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AN ASSESSMENT OF THE HEAVY METAL CONTENTS OF THE

OBAFEMI AWOLOWO UNIVERSITY TEACHING AND RESEARCH

POND I, ILE IFE, OSUN STATE.

BY

IKPE, EMMANUEL CHUKWUMA

B.Sc (HONs) CHEMISTRY

SCP06/07/H/1471

A RESEARCH PROPOSAL SUBMITTED IN PARTIAL FULFILLMENT

OF THE REQUIREMENTS FOR THE AWARD OF POSTGRADUATE

DIPLOMA (PGD) IN ENVIRONMENTAL CONTROL AND MANAGEMENT

THE

SUPERVISOR: PROF. I.F ADENIYI

DEPARTMENT OF ZOOLOGY

OBAFEMI AWOLOWO UNIVERSITY

ILE IFE

AUGUST, 2007.


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INTRODUCTION.

As the world is ushered into the modern era of civilization, water and

its management will continue to be a major issue, which will definitely have

profound impact on our lives and that of our planet Earth than ever before

(Herschy, 1999). Water is indeed life and the most important natural

resources for life. Availability of safe and reliable source of water is an

essential pre requisite for sustainable development. Deserts are not

habitable because of lack of water.

Continuous urban development and large solid waste pose as major

environment risks because of the difficulties in disposal. Landfills and other

solid wastes disposal sites are major targets of pollution because rainfall

and groundwater leach these highly contaminated substances into lakes,

ponds, rivers, streams, and waterways (surface waters) which are

inadvertently used by people residing in such areas. Water borne diseases

kill 50,000 people daily (Herschy, 1999) and yearly about 4 million children

under the age of five die in developing countries due to water related

problems (USAID, 1990; Warner, 1998).

Water pollution is of grave consequence because both terrestrial

and aquatic life may be poisoned; it may cause disease due to the

presence of some hazardous substances, and hence significantly, hinder

economic activities. The causes and forms of water pollution according to

Strandberg (1971) include sewage and other oxygen demanding wastes,

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infectious agents, organic chemicals, other chemicals and mineral

substances, sediments (turbidity), radio-active substances and heat.

Additionally, several human activities that may result to water pollution

include the following, agriculture, irrigation, urbanization, mining fire and

industrialization (Goudie, 1990). These activities have been documented to

have impacted negatively in some specified Nigerian surface waters

especially in the Niger delta region (Izonfuo and Bariweni, 2001).

Heavy metals are of particular interest because they are among the

most toxic pollutants. Heavy metals are metals with a density greater than

5g/cm3. They are less abundant than the light metals. One of their

characteristics is their relative inertness. Because they hold electrons

rather tightly, these metals do not form ions with ease, and they do not

readily yield their electron to electron-hungry element like oxygen.

Therefore, heavy metals tend to resist oxidation, which implies that after

release into the environment they are persistent contaminants.

The noble or coinage metals-Gold (Au), Platinum (Pt), and Silver

(Ag) are heavy metals that keep their metallic luster for ages because

oxidation occurs only slowly or not at all. Some heavy metals, mostly

notably copper (Cu), Zinc (Zn), Cobalt (Co) and chromium (Cr) are

essential to life in trace or small quantities. They are architecture of various

proteins, enzymes and vitamins.

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Natural processes such as bedrock and soil weathering, wind and

water erosion, violence activity, sea salt spray, and forest fires release

heavy metals into the environment. The modern age of heavy metal

pollution has its beginning with the industrial revolution. The rapid

development of industry, intensive agriculture, transportation, and

urbanization, has been the precursor of todays environmental

contamination problems. Anthropogenic utilization has also increased

heavy metal distribution by removing the substances from localized ore

deposits and transporting them to other parts of the environment. Heavy

metal by products result from many activities including ore extraction and

smelting fossil fuel combustion, dumping and land filling of industrial

wastes, exhausts from leaded gasoline, steel, iron, cement and fertilizer

production, refuse and wood combustion. Heavy metal has also increased

through activities such as farming, deforestation, construction dredging of

harbors and the disposal of municipal sludge and industrial wastes on

land.

STATEMENT OF PROBLEM

Heavy metals are one of the causes and forms of water pollution,

which is not commonly addressed. Although these trace elements are

usually present in the environment, they are potentially extremely toxic and

not only would they affect the biota at a water soluble concentration at less

that 1 part per million (ppm), humans can be grossly affected (Freedman,

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1989). Therefore the high concentrations and unacceptable levels of the

elements may constitute risk to health.

However, the emission of airborne metallic pollutant has now

reached such proportions that long-range atmospheric transport causes

contamination, not only in the vicinity of industrialized regions, but also in

more remote areas.

AIMS AND OBJECTIVES

The general aim of this study is to: assess the heavy metal levels of

water in the farm pond.

The specific aims are to:

(i) assess the horizontal and vertical variations in the metals within the

pond.

(ii) show the pattern of seasonal variability in the concentration of the

heavy metals.

(ii) assess the suitability of the pond water for a number of applications,

including for fish culture and irrigation as presently applicable.

SCOPE OF STUDY

To review literature on the heavy metal contents of fresh water

(rivers, lakes and ponds) and the analysis of heavy metal contents of

Research farm pond water collected over one annual cycle.

5


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RESEARCH METHODOLOGY

Three sampling stations will be established along the horizontal axis

of the lake denoted (A, B, and C). Station A will be located towards the

deepest portion of the lake close to the dam, mid-point from the shores.

Station B will be established at the middle basin of the lake while station C

will be located at the riverside portion of the lake.

At station A, four vertical samples will be collected for heavy metal

analysis from the surface, 1metre depth, 2metres depth and the bottom of

the lake. At station B, three vertical samples will be collected from the

surface, 1metre depth and at the bottom of the lake, while at station C, two

samples will be collected, from the surface and the bottom of the lake. An

improvised water sampler will be used for sampling sub-surface water at

these various depths. Field survey will be conducted monthly for a period

of 12 months.

The following parameters of the lake water will be determined on the

field: depth and transparency (using a secchi disc) and temperature (using

a mercury in bulb thermometer). Heavy metals to be determined will

include: (Arsenic (As), Cadmium (Cd), Chromium (Cr), Cobalt (Co), Copper

(Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), Zinc (Zn) All

determinations shall be carried out using atomic absorption spectrometry

(AAS) with adequate quality assurance and quality control measures

(QA/QC).

6


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THE AREA OF STUDY

The Research farm pond is located at the Teaching and Research

farm about 4km from the central campus. The pond was formed by the

impoundment of Elerin and Omifunfun stream in 1976.

Obafemi Awolowo University is located in Ile-Ife, which lies in the Southern

climate belt of Nigeria. The climate of Ile-Ife area is typically humid tropical

with two major seasons, that is, dry and rainy seasons. Rainy season

starts from April and ends in October, while the dry season starts from

November and ends in March.

REFERENCES

Freedman, B. (1989). Environmental ecology, Academic press Inc.,

San Diego.

Goudie, A. (1990). The human impact on the natural environment

(3rd edition). The MIT Press, Cambridge, Massachusetts.

Herschy, R.W. (1999). Hydrometry Principles and Practices.

(2nd edition) John Wiley & Sons, Chichester

Izonfuo, L.W.A: Bariweri (2001). The Effect of Urban Runoff water

and Human Activities on some physico-chemical parameters

of the Epie Creek in the Niger Delta. J. app. sci. environ.

Management. 5 (1): 47 55.

7


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8

Strandberg, C.H. (1971). Water Pollution. In: GH Smith (ed),

Conservation of Natural Resources (4th edition) Wisely, New

York.189 219.

United States Agency for International Development (USAID) (1990).

Strategies for Linking water and sanitation programs to child

survival USAID, Washington, D.C

Warner, D. (1998). Drinking water Supply and environmental

sanitation for health. Presented at the International conference

of water and Sustainable Development, Paris.


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10/12/2008 OAU

AN ASSESSMENT OF THE HEAVYCONTENTS OF THE O.A.U. TEACHI

RESEARCH POND 1,ILE-IFE,OSUN

A PGD Propositional Semina

Presented By

IKPE,EMMANUEL CHUKWUMSCP06/07/H/1471

Institute of Ecology And Environm

StudiesOAU,ILE-IFE.

Supervisor

Prof.I .F Adeniyi


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10/12/2008 OAU

Introduction

Water pollution is of grave consequebecause both terrestrial and aquatic may be poisoned; it may cause diseadue to the presence of some hazardsubstances, and hence significantly,

economic activities.

Heavy metals are of particular interebecause they are among the most topollutants. Heavy metals are metals density greater than 5g/cm3.One of tcharacteristics is their relative inertnewhich implies that after release into tenvironment they are persistentcontaminants..


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10/12/2008 OAU

Introduction cont

Heavy metals occur naturally in thein rocks and ores. They cycle throuenvironment by geological and bioloAnthropogenic activities have also i

release of heavy metals into the envthere by causing environmental polactivities include ore extraction anfossil fuel combustion, dumping andof industrial wastes, exhausts from

gasoline, steel, iron, cement and feproduction, refuse and wood combu


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10/12/2008 OAU

Statement of probl

Heavy metals are one of the causes and pollution, which is not commonly addressthese trace elements are usually present environment, they are potentially extremeonly would they affect the biota at a water

concentration at less that 1 part per milliohumans can be grossly affected (FreedmTherefore the high concentrations and unlevels of the elements may constitute risk

However, the emission of airborne metall

now reached such proportions that long-ratmospheric transport causes contaminatthe vicinity of industrialized regions, but aremote areas.


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10/12/2008 OAU

Aims and Objectiv

Assess the heavy metal levels

the farm pond.

Assess the horizontal and verti

variations in the metals within t Show the pattern of seasonal v

the concentration of the heavy

Assess the suitability of the pona number of applications, includ

culture and irrigation.


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10/12/2008 OAU

Scope of study

To review literature on the heav

contents of fresh water (rivers,

ponds) and the analysis of hea

contents of Research farm poncollected over one annual cycle


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10/12/2008 OAU

Research methodo

Three sampling stations will be estabthe horizontal axis of the lake denoted (AStation A will be located towards the deepthe lake close to the dam, mid-point from Station B will be established at the middle

lake while station C will be located at the portion of the lake. At station A, four verticbe collected for heavy metal analysis from1metre depth, 2metres depth and the bottAt station B, three vertical samples will be

the surface, 1metre depth and at the bottowhile at station C, two samples will be cosurface and the bottom of the lake.


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10/12/2008 OAU

RESEARCH METHODOCONT.

An improvised water sampler will be usedsub-surface water at these various depthswill be conducted monthly for a period of

The following parameters of the lake watedetermined on the field: depth and transpsecchi disc) and temperature (using a methermometer). Heavy metals to be determinclude: (Arsenic (As), Cadmium (Cd), ChCobalt (Co), Copper (Cu), Iron (Fe), MangNickel (Ni), Lead (Pb), Zinc (Zn) All deter

be carried out using atomic absorption sp(AAS) with adequate quality assurance acontrol measures (QA/QC).


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10/12/2008 OAU

THE AREA OF STU

The Research farm pond is locatedTeaching and Research farm aboutthe central campus. The pond was the impoundment of Elerin and Omstream in 1976.

Obafemi Awolowo University is locawhich lies in the Southern climate bThe climate of Ile-Ife area is typicalltropical with two major seasons, tha

rainy seasons. Rainy season starts and ends in October, while the dry sfrom November and ends in March.


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AN ASSESSMENT OF THE HEAVY METAL

THE O.A.U. TEACHING AND RESEARCH F

ILE-IFE,OSUN STATE.

A PGD Final SeminarPresented By

IKPE,EMMANUEL CHUKWUM( B.Sc. Chemistry )

SCP06/07/H/1471

Institute of Ecology And EnvironmentO.A.U.,ILE-IFE.

SupervisorProf. I .F Adeniyi


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INTRODUCTION

Water is life and indeed the most important natural which life would be non-existent.

Water pollution is the addition of undesirable foreig

deteriorates the quality of the water.

Heavy metals are of particular interest because they

toxic pollutants.

Heavy metals are metals with a density greater than

They occur naturally in the environment in rocks and o

Anthropogenic activities have also increased the rele

into the environment,there by causing environmental

Such activities include: ore extration and smelting, fo

dumping and landfilling of industrial wastes, exhaust

gasoline, steel, iron, cement and fertilizer production

combustion.


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STATEMENT OF THE STUDY P

Heavy metals are one of the causes

of water pollution, which is not com

addressed.

They are potentially toxic and not othey affect the biota at a water s

concentration at less than 1 ppm,

be grossly affected ( Freedman, 1Therefore the high concentrations an

unacceptable levels of the elemen

constitute risk to health.


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AIMS AND OBJECTIVES OF

The general aim of this study is to

heavy metal levels of water in the

The specific aims are to :

Assess the horizontal, vertical andvariations in the concentrations of

metals.

Assess the suitability of the pond wnumber of applications, including

culture, and irrigation.


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SCOPE OF THE STUDY

To review literature on the heavy

contents of fresh water (rivers, lak

ponds) and the analysis of farm p

samples collected over one annuaheavy metals using atomic absorp

spectrophotometry.


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GOAL/ESSENCE/PROBABLE APPLICATIO

This work is expected to provide informatof heavy metal concentration or contamina

O.A.U Teaching and Research Farm Pond

bring to focus on the suitability of the pon

number of applications, including for fish c

irrigation.

provide information for O.A.U. Teaching a

Farm Pond I authority or management to dplace an appropriate indicator paramete

the level of heavy metal concentration in t


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THE STUDY AREA

The pond is located at the Faculty of AgrTeaching and Research Farm, O.A.U., Ile-

are located at the farm, this study was ca

the one located after the poultry section

was impounded for the supply of waterto the nearby Teaching and Research far

The pond which was constructed between

July 1967, occupies an estimate area of

maximum fill. The two inflows to the ponStreams which flow from between two vi

and Obagbile, and Omifunfun. They flow

relatively higher plain and through a sec


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THE STUDY AREA CONT

Obafemi Awolowo University is locate

which lies in the Southern climate belt

The climate of Ile-Ife area is typically

tropical with two major seasons, that rainy seasons.

Rainy season starts from April and en

while the dry season starts from Nove

ends in March.


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Area = 11 Acres

Figure 1:The Teaching and Research Farm Pond 1 O.A.U.,Ile-If

THE STUDY AREA CONTD


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MATERIALS AND METH

Sampling Programme and Sampling Sta

Method of Analysis

The heavy metals were determined instrum

atomic absorption spectrometry (AAS) at

wavelengths, Arsenic (As) at the waveleng

nm, Cadmium (Cd) 228.0 nm, Chromium (

Cobalt (Co) 240.0 nm, Nickel (Ni) 232.0

Manganese (Mn) 403.0 nm, Copper (Cu)

(Fe) 2248.0 nm, Lead (Pb) 283.0 nm, and213.0 nm. Concentrations were measured

according to Golterman et al. (1978).


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RESULTS

HeavyMetal

%Detection

Maximium Median Mean S.E

Arsenic 68.4 4.20 0.70 1.022 0.121

Cobalt 43.4 0.14 0.00 0.024 0.004

Cadmium 59.2 2.63 0.36 0.594 0.081

Chromium 53.8 0.32 0.02 0.057 0.009

Copper 92.1 10.00 2.77 2.910 0.218

Iron 63.2 20.20 2.60 3.987 0.563

Manganese 47.4 2.24 0.00 0.371 0.066

Nickel 46.1 2.80 0.00 0.446 0.072

Lead 51.3 0.49 0.02 0.074 0.013

Zinc 53.9 6.92 0.42 1.264 0.185

able 1:Summary of Descriptive Statistics of Heavy Metals Concen

eaching and Research Farm Pond 1 O.A.U.


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RESULTS CONTD

HeavyMetals

Surface (n=30) Mid-depth (n=20)

Max Mean S.E %C.V Max Mean S.E %C.V

Arsenic 4.20 0.783 0.208 145.9 3.30 1.090 0.224 91.8 2

Cobalt 0.10 0.024 0.006 139.1 0.11 0.022 0.007 145.0 0

Cadmium 2.63 0.490 0.128 143.2 0.71 0.480 0.136 126.7 2

Chromium 0.32 0.067 0.015 126.28 0.18 0.046 0.013 125.2 0

Copper 4.60 2.491 0.206 45.2 10.00 3.357 0.538 71.7 1

Iron 20.2

0

5.070 1.049 113.3 17.30 3.405 1.149 150.9 1

Manganese

1.80 0.427 0.103 132.2 2.24 0.420 0.162 172.2 1

Nickel 2.80 0.437 0.132 165.9 1.60 0.410 0.114 124.3 1

Lead 0.49 0.093 0.024 139.0 0.15 0.032 0.011 159.9 0

Zinc 5.08 1.338 0.290 118.8 3.09 1.164 0.265 101.9 6

Table 2:Descriptive Statistics of Heavy Metals Concentration (m

Research Farm Pond 1 O.A.U.


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Heavy

Metals

WHOs

Standards

1993 (mg/l)

EUs Standards

1998 (mg/l)

WHO

Stand

mg/l

Arsenic (As) 0.01 0.01

Cobalt (Co) No guideline Not mentioned No

Cadmium (Cd) 0.003 0.005

Chromium (Cr) 0.05 0.05

Copper (Cu) 2.0 2.0

Iron (Fe) No guideline 0.2 No

Manganese (Mn) 0.5 0.05

Nickel (Ni) 0.02 0.02

Lead (Pb) 0.01 0.01

Zinc (Zn) 3.0 Not mentioned No gu

Table 3: WHO/EU drinking water standards compara


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Elements FAO Canada

Arsenic (As) 0.1 0.1

Cobalt (Co) No guideline No guideline N

Cadmium (Cd) 0.01 0.01

Chromium (Cr) 0.1 0.1

Copper (Cu) 0.2 0.2 1.0

Iron (Fe) No guideline No guideline N

Manganese (Mn) 0.2 0.2

Nickel (Ni) 0.2 0.2

Lead (Pb) No guideline No guideline N

Zinc (Zn) 2.0 1.0 5.0

Table 4: Selected Water quality Criteria for Irrigational

Sources: FAO,1985; CCREM,1987; FEPA,1991.


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Figure 2: The Mean Concentratiions of Arsenic in the Teaching & Research Farm Pon

Figure 3 The Mean Concentratiions of Cobalt in the Teaching & Research Farm Po


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Figure 4: The Mean Concentratiions of Cadmium in the Teaching & Research Farm Po

Figure 5: The Mean Concentratiions of Chromium in the Teaching & Research Farm


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Figure 7: The Mean Concentratiions of Iron in the Teaching & Research Farm Pond 1,

Figure 6: The Mean Concentratiions of Copper in the Teaching & Research Farm


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Figure 8: The Mean Concentratiions of Manganese in the Teaching & Research Farm

Figure 9 The Mean Concentratiions of Nickel in the Teaching & Research Farm Pon


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Figure 10: The Mean Concentratiions of Lead in the Teaching & Research Farm

Figure 11: The Mean Concentratiions of Zinc in the Teaching & Research Farm Pon


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Figure 12: The Concentration of Heavy metals for both Rainy and Dry SeResearch Farm Pond 1 O.A.U.


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DISCUSSION

General Background Levels

All the heavy metals ( As, Co, Cd, Cr, C

Pb and Zn ) analysed in this study we

the pond and their mean concentratioto be in the order of Fe > Cu > Zn >

> Mn > Pb > Cr > Co.


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DISCUSSION CONTD

Vertical Distribution Pattern

Horizontal Distribution Pattern

Seasonal Distribution Pattern

Associated Health Risks


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CONCLUSIONS

The results showed that the levels of Ars

Chromium, Copper, Iron, Nickel and Lea

above the (WHO,1993 and 2006) and

standards for drinking water and water

for irrigation water. This indicates that thunsafe for human consumption. This impl

heavy metal contamination in the pond w

The results obtained in this study would

baseline data for future heavy metal mopond.


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RECOMMENDATIONS

Some suggested solutions include:

The creation of water collection zonesof the field to trap runoff, which wouallowed to enter the pond after treat

Farmers within the catchment area shencouraged to rationalise the fertilizeto reduce the input of heavy metals ffarmland into the pond through runof

To plant hyper accumulating plants the pond for environmental clean up.


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The heavy metal content

Obafemi Awolowo Univers

Teaching and Research FaIle-Ife, Southwest, Nig

By

Adeniyi, I.F., Ikpe, E.C., and

Hydrobiology Section (LabLimnology) Zoology Depart

Ile-Ife, Nigeria.


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INTRODUCTIO

1. Background Information

1.1 Nature of heavy metals

Major group of aquatic pollutants

Non-degradable hence tend to accuthe environment

Accumulation leads to grave conse

man and ecosystem

Toxic, causes mobidity and disease

More toxic than radioactive wastes

organics


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INTRODUCTION CO

1.2 Heavy metals in Africa

Review by Biney et al(1994), information

scattered

Need for information in view of increased

and industrialization in many countries inc

Particularly relevant for Niger Delta and S

1.3 Previous studies of heavy meta

Review by Olabanji and Adeniyi (2006)

Components already covered include rain

effluent, soils.


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INTRODUCTION CO

1.4 Previous studies on pre

study lake

Imevbore et al. (1972)

Aderounmu and Adeniyi. (1972

1.5 Objectives of present st

Levels of ten heavy metals (AsCr, Cu, Fe, Mn, Ni, Pb, Zn) in th


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MATERIALS AND ME

2. Study Area2.1 General features of Ife area Information available in several published

Ako et al. (1990), Adeniyi (1992), Adeniyi(2005).

Geology of Pre Cambrian Basement Com

Soils are Lixoxols and Ultisols, mostly of Owena (uplands), Oba and Apomu (low labottom).

Vegetation of Guinean Congolean fores

Climate of Equatorial Hot and wet type, raconventional type, low peaks (June/July,September/October).

Temperature generally high.


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MATERIAL AND METHODS

2.2 The study lake

Impounded March May 1967 for

to the farm.

070

33.3081

070

33.3981

N, 0040

32.003033.1431E

About 4 ha (11 acres)

Fertilized for fisheries development

Fish include Tilapia, Hemichromis C

Heterobranchusspecies.


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2.3 Sampling programme

Monthly sampling through the columsampling stations (A,B,C) along thethe lake.

Station A (dam site, 6m deep), Stalake, 4m), and Station C (inflow,


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2.4 Chemical analysis

Analysis carried out at Central

OAU, Ife.

By AAS/FAAS methods using c

standards for the instrument.

Statistical analysis include, De

statistics, Anova, Regression acorrelation, and Cluster analysi


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RESULTS

3.1 Statistical Summary

Percent detection generally less 70% except fo

Distribution pattern positively skewed, i.e. mea

values.

Cu and Pb leptokurtic (Kurtosis >3), other plat

3.0).

Median ranking order: Cu>Fe>As>Zn>Cd>Pb>

Relatively low levels of ferrous metals (Co, Cr,

compared to the others (Cu, As, Cd, Pb, Zn).

Occur in four long concentration levels

Cu>Fe (>1.00mgl-1)

As>Zn>Cd (>0.10 1.00mgl-1)

Pb>Cr (0.01 0.10mgl-1)

Mn>NI>Co (


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RESULTS CON

3.2 Spatial distribution patterns Most of the metals (As, Cd, Co, Cr, Cu, N

an increase from surface to bottom.

The degree of difference between surface

values most pronounced and statistically

based on median values.

Fe, Mn and Zn tended to decrease toward

bottom

Most of the metals showed an increased (inflow) to Station A (dam site) As, Fe, Ni

Cd & Cu showed a decrease from Station


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RESULTS CON

3.3 Temporal distribution pattern The values of metals were higher in the ra

in the dry season (most pronounced usingvalues).

Ration of RS/DS also most pronounced at

site). All metals showed dual peaks over the ann

Major peaks at early rainy season = Co, C

Minor peaks, early RS: Pb, Cd, Cr, Zn

Major peaks, late RS; Cd, Cr, Pb

Minor peaks, late RS: Cu, Mn

Major peaks: DS: Mn, Zn

Minor peaks: DS: Fe, Ni, As.


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RESULTS CON

3.4 Heavy metals and other water qparameters

Correlation with other parametegenerally low.

Heavy metals showed negativewith pH.

Heavy metals showed positive

mostly with conductivity, TDS, CTSS.


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Figure 1: The concentration of Heavy metals for both Rainy and Dry season in

Farm Lake O.A.U


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Fig. 2: Cluster analysis of relationship between heavy metals


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DISCUSSION

4.1 Probable sources of me

Most probably of background te

sources within the catchments.

and vegetation).

Inputs mainly through runoff, er

Agricultural practices, mainly th

application of fertilizers, pesticidherbicide, secondary sources.


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DISCUSSION CO

4.2 Likely effect of heavy m

contents

Water not safe for drinking w

treatment, especially in the

season.

Water suitable for irrigation,aquaculture and other agric

purposes.


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ACKNOWLEDGME

Dean Faculty Of Agriculture,

O.A.U. Ile-Ife

Thank you.


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AN ASSESSMENT OF THE HEAVY METAL CONTENTS OF

THE OBAFEMI AWOLOWO UNIVERSITY TEACHING AND

RESEARCH FARM POND I, ILE-IFE, OSUN STATE

BY

IKPE, EMMANUEL CHUKWUMA.

(B.Sc. CHEMISTRY)

SCP 06/07/H/1471

A THESIS SUBMITTED TO THE

INSTITUTE OF ECOLOGY AND ENVIRONMENTAL STUDIES

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR

THE AWARD OF POST GRADUATE DIPLOMA IN

ENVIRONMENTAL CONTROL AND MANAGEMENT,

OBAFEMI AWOLOWO UNIVERSITY (OAU) ILE-IFE,

OSUN STATE, NIGERIA

JUNE, 2008


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CERTIFICATION

This is to certify that this research study was carried out by

Mr.Ikpe Emmanuel Chukwuma (SCP 06/07/H/1471), at the Institute of

Ecology and Environmental Studies, Obafemi Awolowo University, Ile-Ife under

my supervision.

----------------------- --------------------------

Prof. I.F. Adeniyi Date

Supervisor

Institute of Ecology and Environmental Studies

O.A.U. Ile-Ife, Nigeria.

ii


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DEDICATION

I dedicate this research work to God Almighty (I AM) and Prince Pat Abii.

I also dedicate this research work to my late sisters Miss Francisca and Miss

Monica Ikpe, may their soul rest in peace.

iii


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TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgments iv

Table of contents vi

List of Tables viii

List of Figures xii

Abstract xiv

CHAPTER ONE: INTRODUCTION 1

1.1 Importance of Water 11.2 Background to the Study 21.3 Statement of Study Problem 41.4 Aims and Objectives of Study 51.5 Scope of the Study 51.6 Goal/Essence/Probable Application of Study 5CHAPTER TWO: LITERATURE REVIEW 7

2.1 Water quality and its importance 72.2 Effects of Environment and resource use on water quality 82.3 Measurement of water quality. 92.4 The Effects of Water quality on Aquatic Ecosystem. 10

v


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2.5 Previous Studies on the work 122.6 Sources of Heavy Metals 132.7 Distribution Pathways and Fate of Heavy Metals in the

Aquatic Environment. 16

2.8 Effects of Heavy Metals in Organisms 182.9 Nigerian and some African Experience 192.10 Some African Countries 282.11 Levels of Heavy Metals in Different Environment Compartments 352.11.1Concentration of Metals in Water 362.11.2Concentration of Metals in Sediments 362.11.3Concentration of Metals in Aquatic Fauna 372.11.4Concentration of Metals in Aquatic Flora 382.12 Comparison between Metal contents in Sediment and Biota 392.13 Methods of Analysis 43CHAPTER THREE: THE AREA OF STUDY 45

3.1 The Geographical Location and General Features of Ile-Ife 453.2 The Climate and Meteorology of the Area 463.3 The Geology of the area 473.4 Soils of the Area and Land Use 473.5 Vegetation of the Area 48

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CHAPTER FOUR: MATERIALS AND METHODS 49

4.1 Sampling Programme and Sampling Stations 494.2 Method of Analysis 50CHAPTER FIVE: RESULTS 52

5.1 Arsenic (As) 525.2 Cobalt (Co) 535.3 Cadium (Co) 545.4 Chromium (Cr) 615.5 Copper (Cu) 625.6 Iron (Fe) 635.7 Manganese (Mn) 685.8 Nickel (Ni) 695.9 Lead (Pb) 695.10 Zinc (Zn) 70CHAPTER SIX: DISCUSSION 86

6.1 General Background Levels 866.2 Vertical Distribution Pattern 876.3 Horizontal Distribution Pattern 886.4 Seasonal Distribution Pattern 896.5 Associated health Risks 89

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CHAPTER SEVEN: CONCLUSIONS AND RECOMMENDATIONS 92

7.1 Conclusions 927.2 Recommendations 93

REFERENCE 95

List of abbreviations and acronyms used 108

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LIST OF TABLES

Table No. Title Page

Table 2.1: Industrial and Agricultural Source for metals in the

Environment. 15

Table 2.2: Mean metal concentrations in some industrial effluents and

Landfill leachates (ug /ml). 40

Table 2.3: Mean dissolved metal concentrations in inland and coastal

Waters (ug/ml). 41

Table 4.1: Instrument methods used in the chemical analyses of water

quality parameters. 51

Table 5.1: The Concentrations (mg/l) of Arsenic (As) in Teaching and

Research Farm Pond I of Obafemi Awolowo University 55

Table 5.2: The concentrations (mg/l) of Cobalt (Co) teaching and

Research Farm Pond I of Obafemi Awolowo University. 56

Table 5.3 The Concentrations (mg/l) of Cadmium (Cd) in Teaching and


Table 5.4 The Concentrations (mg/l) of Chromium (Cr) in Teaching and


Table 5.5 The Concentrations (mg/l) of Copper (Cu) in Teaching and


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Table 5.6 The Concentrations (mg/l) of Iron (Fe) in Teaching and

Research Farm Pond I of Obafemi Awolowo University 66

Table 5.7 The Concentrations (mg/l) of Manganese (Mn) in Teaching

and Research Farm Pond I of Obafemi Awolowo University. 72

Table 5.8 The Concentrations (mg/l) of Nickel (Ni) in Teaching and Research

Farm Pond I of Obafemi Awolowo University. 73

Table 5.9 The Concentrations (mg/l) of Lead (Pb) in Teaching and


Table 5.10: The Concentrations (mg/l) of Zinc (Zn) in Teaching and


Table 5.11: The Hydrogen ion concentration (pH) (pH Units) of water

samples in the Teaching and Research Farm Pond I of

Obafemi Awolowo University. 79

Table 5.12: The total Depth (m) of water measured in Teaching and


Table 5.13: The Total Depth (m) of Water Measured in Teaching and


Table 5.14: The Water Transparency (m) Values measured at each sampling

station in Teaching and Research Farm Pond I of Obafemi

Awolowo University. 81

Table 5.15: Descriptive statistics of Heavy Metals Concentrations (mg/l)

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in Teaching and Research Farm Pond I of O. A.U. 82

Table 5.16: Descriptive Statistics of Heavy Metals Concentrations (mg/l)

in Teaching and Research Farm Pond I of O. A.U. 83

Table 5:17: WHO/EU drinking water standards comparative table. 84

Table 5.18: Selected Water quality Criteria for Irrigational Water (mg/l) 85

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LIST OF FIGURES

Figure No. Title Page

Figure 2:1: The hydrological cycle 11

Figure 5.1: The mean concentrations of Arsenic in the Teaching and

Research Farm Pond I, O.A.U. 59

Figure 5.2: Figure 5.1: The mean concentrations of Cobalt in the Teaching

and Research Farm Pond I, O.A.U. 59

Figure 5.3: The mean concentrations of Cadmium in the Teaching and


Figure 5.4: The Mean Concentrations of Chromium in the Teaching and


Figure 5.5: The Mean Concentrations of Copper in the Teaching and


Figure 5.6: The Mean Concentrations of Iron in the Teaching and


Figure 5.7: The Mean Concentrations of Maganese in the Teaching and


Figure 5.8: The Mean Concentrations of Nickel in the Teaching and


Figure 5.9: The Mean Concentrations of Lead in the Teaching and


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Abstract

The main aim of this study was to assess the heavy metal levels of water in

the farm pond I at the Faculty of Agriculture Research Farm, Obafemi Awolowo

University, Ile-Ife. The specific aims were to assess the horizontal, vertical and

seasonal variations in the concentration of the heavy metals and also assess the

suitability of the water for a number of applications, including for fish culture

and irrigation with regard to their heavy metal levels.

Water samples were collected monthly at three different sampling stations

( A, B, and C ) from the Teaching and Research farm pond 1, Obafemi Awolowo

University (O.A.U.), Ile-Ife, from September, 2006 to August, 2007. Water

samples collected from the pond were analysed for heavy metals contents. The

levels of pH, temperature, depth and water transparency were also measured in

the water samples. The concentrations of the heavy metals were determined with

an Atomic Absorption Spectrophotometer (AAS).

The results showed that the water quality in the pond has been polluted by

some of the heavy metals, notably Arsenic, Cadmium, Copper, Iron and Lead.

The mean concentration levels were in the order of: Fe > Cu > Zn > As > Cd >

Ni > Mn > Pb > Cr > Co. The results also showed that most of the heavy metals

(As, Cd, Cr, Cu, Fe, Ni and Pb) were higher than the recommended World

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xv

Health Organisation (WHO) and European Union (EU) standards for drinking

water quality and the water quality criteria for irrigation water.

Arsenic and manganese showed definite pattern of vertical variation in the

pond, while, cobalt, cadmium, chromium, copper, iron, nickel, lead, and zinc did

not show any definite pattern in their vertical variation in the pond. There was

also definite pattern of horizontal variation in the concentrations of arsenic,

cadmium, cobalt, copper, iron and zinc. On the other hand, there was no distinct

pattern in the horizontal variation in of chromium, manganese, nickel, and lead.

The concentration of most of the heavy metals (As, Co, Cd, Cr, Cu, Fe, Mn and

Ni) appeared higher during the rainy season than in the dry season, while Zn was

higher in the dry season.

The probable source of the heavy metal into the pond was agricultural

runoff, and recommendations for the control of the pollution in the pond are

suggested.


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CHAPTER ONE

INTRODUCTION

1.1 Importance of Water

Water is life and indeed the most important natural resource without

which life would be non-existent. Availability of safe and reliable source of

water is an essential prerequisite for sustainable development. Deserts are

not habitable because of lack of water

Continuous urban development and large solid waste pose a major

environmental risk because of the difficulties in disposal. Landfills and other

solid wastes disposal sites are major targets of pollution because rainfall and

groundwater leach these highly contaminated substances into lakes,ponds

river, streams and waterways (surface waters) which are inadvertently used

by people residing in such areas.

Water borne diseases kill 50,000 people daily (Herschy, 1999) and

about 4 million children under the age of five die yearly in developing

countries due to water related problems (USAID, 1990; Warner, 1998).

Throughout the world, about 2.3 billion people suffer from disease that are

linked to water related problems (U.N, 1997; WHO, 1997) which, continue

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to kill millions of people yearly, debilitate billions thereby undermining

developmental effort (Nash, 1993; Olshanshy et al., 1997).

1.2 Background to the Study

The terms water pollution and air pollution imply the presence of

undesirable foreign matter in an otherwise pure or natural substance. The

pollution of water is thus the addition of undesirable foreign matter, which

deteriorates the quality of the water.

Water quality may be defined as its fitness for the beneficial uses

which it has provided in the past-for drinking by man and animals, for the

support of aquatic life, for irrigation of the land, for recreation and aesthetics

and for industry. Any substance that prevents the normal use of water is

considered a water pollutant. Pollutant (foreign) matter may be either non-

living, such as compounds of Pb or Hg, or living such as micro-organisms.

Water pollution is of grave consequence because both terrestrial and

aquatic life may be poisoned; it may cause disease due to the presence of

some hazardous substances, and hence significantly, hinder economic

activities.

The causes and forms of water pollution according to Stradberg

(1971) include sewage and other oxygen demanding wastes, infectious

agents, organic chemicals, other chemicals and mineral substances,

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sediments (turbidity), radio-active substances and heat. Additionally, several

human activities that may result to water pollution include the following,

agriculture, irrigation, urbanization, mining, fire and industrialization

(Goudie, 1990). These activities have been documented to have impacted

negatively in some specified Nigerian surface waters especially in the Niger

Delta region (Izonfuo and Bariweni, 2001).

Heavy metals are of particular interest because they are among the

most toxic pollutants. Heavy metals are metals with a density greater than

5g/cm3. They are less abundant than the light metals, one of their

characteristics is their relative inertness, which implies that after release into

the environment they are persistent contaminants. The heavy metals of

interest include the following Arsenic (As), Cadmium (Cd), Chromium (Cr),

Cobalt (Co), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead

(Pb) and Zinc (Zn).

Heavy metals occur naturally in the environment in rocks and ores.

They cycle through the environment by geological and biological means.

The geological cycle begins when water slowly wears away rocks and

dissolves the heavy metals. The heavy metals are carried into streams, rivers,

lakes and oceans. The heavy metals may be deposited in sediments at the

bottom of the water body, or they may evaporate and be carried elsewhere as

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rainwater. The biological cycle includes accumulation in plants and animals

and entry into the food web. Anthropogenic activities have also increased

the release of heavy metals into the environment, thereby causing

environmental contamination or pollution. Such activities include ore

extraction and smelting, fossil fuel combustion, dumping and land filling of

industrial wastes, exhaust from leaded gasoline, steel, iron, cement and

fertilizer production, refuse and wood combustion. Heavy metal has also

increase through activities such as farming, deforestation, construction,

dredging of harbours and the disposal of municipal sludge and industrial

waste on land.

1.3 Statement of Study Problem

Heavy metals are one of the causes and forms of water pollution,

which is not commonly addressed. Although these trace elements are usually

present in the environment, they are potentially extremely toxic and not only

would they affect the biota at a water soluble concentration at less than 1

part per million (ppm), humans can be grossly affected (Freedman, 1989).

Therefore the high concentrations and unacceptable levels of the elements

may constitute risk to health.

However, the emission of airborne metallic pollutant has now reached

such proportions that long-range atmospheric transport causes contamination

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not only in the vicinity of industrialized regions, but also in more remote

areas.

1.4 Aims and Objectives of Study

The general aim of this study is to assess the heavy metal levels of

water in the farm pond.

The specific aims are to

i. assess the horizontal and vertical variations in the concentration ofthe heavy metals.

ii. assess the suitability of the pond water for a number ofapplications, which include: fish culture and irrigation.

1.5 Scope of the Study

To review literature on the heavy metal contents of fresh water (rivers,

lakes and ponds) and the analysis of heavy metal contents of research farm

pond water collected over one annual cycle.

1.6 Goal/Essence/Probable Application of Study

This work is expected to provide information on the level of heavy

metal concentration of the O.A.U Teaching and Research Farm Pond I, Ile-

Ife. The result of this work will also bring to focus on the suitability of the

pond water for a number of applications including fish culture and irrigation.

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It also expected that the result of this work will provide information for

O.A.U. Teaching and Research Farm Pond I authority or management to

design and put in place appropriate indicator parameters for monitoring the

level of heavy metal concentration in the pond water.

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CHAPTER TWO

LITERATURE REVIEW

2.1 Water Quality and Its ImportanceWater is essential to human life and to the health of the environment.

As a valuable natural resource, it comprises marine, estuarine, fresh water

(river and lakes) and groundwater environment, across coastal and inland

areas. Water has two dimensions that are closely linked quality and

quantity. Water quality is commonly defined by its physical, chemical,

biological and aesthetic (appearance and smell) characteristics. A healthy

water environment is one which the water quality supports a rich and varied

community of organisms and is conducive to public health. The water

quality of a body of water influences its use by the riparian communities for

drinking, swimming or commercial purposes. More specifically, the water

may be used by the community for the following:

- Supplying drinking water.- Recreation (swimming, boating)- Irrigation crops and watering live stock- Industrial processes- Navigation and shipping

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- Production of edible fish, shell fish and crustaceans- Protection of aquatic ecosystems- Wildlife habitats- Scientific study and education.

Water quality is rated one of the highest priority environmental issues,

and it has to be improved at the very least, not further degraded.

Our water resources are of major environmental, social and economic

value to us, but if water quality becomes degraded water loses its values.

Water quality is important not only to protect public health-water provides

ecosystem habitats, is used for farming, fishing and mining and contributes

to recreation and tourism. Therefore, if water quality is not maintained, it is

not just the environment that will suffer- the commercial and recreational

value of our water resources will also diminish.

2.2Effects of Environment and Resource Use on Water Quality

Other than in its vapour form water is never pure.This is because,

water quality is closely linked to the surrounding environment and land use.

It is affected by community uses such as agriculture, urban and industrial

uses, and recreation. The modification of natural stream flows by dams and

wiers can also affect water quality. The weather too can have a major impact

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on water quality, particularly in a dry country like Australia which is

periodically affected by droughts (USEPA, 2001).

Generally the water quality of rivers is best in the headwaters, where

rainfalls are often abundant. Water quality often declines as rivers flow

through regions where land use and water use are intense and pollution from

intensive agriculture, large town, industry and recreation areas increases.

2.3 Measurement of Water Quality

The presence of contaminants and the pattern of water use and/or land

use reflect on the quality of water. Water quality indicators can be

categorized as follows:

a. biological: bacteria, algaeb. Physical: temperature, turbidity and clarity, colour, sanity,

suspended solids, dissolved solids.

c. Chemical: pH, dissolved oxygen, biological oxygen demand,nutrients (including nitrogen and phosphorus), organic and

inorganic compounds (including toxicants).

d. Aesthetic: odours, taints, colour, floating matter.e. Radiation: alpha, beta, gamma radiation emitters.

Measurement of these indicators can be used to determine and monitor

changes in water quality, and determine whether the quality of the water is

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suitable for the health of the natural environment and uses for which the

water is required.

2.4 The Effects of Water Quality on Aquatic EcosystemAn ecosystem is a community of organisms plants, animals, fungi

and bacteria-interacting with one another and with the environment in which

they live. Protecting aquatic ecosystem in many ways as important as

maintaining water quality, for the following reasons:

i. Aquatic ecosystems are an integral part of our environment. They

need to be maintained if the environment is to continue to support people.

World conservation strategies stress the importance of maintaining healthy

ecosystem and genetic diversity.

ii. Aquatic ecosystem plays an important role in maintaining water

quality and is a valuable indicator of water quality and the suitability of the

water for other uses.

iii. Aquatic ecosystem is valuable resources. Aquatic life is a major

source of protein for humans. In most countries, commercial and sport

fishing is economically important.

Figure 2.1: below illustrates the variety of physical process related to the

movement and storage of water within the environment.

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(2001).

Figure 2.1: The hydrological Cycle.

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2.5 Previous Studies on the Work

In natural aquatic ecosystem, metals occur in low concentrations,

normally at the nano- gram (ng) to micro- gram (g) per litre levels. In

recent times, however, the occurrence of metal contaminants especially

heavy metals in excess of natural loads has become a problem of increasing

concern. This situation has risen as a result of the rapid growth of

population, increased urbanisation, expansion of industrial activities,

exploration and exploitation of natural resources, extension of irrigation and

other modern agricultural practices as well as the lack of environmental

regulations.

Unlike other pollutants like petroleum hydrocarbons and litter which

may visibly build up in the environment, trace metals may accumulate

unnoticed to toxic levels. This problems associated with trace metal

contamination were first highlighted in the industrially advanced countries

because of their larger industrial discharges and especially by incidents of

mercury and cadmium pollution in Sweden and Japan (Kurland et al., 1960;

Nitta, 1972; Goldberg 1976). In spite of the relatively low level of industrial

activity in less developed regions such as Africa, there is nevertheless

growing awareness of the need for rational management of aquatic resources

including control of waste discharges into the environment. This becomes

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even more important in view of the expected increases in industrial and

urban activities in all parts of the country.

For effective water pollution control and management there is a need

for a clear understanding of the inputs (loads), distribution and fate of

contaminants, including trace metals from land-based sources into aquatic

ecosystems.

In particular, the quantities and qualities need to be considered

together with the distribution pathways and fate and the effects on biota.

2.6 Sources of Heavy Metals.

Heavy metals enter the aquatic environment from both natural and

anthropogenic sources. Entry may be as a result of direct discharge into both

freshwater and marine ecosystems or through indirect routes such as dry and

wet deposition and land runoff. Important natural sources are volcanic

activity, continental weathering and forest fires. The contribution from

volcanoes may occur as large but sporadic emissions, due to explosive

volcanic activity or as other low continuous emissions, including geothermal

activity and magma degassing (Zoller, 1984). The major sources of

atmospheric mercury, for example are land and ocean degassing. In view of

the toxic nature of heavy metals, the knowledge of their sources and fate in

the environment is important.

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The anthropogenic sources include:

i. Mining effluentsii. Industrial effluentsiii. Domestic effluents and urban storm-water run offiv. Leaching of metals from garbage and solid wastes dump.v. Metals inputs from rural areas, e.g metals contained in pesticides.

Atmospheric sources, e.g burning of fossil fuels, incineration of

wastes and industrial emissions.

vi. Petroleum industry activities.

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Table 2.1Industrial and agricultural source for metals in the environment

Source Metal

Batteries and other electricalsCd, Hg, Pb, Zn, Mn, Ni

Pigments and paints Ti, Cd, Hg, Pb, Zn, Mn, Sn, Cr, Al, As,

Cu, Fe

Alloys and solders Cd, As, Pb, Zn, Mn, Sn, Ni, Cu

Biocides(pesticides, herbicides,

preservations)

As, Hg, Pb, Cu, Sn, Zn, Mn

Catalysts Ni, Hg, Pb, Cu, Sn

Glass As, Sn, Mn

Fertilizers Cd, Hg, Pb, Al, As, Cr, Cu, Mn, Ni, Zn

Plastics Cd, Sn, Pb

Dental and cosmetics Sn, Hg

Textile Cr, Fe, Al

Refineries Ni, V, Pb, Fe, Mn, Zn

Fuel Ni, Hg, Cu, Fe, Mn, Pb, Cd

Source: Biney, et al. (1991).

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For most heavy metals, anthropogenic emission are more than or

equal to natural emissions. The combustion of leaded petrol in automobiles

for instance, is responsible for the widespread distribution of lead in the

world. For mercury, however several reports (Hutchinson and Meema, 1987;

GESAMP, 1988) suggest that natural emission are qualitatively more

important than anthropogenic sources.

Heavy metal concentrations in industrial effluents and landfill

leachate in Nigeria are shown in Table 2.2.

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Table 2.2Mean metal concentrations in some industrial effluents and landfill leachates (g ml

-1)

Location Hg Cd Pb Cu Zn Mn Fe Ni Co Reference

NIGERIA

Textilefactory

effluents


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2.7 Distribution Pathways and Fate of Heavy Metals in the Aquatic

Environment:

Once in the aquatic environment, metals are partitioned among

various aquatic environmental compartments (Water, suspended solids,

sediments and biota). The metals in the aquatic environment may occur in

dissolved, particulate and complexed form.

The main processes governing distribution and partition are dilution,

advection, dispersion, sedimentation and adsorption/desorption. The

speciation under the various soluble forms is regulated by the instability

constants of the various complexes and by the physico-chemical properties

of the water (pH, dissolved ions, Eh and temperature).

Adsorption could be the first step in the removal of metals from water.

In the course of distribution, permanent or temporary storage of metals take

place in the sediments of both fresh-water and marine environments.

Microbial activity and redox processes may change the properties of

sediments and affect the composition of interstitial water. As a result, iron

and manganese oxides may be converted to carbonates or sulphides, leading

to a decrease in the adsorption capacity of the sediments. Reworking of the

sediments by organisms will also bring sediments to the surface where a

significant fraction of the metal will be released (Biney, et al., 1991).

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Many transformations of heavy metals in aquatic environments occur

as bio-chemically mediated reduction, methylation, demethylation and

oxidation of single species. Redox reactions may also facilitate some

transformations. The biochemical processes are carried out by micro-

organisms and algae. According to Jernelov (1975), methylation of mercury

takes place when micro-organisms, while consuming organic substances,

happen to come into contact with mercury ions. This may also be true for

As, Sn and Pb (Biney, et al.,1991).

Heavy metals are taken up by both fauna and flora. This uptake could

provoke an increase in the concentration of the metal in the organism; if the

excretion phase is slow, this can lead to the bioaccumulation phenomenon. A

few metals such as mercury have been shown to undergo biomagnification

through the food chain (Biney, et al., 1991).

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2.8 Effects of Heavy Metals in Organisms

Some heavy metals such as Zn, Cu, Mn and Fe are essential for the

growth and well-being of living organisms including man. However, they

are likely to show toxic effects when organisms are exposed to levels higher

than normally required. Other elements such as Pb, Hg and Cd are not

essential for metabolic activities and exhibit toxic properties (Biney, et

al.,1991).

Metals contamination of the aquatic environment may lead to

deleterious effects from localised inputs which may be acutely or chronically

toxic to aquatic life within the affected area. Most published data on the

effects of metals on aquatic organisms, however, report adverse effects at

concentration higher than usually found in the environment (GESAMP,

1985; 1988).

Metals may be taken in the inorganic or organic form. For some

elements, such as arsenic and copper, the inorganic form is the most toxic.

For others, such as Hg, Sn and Pb, the organic forms are the most toxic. At

low concentrations many heavy metals including Hg, Cd, Pb, As and Cu,

inhibit photosynthesis and phytoplankton growth. Effect at higher tropic

level include delayed embryonic development, malformation and reduces

growth of adults of fish, molluscs and crustaceans (Biney, et al., 1991).

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The major routes of heavy metal uptake by man are food, water and

air. For example, aquatic fauna, especially fish, are the most important

source of mercury and arsenic for human beings.

2.9 Nigerian and some African Experience

Studies on the occurrence and distribution of metals in Nigeria have

been conducted on all the major environmental matrices (water, sediments,

fauna and flora) but again with more emphasis on sediments (Biney, et al.,

1991).

Statistical treatment of the result of metal analysis of 176 stream

sediments samples from the Ife-Ilesa area (1800 km2) of southern Nigeria

(Ajayi, 1981) showed that all the elements have density distribution close to

natural background levels. Ojo (1988) also used various statistical methods

for the interpretation of the geochemical data obtained from analyses of Cu,

Pb, Zn, Co, Ni, Fe, Mg, Mn and Ca in 374 stream sediment samples

collected over an area of 700 km2

within Upper Benue Trough and

concluded that these elements exhibit various patterns of association

depending on their nature and prevailing environmental conditions. Other

studies in the area (Kakulu and Osibajo, 1988, 1991) revealed elevated

levels of Pb, Cr, Ni, V and Zn in Port Harcourt and Warri sediments which

suggest that effluents from petroleum refineries located in these cities have

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contributed significantly to the heavy metal pollution of the respective

aquatic ecosystem.

Okoye et al., (1991) reported anthropogenic heavy metal enrichment

of Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, and Zn in the Lagos lagoon and

implicated land based urban and industrial wastes sources. Pollution studies

on 26 rivers in some southern and northern states in Nigeria (Ajayi and

Osibanjo, 1981), on rivers in the Niger Delta (Kakulu and Osibajo, 1991) on

the cocoa growing area of Ondo state (Ogunlowo, 1991) and the Lagos

waters (Okoye, 1991a) showed that, with the exception of iron, the

concentrations of most trace metals in the surface water are generally lower

than the global average levels for surface water and the international

drinking water standards.

Ndiokwere and Guinn (1982) determined As, Cd, Cr, Hg, Mn, Mo,

Ni, Se and Sb in two Nigerian rivers and two harbours and attributed high

metal concentrations to local pollution sources. In their studies of streams

and lakes around Ibadan, Mombesshora et al. (1983) reported much higher

levels of lead in sediments than in water. The highest levels of lead

coincided with areas of high traffic density.

Analyses of sediments and fish from the Niger Delta area of Nigeria

(Kakulu and Osibajo, 1986) revealed that the area was relatively unpolluted

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with mercury compared to some European areas (Mediterranean, Baltic sea

and North-East Atlantic). Report from the same area (Kakulu et al, 1987a)

indicated that the levels of Cd, Cu, Fe, Mn, Pb, and Zn were higher in shell

fish than in finfish. With the exception of the level in some shellfish, levels

of these metals were generally lower than the WHO recommended limits in

foods. Concern about the high level of lead in Lagos lagoon fish has also

been expressed (Okoye, 1991).

Other Nigerian studies included that of Ntekim et al. (1992), they

studied the concentration and area distribution of selected metals (Pb, Zn,

Cu, Cd, Ni, Fe, and Cr) in the sediments of the Calabar River to determined

the extent of anthropogenic input and to estimate the effects of dumping

industrial waste materials into the river. Ntekim et al. (1992) found that the

concentration of Pb, Zn, and Cu indicate relatively moderate pollution

mainly on the left- hand side of the river while Ni, Cr, Co, Cd and Fe levels

are below value found to have adverse effects on the lives of marine biota.

Ntekim et al. (1992) discovered that high metal contents are found

close to industrial establishments. So, they suggested/states that enhanced

metal concentrations are related to industrial sewage and metal leaching

from garbage and solid waste dumps.

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Asonye, et al. (2007) collected water samples of 72 rivers, streams

and waterways in southern Nigeria. Asonye, et al. (2007) carried out the

following physico-chemical analyses on the samples - tesmperature, colour,

taste, turbidity, pH, total dissolved solids (TDS), conductivity and also

assessed the heavy metal profiles (Pb, Cr, Cd, Fe, Zn, Mn, Cu) among the

entire samples they have collected. Asonye, et al. (2007) discovered that the

turbidity (NTU) of 93 % of all the samples was higher than World Health

Organisation (WHO) and European Economic Community (EEC) standards.

Asonye, et al. (2007) found that 57 % of the entire samples had

conductivities above normal limits, and the pH of 81 % of the entire samples

are above WHO and EEC guide limits. The profiles of the heavy metals Pb,

Cd, Cr, Zn and Mn levels in some of the samples are above the guidelines of

WHO and EEC (Asonye, et al. (2007)). Fe had 55 % of all the samples

exceeding recommended 0.05 ppm, Cd had 11 % exceeding 0.03 ppm while

7 % of both Zn and Pb exceeded 3 ppm and 0.10 ppm respectively (Asonye,

et al. (2007)). From their results, they indicated the heavy metal pollution

and toxicity might pose serious risks to the health of communities residing

around and using these surface waters for domestic, commercial and socio-

cultural purposes.

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variations in the concentration of the heavy metals used for the different

evaluation schemes.

Wegwu and Akaninwor (2005) carried out studies on the assessment

of heavy-metal profile of the New Calabar River and its impact on juvenile

Calrias gariepinus. Wegwu and Akaninwor (2005) determined the heavy-

metal status of the lower reaches of the New Calabar River in the Niger

Delta region over a 40-km-long distance, and its impact on the development

of catfish (juvenile Claris gariepinus). Wegwu and Akaninwor (2005) also

determined the total mean concentrations of dissolved trace metals in the

river to be 0.01, 0.85, 0.56, 2.08, 0.05, 12.0 and 6.59mg/1 for Hg, Pb, Cd,

Cu, Cr, Fe and Zn, respectively. Wegwu and Akaninwor (2005) examined

the accumulated concentration of trace metals in the muscles of different

mature fish caught from the river, and their results fell within the action

levels adopted in most countries. Wegwu and Akaninwor (2005) hatched

eggs of C. gariepinus in dilution water spiked with the total mean metal

levels determined in the river water, in order to evaluate the contributions of

trace metals to fisheries depletion. The results of Wegwu and Akaninwor

(2005) showed even at very low concentrations of the majority of the trace

metals studied with mortality rates well above 50% after 216hrs of exposure.

From their findings, they suggested that trace metals (except for Zn), even at

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very low concentration, negatively affect fish hatch and fry rearing,

implying that aquatic milieus contaminated by trace metals are not suitable

as nursery grounds for fish cultures.

Ekpo and Ibok (1999) worked on the temporal variation and

distribution of trace metals in freshwater and fish from Calabar River, S.E

Nigeria. Ekpo and Ibok (1999) investigated on the abundance and

distribution of trace metals (Fe, Cu, Zn, Mn, Cr, Cd and Pb) in water, and

nine species of fish samples from Calabar River. Ekpo and Ibok (1999)

determined the concentrations of iron to be (6.0-7.24 mg/1), Zinc (4.91-7.23

mg/1), and Cadmium (0.003-0.007 mg/1). The results of Ekpo and Ibok

(1999) showed moderate pollution while that of copper (0.42-0.63 mg/1),

manganese (0.023-0.048 mg/1), Chromium (


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Fe>Zn>Cu>Mn>Pb>Cd=Cr and were within the limits that were safe for

consumption.

Oyewale and Musa (2006), studied the pollution assessment of the

lower basin of lakes Kainji/Jebba, Nigeria; heavy metal status of the waters,

sediments and fishes. They examined the heavy metal status of the lower

basin of Kainji dam (used for hydroelectricity generation), which includes

lakes Kainji/Jebba, Nigeria and the potential for human exposure to heavy

metals from eating fish caught in the lakes. Oyewale and Musa (2006)

assessed/evaluated water, sediments and fish samples from the lakes for As,

Cu, Co, Cr, Fe, Hg, Mn, Ni, Pb, Sb, Ti, V and Zn using the EDXRF

technique. Oyewale and Musa (2006) discovered Fe and Mn to be present at

high mean concentrations in the water (0.013 and 0.019 mg/l), sediments

(7.092 and 0.376mg/g) and fish (0.0114 and 0.004.6 mg/g) samples.

Oyewale and Musa (2006) also found Sb (0.0032mg/1), Ti (0.0041 mg/1),

Cr (0.0022 mg/1) Co (0.0012 mg/1), Cu (0.0013 mg/1) and Pb (0.0012

mg/1) in the water samples and Sb (0.029 mg/l), Ti (0.027 mg/1), V (0.027

mg/1), Cr (0.027 mg/1), Co (0.04 mg/1), Ni (0.033 mg/1), Cu (0.025 mg/1),

Zn (0.059 mg/1) and Pb (0.019 mg/1), in the sediment samples to be of

medium mean concentrations. Oyewale and Musa (2006) discovered that As

and Hg are present at trace levels (


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samples. From their results, Oyewale and Musa (2006) discovered an

appreciable increase in metal concentrations in going from the water to the

sediment samples. Oyewale and Musa (2006) suggested that the probable

source of the pollutants is anthropogenic, a rising from agricultural

activities, corrosion/abrasion of the ferrous steel material and additives in the

lubricants and insulation used for auxiliary services on the turbine floor of

the dam constructed on the lakes. They attributed the high levels of Fe and

Mn in the sediments samples to natural geological sourcing from the

underlying lake rock.

They also suggested that, the potential risk for human exposure to

these metals emanates from the fish caught in the lakes and subsequently

consumed, as there are already significant levels of these metals in the two

fish species they analysed, Tilapia (Oreochromis niloticus) and Chrysicthys

(Chrysithys auratus).

Adefemi, et al., (2007), studied the seasonal variation in heavy metal

distribution in the sediment of major dams in Ekiti State. They found iron to

be the most abundant out of all the metals examined for both seasons for the

two years, with an average value of 6.48 and 4.801/100g (2001) and 6.51

and 3.62mg/100g (2002) for dry and wet season respectively. Adefemi, et al.

(2007) discovered that the average metal concentration increased yearly.

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Adefemi, et al. (2007) also discovered that the concentration of most of the

metals appears higher in the dry season than for the wet season and the

values of the metals are below the standard limits of World Health

Organization, (WHO).

2.10 Some African Countries

Studies of heavy metals in Northern Africa have been concentrated on

Egyptian inland waters and coastal zones, particularly on the river Nile and

its two branches (Rosetta and Damietta), as well as on the Delta lagoons.

However, many studies have been conducted within the framework of the

1975 Action Plan for the protection of the Mediterranean and have therefore

focused on the coastal zones. Advanced investigation on the dynamics and

speculations of trace metals are also being conducted in different Egyptian

inland and coastal waters.

Bernhard and Renzoni (1977) differentiated between natural and

anthropogenic sources of mercury pollution in the Mediterranean by

reviewing concentrations in pelagic fishes and benthic organisms as well as

sediments.

Studies on the surface sediments of El-Mex region of the

Mediterranean in front of Alexandria (Saad et al, 1981) revealed two zones,

one of which showed high concentrations of Mn, Cu, Cd, Zn and Fe, as a

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result of discharges of industrial effluents. Their findings also suggested

incorporation of similar proportions of Fe and Mn into the sediments and the

co-precipitation of Cu and Zn by iron oxides.

The seasonal distribution of dissolved and particulate heavy metals in

the water column of the Damietta, El-Rayis and Saad (1985) estimated the

contribution of trace metals from the River Nile to the eastern Mediterranean

by determining the concentrations of dissolved metals in the surface and

subsurface water along the Rosetta branch. The relative abundance was Zn >

Fe > Cu > Mn > Cd.

Saad and Fahmy (1985) studied the occurrence of trace metals in

surficial sediments from the Damietta estuary of the Nile and concluded that

the eastern side of the estuary was exposed to more pollution than the

western side. Also, areas of maximum aver ages of Cu, Zn and Cd coincided

with the discharged sites of sewage wastes.

Heavy metal pollution in lake Mariut has been further investigated by

El-Rayis and Saad (1990), based on the distribution of Cu, Zn, Fe, and Mn

in water, suspended matter and sediments. The contribution of metals from

this lagoon to the Mediterranean Sea via Umum Drain (contaminate land-

based source) was also estimated.

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In other parts of Africa, the concentrations of major and minor ions,

including Cu Mn and Fe in river Jong, Sierra Leone, was determined by

Wright (1982), who found a clear relationship between metal concentrations

and seasonal variations in rainfall.

In Ghana, one of the earliest studies (Amasa, 1975) examined various

matrices, including drinking water, from the Obuasi Gold mining area and

found that arsenic concentrations occurred above normal values. A more

recent study (Akoto Bamford et al, 1990) in which heavy metal pollution

from gold mining activities was assessed by analysing gold ore, tailings,

sediments and water for Cr, Mn, Fe, Cu Zn, As, Pb, Rb, Sr, Y, Zr and Nb

revealed the presence of all the elements in sediments within a concentration

range o f 0.08 to 49000 (g/mg) whereas only iron and zinc were detected in

water at levels of 0.08 -2.4(g/ml).

Total mercury concentrations in commercial fish from different

coastal sites of Ghana have been determined by Ntwo and Khawaja (1989)

who concluded that all values were well below the 0.5g/mg action level

adopted in many countries. Biney and Beeko (1991) conducted a survey of

metals in fish sediments from the River Wiwi in Kumasi and found a

positive correlation between mercury concentration and body weight of fish.

They also reported higher levels of cadmium and mercury in fish than in

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sediments. Studies on the distribution of Hg, Cd, Pb, Zn and Fe in water,

finfish and shellfish macrophytes and sediments from Kpong headpond and

lower Volta river (Biney, 1991) showed the highest concentration of iron

and lead in sediment and of manganese and cadmium in macrophytes.

Finfish had the lowest concentrations of the metal, except for lead.

In Cote dIvoire Marchand and Martin (1985) and Kouadio and Trefy

(1987) have studied sediments of the Ebrie lagoon and reported metal

concentrations in excess of background levels, this was attributed to the

disposal of untreated sewage and industrial effluents.

A comparative study by Metongo (1991) of Cd, Cu, Hg, and Zn in

samples of oysters (Crassotrea gasar) from urban and rural lagoon areas of

Cote dIvoire revealed higher but background of the metals in the urban

area. Likewise, other studies of heavy metals in Callinectes amnicola

(Metongo and Sankare, 1990) and in Thunnus albacares (Metongo and

Kouamenan, 1991) gave concentrations lower than internationally

acceptable limits for seafood.

In Senegal, analyses by Gras and Mondain (1978) of fish and

crustaceans from coastal waters revealed lower mercury concentrations than

the generally acceptable limits (0.5g/g), except in sword fish and sharks

weighing more than 5kg.

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Other studies on the occurrence of trace metals have been conducted

as part of the joint FAO/IOC/WHO/ IAEA/UNEP project on monitoring of

pollution in the marine environment of the West and Central African region.

Within this framework, concentrations in marine biota have been reported

for Cameroon (Mbome et al, 1985; Mbome, 1988), Ghana (Biney, 1985;

Biney and Ameyibor, 1989) Cote dIvoire (Metongo, 1985, 1988) and

Senegal (Ba et al, 1985; Ba, 1988). On the basis of these studies, Portmann

et al (1989) reviewed the levels of contaminants in the marine environment

of the region and concluded that there was little input of mercury and other

metals into the coastal zone from land.

Early studies in Eastern Africa focused on Lake Nakaru in Kenya, one

of a number of Soda lake in the Great Rift Valley which was made a national

park in 1986 because of its world-famous flamingo population.

The effect of copper ions on the photosynthetic oxygen production of

phytoplankton, on the growth rate of blue-green algae (Sprirulina platensis)

and populations of rotifers (Brachionus sp) in water from Lake Nakuru was

experimentally investigated by Kallqvist and Meadows (1978). The rotifers

were less sensitive to copper than algae. Other studies by Lewin (1976)

showed that Lake Nakuru water contained 0.08 mg/1 mainly from pesticide

containing run-off from the surrounding agricultural lands. This value was

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thus higher than the critical value of 0.02 mg Cu/1 which may significantly

reduce algal growth (Kallqvist and Meadows, 1987). Observations by

Ochumba (pers.comm.) have shown that, during the dry season, flamingos

which feed on the algae migrate away from the lake. This may negatively

affect the tourism industry.

Earlier studies on sediments, water and biota of the second largest

natural lake in the world, Lake Victoria (Alala, 1981; Onyari, 1985;

Ochieng, 1987) showed no significant heavy metal pollution. However,

more recent studies in the same area revealed increased lead levels largely

due to increased shipping traffic and associated problems, car washing and

discharge from local industries (Wandiga and Onyari, 1987; Onyari and

Wandiga, 1989). Ochumba (1987) studied physico-chemical parameters,

dissolved oxygen and heavy metal concentrations in Lake Victoria as the

possible causes of periodic fish kills. The author attributed the fish kills to

dissolved oxygen depletion.

In other East African areas, copper ion distribution in the surface

waters of lakes George and Edward in Uganda was studied along other

chemolimnological parameters (Bugenyi, 1979). Concentrations ranged

from 0.07 to 0.13g/ml in Lake George and from 0.006 to 0.02g/ml in

Lake Edward, A direct relationship was established between cooper, water

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hardness, alkalinity and total dissolved solids. Bugengi (1982) studied the

occurrence of Cd, Cu and Fe in sediments of the same lakes and concluded

that the concentrations, although distinct in the different water bodies, did

not show much variation within each of the lakes.

Studies of dissolved metals in the marine environment were

conducted by Norconsult (1977) concluding that the concentrations for

Tudor creek fell within the normal range of unpolluted natural sea water.

Oteko (1987) studied the Mombasa creek and suggested crustal sources to be

responsible for copper concentrations and increased anthropogenic sources

from automobile exhausts for cadmium and lead concentrations.

The concentrations and distributions of metals amongst other

chemical contaminants were investigated by Greichus et al. (1977) in two

South African lakes, Hartbeespoort dam, which receives industrial and

municipal waters from Johannesburg and Voelvlei dam, situated in mainly

agricultural area. Water, sediments, aquatic plants and insects, fish, fish-

eating birds and their eggs were analysed for As, Cd, Cu, Mn, Pb, Zn, and

Hg. The results indicated higher levels in Hartbeespoort dam than in Voevlei

for all metals in sediments and birds, except for copper in bird carcasses.

Mercury levels in birds were 2 to 5-fold greater than in fish, whereas lead

values were 2 to 10-fold greater.

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Greichus et al. (1978) investigated metals among other contaminants

in Lake Mcllwaine, a eutropic water body near Harara, Zimbabwe. Water,

sediment, plankton, bottom fauna and fish were analysed. The data gave

intermediate levels of metals between those found in Hartbeespoort dam and

Voelvlei dam.

Watling and Emmerson (1981) identified areas of metal input to the

River Papenkuils which was considered to be a serious source of pollution to

the marine environment around Port Elizabeth. In contrast, the estuary of

River Swartkops was found generally unpolluted on the basis of metal

concentration in water, surface sediments and sediments cores (Watling and

watling, 1982). Similar studies also showed that the estuary of River Knysna

as well as the Bushmans, Kariega, Kowie and Great Fish Rivers were

unpolluted (Watling and Watling, 1982a, 1983).

2.11 Levels of Heavy Metals in Different Environmental Compartments

A more detailed discussion will be presented on the quantitative

aspects based on concentration levels in the various environmental

compartments. Most studies on the levels and its distribution of heavy

metals in Nigeria and some parts of Africa have concentrated on urban and

industrialized areas.

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2.11.1 Concentration of Metals in Water

Mercury showed the lowest concentrations (Zn>Pb> Cu>As. The levels of metal in the coastal

waters were markedly lower than those found in most inland waters. This

reflects the direct influence of pollution on the lakes and rivers.

Undoubtedly, the very high concentrations of certain metals found in

specific waters are as a result of acute pollution.

2.11.2 Concentration of Metals in Sediments

Most water bodies showed low-to-moderate metal concentration except for

Hartbeespoort dam and river Papenkuils in South Africa, the Niger Delta in

Nigeria and lakes George and Edward in Uganda. Lakes Nozha, MAriut and

Manzaleh and River Nile in Egypt as well as Lake Mcllwaine in Zimbabwe

also showed elevated concentrations of some metals which clearly indicate

considerable anthropogenic inputs.

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Most concentration in inland water sediments thus pose no

environmental concern for the continent except for the above-mentioned

areas which may be considered as hot spots within their respective regions.

Heavy metal concentrations in the Africa marine and coastal

sediments fell within the ranges given for Hg, Cd, Pb and As by GESAMP

(1985, 1988) but higher values occurred in some areas. For example,

sediments from Lagos lagoon in Nigeria had high concentrations of lead and

iron while the Ebrie lagoon in Cote dIviore had high mercury, zinc and iron

concentrations. The result revealed largely anthropogenic heavy metal

enrichment implicating urban and industrial runoff into coastal lagoons

which have poor water exchange (Okoye, 1989; Koudio and Trefry, 1987).

2.11.3 Concentrations of Metals in Aquatic Fauna

Some differences between water bodies were observed with respect to

the levels of certain elements in finfish. For example, zinc showed relatively

higher values in samples from lakes Nakuru, Kenya, followed in decreasing

order by those from Zimbabwe and South Africa, Egypt, Nigeria and Ghana.

Likewise, copper concentrations were higher in samples from Egypt and

lakes Nakuru and Mcllwaine. However, on the whole, the levels of metals in

inland water fish muscle were below WHO limits, except for lead in

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Macrobrachium sp from Niger Delta, Nigeria and Lower Volta River,

Ghana.

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