The entire work is dedicated to my beautiful and lovely ...

CHARACTERIZATION OF THE GEOPHAGIC MATERIALS AND THEIR

OVERLYING ROCKS AND SOILS FROM ANFOEGA, GHANA

THIS THESIS IS SUBMITTED TO THE UNIVERSITY OF GHANA, LEGON IN

PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF

MASTER OF PHILOSOPHY IN SOIL SCIENCE

BY

JUSTICE KWESI BADU

10507248

JULY, 2016

http://ugspace.ug.edu.gh/

i

DECLARATION

I hereby declare that this thesis “Characterization of the geophagic materials and their

overlying rocks and soils from Anfoega, Ghana” has been written by me and that it is the

record of my own research work. It has neither in whole nor in part been presented for

another degree elsewhere. Works of other researchers have been duly cited by references

to the authors and all assistance received also acknowledge.

……………………

JUSTICE KWESI BADU

(Student)

……………………

Dr. T. A. ADJADEH

(Supervisor)

…………………

Dr. D. E. DODOR

(Co-supervisor)


ii

ABSTRACT

Geophagy is the deliberate consumption of earth and clay deposits by animals, including

man. It is a special type of pica, which is defined as the craving and subsequent

consumption of non-food substances. This study was conducted to examine the physical,

chemical and mineralogical properties of the geophagic materials and their overlying rocks

and soils from four sites at Anfoega in order to determine possible relationships among

them and the potential human health risk associated with the consumption of the geophagic

materials. The four sites were Tokorme 1, Tokorme 2, Tokorme 3 and Wuve. Soil samples

and geophagic materials from the selected sites were subjected to the following laboratory

analyses: colour, particle size distribution, pH, electrical conductivity, cation exchange

capacity, organic carbon content and X-ray defractometry. The rock samples and

geophagic materials were also subjected to petrographic and x-ray analysis. Whereas the

pH of the soils from Tokorme 1, Tokorme 3 and Wuve ranged from slightly acidic to

moderately acidic, that of Tokorme 2 was moderately acidic in the surface soils but strongly

acidic in the lower layers. The pH of the geophagic materials was strongly acidic. While

the soil samples generally contained high amounts of sand, the geophagic materials

contained high amounts of clay. With higher amounts of clay, the CEC of the geophagic

materials ranged from 18.0 to 23.2 cmolc kg-1 which was higher than that of the soil

samples (5.3 to 22.6 cmolc kg-1). The thin sections of the rocks showed very high amounts

of quartz and small amounts of feldspars and sericite. The thin sections of the geophagic

materials on the other hand, revealed the presence of large amounts clay and some quartz,

feldspars and sericite. The x-ray diffractograms showed that the soils, rocks, and geophagic

materials were dominated by SIALIC minerals mainly quartz, kaolinite, muscovite and


iii

feldspar. The mineralogy of the soils indicated that they were derived in-situ from the

underlying sandstones. The results also showed that the high amounts of SIALIC minerals

in the geophagic materials was accumulated through leaching of the overlying sandstone.

The health risk index analysis of the geophagic materials calculated based on consumption

of 70 g of clay per day were all less than 1.0. This result indicates that the geophagic

materials were safe for human consumption. Also, the microbial analysis of the geophagic

materials showed high levels of bacteria load in the processed fresh, processed dry,

powdered and smoked samples. However, no coliform group was detected. The microbial

results showed that although the geophagic materials were naturally safe for consumption,

processing them could introduce harmful micro-organisms.


iv

DEDICATION

The entire work is dedicated to my beautiful and lovely wife Mrs. Roselyn Korkor Badu

and my beloved daughter Maame Akosua Adum.


v

ACKNOWLEDGEMENTS

I want to acknowledge the intellectual contributions and support I received from my

Supervisor, Dr. T. A. Adjadeh. I cannot think of anything connected with this work that

has not benefited from his efforts and insight. I am highly indebted to him for his

contributions, ideas and inputs that have really shaped this work. He has readily assisted

me to clarify many of the technical issues and I owe much to him for this. I am equally

indebted to my co-supervisor, Dr. Daniel E. Dodor for his useful suggestions and

cooperation. He has directly and indirectly inspired much of the effort that has gone into

this work.

I wish to sincerely thank Mr. Bernard Anipa, Chief Technician of the Department of Soil

Science for the great help he gave me during the fieldwork at Anfoega. I also wish to thank

the other Technicians, Messrs Victor Adusei-Okrah, and Martin Aggrey for their help

during the laboratory investigations.

It is a pleasure to acknowledge Professor P. M. Nude (Department of Earth Science),

Professor B. B. Kayang (Department of Animal Science), Dr. Martin Egblewogbe

(Department of Physics) and Mr Joseph Eyram Dzata (Department of Computer Science)

for their invaluable assistance offered me during my laboratory work. I am so grateful and

I appreciate everything they contributed towards the success of this project.

I am very grateful to my family for the invaluable help they gave me during the period of

the research work. I am highly indebted to my wife and daughter for their patience when I

was preoccupied with writing the thesis. My mother, Madam Akosua Adum also deserve

special recognition for her support during the period of the MPhil Programme.


vi

TABLE OF CONTENTS

DECLARATION…………………………………………………………………………i

ABSRACT………………………………………………………………………………..ii

DEDICATION ............................................................................................................................ ..iv

ACKNOWLEDGEMENTS .......................................................................................................... v

TABLE OF CONTENTS ............................................................................................................. vi

LIST OF FIGURES ..................................................................................................................... xii

LIST OF TABLES ...................................................................................................................... xiv

LIST OF ABBREVIATIONS .................................................................................................... xvi

INTRODUCTION.......................................................................................................................... 1

CHAPTER TWO ........................................................................................................................... 6

LITERATURE REVIEW ............................................................................................................. 6

2.1 Overview .......................................................................................................................... 6

2.2 Definition of Geophagy ................................................................................................... 6

2.3 Historical Overview ......................................................................................................... 7

2.4 Aetiology of Geophagy .................................................................................................... 9

2.4.1 Geophagy for Cultural and Religious Purposes ...........................................10

2.4.2 Geophagy as a Food Supplement .................................................................11

2.4.3 Soil as Medicine or Medicament .................................................................12

2.4.4 Soil as Food Additives and Detoxifier .........................................................12

2.4.5 Psychiatric and Physiological Causes of Geophagy ....................................13

2.5 Health Implications of Geophagy .................................................................................. 13


vii

2.6 Geophagy: Reports from Ghana .................................................................................... 15

2.7 Geology of the mining site at Anfoega .......................................................................... 16

2.8 Vegetation of Anfoega ................................................................................................... 17

2.9 Chemical Composition of Geophagic Materials ............................................................ 17

2.10 Mineralogical Composition of Geophagic Clays ........................................................... 18

2.11 Biological Properties of Geophagic Clays ..................................................................... 19

2.12 Effects of Microorganisms Associated with Geophagy on Humans ............................. 21

2.13 Effects of Heavy Metals Associated with Geophagy on Humans ................................. 22

2.14 Mining of Geophagic Materials Worldwide .................................................................. 23

2.15 Processing of Geophagic Materials................................................................................ 24

2.16 Marketing of Geophagic Materials ................................................................................ 24

CHAPTER THREE ..................................................................................................................... 26

MATERIALS AND METHODS ................................................................................................ 26

3.1 Site Selection and Description ....................................................................................... 26

3.2 Sample Collection and Storage ...................................................................................... 27

3.3 Physical Analysis ........................................................................................................... 29

3.3.1 Bulk Density of the Soil Samples ................................................................29

3.3.2 Particle Size Distribution .............................................................................30

3.3.3 Soil Colour ...................................................................................................31

3.4 Chemical Analysis ......................................................................................................... 31

3.4.1 pH (H2O) ......................................................................................................31

3.4.2 pH (CaCl2) ...................................................................................................32


viii

3.4.3 Electrical Conductivity ................................................................................32

3.4.4 Organic Carbon ............................................................................................32

3.4.5 Total Nitrogen ..............................................................................................33

3.4.6 Cation Exchange Capacity ...........................................................................34

3.4.7 Determination of Exchangeable Bases ........................................................35

3.4.8 Determination of Total Phosphorus .............................................................35

3.4.9 Available Phosphorus ..................................................................................36

3.4.9.1 Olsen’s Extraction Procedure ........................................................................... 36

3.4.9.2 Bray 1 Method ................................................................................................... 36

3.5 Mineralogical Analysis .................................................................................................. 37

3.5.1 Thin Section Preparation and Petrographic Examination of Rock Samples 37

3.5.2 Fractionation of Samples .............................................................................38

3.5.3 Potassium Saturation of Exchange Complexes............................................38

3.5.4 Sample Preparation ......................................................................................39

3.5.5 X-Ray diffraction .........................................................................................39

3.6 Heavy Metal Analysis .................................................................................................... 39

3.7 Microbial Analysis of the Geophagic Materials ............................................................ 41

3.8 Questionnaire to solicit information on the ingestion of the geophagic materials from

Anfoega…………………………………………………………………………………..41

CHAPTER FOUR ........................................................................................................................ 43

RESULTS ..................................................................................................................................... 43

4.1 Morphological Properties of the Soils ........................................................................... 43

4.2 Physical Properties ......................................................................................................... 46

4.2.1 Particle Size Distribution and Texture .........................................................46


ix

4.2.2 Bulk Density ................................................................................................46

4.3 Chemical Properties ....................................................................................................... 48

4.3.1 pH Water and pH Calcium Chloride of the Soils and the Geophagic

Materials…………………………………………………………………..48


4.3.3 Total Nitrogen Content of the Soils and Associated Geophagic Materials .49

4.3.4 Organic Carbon Content of the Soils and the geophagic materials .............49

4.3.5 Phosphorus Content (Total and Available) of the Soils and the Geophagic

Materials…………………………………………………………………..49

4.3.6 Exchangeable Bases and Cation Exchange Capacity of the Soils and

Geophagic Materials……………………………………...……………….52

4.4 Mineralogical Composition of the Rocks, Geophagic Materials and Soils ................... 54

4.4.1 Thin Section Petrography of Rock Samples ................................................54

4.4.1.1 Thin Section of Rock Sample from Tokorme 1 ................................................ 54

4.4.1.2 Thin Section of Rock Samples from Tokorme 2 .............................................. 55

4.4.1.3 Thin Section of Rock Samples from Tokorme 3 .............................................. 56

4.4.1.4 Thin Section of Rock Samples from Wuve ....................................................... 57

4.4.2 Thin Sections of Geophagic Materials .........................................................59

4.4.2.1 Thin Section of Geophagic Materials from Tokorme 1 ................................... 59

4.4.2.2 Thin Section of Geophagic Materials from Tokorme 2 ................................... 60

4.4.3 X-Ray Diffractograms of Rock Samples .....................................................61

4.4.4 X-Ray Diffractogram of the Geophagic Materials ......................................64

4.4.5 X-Ray Diffractograms of Soil Samples (clay fractions) ..............................66

4.5 Heavy Metal Content of the Geophagic Materials ......................................................... 69

4.5.1 Health Risk Index (HRI) Analyses of Heavy Metals in the Geophagic

Materials…………………………………………………………………..70

4.6 Microbiological Analysis ............................................................................................... 73


x

4.7 Responses from the Interviews ...................................................................................... 75

4.7.1 Miners ..........................................................................................................75

4.7.2 Dealers (women involved in the processing and marketing) .......................75

4.7.3 Health Personnel ..........................................................................................76

CHAPTER FIVE ......................................................................................................................... 77

DISCUSSION ............................................................................................................................... 77

5.1 Physical Properties ......................................................................................................... 77

5.1.1 Particle Size Distribution and Texture…………………………………….76

5.1.2 Bulk Density ................................................................................................77

5.2 Chemical Properties ....................................................................................................... 78

5.2.1 pH (H2O) and pH (CaCl2) of Soils and Geophagic Materials .....................78


5.2.3 Total Nitrogen Content ................................................................................79

5.2.4 Organic Carbon ............................................................................................79

5.2.5 Available Phosphorus and Total Phosphorus content of the Soils and

Geophagic Materials………………………………………………………80

5.2.6 Exchangeable Bases and Cation Exchange Capacity ..................................80

5.3 Mineralogy ..................................................................................................................... 81

5.3.1 Thin Section Petrography of the Geophagic Materials and Rocks ..............81

5.3.2 X-Ray Examination .....................................................................................81

5.3.2.1 The X-ray Diffractograms of Rocks ................................................................. 81

5.3.2.2 The X-ray Diffractograms of the Soils ............................................................. 81

5.3.2.3 The X-ray Diffractograms of the Geophagic Materials ................................... 82

5.4 Levels of Heavy Metals (HM) in Geophagic Materials ................................................. 82

5.5 Microbial Analysis ......................................................................................................... 83


xi

5.5.1 Heterotrophic Bacterial Count and Coliform Numbers in the Geophagic

Meterials…………………………………………………………………..83

5.6 Questionnaire ................................................................................................................. 84

CHAPTER SIX ............................................................................................................................ 85

CONCLUSIONS AND RECOMMENDATIONS ..................................................................... 85

6.1 Conclusions………………………………………………………………………84

6.2 Recommendations……………………………………………………………......85

REFERENCES ............................................................................................................................. 88

APPENDICES ............................................................................................................................ 105

Appendix A .............................................................................................................................. 105

Questionnaire for Consumers ...................................................................................105

Appendix B .............................................................................................................................. 106

Questionnaire for Dealers in White Clay Business ..................................................106

Appendix C .............................................................................................................................. 107

Questionnaire for Miners ..........................................................................................107

Appendix D .............................................................................................................................. 109

Questionnaire for Health Facilities / EPA ................................................................109


xii

LIST OF FIGURES

Fig. 1a Location of study sites………………………………………………………….27

Fig. 1b Vertical cross-section of a pit indicating the position of the geophagic

materials….………………………………………………………………………28

Fig. 2a Sandstone showing sub-rounded to rounded grains cemented by iron oxide in

rock sample from Tokorme 1…………………………………………………….55

Fig. 2b Sub-rounded to rounded grains cemented by iron oxide in rock sample from

Tokorme 2……………………………………………………………………….56

Fig. 2c Sutured and recrystallized quartz in rock sample from Tokorme 3……………...57

Fig. 2d Sandstone with poorly-sorted grains that are slightly elongated in rock sample

from Wuve……………………………………………………………………….58

Fig. 3a Thin lamination of the geophagic materials from Tokorme 1…………………...60

Fig. 3b Silty-sand size quartz grains occurring as impregnation within the fine grained

matrix of sericite in geophagic materials from Tokorme 2………………………61

Fig. 4a X-ray diffractogram of a rock from Tokorme 1………………………………….62

Fig. 4b X-ray diffractogram of a rock from Tokorme 2………………………………….62

Fig. 4c X-ray diffractogram of a rock from Tokorme 3………………………………….63

Fig. 4d X-ray diffractogram of a rock from Wuve……………………………………….63


xiii

Fig. 5a X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic

materials from Tokorme 1………………………………………………………64

Fig. 5b X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic


Fig. 5c X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic


Fig. 5d X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic

materials from Wuve……………………………………………………………66

Fig. 6a X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Tokorme 1………………………………………………………………………..67

Fig. 6b X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Tokorme 2………………………………………………………………………..68

Fig. 6c X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Tokorme 3………………………………………………………………………..68

Fig. 6d X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Wuve……………………………………………………………………………..69


xiv

LIST OF TABLES

Table 4.1 Morphological properties of the soils……………………………………45

Table 4.2 Selected physical properties of the soils…………………………………47

Table 4.3 Selected chemical properties of the soils and geophagic materials……...51

Table 4.4 Exchangeable Bases and Cation Exchange Capacity of soils and

geophagic materials……………………………………………………...53

Table 4.5a Modal Composition of Rock Sample from Tokorme 1…………………54

Table 4.5b Modal Composition of Rock Sample from Tokorme 2…………………56

Table 4.5c Modal Composition of Rock Sample from Tokorme 3…………………57

Table 4.5d Modal Composition of Rock Sample from Wuve………………………58

Table 4.6a Modal Composition of the geophagic materials from Tokorme 1………59

Table 4.6b Modal Composition of the geophagic materials from Tokorme 2………61

Table 4.7 Concentration of Heavy metals in the geophagic materials……….……70

Table 4.8a Health Risk Index of Heavy metal in geophagic materials from Tokorme

1…………………………………………………………………………71

Table 4.8b Health Risk Index of Heavy metal in geophagic materials from Tokorme

2…………………………………………………………………………71

Table 4.8c Health Risk Index of Heavy metal in geophagic materials from Tokorme

3………………………………………………………………………….72


xv

Table 4.8d Health Risk Index of Heavy metal in geophagic materials from

Wuve…………………………………………………………………….72

Table 4.9 Total Heterotroph count, Total Coliform and Faecal Coliform in the

Geophagic materials……………………………………………………74


xvi

LIST OF ABBREVIATIONS

BD Bulk Density

BW Body Weight

CEC Cation Exchange Capacity

DIC Daily Intake of Clay

DIM Daily Intake of Metal

EC Electrical Conductivity

FAO Food and Agriculture Organization

GSS Ghana Statistical Service

HRI Health Risk Index

IAEA International Atomic Energy Agency

LOAEL Lowest Observed Adverse Effect Level

m.a.s.l meters above sea level

MC Metal Concentration

MF Modifying Factor

NOAEL No Observed Adverse Effect Level

RfD Reference Dose

UF Uncertainty Factor


xvii

oC Degree celcius

mL milliliter

mm millimeter

cm centimeter

µm micometer

ηm nanometer

M molarity


1

CHAPTER ONE

INTRODUCTION

Geophagia is the deliberate consumption of soil and clay deposits by animals including

man (Wilson, 2003). Geophagy, the practice of eating earthy or soil-like substances, exists

in animals in the wild and also in humans, most often in rural or preindustrial societies, but

also among children and pregnant women (Vermeer, 1971; Abrahams, 2002). The term is

derived from the two Greek words; geo-(earth) and phag-(eat). It is a form of pica which

is an ingestion of non-food substances (Moore and Sears, 1994; Ziegler, 1997). Records on

the practice of eating earthy materials date back as far as 40 BC (Ghorbani, 2008).

Geophagy was also known and recorded in the 13th century in Greek and Roman Ages

(Rose et al., 2000) but the term was first mentioned by the great philosopher, Aristotle

(Mahaney et al., 2000).

The oldest evidence of geophagy practised by man comes from the prehistoric site at the

Kalambo falls on the border between Zambia and Tanzania where Calcium-rich white clay

was found at the site alongside the bones of Homo habilis (Root-Bernstein and Root-

Bernstein, 2000). Geophagy is practised in almost all continents (Brand et al., 2009) by

people of different cultures, races, ages and socio-economic groupings (Hunter, 1993).

However, the practice is more pronounced in children and pregnant women (Abrahams,

2002; Hooda et al., 2004; Gonyea, 2007).

This ancient phenomenon has been reported in several countries across Africa including

Ghana, Kenya, Cameroon, Malawi, Nigeria, South Africa, Tanzania, Togo, Swaziland,

Uganda, DR. Congo, Zambia and Zimbabwe (Mahaney et al., 2000; Dominy et al., 2004;

Ghorbani, 2008). The practice has also been reported in Asia including India, China,


2

Philippines and Thailand (Utara, 2002), Australia (Reilly and Henry, 2000), Europe

(Woywodt and Kiss, 2002), and the Americas (Ekosse et al., 2010). Although the practice

occurs in all continents, it is more common in the tropical peasant societies than in the

temperate regions (Abrahams and Parsons, 1996).

Various needs including medicinal, psychological, cultural, physiological as well as

nutritional have been advanced to justify the practice of geophagia (Hunter and Kleine,

1984; Vermeer, 1996; Geissler et al., 1998; Callahan, 2000; Harvey et al., 2000), but many

researchers and non-patrons see the practice as an aberrant behaviour which must be

stopped. Three major hypotheses have been advanced to explain geophagic behaviour in

man, viz: the hunger hypothesis, micronutrient deficiency hypothesis and the protection

hypothesis (Wilson, 2003; Young et al., 2010).

The hunger hypothesis postulates that people consume clay materials because they do not

have anything else to eat (Laufer, 1930). The micronutrient deficiency hypothesis states

that people eat clay material in order to supplement nutrients (Hunter, 1973). The

protection hypothesis posits that geophagia is motivated by an attempt to mitigate harmful

effects of toxins, chemical, or microbes in the body (Young et al., 2010). According to

Starks and Slabach (2012), the negatively charged clay molecules can easily bind to

positively charged toxins in the stomach and gut, preventing the toxin from being absorbed

into the bloodstream.

For people of cultural or tribal sentiment, geophagia is more than just a craving, nutritional,

medicinal or psychological need but an identity one that re-affirms their bonds with mother

earth (Siewe et al, 2000). In Mexico, members of the Roman Catholic Church practise clay


3

eating in the Black Christ cult, centered in the shrine of the Santiago de Esquipulas, 241

kilometres northeast of Guatemala City (Hunter, et al., 1984). In the Eastern part of Nigeria,

clay and earthy substances are used by native doctors (Dibias) to cure different diseases

(Izugbara and Emmanuel, 2003).

The Tiv tribe of Nigeria believe that craving for dirt is a sign of pregnancy (Starks and

Slabach, 2012). The Yorubas of Nigeria use clay as one of the active ingredients for the

treatment of dysentery and cholera (Adenuwagun et al., 1979), signifying their medicinal

value. South African urban women believe that ingesting soils enhances their beauty

(Woywodt and Kiss, 2002). Also in Malawi, consuming soil is believed to confirm

pregnancy (Ghorbani, 2008). In the southern parts of the United States of America,

pregnant women ingest soil because they believe it can cure swollen legs, helps babies to

thrive and grow into beautiful children (Tayie, 2004 and Ghorbani, 2008).

According to Reilly and Henry (2000), Woywodt and Kiss (2002), Wilson (2003) and

Tayie (2004), where poverty and hunger are implicated, soil is consumed to suppress

hunger or as a filler, where it acts as a substitute for food. In modern medicine,

pharmaceutical companies have taken advantage of the binding properties of kaolin to

produce kaopectate, a drug used for the treatment of diarrhoea and other digestive ailments

(Starks and Slabach, 2012). Ingestion of clay material has also been associated with bad

health conditions due to the fact that toxic elements are usually ingested along with soil.

Parasitic infestations can also result from soils that have been contaminated with animal

faecal matter.


4

According to Wong et al., (1991) toxoplasmosis, roundworm and other parasites have been

reported to be passed to the earth eater in this way. Malnutrition, oral and dental health

problems, intestinal perforation and blockage have been reported by Tayie (2004), Stiegler

(2005) and Gonyea (2007) as other health risks associated with geophagia. The actual

outcome of clay ingestion, either positive or negative, is dependent upon the mineralogy,

geochemistry and physiochemical properties of the material ingested which to a large

extent is influenced by the pedogenetic activities of the soil (Reilly and Henry, 2000; Ngole

et al., 2010). Laufer (1930), reported that earth materials that are normally eaten possess

some desired qualities such as colour, odour, flavour, softness and plasticity.

In Africa, different tribes have different names for geophagic materials. In Nigeria, the Tiv

and the Yoruba tribes call it Eko while the Hausa people call it farin kasa (Vermeer, 1966).

In Kenya, the material is called undongo in Swahili while in Cameroon it is called Calabar

chalk (Ekosse et al., 2008). In Ghana, the Akans call it eshile or hyire, among the Gas it is

called Ayelor and the Krobos call it Nwo, while the Fantes call it eshrew (Tayie et al.,

2013). Among the Ewes of Ghana, it is popularly known as eye, agatawoe or Kpandoko.

In Ghana, geophagia involves ingestion of a creamy-like clay soil (Tayie et al., 2013). The

major source of supply of geophagic clay in Ghana is the Anfoega area in the Volta Region

(Vermeer, 1971). The material is mined from pits, enriched with weathered shales such as

found in the Accraian and the Togo rocks (Vermeer, 1971).

Several studies have been done on geophagia in Ghana (Woywodt and Kiss, 2002, Tayie

et al., 2013). These studies have focused mainly on reasons for the practice (Vermer, 1971;

Hunter, 1973), health implications (Tano-Debrah and Bruce-Baiden, 2010) and nutritional

benefits (Tayie et al., 2013) of the materials. However, the physical, chemical and


5

mineralogical properties of the geophagic materials from Anfoega have not been

adequately documented. As reported by Mahaney and Krishnamani (2003), most

geophagic materials in Africa are not properly characterised in terms of their texture, pH,

CEC and EC. This study seeks to provide information on the physical, chemical and

mineralogical characteristics of the geophagic materials from Anfoega. The results of the

study are expected to contribute to knowledge and provide information to the people who

mine, process, market or use it as raw material. Also, nutritionists, public health

practitioners, environmentalists and research institutions can possibly draw information

from the findings of this work.

Thus, the objectives of this study are to:

a. Examine the physical, chemical and mineralogical properties of the geophagic

materials and their overlying rocks and soils from Anfoega.

b. Determine the relationship between the geophagic materials and their overlying

rocks and soils.

c. Assess the potential human health risk associated with the consumption of the

geophagic materials.


6

CHAPTER TWO

LITERATURE REVIEW

2.1 Overview

Geophagy is a very complex behaviour which dates from time immemorial. The study of

geophagy cuts across number of academic disciplines such as soil science, anthropology,

medicine, geology, nutrition, geography and ecology (Utara, 2002). Geophagy in humans

is a worldwide habit prevalent in many cultures (Laufer, 1930). The ethnographic accounts

of people and societies indicate that almost every population in their history engaged in

geophagy (Hunter, 1973).

Various aspects of geophagy have been studied such as nutrition (Abrahams et al., 1997),

medicine (Abrahams and Parsons, 1996; Abrahams, 1997), cultural or traditional related

beliefs (Vermeer and Frate, 1979). Other researchers also studied the chemical and physical

characteristics of geophagic soils (Abrahams, 1997; Abrahams and Parsons, 1997;

Aufreiter et al, 1997; Mahaney et al, 2000).

2.2 Definition of Geophagy

Hunter and de Kleine (1984), defined pica as the craving and deliberate consumption of

substances which the consumer does not consider as food for more than one month. It has

also been defined as an ingestion of non-food substances (Moore and Sear, 1994; Ziegler,

1997). The term pica is the Medieval Latin name for the bird called Magpie which has an

indiscriminate eating habit (Solyom, et al., 1991; Moore and sear, 1994). Ambroise Pare′

(1510-1590) a French barber surgeon was the first to use the term as a perverted craving

for substances unfit to be used as food (Danford, 1982). However, inadvertent consumption

of a clod of earth would not be considered pica (Abrahams, 2005).


7

Pica in humans has many different subgroups defined by the substance that is ingested.

Some of the commonly described types of pica are eating of soil (geophagy), starch

(amylophagia), ice (pagophagia), and matches (cautopyrelophagia) (Wilson, 2004). Pica

involving other substances including hair (trichophagia), ashes from cigarettes

(stachtophagia), stones or rocks (lithophagia) and wood toothpicks (xylophagia), have also

been reported (Young, et al., 2008). Wilson (2004) also defined geophagy as the deliberate

or purposeful consumption of soil and clay deposites by animals including man. The term

is derived from the two Greek words geo-(earth) and phag-(eat) (Halstead, 1968). Humans

and animals across all continents practise geophagy in a variety of forms making it one of

the most common types of pica (Landa and Feller, 2009). Geophagy is the oldest and the

most reported form of pica.

2.3 Historical Overview

Archeological evidence of calcium rich clay next to the prehistoric remains of Homo

habilis at the Kalambo Falls on the border between Zambia and Tanzania suggests that the

practice of eating earth predates our evolution as a species (Clark, 2001) and this remains

the oldest evidence of geophagy by humans (Root-Bernstein and Root-Bernstein, 2000).

Throughout history, earth eating has been observed by humans and animals (domesticated

and wild), either voluntarily or involuntarily (Krishnamani and Mahaney, 2002). In the

animal kingdom, several terrestrial vertebrates such as birds, reptiles and mammals have

been reported to practise geophagy and this has prompted several research investigations

conducted on them (Krishnamani and Mahaney, 2002). Geophagy in man is as old as

humankind and it is found among the most civilized nations as well as the very primitive

tribes (Laufer, 1930; Abrahams, 2009).


8

Geophagy was documented by Hippocrates from 460-380 BC (Rose et al., 2000).

However, the term was first used by the great philosopher Aristotle (Mahaney et al., 2000).

During the period from the sixteenth to eighteenth century, geophagy was regarded as

magical and superstitious which called for the need to have the practice prohibited as

therapy for the practitioners (Halsted, 1968). As early as 40 BC, Terra Sigillataor sacred

earth was introduced among the Greeks to combat sickness and diseases (Hunter and de

Kleine, 1984). Clay obtained from the Greek island of Lemnos by priests was mixed with

goat blood, shaped into pellets or lozenges, dried and stamped with a seal of a goat figure

(Abrahams, 2005).

The ancient Greeks and Romans especially Diocorides and Pliny, believed that the clay

had special medicinal powers (Thompson, 1913). Geophagy is not limited solely to the

Greeks and the Romans. Around AD 1000, earth eating in Europe was identified as a

common habit among children and was thought to be abominable (Abrahams, 2005). The

accounts of Alexander Von Humboldt’s expedition to South America from 1799 to 1804,

revealed a long time practice of earth ingestion among the Ottomac tribe along the Orinoco

valley (Halsted, 1968; Abrahams, 2005). In times of famines and drought, soil was used as

food (Mallory, 1926; Aufreiter et al., 1997), especially in China since 1578 (Will, 1990;

Aufreiter et al., 1997), mixed with flour in Sweden to bake bread (Hunter, 1973) and as a

substitute for butter (Von Humboldt, 1885). Indians similarly add clay to reduce the

astringent effects of bitter raw potatoes (Hunter, 1973). In Guatemala, most of the earth

being eaten is in the form of white clay tablets purchased at Esquipulas (Hunter et al.,

1989). A cake of this kind is sometimes worn as an amulet in a leather case (Laufer, 1930).


9

According to Hunter (1973), slaves shipped across the Atlantic during the trans-Atlantic

slave trade transferred the practice of geophagy from Africa to the new world. Slaves in

the plantation ate clay to alleviate gastrointestinal distress, others for reasons of culture and

nutrient supplementation. There were a number of slaves who engaged in excessive soil

consumption only to become ill, avoid work and also to commit suicide in the belief that

their spirit would return to their African homeland (Hunter, 1973). This was a great source

of worry to plantation owners. From Africa to the plantations, the practice subsequently

spread to become almost a world wide phenomenon. In Africa, where geophagy is

predominant, earth from an ancient shrine or from the grave of an ancestor is widely used

in connection with the swearing of oaths and as a medicine (Abrahams, 2005). The Chins

of Burma and the Negroes of Barbados also swallow clay in affirmation of an oath (Laufer,

1930). Earth is widely consumed to control diarrhoea and is also taken as a remedy for

syphilis, especially in the Nile Valley and in Sudan (Anell and Lagercrantz, 1958).

2.4 Aetiology of Geophagy

From antiquity to the present, the aetiology of geophagy has remained elusive and attempts

by various researchers to get enough information from geophagists to ascertain what

triggered the practice have been in futility. According to Laufer (1930), the effects of earth

eating are comparatively easy to recognize but the causes are more difficult to account for.

Even in Africa, where the practice is overt, geophagists are reluctant to give reasons for the

practice (Vermeer, 1987), for fear of stigmatization among laymen and scientists

(Abraham, 2005; Young et al., 2008).

The use of adjectives such as aberrant, abnormal, morbid, odd, primitive, and the like for

the practice puts a distance between the earth-eaters and the information seekers (Vermeer,


10

1987; Abraham, 2005). Certain factors like the environment, belief systems, and the mental

constitution of the geophagists influence their desire to indulge in the practice (Abrahams,

2005). Aside these, certain characteristics of the soil inform the choice of the geophagists.

Laufer (1930), noted as a rule, not every kind of earth is eaten, but only those kinds that

have certain appealing qualities such as colour, odour, flavour, softness and plasticity. In

spite of the difficulties in eliciting enough information from geophagists, several research

works have unraveled some causes of geophagy.

2.4.1 Geophagy for Cultural and Religious Purposes

For cultural or more tribal oriented people, geophagia is more than just a craving,

nutritional, medicinal or psychological need. It is an identity, one that re-affirms their

bonds with the mother earth (Siewe et al., 2000). According to Abraham (2009), with the

evolution of culture among human societies, soil was regarded as a source of life and

fertility and symbolic of one’s homeland.

Hunter and de Kleine (1984) reported that in parts of Central America, tablets of white clay

called tierra santa, benditos or “blessed ones” are sold for consumption in connection with

the Black Christ festival. In China, earth-eating was also connected with religious beliefs

among the Arabs and the Mohammedans of India (Laufer, 1930). Hooper and Mann (1906)

reported that dust from the tomb of Prophet Mohammed is an auspicious article, said to be

a cure for every disease. These sacred earths are believed to have special health-giving

properties that are especially associated with pregnancy to satisfy cravings (Abraham and

Parsons, 1996).


11

A similar causative explanation is presented by Hunter et al. (1989) for the consumption

of soil in present-day Guatemala and neighboring countries. Holy clay tablets of soil

embossed with religious images are consumed medicinally and during times of pregnancy

and the ingestion always has spiritual connotations. African Slaves in the plantation ate

clay to become part of the earth so that when they die, they would return to their homeland

(Anell and Lagercrantz, 1958). Traditionally, the Ewes of Ghana consume clay called the

“eye” which is prepared into the shape of an egg (Vermeer, 1971). According to him, this

symbolizes longevity, fertility, health and well-being. The egg enters the body and blesses

the woman, making her as bountiful and fertile as the earth.

2.4.2 Geophagy as a Food Supplement

The use of soil as food supplement during times of famine is not restricted to distant times

and has been frequently reported by several researchers (Laufer, 1930). Wilson (2003) and

Ghorbani (2008) reported that poverty, starvation and famine are reasons for consuming

soils. Where poverty or hunger is implicated, soil is consumed to suppress hunger or as

filler, where it acts as a substitute for food (Reilly and Henry, 2000; Woywodt and Kiss,

2002; Wilson, 2003; Tayie, 2004). Schurtz (1893) also reported that the original object of

earth-eating was to silence the hungry stomach for a short while with an indigestible

morsel.

According to Alexander Von Humboldt as reported by Halsted (1968), the Ottomac tribe

along the Orinoco valley ate clay at all times. Mallory (1926) and Aufreiter et al. (1997)

also reported that in the times of famines and drought, soils was used as food especially in

China. On several counts, slaves in the plantation farms ate clay to allay pangs of hunger

and to supplement deficient nutrients in their diet (Haller, 1972) and to alleviate gastric


12

pains emanating from hookworm infestation (Hunter, 1973). Even during the recent food

shortage that hit Malawi in 2002, the people engaged in earth eating (Abraham, 2005).

2.4.3 Soil as Medicine or Medicament

The notion that there are links between soils and human health is an ancient one. The

ancient Mesopotamians and Egyptians used clay medicinally as plaster and a cure for

wounds (Starks and Slabach, 2012). In modern medicine, pharmaceutical companies have

taken the advantage of the binding properties of kaolin to produce Kaopectate, a drug used

for the treatment of diarrhoea and other digestive ailments (Starks and Slabach, 2012).

Slaves in the plantation and estates infected with hookworm ate clay to alleviate their

gastric pain (Hunter, 1973). Medically, geophagic clays have been effective in the

treatment of gastrointestinal disorders such as diarrhoea, acid indigestion, nausea, and

stomach aches (Abrahams, 2005) as well as treatment of some types of poisoning. Clays

like kaolin and montmorillonite were also often used in medications (Wiley and Katz,

1998).

2.4.4 Soil as Food Additives and Detoxifier

The uptake of geophagic clay can provide suitable absorptives and detoxicants for the

consumption of phytotoxins, which are typical examples of the Andean tubers (Browman

and Gundersen, 1993). The clays were used to remove toxins or used as condiments or

spices in countries like the Philippines, New Guinea, Costa Rica, Guatemala, the Amazon

and the Orinoco basins of South America and as food during famine (Ross, 1895). In

Ghana, black cotton soils (now called Vertisols) were used to remove the toxin dioscorine,


13

from poisonous wild yam Dioscorea dumentorum during times of famine (Abrahams,

2009).

2.4.5 Psychiatric and Physiological Causes of Geophagy

Geophagy, being frequently considered as an aberrant habit, is a recipe for representing it

as a form of mental disorder (Abrahams, 2002). Geophagy as a sign of disorder has been

noted in both adult (Danford and Huber, 1982; Mitchell, 1968) and children (Marchi and

Cohen, 1990). Abrahams (2005) reported that earth eating was frequently observed in

mentally retarded persons, who were unable to discriminate what was or not food.

According to Danford (1982), brain-damaged individuals also exhibit abnormal eating

habits. Geophagy as a physiological disorder is evident in pregnant women who

persistently crave for clay (Tayie, 2004). It has also been reported that soil is consumed by

pregnant women as a tonic and a remedy for indigestion (Abrahams, 2005).

2.5 Health Implications of Geophagy

Clays consumed in most African populations have been shown to contain appreciable

amounts of calcium (Vermeer, 1966; Hunter, 1993) and iron (Wiley and Kartz, 1991).

Studies comparing the micro-nutritional value of geophagic materials and pharmaceutical

supplements for pregnancy showed surprising similarities for several important nutrients

including calcium, magnesium and iron (Lopez et al., 2004). Many studies have treated

geophagy as a behaviour that may provide nutrients otherwise absent in the diet (Young et

al., 2008). Several studies document the medicinal value of geophagy, for example, its

antidiarrheal effects (Vermeer and Ferrell, 1985).


14

Appropriate soil material can detoxify toxins found as secondary compounds in plant foods

by absorbing them in the gastrointestinal tract (Johns, 1990; Johns and Duquette, 1991).

Although geophagy has many proven health benefits, it can also have negative health

impacts. Most problems associated with earth eating, however, stem from a general abuse

of the practice. Minerals in the soil can cause excessive tooth wear, erosion of the mucosal

surface of the stomach and intestines and accumulation of soil in the gastrointestinal tract

can cause constipation, abdominal pain, reduced absorption of food, and obstruction and

perforation of the colon (Abrahams, 2005). Excessive intake of earth can cause

obstructions, constipation and other undesirable effects, which will ultimately lead to death

(Laufer, 1930). Ingestion of clay with high cation exchange capacity, such as smectites,

can cause deficiency of nutrients such as Fe, Zn, and K (Oliver, 1997; Abrahams, 2005).

Another probable consequence of geophagy is lead poisoning, with numerous reported case

studies suggesting the co-occurrence of lead poisoning and geophagy (Hackley and Katz-

Jacobson, 2003; Mills, 2007). The study of the prevalence and impacts of geophagy is

becoming increasingly important, as the growing widespread use of agrochemicals in

agriculture is causing high levels of toxic chemicals in soils that may be ingested (Nicholls

and Altieri, 1997).

Geophagy has also been associated with heavy metal toxicity (Calabrese et al., 1997;

Abrahams, 2005; Sing and Sing, 2010) and iodine deficiency disorders and infection by a

number of parasitic soil organisms (Hough, 2007; Sing and Sing, 2010). Parasitic infections

can occasionally occur depending on the regions from which the soil is obtained.

Geophagy, when abused can lead to dehydration, malnutrition and possibly a form of

anorexic suicide (Calabrese et al., 1997; Abrahams, 2005). Mengel (1964) also reported


15

that geophagy may cause sluggishness, mental insensibility, severe muscular weakness,

and lassitude. Furthermore, by the principles of osmosis, clay can rob iron and other

nutrients from the body and disrupt equilibrium leading to anemia (Sposito, 1989; Wiley

and Katz, 1998).

2.6 Geophagy: Reports from Ghana

In Ghana, geophagia involves the ingestion of a creamy-white loamy clay soil (Tayie et

al., 2013). The major source of this material in Ghana is Anfoega in the Volta region.

Geophagy in Ghana is an ancient practice that has been sustained for many years (Vermeer,

1971). The practice of eating earthy substances, deliberately in Ghana is a widespread

phenomenon and is not limited to a particular tribe, social classes, sex, age or religion.

However, the practice is more prominent among children and pregnant women (Abraham,

2002; Hooda et al., 2004; Gonyea, 2007). According to Tayie et al., (2013), 28% of women

of productive age in Ghana who practise geophagy consume an average of 70 g of clay

daily. Vermeer (1971), also recorded geophagic rates for men, women and pregnant women

among the Ewes to be 14%, 46% and 63% respectively. He suspected that the actual

percentages may be greater.

In Ghana, geophagists prefer white clay moulded into an egg shape (Vermeer (1971). As

noted by Laufer (1930), not every kind of earth is eaten, but only those kinds that appeal

to consumers through certain qualities such as colour, odour, flavour, softness and

plasticity. According to Vermeer (1971), the annual production of geophagic clay is

approximately 300 tons which are mined from varied environmental settings in Ghana.

Mining of the material is mainly done by men while women perform post mining activities


16

ranging from drying to marketing of the materials. The geophagic materials is sold in open

market in different sizes and shapes.

2.7 Geology of the mining site at Anfoega

According to Kesse (1985), Volta region is underlined by the Dahomeyan, the Togo and

the Buem structural units. Anfoega is mainly dominated by the Buem formation which

forms part of the Pan-African mobile belt. The Buem formation consists of thick sequence

of shale, sandstone, calcareous, argillaceous, greywacke and volcanic rocks with

subordinate limestone, tillite, grit and conglomerate (Kesse, 1985, Dapaah-Siakwa and

Gyau-Boakye, 2009) which is formed from the eroded materials of the Togo series

(Dickson et al., 1995; Abass, 2004).

Jones, (1990), noted that the lenticular shape of the sandstones bodies and paucity of

sedimentary structures in the massive sandstones indicate their deposition as alluvial fan

deposits. The rocks underlie an enlongated area on the eastern part of Ghana extending

northeast to the Republic of Togo where sandstone overlie the basal beds of shale and the

conglomerate and tillite overlie the sandstone (Dapaah-Siakwa and Gyau-Boakye, 2009).

Osae, et al (2006), classified the Buem sandstones as quartz arenite and feldspathic arenite.

The rocks of the Buem formation are not metamorphosed but deformation emanate due to

the thrust tectonics with development of imbricated thrust system and duplexes (Jones,

1990). There are large deposits of kaolin in the Anfoega area particularly at Agatanyigbe,

Wuve, Tokorme, Agata and Agatanyigbe (Vermeer, 1971; GSS, 2010). The Bliku hills of

Anfoega Bume is one of the major hills in the area from which this material is mined with

the highest point at about 381 m.a.s.l (GSS, 2010).


17

2.8 Vegetation of Anfoega

The vegetation of Anfoega is a mixture of Guinea Savannah Woodland and Semi-

deciduous forest (GSS, 2010). The Savannah woodlands consist of grass with scattered

tress like acacia, bamboo and baobabs. The semi-deciduous forests are found on the slopes

of the Akwapim-Togo-Atakora range with many tree species which are also found in the

high forest zones, such as Antiaristxicaria (Tsentsen), odum, and oil palm (GSS, 2010).

2.9 Chemical Composition of Geophagic Materials

It is important to know the chemical composition of the geophagic clays so as to determine

the health implications of consuming them. Clays are formed by the gradual degradation

of rock; this process is most commonly connected with sedimentary shales, mudstones in

addition to various soils (Willey et al., 1998). The properties of clay are dependent upon

the environment in which they are formed and their weathering conditions (Schulze, 2005).

Clays have different structural and chemical compositions with kaolin, montmorillonite,

halloysite, and allophane as major groupings (Sposito, 1989; Schulze, 2005).

The structure of clay is based on two fundamental units and their crystalline shape resulting

from the organization of silicon-oxygen tetrahedrons in hexagonal networks, giving clay a

large surface area and the ability to bind and exchange metals because of the dense

localization of hydroxyl ions and oxygen in the tetrahedron structures (Sposito, 1989).

Frate (1964) discovered ten elements that were consistently present in three separate clay

samples namely silicon, aluminum, iron, calcium, titanium, potassium, manganese, copper,

cobalt, and chromium. Sposito (1989) also found magnesium, iron, and silicon to be

essential elements in clays. Iron is an important element needed by the body (Sposito

1989). Thus, the presence of iron in clay would be a source of nutrient to the body. The


18

concentrations of other elements apart from iron, aluminum, silicon and calcium were

relatively low (Aufreiter et al., 1997).

The properties of clays are controlled mainly by two elements, silicon and aluminum

(Sposito, 1989). He further indicated that silica-aluminum ratio determines the structure of

clays and also their ability to absorb water and organic compounds. Kaolinitic and

montmorillonitic clays are those most frequently consumed by humans (Willey et al.,

1998). The former clay is made up of mostly aluminum and silicon in a 1:1 ratio. Kaolinite

may only absorb organic compounds to their external surface. Conversely,

montmorillonitic clays may absorb cations, water, and organic molecules into the inner

layers (Willey et al., 1998).

2.10 Mineralogical Composition of Geophagic Clays

Clay minerals are secondary minerals derived from chemical alteration of mostly feldspars

and micas (Ekosse et al., 2010). Clay and clay minerals naturally constitute part of the

geological structure of the earth (Mahaney et al., 2000) and are responsible for many of the

soil’s most important and characteristic physical and chemical properties (Schulze, 2005).

Geophagic materials are usually soil sediments that are clay in particle size and contain at

least one clay mineral as mineralogical constituent (Ekosse et al., 2010; Ngole et al., 2010).

Clay minerals are dominantly aluminosilicates made up of tetrahedron and octahedron

sheets constituting a unit cell. Their manner of auto-construction and habit form the unit

cell characterized by layering yielding 1:1 and 2:1 classes of clay minerals (Schulze, 2005).

The 1:1 clay consists of a unit made up of one octahedral and one tetrahedral sheet, with

the apical O2- ions of the tetrahedral sheets being shared with the octahedral sheet. Some


19

of the members are kaolinite, halloysite, nacrite and dickite. Kaolinite is a common mineral

in soils and is the most common member of the 1:1 subgroup (Schulze, 2005; Ekosse et al,

2011). It tends to be particularly abundant in more weathered soils such as Ultisols and

Oxisols (Schulze, 2005). The 1:1 layer has little or no permanent charge because of the low

amount of isomorphous substitution. Consequently, cation exchange capacities and surface

areas are typically low.

The 2:1 clay minerals on the other hand, have two tetrahedrally coordinated sheets of

cations both sandwiching an octahedral sheet. This classification has six subgroups viz:

pyrophyllite, micas, vermiculites, talc, smectites, and chlorites (Schulze, 2005). Other clay

minerals that occur in soil clays include palygorskite, sepiolite, zeolites, allophane and

imogolite.

Geophagic clays vary from one region to another with varied mineralogical and chemical

compositions (Ferrell, 2008). Preferences for choice of geophagic materials are determined

by colour, texture, odour and plasticity which are largely influenced by the mineralogical

properties of the geophagic materials. Materials consumed are usually soft, silky, and

powdery (Reilly and Henry, 2000; Nchito et al., 2004; Ngole et al., 2010).

2.11 Biological Properties of Geophagic Clays

The most important properties of clay are its colloidal characteristics, absorption of water,

associated organic materials, and the exchange of cations which influences the health

benefits of geophagy (Sposito, 1989; Ekosse et al., 2008). Clay may be used as an anti-

diarrhoeal medication (Ashenbach, 1987). Diarrhoea occurs when food substances and

liquids travel too quickly through the intestine. This quick progression does not allow the


20

body adequate time to absorb water from the digested foods. When kaolin clay is eaten, its

colloidal properties enable it to absorb the excess water found in the body, food and

intestines, thus curing the diarrhoea (Katz and Wiley, 1998). Kaolin clay is a primary

ingredient in many modern antidiarrhoeal medicines such as Turns, Maalox, and Rolaids

hence the name Kaopectate (Ashenbach, 1987).

Clay reduces transit time in the intestines and this allows more water to be absorbed,

resulting in absorption of minerals and vitamins by the body and this may be why many

resort to eating clay during periods of starvation (Aufreiter et al., 1997; Katz and Wiley,

1998). Geophagic material can preserve this delicate electrolyte balance (Aufreiter et al.,

1997). Furthermore, the cation-exchange properties of clay will allow for the unnecessary

minerals in the body to be absorbed by the clay, while the clay can also potentially give up

the minerals and ions the body needs.

Clays have the ability to trap organic and non-organic toxins in their structure (Gonzalez

et al., 2004). While clay traps poisonous and possibly deadly substances, it provides the

body with elements it can use, such as potassium which is required for muscle contraction

(Gonzalez et al., 2004).

Katz and Wiley (1998) proposed that clay consumption throughout the course of pregnancy

confers multiple benefits on the pregnant women. Pregnant women have strong desire for

clay, in all the trimesters which provides calcium an important nutrient critical for the

development of strong foetal skeletons (Katz and Wiley, 1998). Furthermore, clay can form

a protective coatings within the digestive tract which then protects the intestinal mucosa

from being damaged by toxins (Johns, 1990; Johns and Duquette, 1991).


21

2.12 Effects of Microorganisms Associated with Geophagy on Humans

Edible soils like any other soils provide a safe dwelling habitat for a host of soil organisms.

These soil organisms derive nutrient, water and energy from the soil in which they habitate

and their activities impact either positively or negatively on the soil. The ubiquitous nature

of microorganisms, predispose earth eaters to a host of pathogenic diseases (Nwoke, 2009).

Geophagic clay may therefore be a source of microbial infection (Tano-Debrah and Bruce-

Baiden, 2010). These pathogenic organisms which may include Sporotrichum schenkii,

Histiplasma capsulatum, Cryptococcus neoformans, Actinomycetes, Clostridium tetenum

and occasionall Escherichia coli and Klebsiellae are usually from feacally contaminated

soils (Aghamirian and Ghiasian, 2009; Bissi-Johnson et al., 2010).

About 3.5 billion parasitic geohelminths exist in the soil and their eggs can be consumed

with ingestion of soil (Abrahams, 2002; Nwoke, 2009) but infection can be significantly

reduced if edible soils are baked (Selinus et al., 2010). Ascariasis and Trichuriasis are

caused by the ingestion of Ascaris lumbricoides and Trichuris trichuira eggs respectively,

while toxocariasis occurs through infection with larvae of Toxocora canis (Nwoke, 2009).

Reports are that chronic liver dosorders or cirrhotic changes may be associated with

ingested soil bacterial and fungi (Selinus et al., 2010). Geophagia has been criticised as

unhygienic and exposing consumers to parasitic infestations (Reilly and Henry, 2000).

Not withstanding the several threats microorganisms pose to geophagists, they also help in

enhancement of bio-activities and maintenance of normal intestinal flora (Tano-Debrah

and Bruce-Baiden, 2010). Microorganisms are the power house for the production of

natural antibiotics (Abrahams, 2002) and also help to biodegrade toxic substances in the

gastrointestinal tract (Ragnarsdottir, 2000).


22

2.13 Effects of Heavy Metals Associated with Geophagy on Humans

Heavy metals are notable for their wide environmental dispersion; their tendency to

accumulate in select tissues of the human body; and their overall potential to be toxic even

at relatively minor levels of exposure (Hu, 2002). Metals such as lead and mercury have

no useful role in human physiology and may be toxic even at trace levels of exposure (Hu,

2002). Even metals that are essential may have the potential to turn harmful at very high

levels of exposure (WHO/FAO/IAEA, 1996). These metals are natural components of the

earth's crust and they cannot be degraded or destroyed (Calabrese et al., 1997). Their

existence in the environment arises from both natural and anthropogenic sources (USEPA,

1989).

Geophagy has been associated with heavy metal toxicity (Calabrese et al., 1997; Abrahams

2005; Sing and Sing 2010). Such toxic metals include iron, zinc, copper, manganese,

nickel, aluminium and lead when ingested into the body of consumers (Al-Rmalli et al.,

2010). Excessive ingestion of clay may have serious health repercussion on humans

(Ekosse et al., 2010) due to the fact that the material in addition to being mostly

contaminated with toxic heavy metals and microorganisms, is associated with iodine

deficiency disorders (Hough, 2007; Sing and Sing, 2010; Ekosse et al., 2015). The effects

of heavy metals, especially Pb, As, Cd, Cr and Hg as a result of repeated exposure has been

documented and they include gastro-enteritis, inhibition of haemoglobin formation,

sterility, miscarriage, growth retardation, central nervous system disorder, kidney

dysfunction, hypertension and mental retardation (Amdur, 1991; Ming-HO, 2001; Meharg,

2005).


23

Several incidents of diseases caused by the presence of metals in soils have been reported

(USEPA, 1989). These heavy metals are commonly found in the environment and diet and

they enter our bodies via what we consume (WHO/FAO/IAEA, 1996). As trace elements,

some heavy metals like copper, selenium and zinc are essential in promoting various

biochemical and physiological functions of the body (WHO/FAO/IAEA, 1996). However,

at higher concentrations they can lead to poisoning (WHO/FAO/IAEA, 1996).

Heavy metals are dangerous because they tend to bioaccumulate (USEPA, 1989). Heavy

metals including lead, cadmium, mercury, and the metalloid arsenic are persistent in the

environment and have been documented to be potential cause of serious health problems

(USEPA, 1989). Long term exposure to heavy metals can lead to physical, muscular, and

neurological degenerative conditions that may result in diseases such as multiple sclerosis,

Parkinson’s disease, Alzheimer’s disease and muscular dystrophy and sometimes cancer

(Jarup, 2003). Heavy metal toxicity may damage the central nervous system,

cardiovascular system, gastrointestinal system, lungs, kidneys, liver, endocrine glands and

bones (Calabrese et al., 1997). Heavy metals are significant environmental pollutants and

their toxicity is a problem of increasing significance for ecological, evolutionary,

nutritional and environmental reasons (Jaishankar et al., 2014).

2.14 Mining of Geophagic Materials Worldwide

Geophagic materials in general are mined from hills and mountains, river beds, valleys and

termitaria (Reilly and Henry, 2000). Mining of the geophagic clays is achieved through

surface collection, pit extraction (Gosselain and Smith, 2005). In most cases, local miners

use simple digging tools similar to those used by traditional potters of sub-Sahara Africa


24

(Gosselain, 1999). No elaborate exploration or prospecting exercise is carried out before

embarking on mining activities (Ekosse et al., 2010).

2.15 Processing of Geophagic Materials

Processing of geophagic materials consist of an array of activities reserved for women with

men offering helping hands when needed (Vermeer, 1971). The geophagic materials are

obtained by local women from pitheads at the mining sites. The materials are dried under

the sun and they become brittle. After drying, the material is pounded in wide mortars or

boards with pestles until very fine particles size is achieved (Reilly and Henry, 2000). An

improvised sieve made from plastics is used to sieve the pounded material. The powder is

then mixed with water and kneaded by hand into different forms of small lozenges or rolls.

In some cases, the women mix the edible clay material with herbs and other plant materials

to spice it (Reilly and Henry, 2000).

After the clay is shaped into small cakes or other shapes, it is baked over fire or dried in

the sun (Reilly and Henry, 2000). The baked clays are ready for distribution to other parts

of the country and other West African countries where they are sold (Hunter, 1973;

Abrahams and Parson, 1996).

2.16 Marketing of Geophagic Materials

The sale of geophagic materials is common in many societies (Gichumbi et al., 2011). The

processing and commercialization of clay tablets, disks, or balls are well documented in

Africa and else where (Hunter, 1993). In African societies, geophagic clay is prepared in

the form of small Lozenges, rolls or balls and sold in local markets (Raily and Henry,

2000). Abraham (1997) reported that in Kampala, Uganda different soils are readily


25

available for purchase from street vendors. In Nigeria, large quantities of geophagic

materials are produced and distributed for sale in other West African countries (Hunter,

1973; Ekosse, 2012) in open market with no standardization, advertisement, labeling or

proper packaging (Raily and Henry, 2000).


26

CHAPTER THREE

MATERIALS AND METHODS

3.1 Site Selection and Description

The study sites are located at Anfoega in the North Dayi District of the Volta Region of

Ghana (Figure 1a). The area was selected for its long standing history in the production of

the edible clay. In all, four mining sites were selected from a range of hills (the Bliku hills).

Site 1, 2 and 3 were located at Tokorme while site 4 was located at Wuve (Table 1). The

area is underlain by rocks of the Buem structural unit (GSD, 2010). The dominant soils in

the area are Lixisols (Soil Research Institute, 1999).

Table 1: Location of the Study Sites.

Site Location Coordinates Altitude (m.a.s.l) Physiographic Position

1 Tokorme 1 N 060o 52ʹ 499ʹʹ 243.23 Shoulder

E 000o 15ʹ 039ʹʹ


E 000o 16ʹ 015ʹʹ


E 000o 16ʹ 002ʹʹ

4 Wuve N 060o 52ʹ 234ʹʹ 238.05 Shoulder

E 000o 16ʹ 100ʹʹ


27

Figure1a: Location of Study Sites.

3.2 Sample Collection and Storage

At each of the four sites, soil, rock and clay samples were taken from pits being mined.

Each pit had a shallow soil (about 60 cm) at the surface underlain by a massive rock of

about 10 metres thick and the white clay deposit below the rock layers (Figure 1b). The

soils were sampled in depth intervals of (0-20 cm, 20-30 cm, 30-40 cm, 40-50 cm and 50-

60 cm). Core samples were also taken within the depth of 0-40 cm for bulk density

determination.

Processed clay samples, were also collected from women involved in the marketing of the

material. All samples were packaged in airtight plastic bags, labelled and then transported

to the laboratory. At the laboratory, the soil and the white clay samples were air dried and


28

then gently disaggregated using an agate mortar and pestle. The disaggregated samples

were then passed through a 2.0 mm mesh sieve and repackaged for physical, chemical and

mineralogical analyses.

Samples for microbial analysis were subsampled from the soil samples and the white clay

material. These were put into well labelled sealed plastic bags and placed on iced cubes in

a well cleaned ice chest and transported to the laboratory where they were stored at 5 oC in

a refrigerator until they were analysed. Rock samples taken from all the four sites were

placed in labelled and sealed plastic bags and then transported to the laboratory for

petrographic examination.

Fig. 1b. Vertical cross-section of a pit indicating the position of the geophagic materials.

(Not drawn to scale)


29

3.3 Physical Analysis

3.3.1 Bulk Density of the Soil Samples

Metal cylindrical sampling cores of 5 cm diameter and 5 cm height with sharp cutting edges

were pushed into each layer of the soils within 0-40 cm. Excess soil at the top and bottom

faces of the cylinder was carefully trimmed with a flat knife. The core soil samples were

then placed in labelled plastic bags and transported to the laboratory for bulk density

determination. In the laboratory, the core sampler plus soil samples were oven-dried at 105

oC for 24 hours. After 24 hours, the samples were removed from the oven and allowed to

cool in a dessicator. After cooling, the samples were weighed (ie weight of core samples

plus oven dried soil). After weighing, the soil cores were pushed out of the samplers, the

samplers washed and put back into the oven to dry. After drying the samplers and allowing

them to cool in the dessicator, they were weighed. The weights of the samplers were then

subtracted from the weight of the samplers plus soil samples. The radius (r) and height (h)

of the samplers were used to determine the volume of the samplers using the formular,

πr2h. The volume of the samplers was used as the total volume of the soil samples.

The soil bulk density was calculated by using the formula:

ρb = Ms ⁄ Vt

Where ρb is soil bulk density (kg m-3)

MS is the mass of soil solids (kg)

Vt is the total volume of the soil (m3)


30

3.3.2 Particle Size Distribution

This is the separation of the mineral part of the soil into various size fractions. After

determining the amount of gravel in each soil sample, the fine earth fraction (˂ 2 mm

fraction) was fractionated according to the sedimentation principle based on Stokes’ Law

which relates the radius of the particles to the velocity of sedimentation. The various size

fractions of the soil were determined using Day’s (1965) modified Bouyoucos hydrometer

method. A 40 g 2.0 mm air-dried soil was weighed into a beaker after which 50 mL of 30%

H2O2 was added to destroy the organic matter in the soil. A 100 mL 5% sodium

hexametaphoshate solution was added to it and the suspension was allowed to stand for 10

minutes and then shaken in a mechanical shaker for 2 hours. The suspension was then

transferred into a graduated cylinder with distilled water and topped up to the 1000 mL

mark. The suspension was allowed to stand to equilibrate at room temperature. The content

of the cylinder was agitated thoroughly using a plunger. Thereafter, the hydrometer and

temperature readings were taken after 5 minutes and 5 hours. Blank hydrometer reading of

5% sodium hexametaphoshate solution, topped up to 1000 mL was taken after 5 minutes

and thereafter 5 hours. After the 5 hour hydrometer reading, the suspension was then

poured directly onto a 50 µm sieve and the effluent discarded. The particles retained on the

50 µm sieve, were thoroughly washed with distilled water, transferred to a moisture can

and oven dried at 105 oC for 24 hours. The dried samples were then weighed to represent

the sand fraction. The particle size distribution was then determined using the following

formular;

(Clay + Silt) % = 5 minute hydrometer reading x100 (1)

Sample mass


31

Clay % = 5 hour hydrometer reading x100 (2)

Sample mass

Silt % = (1) - (2) (3)

Sand % = Oven dry mass (g) of particle retained on 50 µm sieve x 100 (4)

Sample mass

The textural class of the soil was then determined using the USDA textural triangle.

3.3.3 Soil Colour

Determination of the colour of both moist and air dried soil samples was done under bright

light condition. A clean spatula was used to fetch individual soil samples and compared

with the colours in the Standard Colour Chart. The Standard Colour Notation of a chip that

was the closest match was recorded as the colour of the soil sample.

3.4 Chemical Analysis

3.4.1 pH (H2O)

For each sample, 10 g of 2.0 mm air-dried soil was weighed into a 50 mL beaker and 20

mL of de-ionized water was added to give a ratio of 1:2. The mixture was then stirred

vigorously for 30 minutes and left to stand for about 1 hour to allow the suspension to settle

and also to equilibrate at room temperature. Standard buffer solutions of pH 4.0 and 7.0;

(Sigma Chemicals, U.S.A) was used to standardized the pH electrometer. The pH was

measured by immersing the electrode into the supernatant and the pH value recorded. For

each soil sample, triplicate determinations on separate sub-samples were carried out and

the mean values taken. The same procedure was carried out on the geophagic clay samples.


32

3.4.2 pH (CaCl2)

For each sample, 10 g of 2.0 mm air-dried soil was weighed into 50 mL beaker and 20 mL

of 0.01 M CaCl2 was added to give a ratio of 1:2. The mixture was then stirred vigorously

for 30 minutes and left to stand for about 1 hour to allow the suspension to settle and also

to equilibrate at room temperature. Standard buffer solutions of pH 4.0 and 7.0; (Sigma

Chemicals, U.S.A) was used to standardized the pH electrometer. The pH was measured

by immersing the electrode into supernatant and the pH values recorded. For each soil

sample, triplicate determinations on separate sub-samples were carried out and the mean

value taken. The same procedure was carried out on the geophagic clay samples.

3.4.3 Electrical Conductivity

For each sample, 10 g of 2.0 mm air-dried soil was weighed into 50 mL beaker and 20 mL

of de-ionized water was added to give a ratio of 1:2. The suspension was stirred several

times with a glass rod for 1 hour to dissolve soluble salts after which the suspension was

allowed to settle for 30 minutes. The conductivity electrode was dipped into the supernatant

and the electrical conductivity (EC) measured.

3.4.4 Organic Carbon

Organic carbon was determined using the wet oxidation method of Walkley and Black

(1934). A sample of soil 0.5 g screened through 0.5 mm sieve, was weighed into a 250 mL

Erlenmeyer flask. Then 10 mL of 0.167 M potassium dichromate (K2Cr2O7) solution

followed by 20 mL of concentrated H2SO4 were added to the soil. The flask was swirled to

ensure that the solution was in contact with all the particles of the soil.


33

The content of the flask was allowed to stand on an asbestos sheet in the fume cupboard

for 30 minutes for the reaction to complete. Then 200 mL of distilled water and 10 mL of

orthophosphoric acid were added to the content in the flask, swirled to mix the solution

and allowed to cool after which 2.0 mL of barium diphenyalamine sulphonate indicator

was added. The solution was titrated with 0.5 M ferrous ammonium sulphate solution until

the colour changed from orange to a green end-point. The experiment was repeated with

the blank measurement using the same reagents but without soil. For each soil sample,

triplicate determinations of separate sub-samples were carried out and the mean value

taken. The same procedure was carried out on the geophagic clay samples. The percent

organic carbon content of the samples was determined using the formular:

% Organic carbon = M x V1 – V2 x 0.39

Weight of soil (g)

Where, M = Molarity of the FeSO4 solution

0.39 = 3 x 10-3 x 100 x 1.33

V1 = Volume of FeSO4 required for the blank (mL)

V2 = Volume of FeSO4 required for the sample (mL)

3.4.5 Total Nitrogen

The total nitrogen content of the soil and the white clay samples were determined using the

Kjeldahl digestion method (Hesse, 1971). To a sample of 2.0 g of air-dried soil weighed

into a 250 mL Kjeldahl flask, selenium catalyst was added followed by 10 mL of

concentrated H2O2. The mixture was then digested until the digest became clear. The digest

was then allowed to cool and transferred with distilled water into a 50 mL volumetric flask

and made up to the volume.


34

A 5.0 mL aliquot of the digest was pipetted into a Markham distillation apparatus and 5.0

mL of 40% NaOH solution was added. Then 5.0 mL of 2% boric acid and few drops of

mixed indicator (0.13 g of methyl red plus 0.666 g of methlylene blue dissolved in 100 mL

of 95% ethanol) were put into a conical flask and placed under the delivery tube of the

condenser in a way that the tip was below the surface of the liquid. The flask was removed

from the distiller, condenser tip rinsed, and the distillate titrated with 0.01 M HCl until

colour changed from green to a purplish end point. The amount of total nitrogen in the soil

was calculated by

% N = (Titre value-Blank) x Molarity of acid x Volume of extract x 14 x 100

Volume of aliquot x Weight of soil (g) x 1000

3.4.6 Cation Exchange Capacity

For each soil and clay sample, 10 g of air-dried samples were weighed into an extraction

bottle and 100 mL of 1.0 M ammonium acetate solution buffered at pH 7.0 was added. The

bottle with its content was placed in the mechanical shaker and shaken for 1 hour. The

content was filtered through a No. 42 Whatman filter paper into a clean empty plastic

bottle. Immediately after that the sample was leached with four 25 mL portions of methanol

to wash off excess ammonium into empty plastic bottles. The ammonium saturated soil

was then leached with four 25 mL portions of 1 M acidified potassium chloride into clean

empty plastic bottles. A 5.0 mL aliquot of the digest was pipetted into a Markham

distillation apparatus and 5.0 mL of 40% NaOH solution added. Then 5.0 mL of 2% boric

acid and few drops of mixed indicator were put into a conical flask and placed under the

delivery tube of the condenser in a way that the tip was below the surface of the liquid. The

flask was removed from the distiller, condenser tip rinsed, and the distillate titrated with


35

0.01 M HCl until colour changed from green to a purplish end point. The cation exchange

capacity in cmolc kg-1 soil was then calculated from the number of moles of HCl consumed

in the back titration reaction.

3.4.7 Determination of Exchangeable Bases

For each soil and white clay, 10 g of air-dried samples were weighed into an extraction

bottle and 100 mL of 1.0 M ammonium acetate solution buffered at pH 7.0 was added. The

bottle with its content was placed in the mechanical shaker and shaken for 1 hour. The

content was filtered through a No. 42 Whatman filter paper into a clean empty plastic

bottle. The filtered solution was used for the determination of Ca, Mg, K, and Na using

atomic absorption spectrophotometer.

3.4.8 Determination of Total Phosphorus

For each soil and white clay, 2.0 g sample screened through 0.5 mm sieve was weighed

into a 250 mL Erlenmeyer flask. Then 10 mL of concentrated HNO3 and 15 mL of 60%

HClO4 were added and the mixture was then digested till the digest became colourless and

dense white fumes of HClO4 ceased. The digest was allowed to cool and later diluted with

distilled water. The digest was filtered through a No. 42 Whatman filter paper into a 100

mL volumetric flask and made up to the volume. Thereafter, a 5.0 mL aliquot of the digest

was pipetted into 50 mL volumetric flask. The pH was adjusted by adding few drops of P-

nitrophenol indicator and few drops of 4 M NH4OH until the sample solution turned

yellow. Then 8.0 mL of a solution containing concentrated sulphuric acid, ammonium

molybdate, potassium antimony tartrate, and ascorbic acid were added and made up to the

volume with distilled water. The solution was mixed thoroughly and made to stand until


36

blue colour developed. Standards and sample absorbance were measured at a wavelength

of 712 nm.

3.4.9 Available Phosphorus

3.4.9.1 Olsen’s Extraction Procedure

The available P content of the soils was determined following the method of Olsen et al.,

(1954), for samples that had alkaline pH. To 5.0 g of air-dried soil in an extraction bottle,

50 mL of sodium carbonate solution was added. The bottle was corked and shaken for 30

minutes after which the suspension was filtered through Whatman No. 42 filter paper. An

aliquot of the filtrate was pipetted into a test tube and 1.0 mL of 1.5 M H2SO4 added in a

dropwise manner to decolourise the solution by settling the organic matter in solution. The

solution was left in a refrigerator for some time to cool after which it was centrifuged at

5000 rpm for 15 minutes and the content decanted. An aliquot was pipetted for colour

development and intensity readings. The absorbance for standards and samples were

measured at a wavelength of 712 nm.

3.4.9.2 Bray 1 Method

The Bray and Kurtz (1945) method was used to determine the available P content of soils

with acidic pH. To 5.0 g of air-dried soil weighed into an extraction bottle 50 mL of the

extractant (0.03 M NH4F in 0.025 M HCl) was added making a 1:10 soil-to-solution ratio.

The suspension was shaken vigorously for exactly 2 minutes on the mechanical shaker.

The content was filtered through Whatman No. 42 filter paper after which a 5.0 mL aliquot

was pipetted for colour development. The absorbance for the standards and samples were

measured at a wavelength of 712 nm.


37

3.5 Mineralogical Analysis

3.5.1 Thin Section Preparation and Petrographic Examination of Rock Samples

Thin sections of the rock samples were prepared. The rocks were first cleaned to prevent

contamination. Each rock sample was carefully examined and cut with a diamond edge

electrical saw to obtain representative thin slabs with flat surfaces. After that the grinding

machine and corundum dust (silicon carbide 220) were used to smoothen and flatten the

surface of the sliced rocks. With the help of a grinding machine and silicon carbide 600,

the thin slab was further polished to obtain smooth surfaces. The frosted side of the slide

(glass) was then attached to the side of the chip that was grounded down to ensure constant

thickness of epoxy (Canada Balsam) spread across the section. It was later pressed to

escape trapped air after which it was heated on a hot plate. After mounting the rock chip

on the glass slide, the slab was ground to the preferred thickness. The thickness and colour

of the minerals, particularly of quartz were timely observed under the microscope at each

stage of the grinding until the grains showed a yellowish-grey interference colour when

oriented parallel with the optical axis indicating the thickness was up to standard and

therefore the grinding was stopped at this stage. A cover slip was then added to protect the

section from damage and to increase the clarity observed in the microscope before the final

polishing was done. This was heated again on the hot plate, pressed and later washed with

kerosene. The thin section was examined petrographically using a polarized light

microscope. Non-solid rock samples were boiled or impregnated and hardened with

Canada Balsam.


38

3.5.2 Fractionation of Samples

The soil samples were pretreated with 30% H2O2 to remove organic matter. Then, about 40

g of fine earth fraction was weighed into 1 litre beaker after which 20 mL of water was

added. Then, 20 mL of H2O2 was added slowly to the soil sample to avoid excessive

frothing, stirred and the beaker covered with watch-glass to prevent spattering. Strong or

excessive frothing was prevented by adding a few drops of ethanol and allowing the sample

to stand overnight. The next day, the beaker was placed on a water bath at 80 oC and 30%

H2O2 was added in 5-10 mL increments until decomposition of organic matter was

completed.

When the supernatant was clear, soil adhering to the watch glass was washed into the

beaker and water was added and made up to 300 mL. The beaker containing the mixture

was placed on a hot plate and carefully boiled for 1 hour to remove any remaining H2O2.

The beaker was removed from the hot plate and allowed to cool. A 50 mL 5% sodium

hexametaphoshate solution was added to it and the suspension was allowed to stand for 10

minutes and then shaken in a mechanical shaker for 15 minutes. The suspension was then

transferred into a graduated cylinder with distilled water and topped up to the 1000 mL

mark. The suspension was allowed to stand for 5 hours to equilibrate. Then 50 mL of the

clay suspension was pipetted from 20 cm depth into a 100 mL beaker which was carefully

air-dried and powder obtained. The geophagic clay materials were not subjected to the

above methodology because they were found to contain very minimal organic carbon.

3.5.3 Potassium Saturation of Exchange Complexes

To saturate the soil clay samples and geophagic clay with K, 25 mg of air-dried sample

was weighed into a 15 mL centrifuge tube. Then 10 mL 1 M KCl was added to the clay


39

sample and centrifuged at 1500 rpm for 5 minutes after which the supernatant solution was

discarded. This was repeated four times to complete the saturation of the clay with K. The

excess salt was removed from the sample by washing once with 50% methanol, then with

95% methanol, and finally with 95% acetone until the decantate gave a negative test for

chloride with AgNO3.

3.5.4 Sample Preparation

An oriented-aggregate specimen was formed directly from the K-saturated clay. The

sample was mixed with deionized water and the suspension was pipetted and carefully

transferred onto a glass slide placed on a level surface. The suspension was then allowed

to dry on the slide pending further analysis.

3.5.5 X-Ray diffraction

The K-saturated room temperature samples (K-25) were subjected to X-Ray analysis.

Thereafter, the same slides were heated to 350 oC (K-350) for 2 hours and then subjected

to X-ray analysis. Then finally, the 350 oC heated samples were heated to 550o C (K-550)

for 2 hours and then X-ray analysed.

3.6 Heavy Metal Analysis

A 2.0 g of air dried geophagic materials screened through 0.5 mm sieve was weighed into

a 250 mL Erlenmeyer flask. Then 10 mL of concentrated HNO3 and 15 mL of 60% HClO4

were added and the mixture was then digested till the digest became colourless and the

dense white fumes of HClO4 ceased. The digest was allowed to cool to room temperature

and later diluted to 10 mL using distilled water and left to settle overnight. The supernatant

was filtered through a No. 42 Whatman filter paper prior to analysis using AAS (Perkin


40

Elmer). The concentration of metals in each sample was recorded and their means

determined. The dose response assessment was computed following guidelines set by

(USEPA, 2002). A published Reference Dose (RfD) values of the heavy metals for humans

was used to calculate the health risk index (HRI) taking into consideration the daily intake

of the clay and the average body weight of the consumer. The RfD is an estimation of a

daily exposure to the human population that is likely to be without an appreciable risk of

adverse health effect over a lifetime (USEPA, 2002). This is based on the assumption that

there is a threshold for certain toxic effect. The RfD expressed in units of mg kg-1 day-1

was computed using the formular of USEPA, (2002)

1. RfD (mg/kg-day) = NOAEL or LOAEL

UF X MF

Where:

NOAEL = No Observed Adverse Effect Level (mg kg-1 day-1) or

LOAEL = Lowest Observed Adverse Effect Levels (mg kg-1 day-1)

UF = Uncertainty factor

MF = Modifying factor

2. The HRI was calculated using the formular of Cui et al. (2004) and adopting a 70

g clay intake per day of Ghanaian women by reproductive age reported by Tayie et

al. (2013).

HRI = Daily Intake of Metal (DIM)

RfD

3. The DIM was calculated using the following formular

DIM = MC X DIC

BW

Where

MC = Metal Concentration


41

DIC = Daily Intake of Clay

BW = Body Weight 60 kg for consumers (WHO/IAEA, 2006)

The HRI of individual metals were compared with an index of 1 beyond which there is a

potential health effect (Huang et al. 2008).

3.7 Microbial Analysis of the Geophagic Materials

About 10 g of geophagic materials was weighed into medicinal bottle containing 90 mL of

ringer solution. The sample was then vortexed for 30 minutes after which a 1.0 mL of the

90 mL diluent was transferred into a test tube containing 9.0 mL of the ringer solution.

This was serially done to 10-6 with the aid of micropipette. Thereafter, 1.0 mL of the 10-6

diluent was asceptically transferred unto sterile petri–dish and mixed thoroughly. The plate

was allowed to set and incubated at between 35 – 37 oC for between 18-24 hours. After the

incubation period, the colonies were counted to determine how many microorganisms were

present in original samples. Plates with more than 30 of these colonies but less than 300

were counted and their Cfu calculated using the following formular:

B = N/D

B = Number of Bacteria

N = Number of Colonies Counted on a plate

D = Dilution factor

3.8 Questionnaire to solicit information on the ingestion of the geophagic

materials from Anfoega

Structured questionnaires were administered to the miners, sellers and consumers of the

geophagic materials as well as personnel at health facilities in the catchment area of the


42

sites. Questionnaires were conducted in Ewe and English languages. The objective of the

exercise was to find out the impact of clay mininig on the environment, on the people and

the health implications of consuming the geophagic materials. The questionnaires written

in English language were translated to the miners, consumers and the women involved in

processing the clay into the Ewe language. Their responses were however, recorded in

English language. In the case of the health personnel, the interviews were conducted in

English language. In all, four (4) miners, ten (10) women, sixteen (16) consumers and three

(3) health facilities were interviewed according to the questionnaires (see Appendix 1).


43

CHAPTER FOUR

RESULTS

4.1 Morphological Properties of the Soils

The morphological properties of the soils are presented in Table 4.1. Under moist

condition, the colour of Tokorme 1 ranged from brownish black (10YR3/2) in the surface

layer to dull reddish brown (5YR5/4) in the bottom layer. In Tokorme 2, the colour (moist)

ranged from brown (7.5YR4/4) in surface layer to bright reddish brown (5YR5/6) in the

bottom layer. In Tokorme 3, the colour (moist) ranged from brown (7.5YR4/4) in the

surface layer to bright reddish brown (5YR5/6) in the bottom layer. In Wuve, the colour

(moist) ranged from dark reddish brown (5YR3/2) in the surface layer to dull orange

(2.5YR6/4) in the bottom layer. Under dry condition, the colour of Tokorme1 ranged from

greyish brown (7.5YR4/2) in the surface layer to dull orange (5YR7/3) in the bottom layer.

In Tokorme 2, the colour (dry) ranged from dull orange (7.5YR6/4) in surface layer to dull

orange (7.5YR6/4) in the bottom layer. In Tokorme 3, the colour (dry) ranged from dull

reddish brown (5YR5/3) in the surface layer to orange (5YR7/6) in the bottom layer. In

Wuve, the colour (dry) ranged from dull orange (5YR6/3) in the surface layer to dull orange

(5YR7/4) in the bottom layer.

The texture of Tokorme 1 and Wuve were sandy clay loam in all layers. The texture of

Tokorme 2 was clay in the surface and subsurface layers but changed to sandy clay loam

at the bottom layers. In Tokorme 3, the texture was clay in the surface and subsurface layers

but it changed to sandy clay loam in the bottom layer.

The soils from the four sites were well drained. The soils from Tokorme 1 had granular to

subangular blocky structure in the surface and subsurface layer but changed to granular in


44

the bottom layers. The soil from Tokorme 2 had a granular to subangular blocky structure

in the surface layer but changed to subangular blocky in the subsurface layer and the bottom

layers. The soils from Tokorme 3 and Wuve had granular structure in the surface layers

but changed to subangular blocky in the subsurface layers and the bottom layers.

The soil from Tokorme 1 was generally non-sticky, friable and slightly hard in consistence

under wet, moist and dry conditions respectively. The consistence of Tokorme 2 was sticky

(wet), firm (moist) and very hard (dry). Tokorme 3 was non sticky (wet), friable (moist)

and slightly hard (dry) in consistence. The consistence of Wuve, was slightly sticky (wet),

friable (moist) and hard (dry). The sizes and quantity of roots the soils contained reduced

with soil depth.


45

Table 4.1. Morphological Properties of the Soils.

Depth Colour Colour Structure1 Consistence2 Roots3

(cm) (moist) (dry) wet moist dry

Tokorme 1

0-20 10YR3/2 7.5YR4/2 gr-sbk ss fr sh mm, mf

20-30 10YR3/3 10YR4/2 gr-sbk ns fr sh ff

30-40 7.5YR3/2 10YR 5/2 gr ss fr sh ff

40-50 5 YR 5/4 5 YR 8/2 gr ns fr sh ff

50-60 5 YR 5/4 5 YR 7/3 gr ns fr sh vff

Tokorme 2

0-20 7.5YR4/4 7.5YR6/4 gr-sbk ss fi h mm, mf,mvf

20-30 5 YR 4/4 5 YR 6/4 sbk s fi vh mm, mf

30-40 5 YR 4/6 5 YR 6/4 sbk s fi vh fm

40-50 5 YR 4/6 5 YR 6/4 sbk s fi vh vff

50-60 5 YR 5/6 7.5YR6/4 sbk s fi vh vff

Tokorme 3

0-20 7.5YR4/4 5 YR 5/3 gr ss fr sh mm, mf, mvf

20-30 5 YR 5/6 7.5YR6/4 sbk ns fr sh vff

30-40 7.5YR5/4 7.5YR6/4 sbk ss fr sh vf

40-50 5 YR 4/6 5 YR 6/4 sbk ns fr sh vf

50-60 5 YR 5/6 5 YR 7/6 sbk ns fr sh ND

Wuve

0-20 5 YR 3/2 5 YR 6/3 gr ns fr h mm, mf, mvf

20-30 5 YR 4/4 5 YR 6/3 sbk ss fr h vff

30-40 2.5YR6/4 5 YR 6/4 sbk ss fr h vff

40-50 2.5YR6/4 5 YR 7/4 sbk ss fr h ND

50-60 2.5YR6/4 5 YR 7/4 sbk ss fr h ND

1gr = granular, sbk = subangular blocky, 2s = sticky, ss = slightly sticky, ns = non-sticky,

fr = friable, fi = firm, h = hard, sh = slightly hard, vh = very hard, 3ff = few fine, mm =

many medium, mf = many fine, mvf = many very fine, vff =very few fine, ND = Not

determined.


46

4.2 Physical Properties

4.2.1 Particle Size Distribution and Texture

The sand content of Tokorme 1 ranged from 64.7 to 66.7% (Table 4.2). The amounts

decreased slightly with depth. The silt content of Tokorme 1 ranged from 7.6 to 10.3% and

the clay content ranged from 23.0 to 27.7%. In Tokorme 2, the amount of sand ranged from

33.2 to 51.2%. The silt content of Tokorme 2 ranged from 15.2 to 17.2% and the clay

content ranged from 33.6 to 49.6%. The sand content of Tokorme 3 ranged from 25.5 to

57.2%. The silt content of Tokorme 3 ranged from 7.6 to 12.7% and the clay content ranged

from 34.1 to 61.5%. The sand content of Wuve ranged from 64.3 to 69.5%, the silt from

10.1 to 10.6% and the clay from 20.1 to 25.5%. The clay content of the geophagic materials

were 51.4% in the samples from Tokorme 1, 63.5% in Tokorme 2, 68.8% in Tokorme 3

and 66.8% from Wuve. The silt fraction ranged from 28.66% to 45.71% in all four samples

with sand recording less than 5%. The clay fraction clearly dominated in the geophagic

materials.

4.2.2 Bulk Density

The bulk density (BD) of Tokorme 1 ranged from 0.83 to 1.09 Mg m-3 and from 1.29 to

1.45 Mg m-3 in Tokorme 2 and increased with depth. The bulk density of Tokorme 3 ranged

from 0.98 to 1.10 Mg m-3 and from 1.11 to 1.51 Mg m-3 in Wuve and increased with depth.


47

Table 4.2. Selected Physical Properties of the soils.

Depth

Particle Size Distribution Texture1 Bulk Density

(%)

(cm) Sand Silt Clay (Mg m-3)

Tokorme 1

0-20 66.7 10.3 23.0 SCL 0.93

20-30 66.8 7.7 25.5 SCL 0.83

30-40 66.2 7.7 26.0 SCL 1.09

40-50 64.7 10.1 25.2 SCL ND

50-60 64.7 7.6 27.7 SCL ND

Tokorme 2

0-20 33.2 17.2 49.6 C 1.29

20-30 41.3 15.3 43.4 C 1.38

30-40 51.2 15.2 33.6 SCL 1.45

40-50 50.4 15.3 34.3 SCL ND

50-60 46.4 15.4 38.2 SC ND

Tokorme 3

0-20 25.5 12.7 60.9 C 0.98

20-30 30.9 7.6 61.5 C 1.1

30-40 31.2 7.6 61.2 C 1.1

40-50 32.1 9.7 58.2 C ND

50-60 57.2 8.7 34.1 SCL ND

Wuve

0-20 64.3 10.2 25.5 SCL 1.11

20-30 64.7 10.1 25.2 SCL 1.26

30-40 67.3 12.6 20.1 SCL 1.51

40-50 69.5 10.4 20.1 SCL ND

50-60 69.3 10.6 20.1 SCL ND

Geophagic Materials

Tokorme 1 2.9 45.7 51.4 SiC ND

Tokorme 2 4.9 31.6 63.5 C ND

Tokorme 3 2.6 28.6 68.8 C ND

Wuve 4.2 29.0 66.8 C ND

1: S = sand, C = clay, SCL = sandy clay loam, SiC = silty clay

ND = Not determined.


48

4.3 Chemical Properties

4.3.1 pH Water and pH Calcium Chloride of the Soils and the Geophagic

Materials

The soils from Tokorme 1 had alkaline pH which ranged from 7.06 to 7.20 (Table 4.3).

The soil from Tokorme 2 was slightly acidic (pH 6.48) in the surface layer but strongly

acidic in the subsurface to bottom layers (pH 4.28 to 4.97). Below the surface, the pH

decreased gradually with depth. The pH (H2O) of Tokorme 3 showed a trend that was the

reverse of that of Tokorme 2. The soil was slightly acidic in the surface and subsurface

layers but strongly acidic in the bottom layer. The pH (H2O) of the Wuve soil ranged from

slightly acidic (pH 6.71) in the surface layer to moderately acidic (pH 6.05) in the bottom

layer. Apart from Tokorme 1, the pH of the soils decreased with depth. The pH (H2O) of

the geophagic materials was strongly acidic (pH 3.5 to 4.70).

The pH (CaCl2) of the soil from Tokorme 1 was moderately acidic which ranged from pH

(5.94 to 6.22) (Table 4.3). The pH (CaCl2) of Tokorme 2 was moderately acidic at the

surface (pH 5.12) but strongly acidic in the subsurface to bottom layer (pH 3.52 to 3.64).

The soil from Tokorme 3 was moderately to slightly acidic (pH 5.42 to 6.39) in the surface

to the subsurface soils but strongly acidic in the bottom soils (pH 4.61 to 4.93). The pH

(CaCl2) of the Wuve soil was moderately acidic from the surface soil to the bottom soils

(pH 5.53-6.10). Apart from Wuve, the pH (CaCl2) of the soils tended to decrease with

depth. The pH (CaCl2) of the geophagic materials was strongly acidic (pH 3.34 to 3.60).


Generally, the electrical conductivity of the soils decreased with depth (Table 4.3). The

values ranged from 0.07 to 0.16 dS m-1 (Tokorme 1), 0.07 to 0.12 dS m-1 in Tokorme 2,


49

0.07 to 0.15 dS m-1 in Tokorme 3 and 0.05 to 0.13 dS m-1 in Wuve. The electrical

conductivity of the geophagic materials was about two to four folds higher than that of the

soils. It ranged from 0.6 dS m-1 in Tokorme 1 to 0.22 dS m-1 in Tokorme 2.

4.3.3 Total Nitrogen Content of the Soils and Associated Geophagic Materials

The total nitrogen content of the soils and their associated geophagic materials was very

low (Table 4.3). In all the soils, total nitrogen content generally decreased with depth.

However, Tokorme 1 and Tokorme 2, contained relatively higher amounts. Generally, the

geophagic materials, with the exception of Tokorme 3, contained lower amounts of total N

in the surface and subsurface soils than was found in their associated soils.

4.3.4 Organic Carbon Content of the Soils and the geophagic materials

With the exception of Tokorme 3, the organic carbon content of the surface layers of the

soils was moderately high, particularly in Tokorme 1 (3.37%) (Table 4.3). Soils from the

20-30 cm and 30-40 cm at Tokorme 1 contained >1.0% organic carbon. The organic carbon

content of all the soils decreased sharply from the surface soil to the subsurface soils, and

generally decreased with depth. The geophagic materials contained much lower amounts

of organic carbon which ranged from 0.07 to 0.10%.

4.3.5 Phosphorus Content (Total and Available) of the Soils and the Geophagic

Materials

The available P content of the soils was low (< 10.0 mg kg-1) and tended to decrease with

depth (Table 4.3). The geophagic materials also contained small amounts of available P

(5.36 to 11.52 mg kg-1) which were generally comparable to the levels in the soils. The

total P content of the soils was very low (< 50.0 mg kg-1). The geophagic materials also


50

contained very low amounts of total P (< 80.0 mg kg-1) but the levels were relatively higher

than those found in the soils. The total P content in the geophagic materials of Tokorme 1

was about twice the levels in the geophagic materials from the other sites.


51

Table 4.3 Selected Chemical Properties of the Soils and Geophagic Materials.

Depth pH(H2O) pH(CaCl2) E.C1 Total N2 O.C3 Available P4 Total P

(cm) (dS m-1) (%) (%) (mg kg-1) (mg kg-1)

Tokorme1

0-20 7.20 6.22 0.16 0.44 3.37 7.06 31.30

20-30 7.16 6.15 0.14 0.39 1.95 3.50 31.80

30-40 7.06 6.04 0.10 0.37 1.05 6.20 28.35

40-50 7.12 6.00 0.07 0.32 0.63 3.68 48.15

50-60 7.07 5.96 0.07 0.23 0.59 5.10 50.80

Tokorme 2

0-20 6.48 5.12 0.12 0.42 1.80 8.48 48.55

20-30 4.97 3.64 0.07 0.33 0.44 9.62 41.40

30-40 4.95 3.62 0.07 0.27 0.59 6.00 43.05

40-50 4.90 3.52 0.07 0.12 0.33 3.98 46.85

50-60 4.28 3.60 0.09 0.14 0.78 5.10 48.60

Tokorme 3

0-20 6.62 6.39 0.15 0.18 0.51 9.26 43.25

20-30 6.58 5.66 0.08 0.09 0.28 7.38 36.35

30-40 6.33 5.42 0.09 0.10 0.45 4.42 31.85

40-50 6.22 4.93 0.07 0.09 0.27 4.52 31.25

50-60 4.67 4.61 0.08 0.08 0.29 2.60 36.95

Wuve

0-20 6.71 6.10 0.13 0.26 1.97 7.34 40.40

20-30 6.55 5.53 0.07 0.11 0.51 6.12 22.55

30-40 6.48 5.62 0.06 0.07 0.16 3.12 23.25

40-50 6.52 5.57 0.05 0.04 0.16 2.96 18.20

50-60 6.05 5.69 0.05 0.05 0.20 3.84 23.55

Geophagic Materials

Tokorme 1 3.58 3.34 0.60 0.23 0.07 11.52 67.90

Tokorme 2 4.27 3.57 0.22 0.06 0.08 5.36 46.85

Tokorme 3 4.28 3.48 0.20 0.23 0.10 5.82 60.50

Wuve 4.70 3.60 0.12 0.20 0.07 6.00 51.35

1E.C = electrical conduction, 2N = nitrogen, 3O.C = organic carbon, 4P = phosphorus


52

4.3.6 Exchangeable Bases and Cation Exchange Capacity of the Soils and

Geophagic Materials

The four soil samples contained very low levels of exchangeaable bases (Table 4.4). Their

exchangeable Ca content ranged from 0.057 to 0.829 cmolc kg-1. The exchangeable Mg

content of the soils ranged from 0.072 to 0.193 cmolc kg-1. The exchangeable K content

ranged from 0.016 to 0.129 cmolc kg-1 and Na from 0.0001 to 0.0031 cmolc kg-1. The

geophagic materials from the four sites had comparably low levels of exchangeable bases.

The CEC of the soils ranged from 5.29 to 22.56 cmolc kg-1. Generally, the soil from Wuve

had the lowest CEC. The CEC of the geophagic materials was relatively higher (18.00 to

23.18 cmolc kg-1) than that of the soil samples.


53

Table 4.4. Exchangeable Bases and Cation Exchange Capacity of the Soils and Geophagic

Materials.

Depth Ca Mg K Na CEC

(cm) (cmolc kg-1)

Tokorme 1

0-20 0.829 0.168 0.054 0.0028 13.79

20-30 0.548 0.153 0.052 0.0020 19.44

30-40 0.292 0.159 0.035 0.0015 10.69

40-50 0.117 0.117 0.016 0.0001 10.28

50-60 0.173 0.128 0.023 0.0008 8.89

Tokorme 2

0-20 0.237 0.186 0.071 0.0007 17.17

20-30 0.468 0.130 0.034 0.0005 12.57

30-40 0.560 0.177 0.053 0.0017 16.88

40-50 0.434 0.181 0.042 0.0018 16.42

50-60 0.068 0.193 0.042 0.0010 13.04

Tokorme 3

0-20 0.264 0.164 0.107 0.0010 15.81

20-30 0.069 0.150 0.093 0.0009 11.37

30-40 0.060 0.158 0.108 0.0003 13.80

40-50 0.059 0.168 0.129 0.0010 13.46

50-60 0.075 0.158 0.111 nd 22.56

Wuve

0-20 0.474 0.181 0.069 0.0031 14.94

20-30 0.080 0.108 0.041 0.0009 10.85

30-40 0.596 0.094 0.025 0.0009 6.08

40-50 0.215 0.072 0.030 0.0025 5.29

50-60 0.057 0.106 0.027 0.0005 6.59

Geophagic Materials

Tokorme 1 0.020 0.024 0.121 0.0028 20.19

Tokorme 2 0.048 0.170 0.048 0.0040 23.18

Tokorme 3 0.040 0.068 0.043 0.0023 18.00

Wuve 0.092 0.106 0.043 0.0019 21.92

nd = not detected.


54

4.4 Mineralogical Composition of the Rocks, Geophagic Materials and Soils

4.4.1 Thin Section Petrography of Rock Samples

Visual examination and thin section analysis of the rock samples from the pits at the study

sites were done. The visual examination revealed characteristics namely grain sizes,

mineral composition as well as texture of the rocks encountered in the study area. Apart

from the grain size, texture and mineralogical composition, the thin sections also revealed

petrographic features namely structures and deformations of the rock samples. Modal

estimation was done by the visual counting of their individual mineral grains present. The

major rock types encountered in all the study sites were mainly sandstones.

4.4.1.1 Thin Section of Rock Sample from Tokorme 1

This rock was grey, but reddish-brown on the weathered surface (Figure 2a). The rock was

a clastic with fine to medium grains of feldspar, quartz and other clastic materials.

Microscopically, the rock is composed of rounded to sub-rounded grains which were

poorly sorted. It was composed of quartz, minor feldspar, sericite and other rock fragments

which were cemented by iron oxide. The rock was very rich in quartz some of which

exhibited undulose extinction. The feldspars were significantly altered into sericite. The

rock fragments contained rounded fine grains of quartz.

Table 4.5a. Modal Composition of Rock Sample from Tokorme 1.

Minerals Volume (%) Characteristics

Quartz 86 Rounded to sub-rounded, mostly undulose

Feldspar 9 Mostly altered into sericite

Sericite 5 Secondary products of altered feldspar


55

Figure 2a. Sandstone showing sub-rounded to rounded grains that were cemented by iron

oxide in the rock sample from Tokorme 1.

4.4.1.2 Thin Section of Rock Samples from Tokorme 2

The rock was grey, thinly bedded and medium to coarse grained (Figure 2b). It was poorly

sorted and composed of sub-rounded to rounded feldspar and quartz with other rock

fragments. The rock felt gritty to touch and did not fizz with dilute HCl.

Petrographically, the rock was fine to medium grained with rounded to sub-rounded and

poorly sorted grains. It was composed of mainly quartz, feldspars, and other rock

fragments, which had been cemented by iron (Fe) oxide. Quartz exhibited undulose

extinction which indicated deformation. The feldspars were completely or partially altered

into sericite, however, with preserved pseudomorphs.


56

Table 4.5b. Modal Composition of Rock Sample from Tokorme 2.



Feldspar 10 Significantly altered into sericite


Figure 2b. Sub-rounded to rounded grains cemented by iron oxide in rock sample from

Tokorme 2.

4.4.1.3 Thin Section of Rock Samples from Tokorme 3

The rock was grey, thinly bedded and medium to coarse grained. The rock felt gritty to

touch and did not fizz with dilute HCl. The rock was fine to medium grained, rounded to

sub-rounded, and poorly sorted. It was composed of mainly quartz, feldspars, and other

rock fragments, which were cemented by iron (Fe) oxide. Quartz exhibited undulose


57

extinction which indicated deformation. The feldspars were completely or partially altered

into sericite, however, with preserved pseudomorphs.

Table 4.5c. Modal Composition of Rock Sample from Tokorme 3.





Figure 2c. Sutured and recrystallised quartz in rock sample from Tokorme 3.

4.4.1.4 Thin Section of Rock Samples from Wuve

This rock was grey but reddish-brown on weathered surface (Figure 2d). The rock was

clastic with fine to medium grains of feldspar, quartz and other clastic materials. The rock

was massive, gritty and friable. It did not react with dilute HCl.


58

Microscopically, the rock was clastic, fine to medium grained and contained rounded to

sub-rounded grains which were poorly sorted. It was composed of quartz, minor feldspar,

sericite and other rock fragments which were cemented by iron oxide. The rock was very

rich in quartz some of which exhited undulose extinction. The quartz grains were mostly

round to sub-rounded. Feldspars were significantly altered into sericite. The rock fragments

contained rounded fine grains of quartz.

Table 4.5d. Modal Composition of Rock Sample from Wuve.





Figure 2d. Sandstone with poorly-sorted grains that are slightly elongated in rock sample

from Wuve.


59

4.4.2 Thin Sections of Geophagic Materials

Thin sections of the geophagic materials from Tokorme 1 and Tokorme 2 were done.

4.4.2.1 Thin Section of Geophagic Materials from Tokorme 1

The material was purple-grey, slightly weathered and fine to medium grained (Figure 3a).

This material had a clastic texture and was composed of feldspar, clay and quartz. It

exhibited thin parallel laminations with possible tangential cross-laminations and visible

joints. The material was friable, lacked fissility and did not react with dilute HCl.

Petrographically, the material was fine to medium grained, thinly laminated and exhibited

tangential cross-laminations. It was composed dominantly of clay with minor feldspars and

quartz (Table 4.6a). The quartz grains occured as impregnated clasts of silty sand size

particles embedded in the fine grained clay ground mass. The clay was fine and composed

of mainly fine flakes of sericite. The feldspars were significantly altered to sericite with

well preserved pseudomorphs.

Table 4.6a. Modal Composition of the Geophagic Materials from Tokorme 1.


Clay 88 Fine grained, mainly flakes of sericites

Feldspar 8 Significantly altered to sericite but with preserved pseudomorphs

Quartz 4 Secondary, occured as impregnated grains


60

Figure 3a. Thin lamination of the geophagic materials from Tokorme 1.

4.4.2.2 Thin Section of Geophagic Materials from Tokorme 2

The material was purple-grey, slightly weathered and fine to medium grained (Figure 3b).

This material had a clastic texture and was composed of feldspar, clay and quartz (Table

4.7b). It exhibited thin parallel laminations with possible tangential cross-laminations and

visible joints. The material was friable, lacked fissility and did not react with dilute HCl.

The material was fine to medium grained in thin section, thinly laminated and exhibited

tangential cross-laminations. It was composed dominantly of clay with minor feldspars and

quartz. The quartz grains occured as impregnated clasts of silty sand size embedded in the

fine grained clay ground mass. The material was fine and composed of mainly fine flakes

of sericite. The feldspars were significantly altered to sericite with well preserved

pseudomorphs.


61

Table 4.6b. Modal Composition of the Geophagic Materials from Tokorme 2.


Clay 89 Fine grained, mainly flakes of sericites

Feldspar 7 Mostly altered to sericite but with preserved pseudomorphs

Quartz 4 Secondary, occured as impregnated grains

Figure 3b. Silty-sand size quartz grains occuring as impregnation within the fine grained

matrix of sericite in geophagic materials from Tokorme 2.

4.4.3 X-Ray Diffractograms of Rock Samples

The dominant minerals identified in the diffractograms of the rock samples from the study

areas were quartz (3.34 Å), kaolinite (7.20 Å, 4.26 Å, 2.45 Å), mica (10.02 Å, 1.65 Å), and

feldspar (4.98 Å, 2.56 Å, 1.50 Å) in all the samples. Representative X-ray diffractograms

showing the peaks of dominant minerals are presented in (Figures 4a, 4b, 4c, 4d).


62

Figure 4a. X-ray diffractogram of a rock from Tokorme 1.

Figure 4b. X-ray diffractogram of a rock from Tokorme 2.


63

Figure 4c. X-ray diffractogram of a rock from Tokorme 3.

Figure 4d X-ray diffractogram of a rock from Wuve.


64

4.4.4 X-Ray Diffractogram of the Geophagic Materials

X-ray diffractograms of the geophagic materials from the study sites showed the presence

of quartz as the dominant mineral in all the samples. Kaolinite was also in all the samples.

Other minerals present included feldspar and mica. X-ray diffractograms showing the

peaks of the major minerals in a representative geophagic materials are presented in

(Figures 5a, 5b, 5c, 5d). The dominant minerals identified included quartz (3.34 Å),

kaolinite (7.23 Å, 4.26 Å, 3.52 Å, 2.45 Å), mica (10.05 Å), feldspar (3.15 Å), and

muscovite (4.98 Å, 4.50 Å, 2.57 Å).

Figure 5a. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic

materials from Tokorme 1.


65

Figure 5b. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic


Figure 5c. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic



66

Figure 5d. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of the geophagic

materials from Wuve.

4.4.5 X-Ray Diffractograms of Soil Samples (clay fractions)

The X-ray diffractograms of the soils from the study sites showed the presence of quartz

as the dominant mineral in all the samples. Kaolinite was also present in all the samples.

Other minerals present included feldspar, muscovite and mica. Representative X-ray

diffractograms showing peaks of the major minerals in representative soil samples are

presented in (Figures 6a, 6b, 6c, 6d). The dominant minerals identified included quartz

(3.35 Å), kaolinite (7.21 Å, 3.58 Å), mica (10.04 Å, 1.99 Å), montmorillonite (15.43 Å),

and muscovite (5.01 Å, 4.7 Å, 2.57 Å).


67

Figure 6a. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Tokorme 1.


68

Figure 6b. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Tokorme 2.

Figure 6c. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Tokorme 3.


69

Figure 6d. X-ray diffractograms of K-25, K-350, and K-550 clay fraction of soil from

Wuve.

4.5 Heavy Metal Content of the Geophagic Materials

The concentrations of ten heavy metals in the four geophagic materials were determined

(Table 4.7). The concentration of vanadium (V) ranged from 169.2 mg kg-1 in Tokorme 2

to 201.5 mg kg-1 in Wuve. The concentration of chromium ranged from 98.7 mg kg-1 in

Tokorme 2 to 117.0 mg kg-1 in Tokorme 3. Cobalt concentration ranged from 19.2 mg kg-

1 in Tokorme 1 to 27.3 mg kg-1 in Tokorme 3. Nickel concentration ranged from 7.0 to 8.6

mg kg-1. The concentration of Cu ranged from 19.6 to 22.4 mg kg-1. The concentration of


70

Zn ranged from 22.4 mg kg-1 to 31. 7 mg kg-1. The concentrations of As, Cd, and Hg were

0.9 to 1.2 mg kg-1, 0.5 to 1.1 mg kg-1 and 0.1 to 0.5 mg kg-1 respectively. Lead was detected

only in Tokorme 2 and the concentration was 0.06 mg kg-1.

Table 4.7. Concentration of Heavy Metals in the Geophagic Materials.

Sample V Cr Co Ni Cu Zn As Cd Hg Pb

(mg kg-1)

1 171.9 110.2 19.2 8.6 20.9 29.1 1.2 1.1 0.2 nd

2 169.2 98.7 20.3 8.6 21.9 22.4 1.1 0.6 0.5 0.06

3 175.4 117.7 27.3 7.0 19.6 31.7 0.9 0.7 0.3 nd

4 201.5 100.5 21.0 8.5 22.4 30.0 1.2 0.5 0.1 nd

nd = not detected.

4.5.1 Health Risk Index (HRI) Analyses of Heavy Metals in the Geophagic

Materials

The average daily intake of geophagic materials among women of reproductive age in

Ghana is 70 g day-1 (Tayie et al., 2013). Using the WHO/FAO (2010) average body weight

of 60 kg for the Ghanaian geophagist and a daily intake of 70 g of geophagic materials, the

daily intake of metal (DIM) and the health the risk index (HRI) were calculated (Tables

4.8a, 4.8b, 4.8c, 4.8d). The DIM multiplied by the concentration of the metal in the

geophagic clays (mg kg-1) was estimated according to the formula of Cui et al. (2004). The

health risk level of these heavy metals in the geophagic materials from Anfoega was

computed according to the HRI (USEPA, 2002). It is expressed as the ratio of exposure to

the heavy metal to the oral reference dose (RfD) of metal.


71

Table 4.8a. Health Risk Index of Heavy Metals in the Geophagic Materials from Tokorme 1.

Element V Cr Co Ni Cu Zn As Cd Hg Pb

MC 171.9 110.2 19.2 8.6 20.9 29.1 1.2 1.1 0.2 nd

DIM 0.2006 0.1286 0.0224 0.0100 0.0244 0.0340 0.0014 0.0013 0.0002 0.0000

HRI 0.1114 0.7347 0.0250 0.2508 0.0122 0.0023 0.0014 0.1283 0.1167 0.0000

MC = Metal concentration (mg kg-1), DIM = Daily intake of metal = [(MC x DIC)/BW], DIC = Daily intake of

clay

(mg/day), BW = Average body weight (g), HRI = Health risk index, RfD = Reference dose (mg kg-1),

nd = not detected.

Table 4.8b. Health Risk Index of Heavy Metals in the Geophagic Materials from Tokorme 2.


MC 169.2 98.7 20.3 8.6 21.9 22.4 1.1 0.6 0.5 0.06

DIM 0.1974 0.1151 0.0237 0.0100 0.0256 0.0261 0.0013 0.0007 0.0006 0.0001

HRI 0.1097 0.6580 0.0263 0.2508 0.0128 0.0017 0.0713 0.0700 0.2917 0.0000


clay


nd = not detected.


72

Table 4.8c. Health Risk Index of Heavy Metals in the Geophagic Materials from Tokorme 3.


MC 175.4 117.7 27.3 7.0 19.6 31.7 0.9 0.7 0.3 nd

DIM 0.2046 0.1356 0.0319 0.0082 0.0229 0.0300 0.0011 0.0008 0.0003 0.0000

HRI 0.1137 0.7800 0.0354 0.2043 0.0114 0.0025 0.0583 0.0817 0.1750 0.0000


clay


nd = not detected.

Table 4.8d. Health Risk Index of Heavy Metals in the Geophagic Materials from Wuve.


MC 201.5 100.5 21.0 8.5 22.4 30.0 1.2 0.5 0.1 nd

DIM 0.2351 0.1173 0.0245 0.0099 0.0261 0.0350 0.0014 0.0006 0.0002 0.0000

HRI 0.1306 0.6700 0.0272 0.2479 0.0131 0.0023 0.0778 0.0583 0.0583 0.0000


clay


nd = not detected.


73

4.6 Microbiological Analysis

Bacteria count and population of coliform in the geophagic materials are presented in Table

4.9. The total count ranged from 1.0 x 104 to 1.3 x 106 cfu g-1. The processed-fresh and the

processed-dry geophagic materials contained higher counts than the powdered samples.

The processed-fresh geophagic materials showed a count of 6.0 x 104 to 6.3 x 105 cfu g-1.

Whereas the powdered geophagic materials had the smallest bacterial count of 1.0 x 104

to 2.7 x 105 cfu g-1, the processed dry samples had a total count of 1.0 x 104 to 1.3 x 106

cfu g-1

The processed-smoked sample had a similar total heterotroph count (1.0 x 104 cfu g-1) as

the powdered samples from Tokorme 1 and Tokorme 3. The geophagic materials did not

show any total coliform nor faecal coliform.


74

Table 4.9. Total Heterotroph Count, Total Coliform Coliform and Faecal Coliform in the

Geophagic Materials.

Sample Total Count Total Coliform Feacal Coliform

(cfu g-1) (cfu g-1) (cfu g-1)

PF1 6.0x104 nd nd

PF2 3.0x105 nd nd

PF3 6.3x105 nd nd

PF4 4.1x105 nd nd

P1 1.0x104 nd nd

P2 5.0x104 nd nd

P3 1.0x104 nd nd

P4 2.7x105 nd nd

PD1 1.0x104 nd nd

PD2 1.3x106 nd nd

PD3 1.2x105 nd nd

PD4 1.2x105 nd nd

PS 1.0x104 nd nd

1 = Tokorme 1, 2 = Tokorme 2, 3 = Tokorme 3, 4 = Wuve. PF = Processed-fresh,

P = Powder, PD = Processed-dry, PS = Processed-smoked, nd = not detected.


75

4.7 Responses from the Interviews

4.7.1 Miners

Four miners were interviewed about their mining activities. All the miners interviewed

were males aged 27 to 50 years. They indicated that clay mining was the only job in town.

Two of the miners entered the business voluntarily while two others were introduced to it

by close relatives. They had been in the business for periods ranging 5 to 30 years. All of

them decribed the work to be very tedious and risky. They indicated that although the

business was lucrative, they were always afflicted by ailment such as joint pains, bodily

pains and fever. Three of the miners conceded that the mining activities posed

environmental and health threats. None of the miners had plans of reclaiming the land after

mining. They were rather of the opinion that nature will reclaim the mined pits. All the

miners indicated that they also practised geophagy and agreed that the habit predisposed

them to ailments such as constipation, diarrhoea and stomach upset.

4.7.2 Dealers (women involved in the processing and marketing)

Ten dealers were interviewed about their activities. All the dealers interviewed were

females aged 22 to 75 years. They had been in the clay business for periods ranging from

5 to 30 years. They all indicated that they obtained the raw materials from local miners and

that they processed them by themselves. While nine (9) indicated that they practised

geophagy, one was not willing to indicate whether she ingested the material or not. Reasons

they assigned for practising geophagy included, test to determine quality during processing,

nausea, sometimes craving during pregnancy, to alleviate chest pain, ease of heart burn,

control of diarrhoea and mere craving for the material. Eight (8) of them recounted benefits

they derived from eating the clay which included control for nausea, diarrhoea and stomach


76

aches. Two others claimed they were not sure of the benefits of ingesting the material. They

also indicated that consumption of the clay caused constipation, white stool and bloated

stomach. Other women interviewed, outside the dealers, confirmed the views of the dealers

about the practice of geophagy.

4.7.3 Health Personnel

Health personnel were interviewed at the Wuve Health Post, the Anfoega Hospital and the

Margaret Marquart Hospital at Kpando. They all admitted that earth eating was prevalent

in their area. They were of the opinion that the practice could have health implications.

However, none of the outfits had records on practitioners who might have reported at their

facilities with ailments due to the practice of geophagy. They all conceded that as part of

their public health responsibilities they should have captured possible health implications

of mining activities, processing and ingestion of the materials over the many years that the

business had gone on in the area.


77

CHAPTER FIVE

DISCUSSION

5.1 Physical Properties

5.1.1 Particle Size Distribution and Texture

The petrographic examinations revealed that the rock samples were mainly sandstones

(quarzitic). The diffractograms also showed high amounts of quartz in the soils, rocks and

geophagic materials. These results explain the high amounts of sand in the soils. However,

the soils from Tokorme 3 showed relatively high amounts of clay which may be due to the

fact that the Buem units also contained appreciable amounts of calcareous and argillaceous

materials (Kesse, 1985). Moreover, the relatively lower altitude of Tokorme 3 might have

resulted in it receiving a lot of eroded materials from higher elevation. Dickson et al.

(1995), had reported that soils from the area were formed from the eroded materials of the

Togo units and are made up of sedimentary rocks which are basically shales and

sandstones. The geophagic materials contained high amount of clay. They contained

moderate amounts of silt and a very small amounts of sand. The petrographic analysis of

the geophagic material showed that 88% of its volume was made up of clastic sedmentary

clay (mudstone). The high clay content of the geophagic materials makes them easily

ingestible (Ekosse et al., 2010; Ngole et al., 2010) and less harmful to practitioners (Konta,

1995).

5.1.2 Bulk Density

Generally, all the soils showed consistent increase in bulk density with depth. Bulk density

typically increases with soil depth due to decreasing levels of organic matter content, less

aggregation, and root proliferation and compaction caused by the weight of the overlying


78

layers (Tsimba et al., 1999). Soils and horizons with high organic matter tend to have lower

bulk density probably due to higher biological activity which results in the creation of more

soil pores (Alexander, 1980). The bulk density of the soils were lower than levels restrictive

to root growth (Hunt and Gilkes, 1992; McKenzie et al., 2004).

5.2 Chemical Properties

5.2.1 pH (H2O) and pH (CaCl2) of Soils and Geophagic Materials

In general, the soils from Tokorme 2, Tokorme 3, and Wuve were acidic. On the other

hand, the soils from Tokorme 1 was slightly alkaline. The acidic pH of the soils may be

attributed mainly to the mineralogy of the parent materials. The soils were derived from

SIALIC rocks (rocks rich in silica and alumina), mainly sandstones. Also the x-ray

diffractograms of the soils showed that they contained high amounts of SIALIC minerals

namely quartz, feldspars and muscovite. The relatively higher pH (H2O) of Tokorme 1

could be partly due to its location at a higher altitude and thus experienced less leaching of

the basic cations. The pH values of the geophagic materials were generally strongly acidic.

The low pH of the geophagic materials could be attributed to the high concentration of

SIALIC minerals particularly quartz, feldspars and muscovite. Abrahams and Parsons

(1997) reported that many geophagic materials are acidic thus imparting a sour taste to

them. The sour taste of the geophagic materials is beneficial during pregnancy to prevent

excessive secretion of saliva and thus reduces nausea as reported by (Ibeanu et al., 1997)

among women in Kenya and Nigeria.

The pH (CaCl2) values of the soil samples and their associated geophagic materials were

lower than their pH (H2O) values. Thus, their ΔpH [pH (H2O) - pH (CaCl2)] would be


79

negative. The negative ΔpH values is an indication that the geophagic materials would

possess negative charges (Tan, 1982).


The soils and their associated geophagic materials from the study sites were non-saline

because their EC values were far lower than the critical value of 2 dS m-1 (FAO, 1988).

The low EC levels of the geophagic materials implies that they contained low levels of

dissolved salts. Thus the geophagic materials from Anfoega may show poor flocculation

when ingested. This is a positive sign because the geophagic materials will not promote

the coating of the intestinal mucosa.

5.2.3 Total Nitrogen Content

The total nitrogen content of the soils and their associated geophagic materials was very

small and decreased with decreasing organic carbon content. Organic matter (carbon) is a

good source of N from which microbes could synthesize protein (Baddock and Nelson,

2000; Pierzynski et al, 2000).

5.2.4 Organic Carbon

The organic carbon content of the soils declined sharply with depth. This result was due to

the fact that the soil surface served as the repository for litter fall from vegetation and was

also the zone of vigorous microbial activities (Nelson et al. 1994). Generally low levels of

organic carbon in the soils may be mainly due to the generally low biomass generation

from the savanna woodland vegetation in the area. The geophagic materials contained very

low amounts of organic carbon most probably due to their location, more than 9 m below


80

the soil surface. With low levels of organic carbon, the geophagic materials would also be

associated with low levels of microbes in the pits.

5.2.5 Available Phosphorus and Total Phosphorus content of the Soils and

Geophagic Materials

The available P content of all the soils was low and decreased with soil depth and pH. The

geophagic materials also contained very low available P. The acidic nature of the soils and

the respective geophagic materials might have contributed to fixing of P and thus reducing

the levels of available P (Nartey, 1994). The soils and the geophagic materials also

contained small amounts of total P. The geophagic materials contained relatively higher

levels of total P probably due to the fact that they fixed more P because of their lower pH

levels.

5.2.6 Exchangeable Bases and Cation Exchange Capacity

All the soils and the geophagic materials showed very low levels of exchangeable bases

probably due to the paucity of these bases in the parent materials and also leaching. The

soils had moderate amounts of CEC. The geophagic materials had higher CEC levels than

the soil. The levels of exchangeable bases and CEC in the soils and the geophagic materials

may be due to a combination of factors including types of clay minerals, amount of clay

and organic carbon content (Landon, 1991). The relatively higher CEC of the geophagic

mterials may be due to the higher amounts of clay they contained.


81

5.3 Mineralogy

5.3.1 Thin Section Petrography of the Geophagic Materials and Rocks

The composition of the geophagic materials were dominated by clay minerals. They also

contained quartz and sericite (degraded feldspar). This result is due to the fact that the

materials were clastic sedimentary rocks which were lithologically silty mudstones. The

thin section of the rock also revealed quartz and relatively small amounts of feldspar and

sericite. The presence of these minerals showed that the rocks were sedimentary sandstones

(quartz arenite). Kesse (1985) had reported that the Buem formation from which these

rocks were obtained consist of calcareous, argillaceous, greywacke and ferruginous shale,

sandstones and conglomerates. The thin section results revealed that the geophagic

materials and the rocks were dominated by SIALIC minerals.

5.3.2 X-Ray Examination

5.3.2.1 The X-ray Diffractograms of Rocks

The X-ray diffractograms of representative rock samples revealed quartz, feldspar,

muscovite and kaolinite as the dominant minerals present in all the samples. Thus, the

samples were clearly SIALIC in mineralogical composition. The Bliku hills of Anfoega

where the rock samples were taken from, belong to the Buem formation which according

to Kesse, (1985) are predominantly composed of shales and sandstones.

5.3.2.2 The X-ray Diffractograms of the Soils

The X-ray diffractograms of the soils were dominated by minerals like quartz (3.35 Å),

kaolinite (7.21 Å, 3.58 Å), mica (10.04 Å, 1.99 Å), montmorillonite (15.43 Å) and

muscovite (5.01 Å, 4.7 Å, 2.57 Å) in all the samples. These minerals were also revealed by

the x-ray diffractograms of the rocks. These results showed that the soils were probably

Fe

Fe


82

formed in situ from the underlying rocks. The high quartz content of the soils probably

explains why the soils contained high amount of sand. The collapsed peaks at 12.28 (2Ө)

of the samples at 550 oC is a comfirmation of the presence of kaolinite.

5.3.2.3 The X-ray Diffractograms of the Geophagic Materials

The X-ray diffractograms of the geophagic materials showed dominant minerals like quartz

(3.34 Ǻ), kaolinite (7.23 Å, 4.26 Å, 3.52 Å, 2.45 Å), mica (10.05 Å), feldspar (3.15 Å) and

muscovite (4.98 Å, 4.50 Å, 2.57 Å). All these minerals were also revealed in the soils as

well as the rock samples. The collapse of peaks at 12.28 (2Ө) of the geophagic materials

at 550 oC confirms the presence of kaolinite. The low pH values and the presence of

minerals such as quartz, muscovites and feldspars suggest that the geophagic materials

might have been derived from the overlying rocks

5.4 Levels of Heavy Metals (HM) in Geophagic Materials

The HM content of the geophagic materials were low probably due to their inherently low

levels in their parent material and also the low effect of human activity. The health risk

index levels of the heavy metals contained in 70 g (average daily intake) of the geoghagic

clay were all less than 1.0 indicating that the geophagic materials from Anfoega appear to

be safe for human consumption. If the hazard index exceeds 1.0, there could be a potential

human health effect (Huang et al., 2008). The health risk assessment for all the sites in this

study indicated that the geophagic materials from Anfoega do not pose any HM-related

health hazard. However, geophagists would have to be wary of the cumulative effects of

long term exposure to the metals. Long term exposure to Pb, As, Cd, Cr and Hg have been

reported to cause gastro-enteritis, inhibition of haemoglobin formation, sterility,

miscarriage, growth retardation, central nervous system disorder, kidney dysfunction,


83

hypertension and mental retardation (Amdur, 1991; Ming-HO, 2001; Meharg, 2005).

Although some metals such as Cu, Co, Ni, V and Zn are essential micronutrients, they can

also become harmful to the geophagists after prolonged eating of clay materials.

5.5 Microbial Analysis

5.5.1 Heterotrophic Bacterial Count and Coliform Numbers in the Geophagic

Meterials

The total heterotroph count in the geophagic materials generally followed the order,

processed-fresh ≥ processed-dry > powdered > smoked. The relatively high number of

bacteria load present in the freshly processed material was probably the result of

unhygienic or insanitary conditions under which the material was processed. However, no

total coliform or faecal coliform was detected in the samples. The coliform group of

bacteria are reliable indicators of faecal pollution and general insanitary conditions. Thus,

their absence in all the samples is indicative of the possible absence of toxigenic

microorganisms in the samples. Looking at the depth from which the materials were mined

and their strong acidic nature coupled with the fact that there was no coliform group of

bacteria present in all the samples, the high bacteria load would most probably have been

introduced during the production stage through poor handling and exposure to

environmental organisms.

Clearly, application of heat to the material (processed smoked) might have reduced the

bacteria load. In general, the results of the microbiological analysis suggest that the

microbial contamination of the material, occured during processing. The material, therefore

appears to be naturally safe for consumption. Although generally perceived as harmful,

geophagia may enhance bio-activity and maintenance of normal intestinal flora (Tano-


84

Debrah and Bruce-Baiden, 2010), the production of natural antibiotics (Abrahams, 2002)

and biodegradable toxic substances in the gastrointestinal tract (Ragnarsdottir, 2000).

5.6 Questionnaire

Information gathered from the interviews revealed that the mining activities posed serious

threat to the environment and the people in the study area. There appeared to be no

reclamation going on because the activities of the miners were not regulated by the

Environmental Protection Agency. Although not medically ascertained, the ingestion of

the material seemed to provide some benefits to the consumers. The interviews also

revealed that the health facilities in the study area had no records regarding the health

implications of ingesting the material.

Lack of medical records on geophagy may be probably due to the fact that the medical

personnel within the study area did not probe deep to determine the aetiology of some

diseases their patients present. It appeared that all cases were generally treated. On the

other hand, the reluctance of the people to seek medical attention when they fall ill, their

inability to give proper accounts of the cause of their illnesses and failure to disclose their

geophagic status might have contributed to the lack of the medical records on the practice.


85

CHAPTER SIX

CONCLUSIONS AND RECOMMENDATIONS

6.1 Conclusions

The texture of the soils was dominated by sand except for Tokorme 2 which had

high clay content, in the surface and subsurface layers. The geophagic materials

contained higher amounts of clay.

The pH of the soils from Tokorme 1, Tokorme 3 and Wuve ranged from slightly

acidic to moderately acidic. The pH of the soil from Tokorme 2 was moderately

acidic in the surface soil but strongly acidic in the subsoil and bottom layers. The

pH of the geophagic materials was strongly acidic.

With higher amounts of clay, the geophagic materials had higher CEC (18.0 to 23.2

cmolc kg-1) than the soils (5.3 to 22.6 cmolc kg-1).

The thin section petrography showed quartz, feldspar and sericite as the dominant

minerals in all the rock samples. The geophagic materials also showed the presence

of similar minerals but in smaller amounts. The thin sections of the geophagic

materials also revealed high amounts of clay minerals.

The x-ray diffractograms showed that the rock, soil samples and the geophagic

materials contained high amounts of quartz, kaolinite, muscovite and feldspars.

They also contained some small amounts of chlorite, haematite and

montmorillonite.

The high amount of SIALIC minerals in the soils shows that they were derived in-

situ from the underlying sandstones.


86

The strongly acidic pH of the geophagic materials was probably due to the

accumulation of SIALIC minerals through leaching of the overlying sandstone.

The health risks estimates of the geophagic materials, calculated based on a

consumption rate of 70 g day-1, indicated that the concentrations of all the heavy

metals were below the critical levels that would be injurious to human health.

However, long term ingestion of these materials could lead to bioaccumulation.

Microbial analysis revealed that the geophagic materials were naturally safe for

consumption but processing under unhygienic conditions could introduce

microorganisms.

The results of the study revealed that the health facilities in the study area namely,

the Wuve Health Post, the Anfoega Hospital and the Margaret Marquat Hospital,

Kpando had no records on the health implications of geophagia being practised by

mainly women in the study area.

6.2 Recommendations

This work did not conclusively show the direct linkage between the geophagic

materials and the overlying rocks and soils. To ascertain that the geophagic

materials were formed through leaching of the overlying sandstone, more work

including radioactive studies, need to be carried out.

Eventhough, the health risk index analysis of heavy metals in the geophagic

materials from Anfoega indicates that the materials are not unsafe for consumption,

there is the danger of bioaccumulation as a result of long term exposure. There is

therefore the need for proper and intensive education by the public health units of

the health facilities in the study area on the potential dangers of prolong practice of


87

geophagy. Also, periodic health checks must be done by the health personnel to see

if there is any possible build up of heavy metals in the geophagic individuals who

visit their facilities.


88

REFERENCES

Abass, K. (2004). A Regional Geographyy of Ghana. Delcam Publications, Accra, Ghana.

Abrahams, P. W. (1997). Geophagy (soil consumption) and iron supplementation in

Uganda. Tropical Medicine and International Health 2:617– 623.

Abrahams, P. W. (2000). Geophagy: an appraisal of a soil deliberately consumed by

pregnant women of an Asian community within the United Kingdom. European

Journal Soil Science.

Abrahams, P. W. (2002). Soils: their implications to human health. Science of Total

Environment, 291, 1-32.

Abrahams, P. W. (2005). Geophagy and the involuntary ingestion of soil: Essentials of

Medical Geology, 435-455.

Abrahams, P.W. (2009). Earth Eaters: Ancient and Modern Perspectives on Human

Geophagy. In: Landa E.R. and Feller C. eds. Soil and Culture, DOI 10.1007/978-90-

481-2960-73.

Abrahams, P. W., Follansbee, M., Hunt, A., Smith, B. & Wragg, J. (2006). Iron nutrition

and possible lead toxicity: an appraisal of geophagy undertaken by pregnant women

of UK Asian communities. Applied Geochemistry 21: 98 – 108.

Abrahams, P. W. & Parsons J. A. (1996). Geophagy in the Tropics: A literature review in

Geographical Journal vol.162, No. 1.

Abrahams, P. W. & Parsons J. A. (1997). Geophagy in the Tropics: An appraisal of three

geophagical materials. Environmental Geochemistry and Health. 19:19-22.


89

Ademuwagun, Z. A., Ayoade, J. A. A., Harrison, I. E. & Warren, D. M. (1979). The African

Therapeutic Systems. Waltham, Massachusetts USA: Crossroads Press. p. 273.

Aghamirian, M. R. & Ghiasian S. A (2009). Isolation and characterization of medically

important aerobic actinomycetes in soil of Iran (2006 - 2007). Open Microbiology

Journal, 3: 53-57.

Al-Rmalli, S. W., Jenkins, R. O., Watts, M. J. & Haris, P. I. (2010). Risk of human exposure

to arsenic and other toxic elements from geophagy: trace element analysis of baked

clay using inductively coupled plasma mass spectrometry. Environmental Health,

9:79.

Alexander, M. (1980). Effect of acidity on microorganisms and microbial processes in

soils. In: Hutcheinson, J. C. and Havas, M. eds. Effect of acid precipitation on

terrestrial ecosystem. Plenum, New York. 303-38.

Amdur, M. O., Doull, J. & Classen, C. D. (1991). The Basic Science of Poisons. Journal

of Soil Science, 49, 639-643.

Anell, B. & Langercrantz, S. (1958). Geophagical customs. Uppsella (Sweden); Studia

Ethnographica Upsaliensia. 17:1-84.

Ashenbach, J. (1987). "Eating Earth is Normal-At Times’’. The Toronto Star. National

Geographic News Service. 23 August, 1987, 2nd Ed.: H6.

Aufreiter, S., Hancock, R. G. V., Mahaney, W. C., Stambolic R. A. & Sanmugadas, K.

(1997). Geochemistry and mineralogy of soils eaten by humans. International

Journal of Food Science and Nutrition. 48: 293 -534.


90

Baddock, J. A. & Nelson, P. N. (2000). Soil organic matter. CRC Press.

Bisi-Johnson, M. A., Obi, C. L. & Ekosse, G. E. (2010). Microbiology and Health related

perspectives of geophagia. An overview. African Journal of Biotechnology, 9: 19,

5784-5791.

Brady N. C. & Weil R. R. (1999). The nature and properties of soil. 12th ed. Prentice Hall,

New Jersey, USA. p.852.

Brady, N. C. & Weil, R. R. (2002). The nature and properties of soil. 13th ed. Springer

Netherlands, p.249.

Brand, C. E., De Jager, L. & Ekosse, G. (2009). Possible health effects associated with

human geophagic practice: an overview. Medical Technology. SA, 23: 11-13.

Bray, R. H. & Kurtz, L. T. (1945). Determination of total, organic, and available forms of

phosphorus in soils. Soil Science 59: 39-45.

Browman, D. L. & Gundersen, J. N. (1993). Altiplano comestible earths: prehistoric and

historic geophagy of highland Peru and Bolivia. Geoarcheology 8 (5), 413–425.

Calabrese, E. J., Stanek, E. J., James, R. C. & Roberts, S. M. (1997). Soil ingestion: a

concern for acute toxicity in children, Environmental Health Perspective. 105, 1354–

1358.

Callahan, K. L. (2000). Pica, geophagy, and rock art: ingestion of rock powder and clay by

humans and its implication for the production of some rock art on a global basis. A

paper read at the Philadelphia SAA conference in April 8, 2000;

Available:http://www.geocities.com/Anthens/Acropolis/5579/pica.html.


91

Clark, J. D. (201). Kalambo falls prehistoric Site: Volume III. Cambridge (UK): Cambridge

University Press.

Cui, Y. J., Zhu, Y. G., Zhai, R. H., Chen, D. Y., Huang, Y. Z. & Qui, Y (2004). Transfer

of metals from soil to vegetables in an area near a smelter in Nanning, China.

Environment International, 30, 785–791.

Danford, D. E. (1982). Pica and Nutrition. Annual Review of Nutrition. 2, 205-320.

Danford, D. E. & Huber, A. M. (1982). Pica and mineral status in the mentally retarded

adults. American Journal of Clinical Nutrition. 35:958-67.

Dapaah-Siakwa and Gyau-Boakye, (2009). Hydrogeologic frame and borehole yields in

Ghana. Hydrogeology Journal, 8, 408-416.

Day, P. E. (1965). Particle fractionation and particle size analysis. In: Methods of Soil

Analysis. Black, C.A. ed. American Society of Agronomy, Madison, Wisconsin, pp.

545- 567.

Deer, W. A., Howie, R. A. & Zugsman, J. (1992). An introduction to the rock forming

minerals. 2nd ed. Longman.

Delor, C., Fullgraff, T., Urien, P., Le Berre, P., Thomas, E., Roig, J., et al (2009).

Geological Map Exploration sheets in map sheets 0700A/2, 0700B/1, 0800D/1,

0800D/3, 0800C/2, and 0800C/4. Accra: Geological Survey Department of Ghana

(GSD).


92

Dickson, K. B. & Benneh, G. (1995). A new geography of Ghana. Revised Edition.

Longman, UK, 170 pp.

Diko, M. L. (2013). From source to basin of deposition: influence of transportation and

diagenesis on geophagic properties of soil. University of Limpopo, South Africa.

Dominy, N. J., Davoust, E. & Minekus, M. (2004). Adaptive function of soil consumption:

An in vitro study modeling the human stomach and small intestine. Journal of

Experimental Biology, 207: 319-324.

Ekosse, G. E. & Fouche, P. S. (2008). Spatial distribution of selected chemical properties

of soils situated close to an abandoned manganes mine. South African Journal of

Plant and Soil, 25:236-241.

Ekosse, G. I. E., De Jager, L. & Ngole, V. M. (2010). Traditional mining and mineralogy

of geophagic clays from Limpopo and Free State Provinces, South Africa. African

Journal of Biotechnology, 9: 8058-8067.

Ekosse, G. E., Ngole, V. M. & Longo-Mbeza, B. (2011). Mineralogical and geochemical

aspects of geophagic clayey soils from the Democratic Republic of South Africa.

Eastern Cape.

Ekosse, G. E. & Anyangwe, S. (2012). Mineralogical and particulate characterization of

geophagic clayey soils from Botswana. Bulletin of the Chemical Society of Ethiopia

26:373-382.


93

Ekosse, G. E., Ngole, V. M., de Jager, L. & Fosso-Kankeu, E. (2015). Human and enzootic

geophagia: Ingested soils and practices. Lambert Academic Publishing. ISBN 978-

0-620-64308-5.

FAO. (1988). World Agriculture Towards 2000: An FAO Study. N. Alexandratos (ed.).

Bellhaven Press, London. 333 pp.

Ferrell, Jr. R. E. (2008). Medicinal clay and spiritual healing. Clays and Clay Minerals 56:

751-760.

Frate, D. A (1984). Last of the Earth Eaters. 24: 34–38.

Geissler, P. W., Mwaniki, D. L., Thiongo, F. & Friis, H. (1998). Geophagy as a risk factor

for Geohelminth infections: a longitudinal study of Kenyan primary school children

Transactions of the Royal Society of Tropical Medicine and Hygiene 92:7–11.

Ghana Statistical Service, (2010). Population and Housing Census: District Analytical

Report North Dayi, pp 2-39.

Ghorbani, H. (2008). Geophagia, a soil - environmental related disease. International

meeting on Soil Fertility Land Management and Agroclimatology. Turkey 957-967.

Gichumbi, J. & Ocheng, O. (2011). Analyses of geophagic material consumed by pregnant

women in Embu, Meru and Chuka towns in eastern province, Kenya. Journal of

Environmental Chemistry and Ecotoxicology. 3(13): 340-344.

Goldberg, S. & Forster, H. S., (1990). Flocculation of reference clays and arid-zone soil

clays. Soil Science Society of American Journal 4: 714-718.


94

Gonyea, J. (2007). Pica do you know what your patients are eating? Nephrol Nurs J.

34:230–231.

Gonzalez, R., Demedina, F. S., Martinez-Augustin, O., Nieto, A., Galvez, J., Risco, S. &

Zarzuelo, A. (2004). Anti-inflammatory effect of diosmectite in hapten-induced

colitis in the rat. Britain Journal of Pharmacology, 141:951-960.

Gosselain, O. P. (1999). In pots we trust: The processing of clays and symbols in sub-

Saharan Africa Journal of Material Culture. 4: 205-230.

Gosselain, O. P. & Smith, A. L. (2005). The source clay selection and processing practices

in sub Saharan Africa. http://www.ulb.ac.be/socio/anthropo/OGosselain.

Hackley, B. & Katz-Jacobson, A. J. (2003). Midwifery. Women’s Health: 48, 30 -38.

Haller, J. S. (1972). The Negro and the southern physician: a study of medical and racial

attitudes. Medical History. 16:1384-93.

Halsted, J. A. (1968). Geophagia in man. Its nature and nutritional effects. American

Journal. Clinical Nutrition vol. 21.

Harvey, P. W. J., Dexter, P. B. & Darton-Hill, I. (2000). The impact of consuming iron

from non-food sources on iron status in developing countries. Journal of Public

Health, and Nutrition 3: 375–383.

Hesse, P. R. (1971). A textbook of soil chemical analysis. John Murray (Publisher) Ltd.,

London, U.K.


95

Hooda, P. S., Henry, C. J. K., Seyoum, T. A, Armstrong, L. D. M. & Fowler, M. B. (2002).

The potential impact of geophagia on the bioavailability of iron, zinc and calcium in

human nutrition. Environmental Geochemistry and Health, 24(4): 305- 319(15).

Hooda, P. S., Henry C. J. K., Seyoum T. A., Armstrong L. D. M. & Fowler M. B. (2004).

The potential impact of soil ingestion on human mineral nutrition. Science of the

Total Environment 333:75–87.

Hooper, D. & Mann, H. H. (1906). Earth-eating and the Earth-eating Habit in India.

Memoirs of the Asiatic Society of Bengal, Calcutta, I, 1906, pp. 249-270.

Hough, R. L. (2007). Soil and human health: An epidemiological review. European

Journal of Soil Science 58:1200-1212.

Hu, H. (2002). Human health and heavy metals exposure. In: Life Support: The

Environment and Human Health, Michael McCally ed. MIT Press.

Huang, M. L, Zhou S. L, Sun B. & Zhao Q. G. (2008). Heavy Metals in Wheat Grains

Assessment of Potential Health Risk for Inhabitants in Khunshan, China. The Science

of Total Environment. 405(1-3): 54-61.

Hunt, N. & Gilkes R. (1992). Farm Monitoring Handbook. The University of Western

Australia: Nedlands, WA.

Hunter, J. M. (1973). Geophagy in Africa and in the United States: a culture-nutrition

hypothesis. Geographical Review. 63:170-195.

Hunter, J. M. (1993). Macroterm geophagy and pregnancy clays in Southern Africa.

Journal of Cultural Geography 14: 69- 92.


96

Hunter, J. M. & de Kleine, R. (1984). Geophagy in Central America. Geographical Review

74:157–169.

Hunter, J. M., Horst, O. H. & Thomas, R. N. (1989). Religiuos Geophagy as a Cottage

Industry: The Holy Clay Tablet of Esquipulas, Guatemala. National Geographic

Research. 5,281-295.

Ibeanu, G. E. L., Dim L. A., Mallam, S. P., Akpa T. C. & Munyithya, J. (1997).

Nondestructive XRF analysis of Nigerian and Kenyan clays. Journal of

Radioanalytical and Nucleic Chemistry 221:207-209.

Izugbara, C. O. & Emmanuel, C. J. (2003). The cultural context of geophagy among

pregnant and lactating Ngwa women of Southeastern Nigeria. The African

Anthropologist, II (2).

Jaishankar, M., Mathew, B. B., Shah, M. S. & Gowda, K. R. S. (2014). Biosorption of few

heavy metal ions using agricultural wastes. Journal of Environment Pollution and

Human Health 2(1): 1– 6.

Järup L. (2003). Hazards of heavy metal contamination. Britain Medical Bulletin 68 (1):

167–182.

Johns, T. (1990). With better herbs they shall eat it: chemical ecology and the origins of

human diet and medicine. Tucson (AZ): University of Arizona Press.

Johns, T. & Duquette, M. (1991). Traditional detoxification of acorn bread with clay.

Ecology of Food and Nutrition 25:221–228.


97

Jones, W. (1990). The Buem volcanic and associated sedimentary rocks, Ghana: a field

and geochemical investigation. Journal of African Earth Sciences 11(3-4), 373-383.

Kesse, G. O. (1985). The mineral and rock resources of Ghana. A. A. Balkema, Roterdam.

Precambrian Research 46, 139-165.

Konta, J. (1995). Clay and man: clay raw materials in the service of man. Applied Clay

Science 10: 275 - 335.

Kotlyar, I. S., Sparks, B. D., Lepage, Y. & Woods, J. R., (1998). Effect of particlesize on

the flocculation behaviour of ultra-fine clays in salt solutions. Clay Mineralogy, 33:

103-107.

Krishnamani, R. & Mahaney, W. C. (2002). Geophagy among primates: adaptive

significance and ecological consequences. Animal Behaviour. 59: 899–915.

Landa, E. & Feller, C. (2009). Soil and Culture. Springer Publishers, Netherlands, p370.

Landon, J. R. (1991). Booker Tropical Soil Manual. A Handbook for soil survey and

agriculture land evaluation in the tropics and subtropics. Landon, J. R. ed. Booker

Tate, Thame, Oxon, UK, pp.58-125.

Laufer, B. (1930). Geophagy. Field Museum of Natural History – Anthropological Series

18: 97-198.

Lopez, L. B., Soler, C. R. O. & de Portela, M. L. P. M. (2004). Arch. Latinoan. Nutrition

3rd ed. 5.


98

Mahaney, W. C. & Krishnamani, R. (2003). Understanding geophagy in animals; Standard

procedure for sampling soils, Journal of Chemical Ecology, vol. 29(7), 1503-1523.

Mahaney, W.C., Milner, M. W., Mulyono, H. S., Hancock, R. G. V., Aufreiter, S.,Reich,

M. & Wink, M. (2000). Mineral and chemical analyses of soils eaten by humans in

Indonesia. Internationa Journal of Environmental Health, 10: 93-109.

Mallory, W. H. (1926). China: Land of Famine. New York: American Geographical

Society.

Marchi, M. & Cohen, P. (1990). Early childhood eating behaviors and adolescent eating

disorders. Journal of the American Academy of Child & Adolescent Psychiatry,

Volume 29, Issue 1, Pages 112-117.

McKenzie, N. J., Jacquier D. J., Isbell R. F. & Brown K. L. (2004). Australian Soils and

Landscapes an Illustrated Compendium. CSIRO Publishing: Collingwood, Victoria.

Meharg, A. (2005). Venomous Earth - How arsenic caused the world's worst mass

poisoning. UK: Macmillan Science, pp. 11-19.

Mengel, C. E., Carter, W. A. & Horton, E. S. (1964). Geophagia with iron deficiency and

hypokalemia. Arch. International Medicine. 1964. 465-474.

Mills, M. (2007). Nursing for women’s health, 11 (266 -273).

Ming-HO, Y. U. (2001). Impacts of environmental toxicants on living systems.

Environmental Toxicology. London: Lewis Publishers, pp. 151-179.

Mitchell, W. M. (1968). Pica in adults. California Medicine, 109, 156-158.


99

Moore, D. F. J. & Sears, D. A. (1994). Pica, iron deficiency and the medical history. The

American Journal of Medicine. 97: 390 -393.

Nartey, E. (1994). Pedogenic changes and phosphorus availability in some soils of the

Northern Ghana. M.Phil theses, pp 88-94.

Nchito, M., Geissler, P. W., Mubila, L. & Olsen, A. (2004). Effects of iron and multi-

micronutrient supplementation on geophagy: a two-by-two factorial study among

Zambia school children in Lusaka. Transaction of the Royal Society of Tropical

Medicine and Hygiene. 98:218-227.

Nelson, P. N., Dictor, M. C. & Soula. S. (1994). Availability of organic carbon in soluble

and particle size fractions from a soil profile. Soil Biol. Biochem., 26:1549-1555.

Ngole, V. M., Ekosse, G. E., De Jager, L. & Songca, S. P. (2010). Physicochemical

characteristics of geophagic clayey soils from South Africa and Swaziland. African

Journal of Biotechnology 9: 5929-5937.

Nicholls, C. I. & Altieri. M. A. (1997). Int. J. Sust. Dev. World. 4, 93-111.

Nwoke, B. E. B. (2009). Worm and human disease. 69-87, Alphabet Nigeria Publishers.

Oliver, M. A. (1997). Soil and human health: A review, European Journal of soil science.

84 (4): 573 -592.

Olsen, S. R., Cole, C. V., Watanabe, F. S. & Dean, L. A. (1954). Estimation of available

phosphorus in soils by extraction with sodium bicarbonate. USDA Department

circular 939.


100

Oyama, M. & Takehara, H. (1970). Revised Standard Soil Colour Charts. 2nd Edition.

Research Council for Agriculture, Forestry and Fisheries, Ministry of Agriculture

and Forestry, Tokyo, Japan.

Pierzynski, G. M., Sims, J. T. & Vance, G. F. (2000). Soil phosphorus and Environmental

quality. In soils and environmental quality, pp. 155-207, CRC press, Boca Raton.

Radojevic, M. & Baskin, V. (1999). Practical environmental analysis. Cornwall, U.K: The

Royal Society of Chemistry.

Ragnarsdottir, K. V (2000). Environmental fate and toxicology of organophosphate

pesticides. J. Geological Society London, 157(4): 859-876.

Reilly, C. & Henry, J. (2000). Geophagia: why do humans consume soil? Nutrition

Bulletin, 25(2): 141-144.

Root-Bernstein, R. & Root-Bernstein, M. (2000). Honey, mud, maggots and other medical

marvels: the science behind folk remedies and old wives tales. London: Pan Books,

(280 pp).

Rose, E., Porcerelli, J. & Neale, A. (2000). ‘Pica: Common but commonly missed”.

Journal Chemical Ecology. 29(7):1525-1547.

Ross, T. (Translator). (1895). Personal narrative of travels to the equinoctial regions of

American during the year 1799-1804 by Alexander von Humbolt and Aime

Bonpland, vol.2, Routledge.

Schulze, D. G. (2005). Clay Minerals. Vol. 1, p. 246-254 in D. Hillel (editor-in-chief),

Encyclopedia of Soils in the Environment, Elsevier / Academic Press, Boston.


101

Schurtz, H. (1893). Katechismus der Volkerkunde, p. 21.

Selinus, O., Finkelman, R. B. & Centeno, J. A. (2010). Medical Geology, a regional

synthesis. Pub. Springer. pp 88.

Siewe, C. N. & Diko, M. L., (2000). Geophagia among female adolescents as a culturally

driven Practice University of Limpopo, South Africa.

Simons, S. L. (1998). Soil ingested by humans: A review of history, data and etiology with

application to risk assessment of radioactively contained soil. Health Physics 74 (6):

647 – 672.

Sing, D. & Sing, C. F. (2010). Impact of direct soil exposures from airborne dust and

geophagy on human health. International Journal of Environmental Research and

Public Health 7:1205-1223.

Solyom, C., Solyom, L. & Freeman, R. (1991). An unsual case of pica. Canadian Journal

of Psychiatry. 36: 50 – 53.

Soil Research Institute (1999). Soil Map of Ghana, FAO/ UNESCO, 1990. Land suitability

section, Soil Research Institute Ghana.

Sposito, G. (1989). The chemistry of soils. New York: Oxford University Press, 43-68.

Starks, P. T. B. & Slabach, B. L. (2012). The Scoop on eating dirt. Scientific American,

00368733, 306(6). Available from: http://web.ebsocohost.com.

Stiegler, L. (2005). Understanding pica behavior: a review for clinical and educational

professionals. Focus Autism Other Dev Disabil 20:27–38.


102

Tan, K. H. (1982). Principles of Soil Chemistry. Marcel Dekker Inc., Madison, New York,

U.S.A. p.521.

Tano-Debrah, K. & Bruce-Baiden, G. (2010). Microbiological characterization of dry

white clay, a pica element in Ghana, http://www.sciencepub.net/report.

Tayie F. (2004). Pica. Motivating factors and health Issues. African Journal of food

Agriculture, Nutrition and Development, vol. 4, no. 1.

Tayie, F.A., Koduah, G. & Mork, S. A. P. (2013). Geophagia clay soil as a source of

mineral nutrients and toxicants. African Journal of food Agriculture, Nutrition and

Development, vol. 13 (1): 7157-7170.

Thompson, C. J. S. (1913). Terra sigillata, a Famous Medicament of Ancient Times. In

Proceedings of the 17th International Congress of Medical Sciences (Section 23,

History of Medicine), London, pp. 433-444.

Tsimba, R., Hussein, J. & Ndlovu, L. R. (1999). Relationships between depth of tillage and

soil physical characteristics of sites farmed by smallholders in Mutoko and Chinyika

in Zimbabwe. Published in: Kaumbutho P. G, Simalenga T. E (1999). Conservation

tillage with animal traction. A resource book of the Animal Traction Network for

Eastern and Southern Africa (ATNESA). Harare, Zimbabwe. p. 173.

USEPA. (1989). Risk assessment guidance for superfund. In: Human Health Evaluation

Manual Part A. Interim Final, vol. I. United States.

USEPA. (2002). A review of the reference dose and reference concentration process. Risk

assessment forum. Online at http://www.epa.gov/iris/RED. FINAL[1].pdf.


http://www.epa.gov/iris/RED

103

Utara, S. (2002). Chemical analyses of pica soil eaten by villagers in Sisaket Province.

MSc Unpublished. Thesis. Suranaree University of Technology, Thailand. pp 9-10.

Vermeer, D. E. (1966). Geophagy among the Tiv of Nigeria. Annals of the Association of

American Geographers. 56:197–204.

Vermeer, D. E. (1971). Geophagy among the ewe of Ghana. Ethnology 10: 56 – 72.

Vermeer, D. & Frate, D. (1979). Geophagia in rural Mississippi: environmental and

cultural contexts and nutritional implications. American Journal Clinical Nutrition

32: 2122–2135.

Vermeer, D. E. & Ferrell, R. E. Jr. (1985). Nigerian Geophagial Clay: Traditional

Antidiarrheal pharmaceutical. Science 227: 634-636.

Vermeer, D. E. (1987). Geophagy in Africa, Bull. Sbreveport Med. Soc., 38, 13-14.

Von Homboldt, A. (1985). Vom Orinokko zum Amazonas. Wiesbaden, FA Brockhaus, p.

341.

Walkley, A. & Black, I. A. (1934). An examination of the Degtjareff method for

determining soil organic matter and a proposed modification of the chromic acid

titration method. Soil Science 37: 29–38.

WHO/FAO/IAEA. World Health Organization. Switzerland: Geneva; (1996). Trace

Elements in Human Nutrition and Health. Pharmaceutical Science 227:634-636.

Wiley, S. A. & Katz, H. S. (1998). Geophagy in pregnancy: A test of a hypothesis. Current

Anthropology. 39:532-545.


104

Will, P. E. (1990). Bureaucracy and Famine in Eighteenth Century China. Stanford, CA:

Stanford University Press.

Wilson, M. J. (2003). Clay mineralogical and related characteristics of geophagic

materials. Journal of Chemical Ecology.Vol. 29, 1525-1547.

Wong, M. S., Bundy D. A. & Golden M. H. (1991). The rate of ingestion of Ascaris

lumbricoides and Trichuris trichiura eggs in soil and its relationship to infection in

two childrens homes in Jamaica. Transactions of the Royal Society of Tropical

Medicine and Hygiene 85:89 – 91.

World Health Organisation, (1995). Lead environmental criteria, Geneva, pp: 165.

Woywodt, A. & Kiss, A. (2002). Geophagia: the history of earth-eating. Journal of the

Royal Society of Medicine 95: 143–146.

Young, S. L., Wilson, M. J., Miller, D. & Hillier, S. (2008). Toward a comprehensive

approach to the collection and analysis of pica substances, with emphasis on

geophagic materials. PLoS ONE 3:e3147. doi; 10, 137/journal.pone.0003147.

Young, S. L., Wilson, M. J, Hillier, S., Delbos, E., Ali, S. M. & Stoltzfus, J. R. (2010).

Differences and commonalities in Physical, Chemical and Mineralogical Properties

of Zanzibari Geophagic Soils. Journal Chemical Ecology. 36:129-140.

Ziegler, J. L. (1997). Geophagy: A vestige of paleonutrition? Tropical Medicine

International. Health. 2(7): 609-611.


105

APPENDICES

Appendix A

Questionnaire for Consumers

1. Sex…………………………………………………………………………………..

2. Age………………………………………………………………………………….

3. Do you ingest the white clay? Yes / No.

4. Where do you obtain the material from?.....................................................................

5. Do you have any idea as to how the material is prepared? Yes / No.

6. For how long have you been ingesting the material?..................................................

7. How did you start the practice?...................................................................................

8. Why do you ingest the material?.................................................................................

9. What are the benefits of ingesting the material?.........................................................

10. Have you experienced some side effects from ingesting the white clay? Yes / No

11. If yes, state them……………………………………………………………………

12. If yes, what do you think are the causes of the side effects? .......................................

13 In your opinion, how do you think the side effects can be minimized or eliminated?

....................................................................................................................................

14 Would you wish to stop the habit of eating the white clay? Yes/ No

15 If yes, why?...............................................................................................................

16 If no, why?..................................................................................................................


106

Appendix B

Questionnaire for Dealers in White Clay Business

1. Sex………………………………………………………………………………….

2. Age…………………………………………………………………………………

3. How did you get into this business?............................................................................

4. How long have you been in this business?..................................................................

5. Any reason(s) for doing this business?......................................................................

6. Where do you obtain the material from?.....................................................................

7. Do you process it yourself? Yes / No........................................................................

8. If yes, kindly describe the procedures involve in processing?.................................

9. Do you add anything to the clay when processing? Yes / No .................................

10. If yes, kindly list them and state their function(s)…………………………………

11. Why do you process it? ...........................................................................................

12. Do you eat it yourself? Yes / No .................................................................................

13. If yes why? ...............................................................................................................

14. If no, why?.................................................................................................................

15. What benefit do you derive from eating it?................................................................

16. Do you experience any side effects in ingesting it? Yes / No

17. If yes, state the side effects………………………………………………………….

18. List any challenges you face in the business………………………………………..

19. Do you receive complaints from patrons of the white clay? Yes / No

20. If yes, state them…………………………………………………………………….


107

Appendix C

Questionnaire for Miners

1. Sex…………………………………………………………………………………..

2. Age………………………………………………………………………………….

3. How long have you been in this business? .................................................................

4. Who introduced or initiated you into this business of mining clays? .........................

5. Why do you engage in this business? ........................................................................

6. Are you the owner of the land? Yes / No……………………………………………

7. If No, how did you acquire the concession?

8. Are you aware of any environmental problems this mining of clay activities cause?

Yes / No

9. If Yes, list them .........................................................................................................

10. Are you aware of any health risk? Yes No…………………………………………

11. Have you experienced any health problems yourself that you can associate with the

mining? Yes / No

12. If yes, kindly state the health problems……………………………………………..

13. How do you sell the mined clay material? .................................................................

14. Who are your customers?...........................................................................................

15. Is the business lucrative? Yes / No………………………………………………….

16. If No, why are you still involved?..............................................................................

17. Do you ingest the material yourself? Yes / No……………………………………..

18. If Yes, why? ..............................................................................................................


108

19. Do you experience any side effects from the ingestion? Yes / No

20. If yes, list them……………………………………………………………………...

21. If you do not ingest it yourself, why?.........................................................................

22. Are there any health related problems of the physical activity involved in the

mining? Yes/No

23. If yes, state them…………………………………………………………………….

24. Do you reclaim the land after mining? Yes/No

25. If Yes, how?...............................................................................................................

26. If No, why?................................................................................................................


109

Appendix D

Questionnaire for Health Facilities / EPA

1. Is your outfit aware of the white-clay business at Anfoega and its environs? Yes / No

2. Briefly, what do you know about the business?.................................................................

3. Is your outfit aware of any health implications of the business? Yes/No

4. If your answer to Question 3 is yes, list some of the health implications that have come

to the attention of your outfit………………………………………………………………..

5. List the health implications you have stated in Question 4 according to the order of

prevalence…………………………………………………………………………………

6. Are there any environmental implications of the business that have come to the notice

of your outfit? Yes/No………………………………………………………………………

7. If your answer to Question 6 is yes, list up to five most important environmental issues

that have come to the attention of your outfit…………………………………………….

8. If your answer to Qestion 3 is No, what do you think could be some of the potential

health related implications of the white clay business? ..........................................................

9. What advice would you have for those who produce the material and the

consumers?………………………………………………………………………………….


The entire work is dedicated to my beautiful and lovely ...

Documents

Transcript of The entire work is dedicated to my beautiful and lovely ...