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.

7

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

9

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'

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7°58'

7°58'

5

5

Road River

LEGEND

#

#

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##

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#

#

KAN0MAIDUGURI

ENUGU

Study

Area

3 0 3 6 Kilometers

Figure 1: Accessibility Map of the Study Area.

14

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

16

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)

18

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.

23

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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U Y O

B a r r a c k s

P r i s o n

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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

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I b o k o O f f o t

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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

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5 ° 0 0 ' 5 ° 0 0 '

5 ° 2 '

5 ° 2 '

5 ° 4 '

5 ° 4 '

7 ° 5 4 '

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7 ° 5 8 '

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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

25

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

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44

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Figure 10: Areal distribution of Water Samples Locations Affected by Weathering

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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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