STUDIES ON THE PHYSICOCHEMICAL PARAMETERS

OF UTILITY WATER SUPPLIES IN NSUKKA TOWN OF

ENUGU STATE

BY

NDEFO, CHINEDUM JOSEPH

(PG/MSc/03/34746)

DEPARTMENT OF BIOCHEMISTRY

UNIVERSITY OF NIGERIA

NSUKKA

MAY, 2008.

i

TITLE

STUDIES ON THE PHYSICOCHEMICAL PARAMETERS OF UTILITY

WATER SUPPLIES IN NSUKKA TOWN OF ENUGU STATE

A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE

REQUIREMENTS FOR AWARD OF DEGREE OF MASTER OF

SCIENCE (M.Sc) IN MEDICAL BIOCHEMISTRY, UNIVERSITY OF

NIGERIA, NSUKKA

BY

NDEFO, CHINEDUM JOSEPH

(PG/MSc/03/34746)

DEPARTMENT OF BIOCHEMISTRY

UNIVERSITY OF NIGERIA

NSUKKA

SUPERVISOR: DR. E. O. ALUMANAH

MAY, 2008

ii

CERTIFICATION

NDEFO, Chinedum Joseph, a postgraduate student of the Department of Biochemistry with the Reg.

No PG/ MSc/03/34746, has satisfactorily completed the requirement of research work, for the degree

of Master of Science (M.Sc.) in Medical Biochemistry. The work embodied in this project

(dissertation) is original and has not been submitted in part or full for any other diploma or degree of

this or any other university.

DR E. O. ALUMANAH PROF I. N. E. ONWURAH (Supervisor) (Head of Department)

EXTERNAL EXAMINER

iii

DEDICATION

This work is dedicated to the Holy Spirit, who is my mentor, source of inspiration and teacher.

iv

ACKNOWLEDGEMENTS

There are people who have the compassion and the desire to better the lots of others. They will

go any length to encourage and beautify the lives of others.

To such people who I met in my academic career especially during my Master‟s degree

pursuit, I pray that the good Lord will reward them abundantly in Jesus Name. Amen.

Nevertheless, I wish to appreciate the following lecturers: my friend and able supervisor, Dr. E.

O. Alumanah, my friend and very good brother, Prof. I. N. E. Onwurah, the current Head of

Biochemistry Department, our able and versatile Prof. O. U. Njoku, current Dean of Faculty of

Biological Sciences. I equally wish to extend my gratitude to other erudite and respectable lecturers in

the department: Prof. F. C. Chilaka, Dr. O. F. C. Nwodo, Dr. B. C. Nwanguma, Dr. V. N. Ogugua,

Prof. L. U. S. Ezeanyika, Prof. P. N. Uzoegwu and Dr. (Mrs) C. Ezeokonkwo. From all these lecturers,

I received a good academic watering from their wells of knowledge and experiences.

I am also indebted to my good friends and faithful brothers Deacon Parker Elijah Joshua and

Francis Awah, for their numerous contributions to this project. God will also reward others who have

helped me in some ways to the successful completion of this research work. To God be the glory for

His everlasting kindness to us all in Jesus name. Amen.

NDEFO, CHINEDUM JOSEPH.

v

ABSTRACT

Most of our water resources are gradually becoming polluted due to the addition of foreign materials from the

surroundings. These include organic matter of plant and animal origin, land surface washing, and industrial and

sewage effluents (Karnataka State Pollution Control Board, 2002). Rapid urbanization, and industrialization

with improper environmental planning often lead to discharge of industrial and sewage effluents into water

bodies. (Pruss et al, 2002).

The problem of environmental pollution due to toxic metals has begun to cause concern now in most

major metropolitan cities. Nsukka environs have been plagued with perennial problem of water

supplies round the year and a better understanding of its water physicochemically status will help to

address this daunting problem and issues of human health.

The analysis carried out was on the utility water supplies in Nsukka area. Thirteen sampling areas

consisting of four boreholes, six dugwells and three springs were chosen for this research work. A

total of 26 water samples were taken from the sampling areas during the dry season and another 26

samples during the wet season. Water samples were collected from these sampling areas and

refrigerated at 40C for processing. Concentrations of lead, cadmium, nickel, arsenic and zinc were

determined in each sample by spectrophotometric method. Harch Model C50 digital multirange meter

was used to measure pH, and total dissolved solid. Complexiometric titration was employed in the

determination of total hardness of water samples. Other chemical parameters like nitrate, chloride, and

sulphate were also determined by spectrophotometric method. Bacteriological analysis of the water

samples were carried out to ascertain whether there was faecal contamination by the use of multiple

tube/most probable number techniques.

Results Sulphate concentration of water sample from spring sources increased significantly (P<0.05) during

dry season when compared with that of wet season. it was observed that total suspended solid

concentration of water samples from dugwell sources was found to have significant increase (P<0.05)

when compared with the water samples from the samples obtained from borehole and spring sources

during both dry and rainy seasons. Total dissolved solid concentration was found to be significantly

higher (P<0.05) in the water sample from dugwell sources when compared with the total dissolved

solid concentration in the water samples from both borehole and spring sources during both dry and

rainy seasons. Arsenic, nickel, lead and cadmium were not detected in all the water samples from

borehole, dugwell and springs taken during the wet and dry seasons. No significant difference

(P>0.05) exists in the concentration of zinc compared to all other test samples. There was no

significant difference (P<0.05) between the nitrate concentration of borehole and dugwell during the

dry and wet seasons However, significant increase (P<0.05) was observed in the water samples of

borehole and dugwell compared to the water sample of spring source especially during rainy season.

Water sample from dugwell sources had showed significant increase (P<0.05) in the level of total

hardness as compared with water samples from borehole and spring sources during dry and rainy

seasons. Also, there was significant increase (P<0.05) in the level of total hardness of water sample

from borehole sources when compared with the spring sources during dry and rainy seasons. The

chloride (mg/L) concentration of all test samples from all the three water sources (borehole, dugwell

and spring) were found to be no significant (P>0.05) during both seasons. Though slight increase was

observed in the level of chloride concentration in the water sample from borehole sources during dry

and rainy seasons but was considered non-significant (P>0.05). Therefore, from the foregoing, it could

be concluded that these boreholes, springs and dugwells water tested in Nsukka town are

physicochemically good for human consumption as all the physicochemical parameters tested

conformed to WHO, SON and NAFDAC water quality standards except Iyi-adoro spring water which

might not be very good for consumption during rainy season because of possible bacteria

contamination.

vi

TABLE OF CONTENTS

PAGE

Title Page .. .. .. .. .. .. .. .. .. .. i

Certification .. .. .. .. .. .. .. .. .. .. ii

Dedication .. .. .. .. .. .. .. .. .. .. iii

Acknowledgements .. .. .. .. .. .. .. .. .. iv

Abstract .. .. .. .. .. .. .. .. .. .. v

Table of Contents .. .. .. .. .. .. .. .. .. vi

List of Figures .. .. .. .. .. .. .. .. .. .. x

List of Tables .. .. .. .. .. .. .. .. .. .. xi

CHAPTER ONE: INTRODUCTION AND LIETERATURE REVIEW

1.1 Introduction … … … … … … … … 1

1.2 Water, water wells and water Contamination … … … … 2

1.2.1 Understanding the hydrologic cycle … … … … … 2

1.2.2 Surface and Groundwater Supplies … … … … … … 3

1.2.3 How are Surface and Groundwater Related? … … … … … 7

1.2.4 Water Utilization … … … … … … … … 7

1.2.5 Water Well Components … … … … … … … 7

1.2.5.1 Well Casing … … … … … … … … 7

1.2.5.2 Well Screen … … … … … … … … 8

1.2.5.3 Well Termination … … … … … … … … 8

1.2.6. Disinfection … … … … … … … … 9

1.2.7 Sources of Surface and Groundwater Contamination … … … 9

1.2.7.1 Domestic Sources … … … … … … … … 9

1.2.7.2 Agricultural … … … … … … … … 10

1.2.7.3 Urban … … … … … … … … … 11

1.2.7.4 Industrial … … … … … … … … … 11

1.2.8 Protecting Surface Water Supplies … … … … … … 11

1.2.8.1 Ponds … … … … … … … … … 12

1.2.9 Protecting Groundwater Supplies … … … … … … 13

1.2.10 What Individuals Can Do … … … … … … … 14

1.3 Water Pollution … … … … … … … … 14

1.3.1 Point Source pollution … …… … … … … 15

vii

1.3.2 Non-point source pollution … … … … … … … 15

1.3.3 Ground water pollution … … … … … … … 16

1.3.4 Materials and Phenomena Contributing to Water Pollution … … … 16

1.3.4.1 Chemical and other contaminants … … … … … 17

1.3.5 Measurement of Water Pollution … … … … … … 18

1.3.5.1Sampling … … … … … … … … … 18

1.3.5.2 Physical testing … … … … … … … … 19

1.3.5.3 Chemical testing … … … … … … … … 19

1.3.5.4 Biological Testing … … … … … … … … 19

1.3.5.4.1 Alkalinity … … … … … … … … 20

1.3.5.4.2 Aluminium … … … … … … … … 21

1.3.5.4.3 Arsenic … … … … … … … … 21

1.3.5.4.4 Barium … … … … … … … … 22

1.3.5.4.5 Cadmium … … … … … … … … 22

1.3.5.4.6 Chloride … … … … … … … … 22

1.3.5.4.7 Chromium … … … … … … … … 23

1.3.5.4.8 Colour … … … … … … … … 23

1.3.5.4.9 Copper … … … … … … … … 23

1.3.5.4.10 Cyanide … … … … … … … … 24

1.3.5.4.11 Escherichia coli … … … … … … … 24

1.3.5.4.12 Faecal Coliform … … … … … … … 24

1.3.5.4.13 Fluoride … … … … … … … 25

1.3.5.4.14 Heterotrophic Plate Count … … … … … … 25

1.3.5.4.15 Iron … … … … … … … … 25

1.3.5.4.16 Lead … … … … … … … … 26

1.3.5.4.17 Manganese … … … … … … … … 27

1.3.5.4.18 Mercury … … … … … … … … 27

1.3.5.4.19 Nitrate … … … … … … … … 27

1.3.5.4.20 pH … … … … … … … … 28

viii

1.3.5.4.21 Selenium … … … … … … … … 28

1.3.5.4.22 Sodium … … … … … … … … 29

1.3.5.4.23 Sulphate … … … … … … … … 29

1.3.5.4.24 Total Hardness … … … … … … … 30

1.3.5.4.25 Total Dissolved Acids … … … … … … 30

1.3.5.4.26 Turbidity … … … … … … … 31

1.3.5.4.27 Trihalomethanes … … … … … … … 31

1.3.5.4.28 Uranium … … … … … … … 31

1.3.5.4.29 Zinc … … … … … … … 32

1.3.5.4.30 Physicochemical Combined Standards … … … … … … 32

CHAPTER TWO: MATERIALS AND METHODS

2.1 Materials… … … … … … …… … … … 35

2.1.1 Water Sampling Sources … … … … … … … 35

2.1.2 Chemicals/Reagents/Samples … … … … … … 35

2.2 Methods … … … … … … … … … 35

2.2.1 Experimental Design … … … … … … … 35

2.2.2 Sampling Areas … … … … … … … … 36

2.2.3 Heavy Metals‟ Determination … … … … … … 39

2.2.4 Cations and Anions Determination … … … … … 41

2.2.5 Organic Compounds … … … … … … … 42

2.2.6 Alkalinity, Acidity, Chlorides and Hardness … … … … 42

2.2.7 Bacteriological Examination … … … … … … 43

2.2.7.1 Membrane Filtration … … … … … … … 43

2.2.7.2 Multiple tube/Most Probable Number (MPU) … … … … 43

2.2.7.3 Choice of Techniques … … … … … … … 44

2.2.8 Sampling Techniques and Preservation … … … … … 44

2.2.9 Physicochemical Parameters … … … … … … 46

2.2.9.1 Appearance … … … … … … … … 46

2.2.9.2 Determination of pH value … … … … … … 46

2.2.9.3 Conductivity … … … … … … … … 47

2.2.9.4 Total hardness … … … … … … … … 47

ix

2.2.9.5 Total Dissolved Solids (TDs) … … … … … … 49

2.2.9 Nitrate … … … … … … … … … 50

2.2.10 Heavy Metals … … … … … … … … 51

2.2.10.1 Determination of Lead Colorimetric Sulphide Method … … … 51

2.2.10.2 Determination of cadmium … … … … … … … 51

2.2.10.3 Determination of Arsenic … … … … … … … 52

2.2.10.4 Determination of Zinc … … … … … … … 53

CHAPTER THREE: RESULTS

3.1 Effect of pH on different water sources compared

to WHO and NAFDAC … … … … … … … 55

3.2 Effect of Sulphate Concentration on Different Water Sources Compared

to WHO and NAFDAC … … … … … … … 57

3.3 Effect of Total Suspended solid on Different water sources compared

to WHO and NAFDAC … … … … … … … 59

3.4 Effect of Zinc concentration on different water sources compared

to WHO and NAFDAC … … … … … … … 61

3.5 Effect of Total dissolved solid on different water sources compared

to WHO and NAFDAC … … … … … … … 63

3.6 Effect of Total hardness on different water sources compared

to WHO and NAFDAC … … … … … … … 65

3.7 Effect of Chloride concentration on different water sources compared

to WHO and NAFDAC … … … … … … … 67

3.8 Effect of Nitrate concentration on different water sources compared

to WHO and NAFDAC … … … … … … … 69

3.9 Effect of Most Probable Number of Coliform on Different Water

Sources Compared with WHO and NAFDAC … … … … 71

CHAPTER FOUR: DISCUSSION

4.1 Discussion … … … … … … … … 73

4.2 Conclusion … … … … … … … … 79

REFERENCES … … … … … … … … … 80

x

LIST OF FIGURES

PAGE

Fig. 1.1 The hydrologic cycle … … … … … … … 3

Fig. 1.2 Confined and unconfined aquifers … … … … … 5

Fig. 1.3 Showing the supply chain of drinking water for each household … … 20

Fig. 2.1 Map of Nsukka showing the location of sampled areas … … … 37

Fig. 3.1 pH at 20OC of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 56

Fig. 3.2 Sulphate concentration of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 58

Fig. 3.3 Total suspended solid of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 60

Fig. 3.4 Zinc concentration of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 62

Fig. 3.5 Total dissolved solid of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 64

Fig. 3.6 Total hardness of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 66

Fig. 3.7 Chloride concentration of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 68

Fig. 3.8 Nitrate concentration of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 70

Fig. 3.9 Most probable number of coliform of different water sources in Nsukka

compared with WHO and NAFDAC standards … … … … 72

xi

LIST OF TABLES

PAGES

Table 1: Physicochemical combined standards of WHO, SON and NAFDAC … 32

Table 2.1 Sampling areas description table … … … … … 38

Table 2.2 Alpha-AWWA-NPCF requirements for sampling and

handling/preservation … … … … … … 46

1

CHAPTER ONE

INTRODUCTION/LITERATURE REVIEW

THE problem of environmental pollution due to toxic metals has begun to cause concern

now in most major metropolitan cities. The toxic heavy metals entering the ecosystem may lead

to geoaccumulation, bioaccumulation and biomagnification. Heavy metals like Fe, Cu, Zn, Ni

and other trace elements are important for proper functioning of biological systems and their

deficiency or excess could lead to a number of disorders (Ward, 1995). Food chain

contamination by heavy metals has become a burning issue in recent years because of their

potential accumulation in biosystems through contaminated water, soil and air. Therefore, a

better understanding of heavy metal sources, their accumulation in the soil and the effect of their

presence in water and soil on plant systems seem to be particularly important issues of present-

day research on risk assessments (Rajesh et al., 2004). The main sources of heavy metals to

vegetable crops are their growth media (soil, air, nutrient solutions) from which these are taken

up by the roots or foliage (Ward, 1995).

Most of our water resources are gradually becoming polluted due to the addition of

foreign materials from the surroundings. These include organic matter of plant and animal origin,

land surface washing, and industrial and sewage effluents (Karnataka State Pollution Control

Board, 2002). Rapid urbanization and industrialization with improper environmental planning

often lead to discharge of industrial and sewage effluents into lakes. The lakes have a complex

and fragile ecosystem, as they do not have selfcleaning ability and therefore readily accumulate

pollutants. Bellandur Lake, the largest one in Bangalore urban area, recently attracted a lot of

public attention because of the formation of froth during rainy season due to chemicals (soaps,

detergents, etc.) and biosurfactants. For the last few decades, the treated, partially treated and

untreated wastewater has been discharged to this lake and the lake water is being used for

farming purposes (Pruss et al., 2002).

Individual rural homeowners are often responsible for providing and protecting their own

water supplies. Where safety of these sources is concerned, no “short-cuts” can be taken.

Protecting the quality of individual water supplies is a combination of controlling land use

around the supplies and using proper water treatment techniques where necessary. Rural

homeowners must assume responsibility for protecting their families from contaminated drinking

2

water. Assistance in this regard can be obtained from a number of agencies (Ward, 1995). Local

health authorities can answer questions relating to applicable local regulations; health hazards

posed by contaminated water, and suggested procedures for sampling and analyzing drinking

water for contaminants. In some cases, local health officials will analyze individuals‟ water

samples for common pollutants at no cost or for a nominal charge. Complete well water analysis

is the homeowner‟s responsibility and is not free. State regulatory agencies charged with water

resource management can answer questions regarding water use. They usually also have

information regarding the availability and suitability of water sources in the State. Such agencies

usually administer safety regulations for dams as well (Ward, 1995).

1.2 Water, Water Wells, and Water Contamination

1.2.1 Understanding the Hydrologic Cycle

Water is constantly moving. As rain or snow (precipitation) falls to earth, some of it

collects to form lakes, streams, and other bodies of water. The remaining water enters the soil in

a process called infiltration. Some of this water evaporates back into the air and some is used by

growing plants. The remainder seeps d o w n w a rd through the soil, until it accumulates at some

depth and becomes groundwater (Wright et al., 2004).

Downward movement of water thro u g h the soil is percolation. This water eventually

makes its way into a zone of soil where the space around each soil particle is completely filled

with water (saturated). Water in this space is called groundwater, and its upper boundary is

called the water table. Groundwater is located in underground formations called aquifers at

various depths beneath the ground surface, and is generally available for human use. It can move

laterally as groundwater flow to replenish surface water supplies. Groundwater constantly moves

through the soil and reappears on the lowland surface as lakes, streams, swamps, or springs

(Ward, 1995).

Although water is in constant motion, it seems to be stored in lakes, bays, oceans, and

glaciers, as well as in underground supplies as discussed below, because the rate of movement in

these vast bodies is relatively slow. Surface waters constantly evaporate into the air and produce

3

clouds and later precipitation. Thus, water changes constantly from precipitation, to surface

water, to groundwater, back to surface water, to atmospheric moisture, and back to rain or snow.

This cycle of water movement is called the hydrologic cycle (Wright et al., 2004).

Fig. 1.1: The hydrologic cycle (Wright et al., 2004).

1.2.2 Surface and Groundwater Supplies

What Is Surface Water? Surface supplies of water are quite familiar to most of us. They

include rivers and streams, ponds and lakes (reservoirs), and cisterns or other controlled

catchments. For purposes of this discussion, springs are also considered surface supplies

although, strictly speaking, springs originate from groundwater and occur where the water table

intersects the land surface. Each of these sources has different characteristics. Ponds and lakes

occur where nature has created an obstruction to the normal flow of surface runoff or where a

natural waterholding depression has formed. People can also create such supplies by building

dams. Controlled catchments are areas from which nearly 100 percent of precipitation is

collected as run off. Rooftops are the most easily recognized type of controlled catchment.

However, larger areas of land can be manipulated to maximize run off and subsequent collection

(for example, by paving with concrete or asphalt). Springs and seeps occur at the land surface

where water from underground sources appears. Because springs appear at the ground surface,

4

they must be treated differently than groundwater to adequately protect their quality (Clasen and

Bastable, 2003).

What Is Groundwater? Groundwater, water that lies hidden beneath the earth‟s surface, is

an important resource. Although it makes up only 4 percent of the total amount of water on earth,

it constitutes 95 percent of the fresh water that is suitable for human consumption (Wright et al.,

2004).

Groundwater and the way it moves is not as easy to understand or visualize as surface

water simply because we cannot see it. People often imagine that groundwater exists in vast

buried lakes and rivers. However, only in certain soluble deposits, such as limestone, do water-

filled cavern s or channels resemble underground lakes and rivers. Unfortunately, the “hidden”

nature of groundwater has resulted in a “out of sight, out of mind” sentiment and therefore

contributed to its being considered out of danger. We now know that this is not so; too many

cases of groundwater pollution are known. Groundwater occurs beneath the earth‟s surface in

geologic formations called aquifers. In aquifers, all the spaces around individual soil particles

and cracks within rocks are completely filled with water. Aquifers can be relatively small in area

or they can stretch for several thousand s q u a re miles. Aquifers vary in thickness from a few

feet to several thousand feet. Unconfined aquifers have no impermeable layers overlaying them

and usually a re found close to the surface of the land. As shown in Figure 1.2, precipitation

percolates through the soil until it reaches the unconfined aquifer‟s upper boundary, the water

table. Only a very small portion of the water ever filters down to the confined aquifers.

Unconfined aquifers, due to their proximity to people‟s activities on the soil surface, and the fact

that the soil material above them transmits water readily, are especially susceptible to pollution.

A confined aquifer is bounded on the top and bottom by relatively impermeable layers of clay or

solid rock through which only very small amounts of water can pass. Precipitation can enter

these deeper aquifers directly through regions called recharge areas where an aquifer is exposed

to the earth‟s surface (Fig. 1.2). In the Coastal Plains especially, several aquifers might overlie

each other (Wright et al., 2004).

5

Fig. 1.2: Confined and unconfined aquifers. (Wright et al., 2004).

Only about 1 inch of this precipitation ever reaches the deeper aquifers. Most

groundwater is later returned to the surface as base flow; that is, water discharged continuously

into perennially flowing streams. Within an aquifer, groundwater travels along fractures in the

rock, through the pores in sand and gravel, or along chananels carved out of soluble rock, such as

limestone. The direction and rate of this movement are very diff e rent from that of surface

water. Whereas surface water moves at the rate of tens or even hundreds of feet per minute,

groundwater moves at the rate of inches per day or less. Once water enters an aquifer, it can

remain there for centuries. Therefore, if contaminated, it might take aquifers just as long to

cleanse themselves naturally. Though the soil above aquifers might filter some materials

transported by percolating water, these substances can continue to be leached if they are not

degraded in the soil by microbial and/or chemical processes.

Natural water quality in the Coastal Plain aquifers is generally good, but varies with the

type of aquifer material. Some elevation in dissolved mineral content (hardness) is always

present, but is elevated in formations derived from fossilized material and limestone. The content

of total dissolved solids in Coastal Plain groundwater varies widely, making some groundwater

too bitter to drink. Although iron content is generally low, it can be very high in localized areas.

Fractured bedrock formations present unique problems in both locating and protecting

6

groundwater. Because fractures occur randomly and are generally discontinuous, it is very

difficult to predict where adequate supplies of groundwater will be located. Yet, in certain areas,

fractures can extend to the soil surface, providing a direct conduit through which pollutants can

enter the aquifer. Such problems are prevalent in limestone areas where percolating water has

dissolved the limestone, forming caverns underground and, sometimes, sinkholes at the ground

surface. Though the cavernous channels can be productive aquifers from a quantity standpoint,

they are susceptible to pollution from materials that can enter sinkholes with run off, or be placed

there intentionally by people. Unfortunately, it is still possible to find sinkholes being used as

private garbage dumps. Many contaminants exist that cannot be smelled, seen, or tasted. Some of

these substances are believed to be health hazards in very low concentrations, sometimes at

levels of a few parts per billion. (One part per billion would be equivalent to one ounce dissolved

in a pool of water the size of a football field and 27 feet deep.) Although it might be

technologically feasible in some cases to pump and treat contaminated groundwater to remove a

pollutant, such a solution could take many years and a great deal of money. Unfortunately, it

sometimes takes years to discover that groundwater has become polluted by contamination. All

of these facts make it imperative to recognize the importance of groundwater to society, and to

understand what it is, how it moves, and how to protect it. Clearly, the wisest and most

economical approach is prevention and protection, rather than treatment (Trevett et al., 2005).

1.2.3 How are Surface and Groundwater Related?

Groundwater and surface water are intimately connected. Water in streams and lakes is,

in most cases, directly linked to groundwater. For example, the surface of water flowing in most

streams is actually a continuation of the water table (Figure 1.1). During drought periods,

groundwater moves out of the aquifer and into the s t ream to supplement stream flow. During

floods, water can flow from the stream into the surrounding aquifer. Hence, at times, streams

have the potential to pollute groundwater and, at other times, groundwater can pollute surface

water (Wright et al., 2004).

1.2.4 Water Utilization

7

Municipal water supplies meet Federal, State, and local guidelines. These requirements

vary somewhat both with the size of the municipality and the region. Approximately 50 percent

of the State‟s drinking water is supplied by municipalities. Most of the water on the Eastern

Shore and much of the water to many rural homes is supplied by groundwater. If you are on an

individual well or one that supplies only a few homes, you are pro b ably responsible for your

own water quality. Since you more than likely obtain your water from a well, the following is a

discussion of how groundwater is delivered (Lokhande and Kelkar, 1999).

1.2.5 Water Well Components

A well consists of two main elements. One element is the hole, or bore, through which

water flows upward to the pump intake. This bore is commonly lined with a pipe or casing. The

second element is the intake section where water enters the well. The intake usually is a screen at

the bottom of the casing in a sand stratum, or it can be the open bore hole in a rock formation

(Wright et al., 2004).

1.2.5.1 Well Casing

A drilled or driven well in unconsolidated material (such as sands, gravels, and unstable

clays) must have a permanent well casing the full depth of the well, and a well screen. In

unconsolidated material, soil usually packs tightly against the casing, providing a good seal. W h

e re rock or other stable material overlays water-bearing sand or gravel, the upper part of the well

must be sealed artificially on the outside of the casing to prevent contaminated water from

moving through this upper layer along the outside of the pipe and down into the aquifer. Sealing

usually is done with grout (a cement mix) or other sealants. Steel pipe has been used extensively

for well casing even in soils or waters that are somewhat corrosive. Where abnormally corrosive

conditions exist, a casing material of corrosion - resistant metal, such as brass or stainless steel,

might be used. Plastic pipe can be used for well casings, but only when special methods can be

employed to install the pipe without structural damage (Shivashankara et al., 1999).

1.2.5.2 Well Screen

A well screen fitted to the bottom of the casing allows water to enter the well freely, but

prevents the entrance of coarse sand. The selection of the screen material usually is based on the

cost of the material and the chemical character of the water. In some instances, where the

8

waterbearing strata contain fine sands or silts, the well can be gravel-packed. The gravel pack

acts as a primary filter and is held in place by the screen. Without the gravel pack the bottom of

the bore hole would erode and cave in, while continually passing sand and silt to the pump

(Wright et al., 2004).

1.2.5.3 Well Termination

The upper end of the casing pipe of the well can terminate on a pump house floor,

platform, or soil surface. The casing should extend at least 8 inches above this surface. The

entrance of any pump pipes, cable, air lines, or other device into the well casing must be

effectively sealed with an approved sealing device to maintain well sanitation. Where the pump

is mounted directly over the well, a sanitary well seal should be used. If the pump is offset from

the well, the seal should consist of a watertight expandable seal that fits into the casing and at the

same time seals the drop pipes, cables, and air line. If the pump is offset from the casing with

pipes buried below the soil surface, a sealing device, called a pitless adapter, is used. In this case,

the top of the casing still projects above the soil level and is fitted with a protective cap (Clesceri,

1998).

1.2.6 Disinfection

For drinking water, the well and pumping equipment should be disinfected before being

placed in service. Disinfection should be with a chlorine solution poured into the well at a rate

dependent on well size and water storage capacity. After 8 or more hours, the water is then

pumped until the amount of chlorine has been reduced sufficiently. This water might burn shrubs

and grasses and should be disposed of where damage will be minimal (Lark et al., 2002).

1.2.7 Sources of Surface and Groundwater Contamination

There are many sources of contamination for both surface and groundwater. Potentially,

any substance that is placed in the air, in surface water, in soil, on the land, or below ground, can

become a water pollutant. In addition, substances that occur naturally (such as minerals, soil

particles, and decaying leaves) can also contaminate water. Pollutants can originate in both rural

and urban settings. In rural, unsewered areas, effluent from septic tank disposal fields can pose a

9

significant threat to groundwater. Bacteria, nitrogen, and other inorganic and organic substances

can leach downward to the water table of an unconfined aquifer. Agrochemicals used in food

production can pose similar threats to groundwater. In urban areas, pollutants can originate from

a variety of sources, such as gasoline service stations, municipal and industrial wastewater

treatment facilities, and homeowners‟ lawns. Pollutant sources over which people have control,

and can be managed effectively, include domestic, agricultural, urban, and industrial. Each

category can pollute both surface and groundwater. Contaminants include a variety of physical,

chemical, and biological substances (such as eroded soil, dissolved nutrients, and bacteria).

However, because the soil can physically filter most undissolved substances from percolating

water, generally only dissolved contaminants and bacteria actually reach groundwater supplies.

Both dissolved and undissolved substances can reach surface supplies (Ward, 1995).

1.2.7.1 Domestic Sources

Contaminants that originate around the home include chemicals used on lawns and

gardens and, conceivably, pesticides used around foundations. Probably the greatest potential

domestic source of groundwater contamination is from septic tanks. Though not a surface

contaminant, effluent from septic systems can contaminate surface water supplies if improper

design and/or maintenance maintenance procedures are followed, or if the surface supplies are

located too closely to septic systems. Septic systems are used in

20 mill ion (29 percent) households throughout the country. Nitrate from these systems moves

readily through soil and can reach groundwater in significant amounts. Nitrate is a major nutrient

problem for the Chesapeake Bay. Household chemicals, such as paints and paint thinner,

degreasers, polishes, cleaning solvents, and even waste oil from home car oil changes, are also

potential threats to groundwater. Many of these products are disposed of improperly by being

flushed down the toilet. If the sewage water goes to a wastewater treatment plant, the pollutants

are not removed by the treatment processes (Wright et al., 2004).

When poured down the drain, the substances make their way to the drain field of the

onsite disposal system, where they can leach into the groundwater. Septic tank cleaners are of

particular concern, since many of these contain toxic organic chemicals that can leach through

the soil. Household chemicals and waste oil can also move readily through the soil even if they

have been spread on the soil surface. In most cases, only small quantities of these materials in a

10

water supply can cause severe contamination. Faecal wastes from both domestic and wild

animals (for example, bird droppings on rooftops) and eroded soil are the major contaminants of

surface water (Rajesh et al., 2004).

1.2.7.2 Agricultural

The major contributors of water pollution from agriculture are eroded soil, animal wastes,

fertilizers, and other agrochemicals. By volume, eroded soil is the largest agricultural pollutant of

surface water supplies. Nevertheless, pesticides, nutrients (especially phosphorus attached to

eroded soil), and animal waste applied to the land can be transported to surface supplies by

runoff. Storage and application of manures and fertilizers also have contributed to increased

nitrate levels in groundwater nationwide. In many areas, nitrate levels re above drinking water

standards for “safe” water. Improper storage of manures and overapplication of manures and

fertilizers have a significant impact especially in areas of the Coastal Plain and in glacial

deposits. Waste storage ponds and lagoons also have the potential to contribute to groundwater

pollution (Lark et al., 2002).

1.2.7.3 Urban

Urban areas can contribute the same contaminants to surface run off as rural domestic

areas. In addition, run off from urbanized areas can carry any number of organic and inorganic

chemicals washed from streets and parking lots. Construction activities in urban areas contribute

large amounts of sediment. Sewage treatment plants discharge treated wastewater directly to

rivers and streams. Urban areas also can contribute to groundwater pollution from landfills,

wastewater treatment plants, storm water collection basins, and leaking sewer pipes. A wide

variety of pollutants are associated with these activities. Many active and inactive landfills

throughout the country a re unlined and not monitored to determine if leachate is moving from

the landfills. Storm water catchments collect runoff during rainfall events and “dispose” of the

run off by having it infiltrate into the soil. If the storm water contains dissolved contaminants, the

soil will provide only slight treatment and the contaminants can percolate to the groundwater

supply (Wright et al., 2004).

1.2.7.4 Industrial

11

Treated industrial wastes are also usually discharged directly to receiving streams. The

contaminants such effluents contain depend on the nature of the industry. These can range from

easily degraded organic matter to more resistant chemicals and bacteria (Wright et al., 2004).

1.2.8 Protecting Surface Water Supplies

Surface water supplies are highly susceptible to contamination. They should be used as a

drinking water source only as a last resort, when obtaining groundwater would be technically

infeasible or too expensive (Wright et al., 2004). If surface supplies become a necessity, they

should be sought in the following order of preference: springs, controlled catchments, ponds, and

lastly, streams and rivers. In addition, strict attention must be paid to protecting each source from

contamination to the maximum extent possible. Where springs are involved, make sure that the

area contributing flow to the spring is safe and that contamination is excluded from the spring

where it comes out from the ground. Springs can occur at relatively shallow depths below the

ground surface and are therefore susceptible to contamination by percolating water that has

picked up pollutants as it moves through the soil (Wright et al., 2004). Thus barn yards, septic

systems, trash dumps, underground storage tanks, and the like should not be located on land

above the spring. Also, take special care when you use springs in limestone areas. Springs here

are often replenished by surface flow into sinkholes that might be long distances from where the

spring appears. Very little purification occurs in water flowing in limestone areas, so it is

important that you check land use practices in the area surrounding the spring. Springs are almost

always high in fecal bacteria contamination. The immediate area around the spring must be

protected from contamination as the water exits the ground. Surface run off must be diverted

from the spring by ditches or by berms. The runoff should be discharged in a safe manner

downhill from the spring. Animals should be kept from the spring by a fence at least 100 feet

away from the spring. Also essential to proper protection is a properly constructed spring house.

Restricted access should be provided to the house and the cover should be locked at all times

(Trevett et al., 2005).

1.2.8.1 Ponds

Most ponds receive direct surface runoff, although dug ponds can be fed by springs or

shallow groundwater. Protecting ponds from contamination chiefly involves keeping the area

12

draining into the pond as free from contamination as possible. To accomplish this, strict control

must be exercised over land use in the watershed. Water quality from forested areas is usually

considered to be among the highest that occurs in nature. Runoff from grassed areas is also of

relatively high quality. Therefore, the area that contributes water to a pond used for a domestic

water supply should be maintained in one of these land uses. Obviously, the watershed should be

free of barn yards, septic systems, and other onsite wastewater systems. Fencing should be used

to exclude animals from the watershed. Best management practices should be employed to

control erosion and loss of nutrients. Agricultural chemicals should not be used in the watershed.

These re commendations apply regardless of the type of pond used (Wright et al., 2004).

1.2.9 Protecting Groundwater Supplies

The best way to protect groundwater used for human or animal consumption involves

proper location of the well, coupled with proper well construction. All wells should be located

safe distances from sources of contamination. However, because many factors affect the

movement of contaminants into groundwater, it is impractical to set a fixed distance between

well location and contaminant contaminant source that would be applicable in all cases. There is

NO safe distance between contaminant source and an improperly constructed well (Wright et al.,

2004).

In general, unconsolidated materials typical of Coastal Plain aquifers provide better

“filtration” of percolating water than do consolidated fractured rock aquifers, typical in the

central and western part of the State. Most experts agree that even under the best conditions (for

example, when soil and aquifer conditions retard the movement of contaminants), the separation

distance should be no less than 50 feet. For an added safety measure, many local ordinances

often consider 100 feet to be the minimum separation distance. Since the safety of a groundwater

source depends mainly on geological and soil

conditions, and well construction practices, these variables must be considered in determining

the separation distance between well and contaminant source. Wherever possible, wells should

always be placed “up-gradient” of any source of contamination. In many cases, groundwater

gradients (tendency for flow) follow surface topography, therefore wells should be located uphill

from any contamination source. The direction of groundwater flow does not always follow the

slope of the land surface, however. Therefore, well siting should be done by a person with

13

sufficient training and experience to evaluate the various factors involved. Groundwater

contamination can continue for long periods before any problem is discovered. The volume of

polluted water by then can be large and the source of contamination far removed from the site of

the discovery (Wright et al., 2004).

1.2.10 What Individuals Can Do

Individuals can help protect our groundwater resources by recognizing that activities on

the soil surface and upper profile can, and do, affect groundwater. We need to manage our

activities accordingly. Like many public issues, however, awareness of problems and solutions is

not enough. Often, we as individuals acknowledge that a problem might exist, but deny that we

contribute to it. Even to a greater extent than with surface water, groundwater is shared by all

users, and all users similarly share in its contamination.

Here are some key things that individuals can do to protect groundwater:

• Keep a close watch on the inventory of liquids in underground tanks to detect possible losses

caused by leakage. If a buried tank is more than 15 years old it has a good chance of leaking.

Have it checked.

• Use agrochemicals and lawn and garden chemicals wisely, following re commended

application rates, timing, and methods.

• Manage septic tank systems to prolong their life and maximize their efficiency in removing

pollutants.

• Support legislation at the local level that will encourage the use of state-of-the-art technology in

solid waste management and waste water treatment.

1.3 Water Pollution

Water pollution is a major problem in the global context. It has been suggested that it is

the leading worldwide cause of deaths and diseases (Cohen, 1996; CDC, 1995) and that it

accounts for the deaths of more than 14,000 people daily (CDC, 1995). In addition to the acute

problems of water pollution in developing countries industrialized countries continue to struggle

with pollution problems as well. In the most recent national report on water quality in the United

14

states, 45 percent of assessed stream miles, 47 perent of assessed ladke acres, and 32 percent of

assessed bay and estuarine square miles were clssified as polluted (Rose, 1993).water qualitya in

the United States, 45 percent of assessed stream miles, 47 percent of assessed lake acres, and 32

percent of assessed bay and estuarine square miles were classified as polluted (Rose, 1993).

Water is typically referred to as polluted when it is impaired by anthropogenic

contaminants and either does not support a human use, like serving as drinking water, and/or

undergoes a marked shift in its ability to support its constituent biotic communities, such as fish.

Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major

changes in water quality and the ecological status of water. Water pollution has many causes and

characteristics (Trevett et al., 2005).

Surface water and groundwater have often been studied and managed as separate resources,

although they are interrelated (Payment, 1991). Sources of surface water pollution are generally

grouped into two categories based on their origin (Trevett et al., 2005).

1.3.1 Point source pollution

Point source pollution refers to contaminants that enter a waterway through a discrete

conveyance, such as a pipe or ditch. Examples of sources in this category include discharges

from a sewage treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act

(CWA) defines point source for regulatory enforcement purposes (Wiles, 1994).

1.3.2 Non-point source pollution

Non-point source (NPS) pollution refers to diffuse contamination that does not originate

from a single discrete source. NPS pollution is often a cumulative effect of small amounts of

contaminants gathered from a large area. Nutrient runoff in stormwater from "sheet flow" over

an agricultural field or a forest are sometimes cited as examples of NPS pollution. Contaminated

stormwater washed off of parking lots, roads and highways, called urban runoff, is sometimes

included under the category of NPS pollution. However, this runoff is typically channeled into

15

storm drain systems and discharged through pipes to local surface waters, and is a point source.

The CWA definition of point source was amended in 1987 to include municipal storm sewer

systems, as well as industrial stormwater, such as from construction sites (Olson, 1995).

1.3.3 Groundwater pollution

Interactions between groundwater and surface water are complex. Consequently,

groundwater pollution, sometimes referred to as groundwater contamination, is not as easily

classified as surface water pollution ((Payment, 1991). By its very nature, groundwater aquifers

are susceptible to contamination from sources that may not directly affect surface water bodies,

and the distinction of point vs. nonpoint source may be irrelevant. A spill of a chemical

contaminant on soil, located away from a surface water body, may not necessarily create point

source or non-point source pollution, but nonetheless may contaminate the aquifer below.

Analysis of groundwater contamination may focus on soil characteristics and hydrology, as well

as the nature of the contaminant itself (Payment, 1991).

1.3.4 Materials and Phenomena Contributing to Water Pollution

The specific contaminants leading to pollution in water include a wide spectrum of

chemicals, pathogens, and physical or sensory changes such as elevated temperature and

discoloration. While many of the chemicals and substances that are regulated may be naturally

occurring (calcium, sodium, iron, manganese, etc.) the concentration is often the key in

determining what is a natural component of water, and what is a contaminant. Oxygen-depleting

substances may be natural materials, such as plant matter (e.g. leaves and grass) as well as man-

made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness)

which blocks light and disrupts plant growth, and clogs the gills of some fish species (Reilly,

1990).

Many of the chemical substances are toxic. Pathogens can produce waterborne diseases

in either human or animal hosts. Alteration of water's physical chemistry include acidity (change

in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is the fertilization

of surface water by nutrients that were previously scarce (Pruss et al., 2002).

16

1.3.4.1 Chemical and other contaminants

Contaminants may include organic and inorganic substances.

Organic water pollutants include:

Detergents

Disinfection by-products found in chemically disinfected drinking water, such as

chloroform

Food processing waste, which can include oxygen-demanding substances, fats and grease

Insecticides and herbicides, a huge range of organohalides and other chemical

compounds

Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and

lubricants (motor oil), and fuel combustion byproducts, from stormwater runoff.

Tree and brush debris from logging operations

Volatile organic compounds (VOCs), such as industrial solvents, from improper storage.

Chlorinated solvents, which are dense non-aqueous phase liquids (DNAPLs), may fall to

the bottom of reservoirs, since they don't mix well with water and are denser.

Various chemical compounds found in personal hygiene and cosmetic products

Inorganic water pollutants include:

Acidity caused by industrial discharges (especially sulfur dioxide from power plants)

Ammonia from food processing waste

Chemical waste as industrial by-products

Fertilizers containing nutrients--nitrates and phosphates--which are found in stormwater

runoff from agriculture, as well as commercial and residential use.

Heavy metals from motor vehicles (via urban stormwater runoff) and acid mine drainage

Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land

clearing sites

17

Macroscopic pollution--large visible items polluting the water--may be termed

“floatables” in an urban stormwater context, or marine debris when found on the open seas, and

can include such items as:

Trash (e.g. paper, plastic, or food waste) discarded by people on the ground, and that` are

washed by rainfall into storm drains and eventually discharged into surface waters

Nurdles, small ubiquitous waterborne plastic pellets

Shipwrecks, large derelict ships

1.3.5 Measurement of Water Pollution

Water pollution may be analyzed through several broad categories of methods: physical,

chemical and biological. Most methods involve collection of samples, followed by specialized

analytical tests. Some methods may be conducted in situ, without sampling, such as temperature.

Government agencies and research organizations have published standardized, validated

analytical test methods to facilitate the comparability of results from disparate testing events

(Reilly, 1990).

1.3.5.1 Sampling

Sampling of water for physical or chemical testing can be done by several methods,

depending on the accuracy needed and the characteristics of the contaminant. Many

contamination events are sharply restricted in time, most commonly in association with rain

events. For this reason "grab" samples are often inadequate for fully quantifying contaminant

levels. Scientists gathering this type of data often employ auto-sampler devices that pump

increments of water at either time or discharge intervals. Sampling for biological testing involves

collection of plants and/or animals from the surface water body (Karnataka State Pollution

Control Board, 2002).

1.3.5.2 Physical testing

18

Common physical tests of water include temperature, solids concentration and turbidity.

1.3.5.3 Chemical testing

Water samples may be examined using the principles of analytical chemistry. Many

published test methods are available for both organic and inorganic compounds. Frequently-used

methods include pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD),

nutrients (nitrate and phosphorus compounds), metals (including copper, zinc, cadmium, lead

and mercury), oil and grease, total petroleum hydrocarbons (TPH), and pesticides (Pruss et al.,

2002).

1.3.5.4 Biological Testing

Biological testing involves the use of plant, animal, and/or microbial indicators to

monitor the health of an aquatic ecosystem. Diarrhoeal diseases account for 4.3% of the total

global disease burden (62.5 million DALYs). An estimated 88% of this burden is attributable to

unsafe drinking water supply, inadequate sanitation, and poor hygiene. These risk factors are

second, after malnutrition, in contributing to the global burden of disease (Pruss et al., 2002).

Target #10 of the Millennium Development Goal for water (number 7) is to “Reduce by

half the proportion of people without sustainable access to safe drinking water.” Because many

developing countries have little or no water quality monitoring, particularly in rural areas, the

organisations responsible for assessing progress towards this target (UNICEF and WHO) have

adopted the following indicator as a modified version of the target (United Nations, 2005):

“Indicator 30. Proportion of population with sustainable access to an improved water source,

urban and rural.” This modified version implies an equivalence between „safe‟ water and water

from an „improved‟ source. The justification for this equivalence is not provided on the

referenced webpage. In rural areas of most developing countries, women and children collect

water from a communal source, often located several hundred metres from the home. The

sources themselves may be unimproved (hand dug wells, unprotected springs, rivers), with low

and seasonal flow rates, or improved (public taps, boreholes or pumps, protected wells, protected

springs or harvested rainwater). A systematic review of 57 studies published before 2002 by

Wright et al. (2004) showed that water contamination occurs between source and point-of-use.

19

This pattern has been confirmed by subsequent studies of water contamination in rural Sierra

Leone (Clasen and Bastable, 2003) and rural Honduras (Trevett et al., 2005). However, it is

unclear exactly when this contamination takes place.

Fig. 1.3: Showing the supply chain of drinking water for each household. (Trevett et al., 2005).

1.3.5.4.1 Alkalinity

Alkalinity is an index of the buffering capacity of water. It is closely linked to hardness.

For the most part, alkalinity is produced by anions or molecular species of weak acids, mainly

hydroxide, bicarbonate and carbonate; other species such as borates, phosphates, silicates and

organic acids may also contribute to a small degree. Alkalinity is expressed in terms of an

equivalent quantity of calcium carbonate. As the alkalinity of most Canadian surface waters is

due to the presence of carbonates and bicarbonates, their alkalinity is close to their hardness

(Pruss et al., 2002).

1.3.5.4.2 Aluminum

Neither a health-based guideline (MAC) nor an aesthetic objective (AO) has been

established for aluminum in drinking water. Aluminum is the most abundant metal on Earth –

about 8% of the Earth‟s crust. It is found in a variety of minerals. Aluminum is chiefly mined as

“Flamed

” “Unflamed” Vessel Cu

p

TRANSPORT POINT-OF-USE

IN HOUSEHOLD

COLLECTION

FROM SOURCE

Intrinsic Accessible Stored Consumed

20

bauxite, a mineral containing 40–60% aluminum oxide (alumina). Aluminum is also found as a

normal constituent of soil, plants and animal tissues. As a precaution, water treatment plants

using aluminum-based coagulants should optimize their operations to reduce residual aluminum

levels in treated water to the lowest extent possible. For plants using aluminum-based

coagulants, recommended values are less than 0.1 mg/L total aluminum for conventional

treatment plants and less than 0.2 mg/L total aluminum for other types of treatment systems (e.g.,

direct or in-line filtration plants, lime softening plants). These values are based on a 12-month

running average of monthly samples (Trevett et al., 2005).

1.3.5.4.3 Arsenic

The interim maximum acceptable concentration (IMAC) for arsenic in drinking water is

0.025 mg/L. Levels of arsenic in natural waters generally range between 0.001 and 0.002 mg/L.

Sources of arsenic in the air around us come from the burning of fossil fuels (especially coal),

metal production, agricultural use and waste incineration. Arsenic is introduced into water

through the dissolution of minerals and ores, from industrial effluents and from the atmosphere.

Natural sources, such as arsenic-containing rock that dissolves, often contribute significantly to

the arsenic content of drinking water and groundwater (Rajesh et al., 2004).

1.3.5.4.4 Barium

The maximum acceptable concentration (MAC) for barium in drinking water is 1.0 mg/L.

Barium is present as a trace element in both igneous and sedimentary rocks. Although it is not

found free in nature, barium occurs in a number of compounds, most commonly barite (BaSO4)

and, to a lesser extent, witherite (BaCO3). Barium is not considered a contaminant in the

Northwest Territories (Trevett et al., 2005).

1.3.5.4.5 Cadmium

21

The maximum acceptable concentration (MAC) of 0.005 mg/L for cadmium in drinking

water was set based on health considerations. Cadmium is a silvery-white, lustrous, but

tarnishable metal that closely resembles zinc. It is soft and ductile and has a relatively high

vapour pressure. Cadmium is not considered a contaminant of concern in the Northwest

Territories (Rajesh et al., 2004).

1.3.5.4.6 Chloride

The aesthetic objective (AO) for chloride in drinking water is 250 mg/L. At

concentrations above the AO, chloride makes water, and drinks made from water, taste bad. It

may also cause corrosion in the distribution system (Morris, 1992). Chloride is widely

distributed in nature, generally as sodium (NaCl) and potassium (KCl) salts. By far the greatest

amount of chloride found in the environment is in the oceans. Chloride in drinking water sources

can come from dissolving salt deposits, salting of highways to control ice and snow, effluents

from chemical industries, oil well operations, sewage, irrigation drainage, refuse leachates, sea

spray and seawater intrusion in coastal areas. Chloride is generally present at low concentrations

in natural surface waters in Canada. Concentrations are normally less than 10 mg/L and often

less than 1 mg/L (Wright et al., 2004).

1.3.5.4.7 Chromium

The maximum allowable concentration (MAC) of 0.05mg/L for chromium in drinking water was

set based on health considerations.

Trivalent chromium, the most common natural state of chromium, is essential in humans and

animals for efficient lipid, glucose and protein metabolism. It is considered to be non-toxic.

However, if it is present in raw water, it may be oxidized to hexavalent chromium during

chlorination. Concentrations of total chromium in drinking water are usually well below the

22

MAC. Chromium is not considered a contaminant of concern in the Northwest Territories

(Trevett et al., 2005).

1.3.5.4.8 Colour

The aesthetic objective (AO) for colour is 15 TCU (total colour units). Colour is not a

health-related parameter. Colour in drinking water may be due to the presence of coloured

organic substances, metals such as iron, manganese and copper or highly coloured industrial

wastes. Although presence of colour in drinking water is not directly related to health, experience

has shown that consumers may turn to alternative, possibly unsafe, sources, if their drinking

water is highly coloured (Wright et al., 2004).

1.3.5.4.9 Copper

The aesthetic objective (AO) for copper in drinking water is 1.0 mg/L. This was set to

ensure the water tastes okay and to minimize staining of laundry and plumbing fixtures. Copper

is an essential element in human metabolism, and deficiencies result in a variety of clinical

disorders, including nutritional anemia in infants. Although large doses of copper may result in

adverse health effects, the levels at which this occurs are much higher than the aesthetic

objective (AO). Copper occurs in nature as a metal and in minerals. Copper is not a contaminant

of concern in the Northwest Territories (Rajesh et al., 2004).

1.3.5.4.10 Cyanide

Cyanide is toxic to humans, and the maximum acceptable concentration (MAC) for free

cyanide in drinking water is 0.2 mg/L. Cyanides may be released into the aquatic environment

through waste effluents from various industries such as gold mining. Representative data suggest

that Canadian drinking water has very low concentrations of cyanide. Contamination through

industrial spillage or transport accidents could result in high cyanide levels in raw water supplies.

Cyanide is not considered a contaminant of concern in the Northwest Territories (Rajesh et al.,

2004).

23

1.3.5.4.11 Escherichia coli (E. coli)

Of all contaminants in drinking water, human and animal feces present the greatest

danger to public health. E. coli are naturally occurring fecal coliforms found in human and

animal intestines. While the strain of E. coli known as E. coli 0157:H7, which contaminated the

water in Walkerton, Ontario, is very harmful and potentially deadly, most strains of E. coli are

relatively harmless. The reason E. coli is relied on so heavily as a measure is that it is a good

indicator of the bacteriological safety of drinking water. It is the only species in the coliform

group that is exclusively found in the intestinal tract of humans and other warm-blooded animals

and it is excreted in large numbers in feces. If E. coli is found in the water, it means that the

water has been contaminated by human or animal feces that can harbour a number of other

pathogenic, or disease causing, organisms. The maximum acceptable concentration (MAC) of E.

coli in drinking water is zero (Trevett et al., 2005).

1.3.5.4.12 Faecal Coliforms

Faecal coliforms, otherwise known as thermotolerant coliforms, are a type of coliform

bacteria generally found in the intestines of healthy humans and animals. Coliform bacteria can

be found everywhere in the environment, and most coliforms, including most faecal coliforms

are relatively harmless, naturally occurring organisms. Faecal coliforms, which include E. coli

and a few other species, are an indicator of faecal contamination. Faecal coliform testing has

been replaced by E. coli testing in most jurisdictions as more specific tests for E. coli have

become routinely available. The maximum acceptable concentration (MAC) of faecal coliforms

in drinking water is zero. If fecal coliforms are found in treated drinking water, a boil water

advisory is generally issued right away (Rajesh et al., 2004).

1.3.5.4.13 Fluoride

The maximum acceptable concentration (MAC) for fluoride in drinking water is 1.5

mg/L. Fluoride-containing compounds are added to drinking water to help prevent dental

cavities. Fluoride can occur naturally in surface waters. Groundwater can also contain high

24

concentrations of fluoride due to leaching from rocks. Fluoride can be present in plant and

animal tissues. Fluoride is not considered a contaminant of concern in the Northwest Territories.

Some communities, such as Yellowknife, add fluoride to the water to help prevent tooth decay

(Wright et al., 2004).

1.3.5.4.14 Heterotrophic Plate Count

The heterotrophic plate count (HPC), formerly known as the standard plate count (SPC),

is an indicator of the general bacteriological content of the water. High HPC levels are not

associated with waterbourne disease outbreaks. Proper chlorine disinfection can generally reduce

HPC levels to less than 10 cfu/mL. HPC levels above 500 cfu/mL should be investigated, but

would not normally result in a boil water advisory (Trevett et al., 2005).

1.3.5.4.15 Iron

The aesthetic objective (AO) for iron in drinking water is 0.3 mg/L. At concentrations

above the AO, iron can make water taste bad and can cause staining of laundry and plumbing

fixtures. Iron is an essential element in human nutrition, and deficiencies can result in impaired

mental development in children, reduced work performance in adults and, in severe cases,

anemia or impaired oxygen delivery. Iron is the fourth most abundant element in the earth‟s crust

and the most abundant heavy metal. It is present in the environment mainly as Fe(II) or Fe(III).

The concentrations of iron in Canadian surface waters are generally below 10 mg/L. Iron is

generally present in surface waters as salts containing Fe(III) when the pH is above 7. Most of

those salts are insoluble and settle out or are adsorbed onto surfaces Therefore, the concentration

of iron in well-aerated waters is seldom high. Under reducing conditions, which may exist in

some groundwaters, lakes or reservoirs, and in the absence of sulphide and carbonate, high

concentrations of soluble Fe(II) may be found. The presence of iron in natural waters can be

attributed to the weathering of rocks and minerals, acidic mine water drainage, landfill leachates,

sewage effluents and iron-related industries (Rajesh et al., 2004).

1.3.5.4.16 Lead

25

The maximum acceptable concentration (MAC) for lead in drinking water is 0.010 mg/L.

Lead is a poison that can negatively affect the central nervous system. Pregnant women, infants

and children up to 6 years of age are most vulnerable. Lead is present in tap water as a result of

dissolution from natural sources or from old household plumbing systems containing lead in

pipes, solder or househould service connections. The amount of lead from the plumbing system

that may be dissolved depends upon several factors, including the acidity (pH), water softness

and standing time of the water.

Lead has not been used in drinking water distribution systems or in household plumbing since

1945. People living in older homes in particular, should run the water for a few minutes to clear

out the water that has been sitting in the pipes before drinking it. Faucets should also be flushed

before water samples are taken for testing. Lead is generally not a concern in the Northwest

Territories, where there are few older houses or distribution systems (Trevett et al., 2005).

1.3.5.4.17 Manganese

The aesthetic objective (AO) for manganese in drinking water is 0.05 mg/L. Manganese

in drinking water supplies can cause a number of problems. At concentrations above 0.15 mg/L,

manganese stains plumbing fixtures and laundry and produces undesirable taste in drinks.

Manganese may cause microbial growths in the distribution system. Even at concentrations

below 0.05 mg/L, manganese may form black coatings on water distribution pipes. The element

manganese is present in over 100 common salts and mineral complexes that are widely

distributed in rocks, in soils and on the floors of lakes and oceans. Manganese is most often

present as the dioxide, carbonate or silicates. Manganese is most often a concern for systems that

use a groundwater source (Rajesh et al., 2004).

1.3.5.4.18 Mercury

26

Mercury is a toxic element and provides no benefit to humans. The maximum acceptable

concentration (MAC) for mercury in drinking water is 0.001 mg/L. Mercury is a concern because

organic mercury accumulates in fish. Elevated mercury levels have been found in freshwater fish

taken from areas with suspected mercury contamination and frequently render the fish unsafe to

eat. Long-term daily intake of approximately 0.25 mg of mercury as methyl mercury has caused

the onset of neurological symptoms; however, even in heavily polluted Canadian waters,

mercury concentrations rarely exceed 0.03 mg/L. The MAC for mercury, therefore, provides a

considerable margin of safety. Mercury levels in both surface water and tap water are generally

well below the maximum acceptable concentration. Mercury is not considered a contaminant of

concern in the Northwest Territories (Trevett et al., 2005).

1.3.5.4.19 Nitrate

The maximum acceptable concentration (MAC) for nitrate in drinking water is 45 mg/L.

In cases where nitrite is measured separately from nitrate, the concentration of nitrite should not

exceed 3.2 mg/L. The most commonly reported toxic effect of nitrate-contaminated drinking

water is methaemoglobinaemia, which results in reduced oxygen transfer to body tissues. Infants

up to 3 months of age are most vunerable. Nitrate (NO3‾) and nitrite (NO2‾) are naturally

occurring ions that are found everywhere in the environment (Wright et al., 2004).

Both are products of the oxidation of nitrogen (which comprises roughly 78% of the atmosphere)

by micro-organisms in plants, soil or water and, to a lesser extent, by electrical discharges such

as lightning. Nitrate is the more stable form of oxidized nitrogen but can be reduced by microbial

action to nitrite, which is moderately reactive chemically. Sources of nitrates in water

(particularly groundwater) include decaying plant or animal material, agricultural fertilizers,

manure, domestic sewage, or geological formations containing soluble nitrogen compounds.

Nitrate is not considered a contaminant of concern in the Northwest Territories, as there is very

little commercial agriculture (Trevett et al., 2005).

1.3.5.4.20 pH

27

An acceptable range for drinking water pH is from 6.5 to 8.5. Water with a pH below 6.5

is considered acidic and may cause corrosion. Water with a pH above 8.5 is considered basic,

and may result in incrustation and scaling problems. As pH increases, there is a progressive

decrease in the efficiency of the chlorine disinfection process (Rajesh et al., 2004).

1.3.5.4.21 Selenium

The maximum acceptable concentration (MAC) for selenium in drinking water is 0.01

mg/L based on health considerations. Food is the main source of selenium for people who are not

occupationally exposed; thus, toxic effects have most often been associated with food. A safe

and adequate range of selenium intake of 0.05 to 0.2 mg per person per day has been

recommended for adults, with correspondingly lower ranges for infants and children. Drinking

water containing selenium at the MAC would be the source of between 10 and 25 percent of total

selenium intake; the MAC provides a reasonable factor of safety from adverse effects of

selenium. Selenium is not considered a contaminant of concern in the Northwest Territories

(Rajesh et al., 2004).

1.3.5.4.22 Sodium

The aesthetic objective (AO) for sodium in drinking water is 200 mg/L. Drinking water

generally tastes bad at sodium concentrations above the AO. Sodium is not considered a toxic

element. Adults normally consume up to 5 grams of sodium a day. Although the average intake

of sodium from drinking water is only a small fraction of that consumed in a normal diet, the

intake from this source could be significant for people suffering from hypertension or congestive

heart failure who may require a sodium-restricted diet. Sodium is the most abundant of the alkali

elements and makes up 2.6% of the Earth's crust. Sodium compounds are widely distributed in

nature. Sodium is a soft, silvery-white, highly reactive metal. It is never found in nature in the

uncombined state and has a strong tendency to exist in the ionic form. In biological systems and

even in solids such as sodium chloride, sodium remains distinctly separate as the sodium ion

(Wright et al., 2004).

28

1.3.5.4.23 Sulphate

The aesthetic objective (AO) for sulphate in drinking water is 500 mg/L, based on taste.

Because of the possibility of adverse physiological effects at higher concentrations, health

authorities should be notified if drinking water sulphate concentrations exceed 500 mg/L.

Sulphur is a non-metallic element. Sulphur, principally in the form of sulphuric acid, is one of

the most widely used chemicals in industrialized society. Most sulphur is converted into

sulphuric acid. Sulphates or sulphuric acid products are also used in the manufacture of

numerous chemicals, dyes, glass, paper, soaps, textiles, fungicides, insecticides, astringents and

emetics. They are also used in the mining, pulping, metal and plating industries. Aluminum

sulphate (alum) is used as a sedimentation agent in the treatment of drinking water, and copper

sulphate has been used for the control of blue-green algae in both raw water and public water

supplies in the United States. Sulphate is not considered a contaminant of concern in the

Northwest Territories (Trevett et al., 2005).

1.3.5.4.24 Total Hardness

Although hardness may have significant aesthetic effects, a maximum acceptable level

has not been established because public acceptance of hardness may vary considerably according

to the local conditions. Water supplies with a hardness greater than 200 mg/L are considered

poor, but have been tolerated by consumers; those in excess of 500 mg/L are unacceptable for

most domestic purposes. Higher levels are generally associated with groundwater sources. Water

hardness is a traditional measure of the capacity of water to react with soap. Hard water requires

a considerable amount of soap to produce a lather, and it also leads to scaling of hot water pipes,

boilers and other household appliances. Water hardness is caused by dissolved polyvalent

metallic ions. In fresh waters, the principal hardness-causing ions are calcium and magnesium;

strontium, iron, barium and manganese ions also contribute (Rajesh et al., 2004).

1.3.5.4.25 Total Dissolved Acids (TDS)

29

An aesthetic objective (AO) for total dissolved solids (TDS) in drinking water is 500

mg/L. At higher levels, excessive hardness, poor taste, mineral deposition and corrosion may

occur. At low levels, however, TDS contributes to the good taste of water. Total dissolved solids

(TDS) include inorganic salts and small amounts of organic matter that are dissolved in water.

The principal constituents are usually the cations calcium, magnesium, sodium and potassium

and the anions carbonate, bicarbonate, chloride, sulphate and, particularly in groundwater, nitrate

(from agricultural use). Total dissolved solids in water supplies originate from natural sources,

sewage, urban and agricultural runoff and industrial wastewater (Trevett et al., 2005).

1.3.5.4.26 Turbidity

Turbidity is a measure of the relative clarity or cloudiness of water. Turbidity in water is

caused by suspended and colloidal matter, such as clay, silt, finely divided organic and inorganic

matter, and plankton and other microscopic organisms (Wright et al., 2004). Turbidity is not a

direct measure of particles suspended in the water. It is, rather, a measure of the scattering effect

that such particles have on light. A beam of light remains relatively undisturbed when it shines

through absolutely pure water, but if there are particles in the water, the light will bounce off the

particles and scatter in different directions. Turbidity is considered a health-related parameter

because the particles can shelter bacteria from chlorine disinfection and act as a food source for

micro-organisms. Water with high turbidity may increase the amount of chlorine required for

disinfection and the possibility of water-borne illness (Wright et al., 2004).

1.3.5.4.27 Trihalomethanes (THMs)

The interim maximum acceptable concentration (IMAC) for total

trihalomethanes(THMs) in drinking water is 0.1mg/L. THMs are the by-products that result

when chlorine is mixed with organic particles. If raw water has a lot of organic material, THMs

can be produced during disinfection. Drinking water with a lot of THMs over a very long period

of time may be linked to cancer, but drinking water that is not disinfected with chlorine is a

much bigger health risk (Rajesh et al., 2004).

30

1.3.5.4.28 Uranium

The interim maximum acceptable concentration (IMAC) for uranium in drinking water is

0.02 mg/L. Uranium is present in water supplies as a result of leaching from natural deposits,

release from mill tailings, emissions from the nuclear industry, and the combustion of coal and

other fuels. Phosphate fertilizers may also contribute to the uranium content of groundwater.

Uranium is not considered to be a contaminant of concern in the Northwest Territories (Trevett

et al., 2005).

1.3.5.4.29 Zinc

The aesthetic objective (AO) for zinc is 5.0 mg/L. Zinc is an essential element is

generally considered to be non-toxic. Drinking water is not considered an important nutritional

source of this element. Water containing zinc at concentrations above 5.0 mg/L tends to be

opalescent, develops a greasy film when boiled, and has an undesirable astringent taste. Zinc is

an abundant element. The most common zinc mineral is sphalerite (ZnS), which is often

associated wth the sulphides of other metallic elements, such as lead, copper, cadmium, and iron.

Zinc is not considered to be a contaminant of concern in the Northwest Territories (Wright et al.,

2004).

1.3.5.4.30 Table 1: Physicochemical Combined Standards of WHO, SON AND NAFDAC

(IPAN, 2005)

S/No. Parameter NAFDAC MAXIMUM

ALLOWED LIMITES

SON

STANDARD

Highest Desirable

1. Color 3.0TCU 3.0 TCU 3.0TCU 15.0TCU

2. Odour Unobjectionable Unobjectionable Unobjectionable Unobjectionable

3. Taste Unobjectionable Unobjectionable Unobjectionable Unobjectionable

Maximum

permissible

WHO STANDARDS

31

4. pH at 200C 6.50-8.5 6.50-8.5 7.0-8.9 6.50-9.50

5. Turbidity 5.0 NTU 5.0 NTU 5.0 NTU 5.0 NTU

6. Conductivity 1000 (us/cm-1

) 1000 (us/cm-1

) 900 (us/cm-1

) 1200 (us/c-1

)

7. Total solids 500 mg/L 500 mg/L 500 mg/L 1500 mg/L

8. Total Alkalinity 100mg/L 100 mg/L 100 mg/L 100 mg/L

9. Phenolphthalein

Alkalinity

100mg/L 100 mg/L 100 mg/L 100 mg/L

10. Chloride 100mg/L 100 mg/L 200 mg/L 250 mg/L

11. Fluoride 1.0mg/L 1.0 mg/L 1.0 mg/L 1.5 mg/L

12. Copper 1.0mg/L 1.0 mg/L 0.5 mg/L 2.0 mg/L

13. Iron 0.3 mg/L 0.3 mg/L 1 mg/L 3 mg/L

14. Nitrate 10 mg/L 100 mg/L 10 mg/L 50 mg/L

15. Nitrite 0.02 mg/L 0.02 mg/L 0.2 mg/L 3 mg/L

16. Manganese 2.0 mg/L 0.05 mg/L 0.1 mg/L 0.4 mg/L

17. Magnesium 20 mg/L 20 mg/L 20 mg/L 20 mg/L

18. Zinc 5.0 mg/L 5.0 mg/L 0.01 mg/L 3.0 mg/L

19. Selenium 0.01 mg/L NS 0.01 mg/L 0.01 mg/L

20. Silver - - NS NS

21. Cyanide 0.01 mg/L 0.01 mg/L 0.01 mg/L 0.07 mg/L

22. Sulphate 100 mg/L 100 mg/L 250 mg/L 500 mg/L

23. Calcium 75 mg/L 75 mg/L NS NS

24. Aluminum 0.5 mg/L NS 0.2 mg/L 0.2 mg/L

25. Potassium 10.0 mg/L 10.0 mg/L NS NS

26. Lead 0.01 mg/L 0.01 mg/L 0.01 mg/L 0.01 mg/L

27. Chromium 0.05 mg/L 0.05 mg/L 0.05 mg/L 0.05 mg/L

32

28. Cadmium 0.003 mg/L 0.003 mg/L 0.003 mg/L 0.003 mg/L

29. Arsenic 0.01 mg/L 0.01 mg/L 0.01 mg/L 0.01 mg/L

30. Barium 0.05 mg/L 0.05 mg/L 0.05 mg/L 0.07 mg/L

31. Mercury 0.001 mg/L 0.001 mg/L 0.001 mg/L 0.001 mg/L

32. Antimony NS NS - 0.02 mg/L

33. Tin - - - 1.2 g/L

34. Nickel - - - 0.02 mg/L

35. Total Hardness

(CaCO3)

100 mg/L 100 mg/L 100 mg/L 500 mg/L

36. Vinyl chloride 0 mg/L 0 mg/L 0 mg/L 0003 mg/L

(IPAN, 2005)

NAFDAC - NATIONAL AGENCY FOR FOOD AND DRUG ADMINISTRATION AND

CONTROL.

SON - STANDARDS ORGANIZATION OF NIGRIA

WHO – WORLD HEALTH ORGANIZATION

IPAN – INSTITUTE OF PUBLIC ANALYSTS OF NIGERIA.

33

CHAPTER TWO

MATERIALS AND METHODS

2.1 Materials

2.1.1 Water Sampling Sources

Thirteen sampling areas consisting of four boreholes, six dug wells and three springs

were chosen for this research work. A total of 26 samples were taken during the dry season and

another 26 during the wet season. The sampling was carried in Nsukka (Fig. 2.1) and were

sampled seasonally as follows: dry season (January, 2004); and rainy season proper (August,

2004). All were equipped with headwall and cover, and some had a cemented surrounding. The

analyses carried out were on the utility water supplies in Nsukka area. Water samples were

collected from these sampling areas and refrigerated at 4OC for processing.

2.1.2 Chemicals/Reagents/Samples

All chemicals used in this study were of analytical grade and products of May and Baker,

England; BDH, England and Merck, Darmstadt, Germany.

2.2 Methods

Spectrophotometric and complexiometric methods were employed in the work.

2.2.1 Experimental Design

The analyses carried out were on the utility water supplies in Nsukka area. Five sampling

stations consisting of four bore holes, six dug wells and three springs were chosen for this

research work. A total of 26 samples were taken during the dry season and another 26 during the

wet season. Water samples were collected from these sampling stations and refrigerated at 4OC

for processing. Concentrations of lead, cadmium, nickel, arsenic and zinc were determined in

each sample by spectrophotometric method. Complexiometric titration method was employed in

the determination of acidity and total hardness of water samples, while Harch Model C50 digital

multirange meter was used to measure pH, electrical conductivity and total dissolved solids.

Other chemical parameters like nitrate, chloride and sulphate were also determined by

spectrophotometric method. Bacteriological analysis of the water samples were carried out to

34

ascertain whether there was faecal contamination by the use of multiple tube/most probable

number techniques.

2.2.2 Sampling Areas

The analyses carried out were on the utility water supplies in the University Campus of

Nsukka town. The Sampling areas are shown on the sampling map. The sampling areas consists

four boreholes, two of which are located in University of Nigeria, Nsukka Campus, they are

Franco Hostel borehole and the UNN water works borehole. The other two boreholes are found

in Nsukka town, they include Work and Pay borehole near Peace Mass Transit Motor Park, and

the Nsukka water scheme borehole. Sampling areas also include six dug wells and three springs.

The dug wells are found, one at No 4 Saint Theresa Road one at No 95 New Anglican Road, one

at Amaozala village, three at Eburu Mmili village after Saint Cyprian‟s college.

The three springs are Asho spring off Ugwuawarawa/Onuiyi Road. Ajie spring behind

El-rina hostels limited, and Iyi- Adoro at Alo-uno village. These are utility water supplies in

Nsukka town and environs. Contamination of these water sources will result in epidemic

outbreak or health problems in the Nsukka populace.

35

Fig. 2.1: Map of Nsukka showing the location of sampled areas

36

Table 2.1 Sampling points description table

Sampling points Description and location

UNN water works

borehole

The UNN water scheme borehole is located near the gate leading to

Owerre-Eze-Orba village. The University of Nigeria, Nsukka

Campus receives greater supply of water from this borehole.

Occasionally water is pumped to the surface and aerated before

storage. Currently there is a major work going on around the place

to upgrade it.

Franco borehole This is the second borehole from which the University Community

receives her supply of water. It is about 700ft deep and it is

surrounded by small farm land. The inhoff sewage treatment plant is

about 350-450 meters away.

Nsukka water scheme

borehole

Sample of water was collected from the overhead pipe feeding the

water-tankers that collect water for sale and distribution to Nsukka

inhabitants.

It has a dept of 725ft, and is located behind peace mass transit. It

belongs to Mr. Augustine Madueke of No 23c Amaeze Lane

Nsukka.

Saint Theresa‟s Road

Dug well ( Mr.

Vincent Ezeh)

This is located at No 47 Saint Theresa‟s road, behind Bishop

Shanahan Hospitals, Nsukka. It has a dept of about 30ft.

New Anglican Road

(Mr. N.E. Ogboso)

Dug well

This is situated at No 95 New Anglican Road, Nsukka. It is about

60ft. They use water pumping machine to pump out water

hygienically

Amaozala village. Dug

well

The well is about 28ft deep with clean surroundings. It is cited along

the road off New Anglican Road to Aku.

Mr. Francis Ukwueze

of Eburu Mmili

village. Dug well

Mr. Francis Ukwueze‟s dugwell in Eburu Minili village is about 32ft

deep. The surrounded well is by shruba.

Mrs. Mercy Onah of

Eburu-Minili

Mrs. Mercy‟s dugwell in Eburu-Minili village is about 40ft deep. It

is surrounded by farm lands.

Work and pay

borehole

37

village.dug well

Mr. Victor

Ugwuanyi‟s dug well

Mr. Victor Ugwuanyi dugwell located in front of his house is about

38ft deep. The surroundings is relatively clean.

Asho spring water This is off Ugwuawarawa /Onuiyi Road just after Tochukwu motor

depot as one goes to Odenigbo roundabout. The water is channeled

through a pipe as it descends the forested steep hill of the area

Ajie spring water This is located right behind Elrina Hotels limited. The water is also

channeled through a pipe.

Iyi-adoro spring water This is located at Alo-Uno village. It is on a think forested hill just

as one passes the Adoro shrine. The water perculates from the rocks

and it is exposed to dust and fallen leaves as it collects in a trough of

the rocks.

2.2.3 Heavy metals determination

There are some methods employed in the determination of heavy metals in water.

A) Spectrophometry method

This technique employs the use of ultraviolet, infrared and fluorescent methods of

chemical analysis in the detection and measurement of toxic substances in body tissues and

fluids. Absorption curves for most substances enable accurate quantitative and qualitative data to

be obtained.

The spectrophotometer instrument works by comparing the intensities of two differently

coloured light sources by resolving their light into spectra and measuring the relative intensities

of those spectra, wavelength by wavelength.

(i) Atomic Absorption spectrometry (AAS)

This depends on the absorption of characteristic electromagnetic radiation by vapourized

metal atoms in a flame. The extent of absorption of the radiation is proportional to the

concentration of the metal atom in solution. The use of organic solvents in the presence of

reducing flame such as oxyhydrogen or nitrous oxide acetylene flame enables the determination

of refractory metal oxides.

38

(ii) Colorimetric Determinations

The basis of colorimetry is the variation of the colour of a system with change in the

concentration of some components. Quantitation in colorimetric analysis is based on Bar-

Lambert‟s law, and the fundamental equation of colorimetry. Spectrophotometry often referred

to as Beer-Lambert‟s equation is given as:

acltI

Icl

TA

t

0log

1log

Where A or (a) = absorbance, T = transmittance

E = molar absorptivity, C = concentration

I = path length of radiation

The relationship between absorbance and concentration for the system is determined

to ascertain the range over which Beer‟s law applies. This kind of plot is called standard or

calibration curve. A number of researches have been successfully accomplished with the use of

colorimetric method of analysis. For instance, the International Institute of Tropical Agriculture

(IITA) used the colorimetric technique immensely in their manual for heavy metals and nitrate

determination.

B) Chromatographic method

This is a method of separating two or more chemical compounds in solution by taking

advantage of the fact that they are removed from the solution at different rates when the latter is

percolated down a column of a powdered absorbent or passed across the surface of an absorbent

paper. These include gas chromatography (GC), High performance liquid chromatography

(HPLC) and thin layer chromatography (TLC) to mention but a few. Chromatographic methods

have great application in chemical analysis, sometimes in conjunction with other analytic

instruments. Marina et al. () used Reversed Phase HPLC with UV detection to determine Fe, Cr,

Ni, Cu, Mn, Pb as EDTA complexes.

C) Polarography

39

This is a method of chemical analysis depending upon variations in the potential curve

observed when the given substance is electrolyzed, employing a dropping mercury electrode.

There are various types of this technique; pulse polarography, differential pulse

voltammetry, and differential pulse anodic stripping voltammetry. Polarography is useful for the

determination of heavy metals and their speciation in water and waste water. Thesemethods are

recommended by STM and vogel for analysis of heavy metals.

D) The Ionic Heavy Metal Test (IHMT)

The IHMT is a simple, fast and inexpensive method to detect ionic or heavy metals and

free radical producing metals (copper, zinc, iron, lead, mercury, cadmium etc) in the body and

our environment. The IHMT does not detect chelated metals. The IHMT assesses the chelation

ability of a person from a small urine sample. (i.e. how well someone copes with ionic,

electromagnetically active and free radical producing metals. The chelation ability in turn

determines (besides other influences) how many free radicals are produced.

Apart from urine IHMT can also show the presence of electrically active ionic heavy

metals in saliva, water, dust, paint, soil, fruit vegetables etc. If the test is positive in urine sample

we know that the system suffers from an ionic metal overload and that the body cannot cope with

ionic metals.

2.2.4 Cations and Anions Determination

A variety of analytical methods are available for this determination. In the separation and

determination of cations and anions, inorganic and organic ions, the “Ion Exchanged

Techniques” can be applied. Moreover, the rapid estimation of certain constituents in water

could be done by “Selective Ion Electrode Method”. These methods can be applied to remove

interfering ions, determine total ion content, indicate approximate volume of sample for certain

gravimetric determination and concentrate trace quantities of anions for analysis. These methods

are not only recommended by the standard method (STM) but have also been employed

successfully by some researchers.

2.2.5 Organic Compounds

40

Analytical methods used for the determination of organics involve an extraction and

concentration process followed by separation and detection with laboratory equipment. The

techniques employed include. Thin Layer Chromatography (TLC), Gas Chromatography (GC)

coupled with Flame Ionization Detection (FID) Election Capture Detection (ECD), Nitrogen

Phosphorus Detection (NPD), Flame Photometric Detection (FPD), Mass Spectrometry (MS) or

Atomic Absorption Spectrometry (AAS), and High Performance Liquid Chromatography

(HPLC) as well as Reverse Phase HPLC.

2.2.6 Alkalinity, Acidity, Chlorides and Hardness

These parameters are usually determined by titrimetric techniques of analysis. This

traditional method of analysis involves a volumetric reaction between the substance to be

measured and solution of a reagent of known concentration. When the amount of the reagent

added equals chemically with the substance being determined, the equivalent point or theoretical

endpoint (or stoichiometric endpoint) has been reached. This endpoint is identified by an

indicator, by way of a colour change. At this point the weight of the substance can be calculated

usually from the volume and concentration of the standard solution. The titrimetric method,

though an old method of chemical analysis is very reliable if all the conditions are well observed.

Probably, the most broadly applicable approach to making chemical measurement is

titrimetry or litrimetric analysis, sometimes called volumetric analysis, the wide adoption of

titrimetric methods is a result of their several practical advantages. They are highly precise,

accurate and rapid and often require only simple and inexpensive equipment.

Acidity and alkalinity of water samples are titrimetrically determined by neutralization

reactions of acids with alkalis which involve the following reaction .

OHH H20

The carbonates and bicarbonates exist in equilibrium with carbon-dioxide in accordance

with the following equation.

23

2

3COHCOCO

In natural waters alkalinity is estimated by titrating with standard acid to the bicarbonate

equivalence point of pH 8.3. On the other hand, acid pollutants entering a water supply in

sufficient quantity will disturb the carbonate-bicarbonate-carbon dioxide equilibrium shown

41

above. The extent of this disturbance can be estimated by titrating with standard alkali to the

endpoint range of pH 4.5 and pH 8.3.

The determination of halides (e.g. chloride ions) in water and the hardness of water

require the use of precipitation and complexometric methods.

2.2.7 Bacteriological Examination

The bacteriological analysis of water can confirm whether a water supply has been

faecally contaminated. The E. coli count is the most useful test for detecting faecal

contamination of water supplies in water quantity analysis. Two principal techniques are

available for counting faecal coliforms.

2.2.7.1 Membrane filtration

In this technique, a 100ml water sample or a diluted sample is filtered through a

membrane filter. The membrane with the coliform organisms on it is then cultured on a pad of

sterile selective broth containing lactose and an indicator. After incubation, the number of

coliform colonies can be counted. This gives the presumptive number of E. coli in the 100ml

water sample.

2.2.7.2 Multiple tube/Most Probable Number (MPU)

In this technique, a 100ml water sample is distributed (five 10ml amounts and one 50ml

amount) in bottles of sterile selective culture broth containing lactose and an indicator. After

incubation, lactose fermentation with acid and gas production has occurred are counted. The

lactose is fermented by the coliform in the water. By reference to probability tables, the most

probable number of coliforms in the 100 water sample can be estimated.

2.2.7.3 Choice of Technique

The membrane filtration technique is recommended for its accuracy, speed of result and

because it can be performed in the field. The membrane technique is significantly more accurate

than the multiple tube technique and this may be important when attempting to decide whether a

42

slightly contaminated unchlorinated water source is fit for consumption. The multiple tube

technique, an E. coli colony count can be obtained in 12 – 18 hours and does not depend on the

use of probability tables. The multiple tube/MPN technique requires up to 48 hours to obtain a

presumptive E. coli count and biochemical confirmation may be required. The multiple

tube/MPN technique is less expensive than the membrane technique; although large quantities of

culture media and glassware are required and also a relatively large capacity autoclave. For the

filtration technique, smaller amounts of media and other laboratory wares are required. The

membrane filtration technique is not suitable for turbid water samples due to membrane

clogging.

2.2.8 Sampling techniques and preservation

A total of 26 samples were taken during the dry season of January and another 26 during

the wet season of August. Water samples were collected by drawing water out of the well with a

rubber bag fastened to a long rope. The water samples obtained were poured into five white

plastic containers of 100 mls each. The samples from boreholes were obtained by collecting the

water samples through taps nearest to the source. Spring water samples were collected from the

sources which are channeled by the help of pipes inserted into the issuing holes for Asho and

Ajie springs. Samples from Iyi-Adoro were collected directly from the water trough after

clearing the water surface of dead leaves.

The sample was used to rinse the plastic containers on the sampling site before collecting

the ones to be analysed to ensure the collection of a clean uncontaminated sample. These

containers were labeled appropriately from numbers one to thirteen, with each number

representing the sources of collection. The plastic water containers for heavy metal analysis were

additionally rinsed with HNO.

The appearance of the water was recorded and the environmental conditions of the wells

were also noted. The dept of the wells were also obtained from the owners. Within the

limitations of the facility available, samples were as strictly as possible handled and preserved as

recommended by standard methods by APHA-AWWA-NPCF (reenberg, 1992).

43

Table 2.2: Alpha-AWWA-NPCF requirements for sampling and handling/preservation

(Greenberg, 1992).

Parameter Container Sample

size

Preservation Maximum

storage

pH Plastic, glass Not stated

in cited

reference

Analysed

immediately

2hrs

/immediately

Nitrate Plastic, glass 25 Add H2SO4 to pH <

2, refrigerate

None /28 days

Chloride Plastic, glass 50 Analyse immediately Not stated in

cited reference

Hardness Plastic, glass 100 Add HNO3 to pH < 2 6 months /6m

Suspended

solid

Plastic, glass 100 Immediately Not stated in

cited reference

Total dissolved

solid

Plastic, glass 100 Analysed

immediately

Not stated in

cited reference

Heavy metals Plastic, glass

rinsed with

HNO3

Not stated

in cited

reference

Add HNO3 to pH < 2 6 months /6m

2.2.9 Physicochemical parameters

2.2.9.1 Appearance

Water for most applications should be clear, free of particulate. A first step towards the

assessment of the quality of a water sample is to visually inspect it for colour and suspended

matter. Presence of particles may suggest microbial growth.

2.2.9.2 Determination of pH value

Principle:

The pH of an aqueous solution is defined by the expression.

][log10

HpH

44

Where [H+] is the mole concentration of hydrogen ion in the solution. The pH of water is

one of the most important water quality parameters it is a measure of acidity or alkalinity of

water. An optimal pH range is necessary to ensure clarification, disinfection and minimize

corrosion of pipes. The pH of most natural water falls within the range of 4 to 9. The pH values

outside the limit can result in the contamination of the water and adverse effect on the taste,

odour and appearance.

Procedure

The glass electrode of pH determination is the standard technique used in this

investigation. The pH meter was standardized using pH 4 and pH 7 of buffer solutions at 20oC.

The pH knobs were switched off and the glass electrode was also removed from the buffer

solution. The electrode was rinsed with distilled water and tip of the electrode was dried with

soft tissue paper. The clean and dried glass electrode was inserted into the water sample, the pH

Knob was switched on, and the pH value was read directly from the scale (Greenberg, 1992).

2.2.9.3 Conductivity

This is the property of a solution to conduct electricity. The larger the number of ionic

constituents in a sample of water, the larger is its conductivity. Conductivities are measured in

the field and at the laboratory using conductivities meter and it is commonly expressed on

Siemens per centimeter (Scm-1

) or micro Siemens per centimeter (Uscm-1

). The meter was

standardized with 0.01m KCl. The Harch Model C50 digital multirange meter was used.

2.2.9.4 Total hardness

Principle

Originally water hardness was understood to be a measure of the capacity of water to

precipitate soap, but in conformity with current practice, total hardness is defined as the sun of

the calcium and magnesium concentrations, both expressed as calcium carbonate in milligrams

per litre (mg /l). The significance of this analysis is to check if the water is hard, so as to know

the kind of treatment the water will be subjected to.

Reagent

45

1) Buffer solution (pH 10)

This was prepared by missing 16.9g of ammonium chloride (NH4Cl) in 143ml of NH40H,

plus 1.79g of disodium salt of EDTA, and 0.780g MgS04.7H20 mixed in 50ml distilled water.

This solution was them distilled to 250ml with distilled water.

2) Standard calcium solution

About 1g calcium carbonate (CaCO3) was placed in a 500ml Erlenmeyer flask, 1.1 HCl

was added through a funnel until all the CaCO3 dissolved. About 200ml of distilled water was

added and boiled for a few minutes to expel all the CO2. The solution was cooled and a few

drops of methyl red indicator added, the intermediate methyl orange colour was adjusted by the

addition of a few drops of 3N NH40H solution. The solution was transferred to a 1 litre flask and

made up to mark. This solution was used to standardize the EDTA solution according to the

procedure below (Welcher, 1965).

Procedure

About 50ml of sample was placed in Erhenmeyer flask, 1ml of buffer added to it and 2

drops of indicator, (Eriochromic Black 1) was added and titrated with EDTA solution within 5

minutes (for standardization, 25ml of calcium solution was diluted to 5ml). The endpoint is

indicated by the change from reddish tinge to blue-green colour.

Calculation

sampleml

xBxALCaComgasEDTAHardness

1000/)(

3

Where A = ml titration for sample

B = mg CaCo3 equivalent to 1ml EDTA titrant

2.2.9.5 Total Dissolved Solids (TDs)

Principle:

It is the expression used to describe the total amount of minerals dissolved in a water

sample. TDS is commonly expressed in ppm (part per million or mg/l). Water with high

46

dissolved solid greater than 500ppm often have a laxative effect upon people whose bodies are

not adjusted to them.

Anions

Chloride

Reagents

1) Potassium chromate indicator solution. This was prepared by dissolving 50g of K2CO4 in

a little distilled water, AgNO3 solution was added to it until definite red, precipitate was

formed. It was left to stand for about 12hours; it was then filtered and diluted to 1litre.

2) Standard AgNO3 (0.014) solution. This was prepared by dissolving 2.395g AgNO3 in

distilled water and then diluted to1litre

3) Standard sodium chloride prepared by dissolving 0.824g NaCl (previously dried at

140oC) in distilled water and then diluted to 1 litre.

4) 0.1N sodium hydroxide solution standardization of silver nitrate (AgNO3) solution 25ml

of the NaCl solution was diluted to 50ml, 1ml of 0.1N NaOH added to it to being the

sample to pH 7-10, 1ml of K2CrO4 indicator solution was added and titrated against

AgNO3 solution to pinkish-yellow coloration end-point.

Procedure

About 50ml of the sample was taken in a conical flask and was titrated as the standard

above. A blank titration was also determined as the standard.

47

Calculation

sampleml

xBALClMg

450,35/

Where

A = ml titrant for sample

B = ml titrant for blank

N = normality of AgNo3

Note: (Mg–NaCl / L = Mg – Cl /L x 1.65) (Haris et al, 1981).

2.2.9 Nitrate

Colormetric determination of nitrate using the phenoldisudphonic acid method (Michael,

1991).

Reagents

1) Magnesium oxide (MgO)

2) Phenoldisulphonic acid reagent

This is prepared by dissolving 25g of prea while phenol in 150cm3 of 95% H2SO4 and 75cm

3 of

fuming H2SO4. Mixed and heated at 95 to 100oC for about 2 hours.

3) Ammonium citrate

This is prepared by taking 220cm conc. NH4OH and adding 5g ammonium citrate to it

then diluted to 1 litre with distilled water.

Procedure

MgO (0.029) was added to the simple (about 10-25mls) and was evaporated to dryness in

a beaker containing about ½ inch of clean sand, which was heated gently. The dried sample was

added about 0.5cm3 phenoldis sulphonic acid reagent. The tube was rotated in order to wet the

entire residue with the reagent, and it was placed on boding water for 10 minutes.

On cooling the tube, about 9.5cm of dilute solution of ammonium citrate was added to it.

The intensity of the yellow colour developed was measured in a photoelectric colorimeter of 410

nm using a blue fitter of 470/420 Erma filter range standard curve.

48

Standard solutions of nitrate containing 0, 2.5, 5, 10, 15 and 20 ppm NO3 was prepared

and dispensed into test-tubes accordingly, 2cm3 of each was pippetted into a test-tube, and 0.02g

of MgO was added to develop the colour.

Calculation

443/

/

3xNnitrateLMgNOLMg

sampleml

NnitrateNnitrateLMg

2.2.10 Heavy Metals

2.2.10.1 Determination of Lead colorimetric sulphide method (Baldwin et al 1999).

Reagents:

10% tartaric acid-for blank and control

1:2 Ammonium citrate

10% sodium sulphide

Lead standard 0.160g Pb (NO3)2

(10cm3 was diluted to 100cm

3 = 0.1mg /cm

3.

Procedure

To 10cm3 Tartaric acid, add aliquot of sample 5cm

3 to 10cm

3, add 1cm

3 of 10% KCN,

add 10-25cm3 of 1:2 Ammonia and mix well, add 0.5cm

3 10% Na2S and make up volume to

50cm3 with distilled water. Keep for 10 minutes.

Read at 430nm, using blank to zero.

Prepare a calibration curve with standard Pb (NO3)2 solution.

Readings are extrapolated from the curve.

2.2.10.2 Determination of cadmium using xylenol orange as indicator and read colour at

510nm (Baldwin et al 1999).

Reagents

EDTA – 0.05m

Xylenol orange indicator

49

Cadmium ion solution about 0.05m

Weigh out accurately 3.21g of cadmium

Sulphate (3 Cel SO4.8H20) and dissolve it in 250cm3 of distilled water in volume five flask.

Procedure

Dilute 25cm3 (suitable aliquot) of the cadmium ion solution with 50cm

3 of d-H20. Add 3

drops of the indicator, 1 drop of dilute H2SO4; the solution turns yellow. Add powdered

Hexamine with agitation until the colour is deep red. Titrate with standard EDTA, slowly near

the end-point to a colour change from red to yellow.

Calculation 1cm3 0.05m EDTA = 5.621mg

Factor 1cm3 of 0.15N EDTA = 0.8431mg.

2.2.10.3 Determination of Arsenic in sodium Arsenite solution (Baldwin et al 1999).

This is an example of iodometric determination of reducing agents. This determination is

based on the reaction.

HIASOOHIASO

OR

HIASONaOHIASONa

22

2

4223

432233

Na3 ASO3 solution is usually prepared by dissolution of AS2O3 in NaOH.

OHASONaNaOHOAS23232

326

Procedure

Put the arsenic solution into a 250cm3 conical flask, dilute with about 70-100cm

3 d-H2O

and neutralize it with 2N H2SO4 in the presence of 2 drops of phenolphthalein indicator until the

pink colour vanisshes. Then add 4-5gm solid NaHCO3 into the solution in flask, shake or stir to

get NaHCO3 dissolved. An aliquot arsenic solution may be used for titration. Add 1-2cm3 of 1%

starch solution. Titrate the solution with standardize iodine solution to a stable blue end-point.

Calculation

50

Remember that trivalent arsenic is oxidized, yielding two electrons, the gram equivalent

of arsenic is:

gAsegg 46.372

92.74

2.2.10.4 Determination of zinc using Zincon method (Baldwin et al 1999).

Reagents

Std zinc solution: 1ml = 10ug Zinc.

Sodium ascorbate

Potassium cyanide solution: 1g of KCN dissolved in 50ml D-H2O and diluted to 100ml.

Buffer solution: 1N NaOH

Zincon reagent: 130mg Zincon powder dissolved in 100ml methyl alcohol.

Chloral hydrate solution: 10g chloral hydrate dissolved in 50ml D-H2O and diluted to

100ml

Hydrochloric acid (Conc)

Sodium Hydroxide 6N.

Procedure

Colorimetric standards were prepared serially from 2.5mg – 50μg in Erlenmeyer flasks,

each 10ml volume. To each flask 0.5g sodium ascorbate was added, followed by 1ml KCN

solution in sequence, 5ml buffer solution and 3ml zincon solution. The flask was thoroughly

mixed after each addition. Chloral hydrate (3ml) was added and time noted. The absorance at

620nm exactly 5 min after adding the chloral hydrate solution was carried out.

Calculation:

Zn (Mg/l) = Sampleml

Zng

Reagents

Standard nickel sulphate solution im = 100mg Ni.

Hydrochloric acid (IN)

51

Bromine water.

Ammonium hydroxide (NH4OH) Conc

Heptoxime reagent 0.1g heptoxime dissolved in 100ml, 95% ethyl alcohol.

Ethyl alcohol 95%

Chloroform (CHCl3)

Sodium Tartrate solution (10g Na2C4H4O6.2H2O) in 90ml D-H2O.

Procedure

Portions of the standard nickle sulphate solutions were pipetted into 100ml volumetric

flasks. The series cover from 50 - 250μg Ni, 25ml IN HCl and 5ml bromine water were added.

After cooling under running tap water, 10ml conc. NH4OH was added, and to it 20ml heptoxime

reagent and 20ml ethyl alcohol were added and mixed.

Absorbance at 445nm, 20 mins after addition of the reagent was taken using of course a

reagent blank as reference.

CHAPTER THREE

RESULTS

3.1 Effect of pH on Different Water Sources Compared to WHO and NAFDAC

52

The result as shown in Fig. 3.1 shows significant difference (P<0.05) in pH value of water

sources from borehole, dugwell and spring when compared with both the standards of World

Health Organization (WHO) and National Agency of Food and Drug Administration Control

(NAFDAC). However, there was no significant difference (P>0.05) in pH values across

borehole, dugwell and spring. The figure below also shows a relatively higher standard pH value

of WHO (7.0–8.9) as compared with the NAFDAC standard pH value (6.5–8.5). On the other

hand, there was non-significant difference (P>0.05) in pH value between the dry and rainy

seasons of borehole, dugwell and spring water sources

7.0–8.9

0

1

2

3

4

5

6

7

8

9

Borehole Dugw ell Spring WHO NAFDAC

pH

at

20o

C

Dry Season

Rainy Season

53

Fig. 3.1: pH levels of different water samples in various sampling areas in Nsukka compared

with WHO and NAFDAC Standards

6.5 – 8.5

54

3.2 Effect of Sulphate Concentration on Different Water Sources Compared to WHO and

NAFDAC

The result in Fig. 3.2 shows no significant difference (P>0.05) in the sulphate

concentrations between water sample from borehole sources and water sample from dugwells

sources during both dry and rainy seasons. Significant increase (P<0.05) was observed in the

sulphate concentration of water sample from spring sources compared to water samples from

both borehole and dugwell sources during dry season. But there was no significant difference

(P>0.05) in the sulphate concentrations of water sample from spring sources compared to the

sulphate concentration of both boreholes and dugwells water sources during rainy season. In

comparison with WHO and NAFDAC standards, it was observed that there was significant

difference (P<0.05) in the sulphate concentration between WHO standard (250mg/L) and water

samples from the three test samples (borehole, dugwell and spring sources) during both dry and

rainy seasons. Also significant difference (P<0.05) exists in the sulphate level between

NAFDAC standard value (100mg/L) and all other test samples (borehole and dugwell sources)

with the exception of spring water sample which shows no significant difference (P>0.05) in the

sulphate concentration when compared with the NAFDAC standard.

55

Fig. 3.2: Sulphate concentration of different water sources in Nsukka compared with WHO and

NAFDAC Standards

250mg/L

100mg/L

56

3.3 Effect of Total Suspended Solid on Different Water Sources Compared to WHO And

NAFDAC

Total suspended solid concentration of water samples from dugwell sources was found to

have significant increase (P<0.05) when compared with the water samples from the other test

water samples from borehole and spring sources during both dry and rainy seasons (as shown in

Fig. 3.3). There was no significant (P>0.05) difference in the total suspended solid level between

the dry season and rainy season of all test samples when considering different seasons. Likewise,

the water samples from borehole and spring sources showed no significant difference (P>0.05) in

the level of total suspended solid as shown in Fig. 3.3. The levels of total suspended solid in the

two standards (WHO and NAFDAC) are found to be relatively higher than the three test samples

(borehole, dugwell and spring).

57

Fig. 3.3: Total suspended solid (mg/L) concentration of different water sources in Nsukka

compared with WHO and NAFDAC Standards

0

5

10

15

20

25

30

35

Borehole Dugwell Spring WHO NAFDAC

To

tal

Su

sp

en

de

d S

oli

d (

mg

/L)

Dry Season

Rainy Season

30mg/L 30mg/L

58

3.4 Effect of Zinc on Different Water Sources Compared to WHO And NAFDAC

Fig. 3.4 shows a relatively low concentration of zinc in all the test water samples from all

the water sources (borehole, dugwell and spring). In other words, there was no significant

difference (P>0.05) in the concentration of zinc when carrying out comparison in all the test

samples. There was significant difference (P<0.05) in the level of zinc concentration between the

two standards (WHO and NAFDAC) and water samples from the three test samples as shown in

Fig. 3.4.

59

Fig. 3.4: Zinc (mg/L) concentration of different water sources in Nsukka compared with WHO

and NAFDAC Standards

3mg/L

5mg/L

60

3.5 Effect of Total Dissolved Solid Concentration on Different Water Sources Compared to

WHO and NAFDAC

Total dissolved solid concentration, as shown in Fig. 3.5, was found to be significantly

higher (P<0.05) in the water sample from dugwell sources when compared with the total

dissolved solid concentration in the water samples from both borehole and spring sources during

both dry and rainy seasons. In terms of seasonal comparison, the total dissolved solid

concentration of water sample from spring source during rainy season was observed to be

relative higher than that observed during the dry season. However, significant difference

(P<0.05) was also observed between the two standards and the test water samples from the three

sources (borehole, dugwell and spring) during both dry and seasons. Comparatively, Fig. 3.5

shows that the two reference standards (WHO and NAFDAC) have the same value (500mg/L) of

total dissolved solid.

61

Fig. 3.5: Total dissolved solid (mg/L) concentration of different water sources in Nsukka

compared with WHO and NAFDAC Standards

0

100

200

300

400

500

600

Borehole Dugw ell Spring WHO NAFDAC

To

tal D

isso

lved

So

lid

(m

g/L

)

Dry Season

Rainy Season

500mg/L 500mg/L

62

3.6 Effect of Total Hardness Concentration on Different Water Sources Compared to

WHO and NAFDAC

Fig. 3.6 shows significant increase (P<0.05) in the level of total hardness in the water

sample obtained from dugwell sources as compared with water samples from borehole and

spring sources during dry and rainy seasons. Also, there was significant increase (P<0.05) in the

level of total hardness of water sample from borehole sources when compared with the spring

sources during dry and rainy seasons. There was no significant difference (P>0.05) in the level of

total hardness when comparing between the dry and rainy seasons across the test water samples

from the three test sources (borehole, dugwell and spring). The standards (WHO and NAFDAC)

had relatively higher values (100mg/L each) of total hardness compared to the test samples. But

the two reference standards (WHO and NAFCON) have the same level of total hardness as

shown in Fig. 3.6 above.

63

Fig. 3.6 Total hardness (mg/L) concentration of different water sources in Nsukka compared

with WHO and NAFDAC Standards

0

20

40

60

80

100

120

Borehole Dugw ell Spring WHO NAFDAC

To

tal H

ard

ness (

mg

/L)

Dry Season

Rainy Season

100mg/L 100mg/L

64

3.7 Effect of Chloride Concentration on Different Water Sources Compared to WHO and

NAFDAC

The chloride (mg/L) concentration of all test samples from all the three water sources

(borehole, dugwell and spring) were found to be no significant (P>0.05) during both seasons.

Though slight increase was observed in the level of chloride concentration in the water sample

from borehole sources during dry and rainy seasons but was considered non-significant (P>0.05).

On the other hand, chloride concentration was observed to be relatively higher in WHO standard

(200mg/L) compared to NAFDAC standard (100mg/L); indicating that the chloride

concentration in WHO doubles that of NAFDAC as shown in Fig. 3.7. There was significant

difference (P<0.05) in the level of chloride concentration when comparing the standards (WHO

and NAFDAC) and the test samples (borehole, dugwell and spring).

0

50

100

150

200

250

Borehole Dugwell Spring WHO NAFDAC

Ch

lori

de (

mg

/L)

Dry Season

Rainy Season

65

Fig. 3.7: Chloride (mg/L) concentration of different water sources in Nsukka compared with

WHO and NAFDAC Standards

200mg/L

100mg/L

66

3.8 Effect of Nitrate Concentration on Different Water Sources Compared To WHO and

NAFDAC

Fig. 3.8 shows no significant difference (P>0.05) in the level of nitrate concentration

when carrying out comparison between the two reference standards (WHO and NAFDAC) and

water samples from borehole and dugwell sources during both dry and rainy seasons. Borehole

and dugwell water sources had nitrate concentrations that were found to be significantly higher

(P<0.05) than nitrate concentrations obtained in the water sample from spring sources during dry

and rainy seasons. Nitrate concentrations in the water samples of dugwell and spring sources

during dry season were found to be relatively lower than the nitrate concentrations in the water

samples of dugwell and spring during rainy season; though no significant (P>0.05). The nitrate

concentration of water sample from spring sources had significant decrease (P<0.05) as

compared with the two reference standards (WHO and NAFDAC).

0

2

4

6

8

10

12

Borehole Dugw ell Spring WHO NAFDAC

Nitra

te (

mg/L

)

Dry Season

Rainy Season

67

Fig. 3.8: Nitrate (mg/L) concentration of different water sources in Nsukka compared with WHO

and NAFDAC Standards

3.9 Effect of most Probable Number of Coliform on Different Water Sources Compared to

WHO and NAFDAC

10mg/L 10mg/L

68

Most probable number of coliform was found to be significantly higher (P<0.05) in the

three test water samples (borehole, dugwell and spring) during the rainy seasons as compared

with the dry season. The most probable number of coliform in the water sample of spring sources

during rainy season showed significant increase (P<0.05) as compared with the two reference

standards (WHO and NAFDAC). Both WHO and NAFDAC had relatively the same range of

most probable number of coliform range of values (1 – 10 npm). The standards (WHO and

NAFDAC) had most probable number of coliform count to be significantly higher (P<0.05) than

that of the water samples from the test sources with the exception of most probable number of

coliform count obtained in water samples from spring sources during rainy season.

0

2

4

6

8

10

12

14

16

Borehole Dugw ell Spring WHO NAFDAC

Mo

st

Pro

bab

le N

um

ber

of

Co

lifo

rm /100m

l

Dry Season

Rainy Season

69

Fig. 3.9: Most probable number of coliform of different water sources in Nsukka compared with

WHO and NAFDAC Standards

CHAPTER FOUR

4.1 Discussion

1 – 10 mpn 1 – 10 mpn

70

The heightened concern for reduction of environmental pollution (especially water) that

has been occurring over the past 20–25 years has stimulated active continuing research and

literature on the toxicology of heavy metals. While the toxic effect of these substances is a

widespread concern in the modern industrial context, man has succeeded in poisoning himself

with them repeatedly throughout recorded history. Virtually all metals can produce toxicity when

ingested in sufficient quantities, but there are several which are especially important because

either they are so pervasive, or produce toxicity at such low concentrations. In general heavy

metals produce their toxicity by forming complexes or "ligands" with organic compounds. These

modified biological molecules lose their ability to function properly, and result in malfunction or

death of the affected cells. The most common groups involved in ligand formation are oxygen,

sulfur, and nitrogen. When metals bind to these groups they make inactive important enzyme

systems, or affect protein structure.

Various physico-chemical parameters were studied and are given in the different figures

in Chapter three. Different physical parameters studied are total suspended solids and total

dissolved solids. Different chemical parameters studied are pH, alkalinity, total hardness, zinc,

chloride and sulphate with extension to the number of coliforms. The values were compared with

the WHO and NAFDAC standard values which are given in the same figures (Figures 3.1 to

3.9). The results indicate that the quality of water considerably varies from location to location.

Water quality in Nsukka area of Enugu State of Nigeria is spatially variable and has been

impacted by some contaminants which are mostly organic. The result as shown in Fig. 3.1 shows

that all the water samples from all samples sources/locations were found to fall below 7.0. The

most acidic among the water sources was found to be water samples from borehole sources (pH

of 5.0) during dry season. Interestingly, the result as shown in Fig. 3.1 also indicated relative low

pH values of water samples from all water sources during dry season. Water samples from

dugwell sources had (pH of 5.8) during rainy season. This was closely followed by water sample

from spring sources (pH of 5.7) during rainy season. However, there was no significant

difference (P>0.05) in pH values across borehole, dugwell and spring. In comparing the pH

value of WHO (7.0–8.9) with that of NAFDAC standard (6.5–8.5), it was discovered that all

71

water samples from all sources had closer values to NAFDAC. It could be deduced that since the

pH values in the result indicated pH values below 7, the water could be corrosive to plumbing,

resulting in lead leaching into tap water.

Sulphate concentration of water sample from spring sources increased significantly

(P<0.05) during dry season when compared with that of dry season. This may be attributed some

sulphur-containing contaminants in the environment during dry season. Also, the concentration

of sulphur increased (though not significant) during dry season in dugwell when compared with

the sulphur concentration during rainy reason. Generally, dugwells are at higher risk of

contamination than drilled wells because they obtain water from shallow groundwater aquifers,

and contaminants are more likely to be found closer to the surface, especially during dry season.

However, in comparison with WHO and NAFDAC standards, it was observed that there was

significant difference (P<0.05) in the sulphate concentration between WHO standard (250mg/L)

and water samples from the three test samples (borehole, dugwell and spring sources) during

both dry and rainy seasons. Levels of sulfate in rainwater and surface water correlate with

emissions of sulfur dioxide from anthropogenic sources (Keller and Pitblade, 1986; WHO,

2004). WHO (2003) in its documentary tiltled „Background document for preparation of WHO

Guidelines for drinking-water quality‟stated that sulphates occur naturally in numerous minerals

and are used commercially, principally in the chemical industry. They are discharged into water

in industrial wastes and through atmospheric deposition; however, the highest levels usually

occur in groundwater and are from natural sources. In general, the average daily intake of sulfate

from drinking-water, air and food is approximately 500mg, food being the major source.

However, in areas with drinking-water supplies containing high levels of sulfate, drinking-water

may constitute the principal source of intake.

The replacement of forestland with impervious surfaces during urbanization can have

significant effects on watershed hydrology and the quality of stormwater runoff. One component

of water quality, total suspended solids (TSS), is both a significant part of physical and aesthetic

degradation and a good indicator of other pollutants, particularly nutrients and metals that are

carried on the surfaces of sediment in suspension. A TSS turbidity relationship can be affected

by water colour from dissolved organic compounds which can absorb more light than inorganics

(Packman et al., 1999). In Fig. 3.5, it was observed that total suspended solid concentration of

72

water samples from dugwell sources was found to have significant increase (P<0.05) when

compared with the water samples from the other test water samples obtained from borehole and

spring sources during both dry and rainy seasons. Total Suspended Solids (TSS) are solids in

water that can be trapped by a filter. TSS can include a wide variety of material, such as silt,

decaying plant and animal matter, industrial wastes, and sewage. High concentrations of

suspended solids can cause many problems for stream health and aquatic life. This could also be

attributed to the fact that dugwells are at higher risk of contamination than drilled wells because

they obtain water from shallow groundwater aquifers, and contaminants are more likely to be

found closer to the surface. There was no significant (P>0.05) difference in the total suspended

solid level between the dry season and rainy season of all test samples when considering

different seasons.

Total dissolved solids (TDS) is the term used to describe the inorganic salts and small

amounts of organic matter present in solution in water (WHO, 1996). Water with extremely low

concentrations of TDS may also be unacceptable because of its flat, insipid taste (WHO, 1996).

Total dissolved solid concentration was found to be significantly higher (P<0.05) in the water

sample from dugwell sources when compared with the total dissolved solid concentration in the

water samples from both borehole and spring sources during both dry and rainy seasons. This

may be attributed to the principal constituents which are usually calcium, magnesium, sodium,

and potassium cations and carbonate, hydrogencarbonate, chloride, sulfate, and nitrate anions, as

outlined by WHO (1996), found in the surrounding environmental sources where the dugwells

are located. The result as shown in Fig. 3.5 showed that concentration threshold of total

dissolved solids (TDS) fell below 300 mg/litre. This is consistent with the findings of WHO

(1996) which stated that the palatability of drinking water has been rated by panels of tasters in

relation to its TDS level as follows: excellent, less than 300 mg/litre; good, between 300 and 600

mg/litre; fair, between 600 and 900 mg/litre; poor, between 900 and 1200 mg/litre; and

unacceptable, greater than 1200 mg/litre.

Stone and Droppo (1994) suggest suspended solids probably act as the primary transport

mechanism for pollutants and nutrients in streams through flocculation, adsorption and colloidal

action.

Zinc concentration was found to be in trace amount (almost absent) which indicates

relatively low concentration of zinc metal in all the test water samples from all the water sources

73

(borehole, dugwell and spring). This indicates that non-significant difference (P>0.05) exists in

the concentration of zinc when carrying out comparison in all the test samples. In natural surface

waters, the concentration of zinc is usually below 10 μg/litre, and in groundwaters, 10–40

μg/litre (Elinder, 1986). In tapwater, the zinc concentration can be much higher as a result of the

leaching of zinc from piping and fittings (Nriagu, 1980). The most corrosive waters are those of

low pH, high carbon dioxide content, and low mineral salts content. In a Finnish survey of 67%

of public water supplies, the median zinc content in water samples taken upstream and

downstream of the waterworks was below 20 μg/litre; much higher concentrations were found in

tapwater, the highest being 1.1 mg/litre (WHO, 1986). Even higher zinc concentrations (up to 24

mg/litre) were reported in a Finnish survey of water from almost 6000 wells (WHO, 1986).

Drinking water high in nitrate is potentially harmful to human and animal health. Nitrate

(NO3) is a naturally occurring form of nitrogen (N) which is very mobile in water. It is essential

for plant growth and is often added to soil to improve productivity. In this way, nitrate enters the

water supplies of many homeowners who use wells or springs. It is estimated that about three

percent of residential wells in North Carolina contain nitrate at levels exceeding the safe drinking

water standard (Jennings et al., 1996). Nitrate concentration was found to be non-significant

difference (P>0.05) when carrying out comparison between water samples from borehole and

dugwell sources during both dry and rainy seasons. However, significant increase (P<0.05) was

observed in the water samples of borehole and dugwell as compared to the water sample of

spring source especially during rainy season. This may be due water moving down through soil

after rainfall or irrigation carries dissolved nitrate with it to ground water (Jennings et al., 1996).

Water sample from dugwell sources had showed significant increase (P<0.05) in the level

of total hardness as compared with water samples from borehole and spring sources during dry

and rainy seasons. Also, there was significant increase (P<0.05) in the level of total hardness of

water sample from borehole sources when compared with the spring sources during dry and

rainy seasons. Geetha et al (2008) attributed total hardness contamination on the probable

effluent effect, though it affects the ground water, and it has no adverse effect on human health.

In most of the samples, total hardness value exceeds the tolerance limit; this may be due to

industrial discharge of the effluents on to the land.

The chloride (mg/L) concentration of all test samples from all the three water sources

(borehole, dugwell and spring) were found to be non-significant (P>0.05) during both dry

74

seasons. Though slight increase was observed in the level of chloride concentration in the water

sample from borehole sources during dry and rainy seasons but was considered non-significant

(P>0.05). On the other hand, chloride concentration was observed to be relatively higher in

WHO standard (200mg/L) as compared with NAFDAC standard (100mg/L); indicating that the

chloride concentration in WHO doubles that of NAFDAC as shown in Fig. 3.7. There was

significant difference (P<0.05) in the level of chloride concentration when comparing the

standards (WHO and NAFDAC) and the test samples (borehole, dugwell and spring).

The sample collected from borehole was found to have relatively higher, though non-

significant (P>0.05), chloride concentration when compared with water samples from dugwell

and spring. It may be due to the presence of soluble chlorides from rocks/hills as Nsukka is

known for its hilly nature. This is consistent with findings of Jain and Bhatia (1988) and Geetha

et al. (2008) who attributed slight increase of chloride concentrations from rocky and hilly

sources.

The research findings as indicated in Fig. 3.8 showed non-significant difference (P>0.05)

in the level of nitrate concentration between water samples from borehole and dugwell sources

during both dry and rainy seasons. But significant increase (P<0.05) of nitrate concentration was

observed when carrying out comparison between water samples from borehole and dugwell, and

water samples from spring water source. This may be attributed to the fact that nitrite/nitrate

being a chemical, could have seeped into the drinking water from sources such as fertilizer,

sewage, feed lots and other geological elements in the surrounding environment. It should also

be noted that nitrate of over 10 ppm (or more than 50 milligrams per liter nitrate-nitrogen) has

the potential to reduce the amount of oxygen available to the fetus in pregnant women causing

"Blue Baby Syndrome" (methemoglobulinemia) (Feig, 1981). However, there was no significant

difference (P>0.05) in nitrate concentration found in samples from borehole and dugwell sources

when compared with the standard values of WHO (10 mg/L) and NAFDAC (10 mg/L). Hence, it

could be deduced that water sources from Nsukka environ are safe to drink in terms of nitrate

concentration.

In terms of seasonal variation, the result x-rayed the fact that most probable number of

coliform was found to be significantly higher (P<0.05) in all the three test water samples

(borehole, dugwell and spring) during the rainy seasons as compared with the dry season. The

most probable number of coliform in the water sample of spring sources was found to have the

75

highest significant increase (P<0.05) during the rainy season. This may be as a result of possible

contamination of spring water sources with sewage from immediate surroundings of Nsukka

environ. The coliform group is an indicator bacteria to evaluate the quality of drinking water and

any presence of coliforms indicates the contact of water with sewage or inadequate

treatment/post treatment contamination. In unpiped water supplies, sometimes up to 10

coliforms/100 ml are as allowed per WHO standards for tropical countries but this should not

occur repeatedly; if occurrence is frequent and sanitary conditions cannot be improved, an

alternative source must be found if possible (Geetha et al., 2008).

4.2 CONCLUSION

Therefore, from the foregoing, it could be concluded that these boreholes, springs and

drugwells water samples tested in Nsukka town are physicochemically good for human

consumption as all the physicochemical parameters tested conformed to WHO, SON, and

NAFDAC water quality standards, although Iyi-adoro spring water might not be very good for

consumption during the rainy season because of possible bacteria contamination.

76

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