50 8.6%
Sulphate 3.13 0.0 – 18.0 3.66 500 100 Within the range
Ph 4.89 3.78 – 7.53 1.02 6.5– 9.5 6.5-8.5 91%
Electrical Conductivity
108.77 20.0 – 435.0 91.83 - -
Total Hardness 26.56 5.0 – 62.0 18.54 - -
Acidity 15.0 – 150.0 - -
Temperature 29.90 28.8 – 32.0 1.11 - -
TDS 64.41 14.0-282.75 57.63 1200 500 Within the range
Colour 68.47 0.0 – 280.0 72.33 - -
Turbidity 17.08 0.00 – 63.0 15.34 - -
Total Suspended Solids
9.60 0.00 – 49.0 4.66 - -
Total heterotrophic Bacteria
3.05 0.0 – 30.0 6.84 0cfu/100ml
1cfu/100ml
34.7%
Total Faecal Coliform
0.35 0.0 – 4.0 0.93 - 10cfu/100ml
Within the range
Arsenic 0.08 0.0000- 1.01 0.21 0.01 - 47.8%
Lead 0.62 0.001 – 1.56 0.57 0.01 0.01 78.2%
Cadmium 3.25 0.0000 – 0.43 15.42 0.003 0.003 39.1%
Chromium 0.57 0.000– 1.96 0.73 0.005 0.005 60.8%
Manganese 0.39 0.000 – 0.99 0.34 0.4 0.2 52.1%
30
Table 3: Classification of Water Based on salinity
Name Concentration of total dissolved solids ppm
Fresh 0 – 1000
Brackish 1000 – 10,000
Salty 10,000 – 100,000
Brine Over 100,000
Adapted from Hem, 1985.
Table 4: Classification of water based on Hardness
Name Hardness as CaCO3 ppm
Soft 0 – 60
Moderately hard 61 – 120
Hard 121 – 180
Very hard Over 180
Adapted from Hem, 1985
31
The high concentration of potassium may be as a result of the presence of
feldspars and silicates in the Benin Formation. The values of all the cations fall
within the World Health Organisation (2006) Standard guideline values for
drinking water except the values of potassium.
Sulphate (SO 24 ) has concentrations range, mean and standard deviation of
0.0 to 18.0mg/l, 3.13mg/l and 3.66mg/l respectively. These concentration values
are below the WHO (2006) limit of 500mg/l (Table 4).Chloride (Cl ) has
concentration range and mean of 4.1 to 20.1 mg/l and 18.79 respectively. The
concentration values are very low compared to the WHO (2006) permissible limit
of 250mg/l. Hydrogen phosphate (PO 34 ) has concentration range, mean and
standard deviation of 0.06 to 3.32mg/l, 0.48 and 0.78 respectively. The highest
concentration of SO42-
, Cl- and PO 34 occurred in surface water. The range, mean
and standard deviation values of Nitrates (NO 3 ) are 16.28 – 63.36, 32.05 and
13.48 respectively. The values for nitrate in the study area exceed the WHO
(2006) limit of 50mg/l.
For the trace elements analyzed from the water samples, it is observed that
the concentration of arsenic (As ) is between 0.00 and 1.0µg/l. This range of
concentration is within WHO (2006) permissible limits. Lead (Pb2+) ranges from
0.00 to 1.56mg/l, and thus exceeds the WHO (2006) limits of 0.01mg/l. Cadmium
(Cd3+) concentration ranges from 0.00 to 0.43µg/l. The concentrations of
cadmium is within the WHO (2006) limits of 0.003mg/l. Chromium has range of
0.00 to 0.43mg/l and thus exceeds the WHO (2006) limits of 0.05mg/l. Manganese
has a range and mean of 0.00 to 0.99mg/l and 0.3961 respectively. Sixty percent
(60%) of the water samples has manganese concentration exceeding the WHO
(2006) limits of 0.4mg/l. Feacal coliform ranged from 0 to 4/100ml and total
heterotrophic bacteria (THB) ranged from 0 to 30/100ml. Some concentrations of
both total heterotrophic bacteria and feacal coliform exceeds the WHO (2006)
limit of 1/100ml.
32
4.2 Comparison between Surface water and Groundwater
The amount of solute dissolved in surface water sources differs from that of
groundwater samples. This difference in the concentration of variables in surface
and groundwater sources is explained using a statistical tool of analysis of
variance. Table 5 shows the result of the analysis. Factor probability measured in
percentage explains the level of similarities between the two sources. In the
analysis, variables having factor probability greater than 5% (which is the set
value for least significance difference in this work) shows that the parameter
concentrations in surface and groundwater are significantly not different from
each other. For this analysis factor probability less than 5% implies that there is
significant difference between the concentrations of the parameters in both
sources. From table 5 the concentrations values of pH, conductivity, colour,
calcium, potassium, chloride, phosphate, sulphate and total feacal coliform
measured in both sources have significant difference, whereas bicarbonate,
magnesium hardness, nitrate, arsenic, chromium, cadmium and total
heterotrophic bacteria have no significant difference. Total feacal coliform is
higher in surface water than groundwater of the study area .USEPA (1977)
explains that microorganisms carried into the aquiferious zone are deprived of a
good nutrient supply and are subjected to a cooler temperature than in the
unsaturated zone. This results in frequent lowering of biochemical activity to the
point of cessation and explains why total feacal coliform is higher in surface water
than groundwater.
4.3 Sources and Controlling Processes of Elements in Water
The result of the principal component analysis is presented in Table 6
below and shown graphically in figure 6 and 7. From the principal component
analysis result presented in Table 6, four (4) components were generated. These
four components illustrate 64.713% of the variance in the data set. In each
component, variables which have factor loading greater than 0.700 was
considered and is written in bold. The four generated components are as follows:
33
Table 5: Analysis of Variance
Parameter Surface Water (Mean concentration)
Groundwater (Mean concentration)
Factor probability (%)
pH 6.25 4.44 0.1
Temperature 29.7 29.9 0.4
Conductivity 194 85 0.1
Colour 122 56 0.9
Total suspended solid 22 6.2 0.1
Turbidity 26.1 14.6 3.3
Calcium hardness 39.1 20.8 0.1
Magnesium hardness 3.58 2.94 70
Total hardness 42.7 23.8 0.3
Total solid 165.2 51.9 0.1
Calcium 15.66 8.13 0.1
Potassium 12.98 6.26 0.1
Potassium 12.98 6.26 0.1
Chloride 18.5 11.3 0.4
Phosphate 1.43 0.22 0.1
Sulphate 6.98 2.06 0.1
Nitrate 31.2 33.8 54
Bicarbonate 56.8 28.5 5.4
Arsenic 0.048 0.085 68
Chromium 0.62 0.57 83
Cadmium 0.047 0.044 92
Total heterotrophic bacteria
2.4 2.7 89
Total feacal coliform 0.80 0.17 3.8
34
Table 6: Rotated Component Matrix of Chemical Data of Water Samples
Variable Component 1 Component 2 Component 3 Component 4
Ph 0.626784 0.303678 0.347653 0.497135
CONDUCTIVITY 0.930478 -0.084691 0.066885 -0.161817
TEMPERATURE -0.208521 0.369320 0.573611 -0.414984
TDS 0.933420 -0.039676 0.103569 -0.141626
COLOUR 0.213300 0.490830 -0.101519 0.343519
TURBIDITY 0.049854 0.734005 -0.136029 -0.045113
TOTAL SUSPENDED SOLID
0.402233 0.743140 -0.071356 0.123300
TOTAL SOLID 0.926948 0.190652 -0.077977 -0.049174
TOTAL HARDNESS
0.750579 0.091039 0.496520 0.054004
CALCIUM HARDNESS
0.813218 0.131386 0.249027 0.053657
MAGNESIUM HARDNESS
0.221979 -0.051649 0.925320 0.014920
CALCIUM 0.813218 0.131386 0.249027 0.053657
MAGNESIUM 0.222337 -0.051124 0.925278 0.015104
IRON 0.160935 0.842582 0.152589 0.095883
SODIUM 0.867035 0.126243 0.183672 0.032307
POTASSIUM 0.828491 0.153939 0.165089 -0.022466
ARSENIC 0.137027 0.069982 0.121015 -0.078882
LEAD -0.142215 0.501362 -0.143732 -0.142641
CADMIUM -0.235057 0.213254 -0.144026 0.041553
CHROMIUM -0.334727 0.673805 0.026195 -0.331423
MANGANESE 0.520537 0.646997 -0.143607 0.128558
SULPHATE 0.696733 0.143953 -0.291900 0.159636
CHLORIDE 0.792600 -0.282309 0.064907 0.034891
BICARBONATE -0.633133 -0.526170 -0.377119 -0.421258
NITRATES 0.184032 -0.025096 -0.141730 -0.768188
PHOSPHATE 0.636621 0.312376 -0.180909 0.307631
ACIDITY 0.108877 -0.065326 0.514022 0.199641
THB -0.125986 -0.187656 -0.194104 0.358265
TFC -0.018660 0.098188 -0.090105 0.341047
TOTAL VARIANCE (%)
32.76596 13.04430 10.21791 8.68524
CUMMULATIVE VARIANCE (%)
32.76596 45.81026 56.02818 64.71341
35
Figure 6: The principal components plots of variables in rotated space
36
Component 1: Comprises Conductivity, Total Dissolved Solids, Total solid, Total
hardness, Calcium hardness, Calcium, Sodium, Potassium and Chloride. This
association accounts for 32% of the data variability.
Component 2: Consists of turbidity, total suspended solid and iron, which
accounts for 13% of the total variance of the data set.
Component 3 consisting of Magnesium hardness and Magnesium, accounts for
10% of the data variability.
Component 4 comprises Nitrates (NO3-) and accounts for 8% of the total data
variability.
The processes releasing high concentrations of the various elements in each
component are listed in Table 7. The high concentrations of TDS, Na , Ca 2 ,
K and Cl on principal component one (1) indicates that the first principal
component is associated with a combination of hydro-geochemical processes. For
instance, high concentration of Na ion is linked to ion exchange reactions on the
clay intercalations of the Benin Formation in the area. This may have been
initiated by the leaching of the adjoining Precambrian and Cretaceous rock (Edet
et al., 2003 and Hem, 1991). The process of dissolution of Na and Cl ions from
the rock sediments in the study area may as well be responsible for the
enrichment of Na and Cl ions in the water of the study area. Ca 2 and k in
component one are probably sourced from the weathering of feldspars and clay
minerals of the Benin Formation (Edet et al., 2003).Hem (1991), Zhang et al.
(1995), Satyanarayana and Periakali (2003) and Subba et al. (2006).The high
concentration of the variables in component one in waters of the study area is
thus controlled by ion-exchange processes, dissolution processes and weathering
processes.
Component two consists of Iron, turbidity and total suspended solid. The
major possible source of Iron (Fe 2 ) in the study area is the weathering of
ferromagnesian minerals and dissolution of iron hydroxide, which is the main
cementing material of the sandstone in the Benin formation (Edet et al., 2003)
37
Component Three is made up of Mg 2 and Magnesium hardness. The high
concentration of magnesium in the waters in the study area is as a result of the
weathering of silicate minerals. The first three components correlate with
geogenic sources of contamination (Table 7).
Component Four which is made up of Nitrates (NO3-) shows strong
correlation with anthropogenic sources of contamination. The high concentration
of Nitrates (NO3-) in the study area is attributed to leaching from waste dumps.
4.4 Impacts of Wastes on Surface and Groundwater Sources
The sample location numbers was used to generate a component plot
(Figure 7) which explains the relationship between the water sample locations
and the controlling processes. Principal component one, two, three and four are
denoted on the component plot by clusters I, II, III and IV respectively. The water
sample(s) in each cluster represents those that are strongly affected by the
controlling processes and those that are not in any cluster are those that are
slightly affected by one process or the other.
From Figure 7, it is observed that the sample location in cluster Ia (16), a
surface water (see Figure 4) is highly affected by the cation exchange and
dissolution processes (Table 8) and is located close to Barrack Waste Dump(see
figure 4). Water samples in cluster Ib (8, 9 and 19) are all groundwater (see figure
4) and are strongly affected by cation exchange and dissolution processes and are
located around Four Towns Dump Site (see figure 4). It thus shows that surface
water around Barrack Dump Site and groundwater around Four Towns Dump Site
is not affected by leachates and drains from these dump sites.
The groundwater sample locations in cluster II (5, 6 and 12) are strongly
affected by weathering of ferromagnesian minerals and are all located outside the
two dump site areas (see figure 4).The samples in this cluster are not affected by
the activity of the dump sites.
38
Table 7: The Processes Controlling each Principal Component
Components Controlling Processes Major Processes
One: Conductivity, TDS, Total solid, Total hardness, Calcium hardness, Ca2+, Na+, k+, Cl-
Cation exchange, weathering and dissolution processes
Geogenic (hydrogeochemical processes)
Two: Turbidity, Total suspended solid and Fe2+
Weathering of ferromagnesian minerals
Geogenic (hydrogeochemical processes)
Three: Magnesium hardness and Mg2+
Weathering of silicate minerals (olivine, pyroxene and hornblende)
Geogenic (hydrogeochemical processes)
Four: NO3- Human activities Anthropogenic activities
39
Figure 7
40
Table 8: Distribution of Clusters of water sample locations
Clusters Station code Main Controlling processes
Ia 16 Cation exchange and dissolution process
Ib 8,9,19 Cation exchange and dissolution process
II 5,6,12 Weathering of ferromagnesian Minerals
III 2,20 Weathering of silicate minerals
IV 13,21,22,23 Anthropogenic sources
41
The sample locations in cluster III (2, 20) which are from groundwater
sources (see figure 4) are strongly affected by the weathering of silicate minerals.
Sample 20 is located outside the vicinity of the two dump sites while sample 2 is
in the vicinity of four towns dump site (see figure 4). It was later observed that
sample 2 is slightly affected by leachate from four towns dump site because of its
proximity to the dump site.
The water sample locations in cluster IV (13, 21, 22; groundwater, 23;
surface water) are strongly affected by the anthropogenic processes (leachate
from the Barrack Dump Site) and are predominantly located around the Barrack
Dump Site (see figure 4). Samples in clusters I – III are strongly affected by hydro-
geochemical processes while those in cluster IV are affected by anthropogenic
process.
Figure 8 shows the distribution of sample locations inferred to have been
affected by cation exchange and dissolution processes. From the figure it is
evident that sample locations 8, 9, 16 and 19 are strongly affected by the process
and sample locations 2, 4, 5, 6, 10, 12, 15 and 20 are slightly affected by the
processes while other sample locations not listed are not affected.
Figure 9 which displays the distribution of samples affected by weathering
of ferromagnesian minerals, it can be seen that samples 5, 6 and 12 are strongly
affected by the processes while samples 1, 3, 7, 8, 9, 13, 15 and 17 are slightly
affected. Other sample locations not listed are not affected by this process.
Figure 10 which present the distribution of water samples locations affected
by weathering of silicate minerals shows that sample locations 2, 20 and 1, 4, 5, 9,
12, 14, 16, 19, 22 are strongly and slightly affected respectively.
Figure 11 shows the distribution of sample locations inferred to have been
affected by anthropogenic processes (leachate from the dump sites). From the
figure sample locations 13, 21, 22, 23 are strongly affected by the process while 2,
14 and 18 are slightly affected. Other samples locations not listed are not
affected.
42
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Figure 8: Areal distribution of Water Samples Locations Affected by Cation
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43
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Figure 9: Areal distribution of Water Samples Locations Affected by Weathering of
Ferromagnesian Minerals
44
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Figure 10: Areal distribution of Water Samples Locations Affected by Weathering
of Silicate Minerals
45
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Figure 11: Areal distribution of Water Samples Locations Affected by
Anthropogenic Sources
46
4.5 Stiff Plots
A common method of presentation of hydro-geochemical data is the Stiff
pattern (1951). A polygonal shape is created from the plotting of the geochemical
data along horizontal axes which are separated from each other by a vertical
centre line. Major cations measured in milliequivalents per litre are plotted on the
right side of the pattern and major anions also measured in milliequivalent per
litre are plotted on the left side (Fetters, 1994). Stiff patterns facilitate rapid
comparison among water sources with different chemical compositions as a result
of their distinctive shapes. The width of each pattern (polygonal shape) is an
approximation of total ionic strength of that water sample (Hem, 1985). Based on
the Stiff plot shown in figure 12 the waters in the study area are classified into
two categories: They are
(a) Waters with low ionic strength: (Locations: 1, 2, 3, 4, 5, 7, 8, 9, 10, 11,
13, 14, 17, 18, 19, 20, 21 and 22)
(b) Waters with high ionic strength: (Locations: 15, 16 and 23)
The stiff plots show that surface water samples (15, 16 and 23) have high total
ionic strength while groundwater samples (1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14,
17,18, 19, 20, 21 and 22) have low ionic strength. The high concentration of
dissolved constituent in these water samples locations may be due to
introduction of chemical and biological species from surface contamination.
4.6 Piper Trilinear
The piper trilinear plot is a traditional method of classification in the study of
hydrochemistry (Ophori and Toth , 1989; Hem, 1992).The method has limited
usage due to the selection of available parameters (Ca 2 , Mg 2 , Na ,k ,HCO 3 , Cl
and SO 24 ). The hydro-geochemical data plotted on piper diagram, is presented in
Figure 13. The most dominant water type in the study area is the calcium –
magnesium sulphate chloride type. Similar observation was reported by Esu et al.
(1997).Sodium sulphate chloride water types are less dominant.
47
48
Figure 12: Stiff Diagrams Showing the Relative Concentrations of Major Cations
and Anions in Waters in the Study Area.
49
Figure 13: Piper Tri-linear Diagram.
50
The inability of the different sources of water contamination to be represented by
the different water types in the piper diagram is mainly due to the limited use of
geochemical data (only major constituents) in the piper plot.
51
CHAPTER FIVE
CONCLUSIONS
Waters (ground and surface) in the study area are acidic and soft. The
concentrations of TDS, TH, Ca 2 , Mg 2 Na HCO 23 Cl and SO 24 are within the
WHO (2006) permissible limits while the concentrations of pollution indicator
(NO 3 ) exceeds both the WHO (2006) and SON (2007) permissible limits for
drinking water. Analysis of variance shows that the concentrations of physical
parameters and most cations are higher in surface water than groundwater while
there is no significant difference in the concentrations of trace elements nitrate,
bicarbonate and total heterotrophic bacteria.
The principal component analysis was used to determine the controlling
processes affecting biological and physiochemical characteristics of water in the
study area. Four components which accounts for 64.7% of the total variance in
the data sets were chosen; the first, second, third and fourth components
account for 32.7%, 13%, 10% and 8.6% respectively of the variance. The first
principal component is characterized by Conductivity, TDS, Total solid, Total
hardness, Calcium hardness, Ca 2 , Na , K Cl parameters; the second Turbidity,
Total suspended solid, Fe2+; the third Magnesium, Mg 2 ; and the fourth N032-.
These components are interpreted to be controlled by geogenic processes (hydro
geochemical) such as Cation exchange and dissolution processes, weathering of
ferromagnesian minerals and silicate minerals and anthropogenic processes of
sewage waste and leachate from the solid refuse disposal sites.
From the location plot, the water sample locations were demarcated into
clusters as I – IV. The samples in clusters I, II and III are highly affected by the
geogenic (hydro geochemical) processes, while cluster IV (mostly located around
the vicinity of the Barracks dump site) are highly affected by anthropogenic
processes. Most of the groundwater sample locations close to Four Towns dump
site and surface water samples around barracks dump sites are strongly affected
by hydro-geochemical processes while the groundwater sample locations close to
Barracks dump site are strongly affected by the anthropogenic activities. It thus
52
shows that the anthropogenic activities (sewage waste and leachate from waste
dump) around the Four Towns dump site had little or no effects on the
groundwater quality of that area whereas the Barracks dump sites strongly affects
the quality of the groundwater around it.
The result of the stiff plot shows that most surface water samples have
higher ionic strength than groundwater samples. The most dominant water type
in the study area deduced from the piper diagram is calcium magnesium sulphate
chloride type.
The present study shows that principal component analysis can help in
grouping water quality result from different sources by explaining the genetic
processes, (hydrogeochemical processes and anthropogenic processes) affecting
them. This knowledge will help in projecting future trends.
53
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