A Geospatial Analysis of the Health Impacts of Oil Spills in the Niger Delta Region of Nigeria a Thesis Presented to the Faculty

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A Geospatial Analysis of the Health Impacts of Oil Spills in the Niger Delta Region of

Nigeria

A thesis presented to

the faculty of

the College of Arts and Sciences of Ohio University

In partial fulfillment

of the requirements for the degree

Master of Science

Chijioke I. Anyanwu

May 2019

This thesis titled

A Geospatial Analysis of the Health Impacts of Oil Spills in the Niger Delta Region of

Nigeria

CHIJIOKE I. ANYANWU

has been approved for

the Department of Geography

and the College of Arts and Sciences by

James K. Lein

Professor of Geography

Joseph Shields

Interim Dean, College of Arts and Sciences 3

ABSTRACT

ANYANWU, CHIJIOKE I., M.S., May 2019, Geography

A Geospatial Analysis of the Health Impacts of Oil Spills in the Niger Delta of Nigeria

Director of Thesis: James K. Lein

This study presents an application of Geographic Information systems (GIS) to examine the geographic pattern and spatial relationship between oil spills and child diarrhea, investigating whether the prevalence of diarrhea disease among children in the

Niger Delta is associated with proximity to an oil spill. Oil spills are common in the

Niger Delta and previous research has linked oil spills to human health hazards such as dermatoxic diseases, cancer, neonatal and child mortality. Investigating infant diarrhea is critical to understanding the underlying causes of infant mortality. This study is based on analysis of georeferenced oil spill data from the Nigerian Oil Spill Monitor, and spatial health data from the Nigeria National Demographic and Health Survey (DHS, 2013). The

DHS contains a sample survey of 33,385 women of reproductive aged 15-49 years and

15,486 men aged 15-59 years in randomly selected households. The sample for this thesis contains 4,060 children under the age of 5 years in 3,384 households from 206 DHS clusters in the Niger Delta. This study reveals that both oil spills and infant diarrhea express a clustered pattern in the study area. There is also a significant spatial association between oil spills and infant diarrhea in the Niger Delta. Finally, the research concludes that addressing oil spills in the Niger Delta is critical to tackling infant diarrhea and minimizing human exposure to environmental hazards.

DEDICATION

To the advancement of the fight against child morbidity and mortality, and environmental

degradation in the Niger Delta. To all who contributed in one way or another to the

success of this thesis.

ACKNOWLEDGMENTS

I express my profound gratitude to my advisor, Dr. James Lein, for his guidance and mentoring throughout this research. My sincere gratitude also goes to Dr. Tom

Smucker for his contribution in developing this project. I wish to acknowledge members of my committee, Dr. Risa Whitson, and Dr. Dorothy Sack, whose immense contributions led to the successful completion of this thesis.

I am grateful to Professor Anna Myers and Dr. Howard Welser, who, although not members of my thesis committee, dedicated their time and resources to this research, and the USAID, the Nigeria DHS, and the National Oil Spill Detection and Response Agency

(NOSDRA) for creating and approving the use of their data for this thesis.

I am grateful to the faculty, staff, and my colleagues in the Geography Department for their support and enormous contributions to my experiences as a graduate student at

Ohio University. Finally, I am eternally grateful to my family and friends who continually support me and serve as my sources of inspiration and strength.

TABLE OF CONTENTS

Page

Abstract ...... 3 Dedication ...... 4 Acknowledgments...... 5 List of Tables ...... 7 List of Figures ...... 8 Chapter 1: Introduction ...... 9 1.1. Research Questions and Objectives ...... 10 1.2. Presentation of the Research ...... 11 Chapter 2: Crude Oil and Human Health Assessment ...... 12 2.1. The Niger Delta of Nigeria ...... 17 2.2. Infant Diarrhea ...... 28 2.3. Geographic Information Systems in Spatial Epidemiology ...... 31 Chapter 3: The Study Area ...... 34 3.1. Physical Geography ...... 34 3.2. Human Geography of the Niger Delta ...... 35 Chapter 4: Data and methods ...... 37 4.1. Data ...... 37 4.2. Limitations of the data ...... 39 4.2.1. Health Data ...... 39 4.2.2. Oil Spill Data ...... 40 4.3. Methods ...... 41 Chapter 5: Results and Discussion ...... 47 Chapter 6: Conclusion...... 66 References ...... 69

LIST OF TABLES

Page

Table 1. Cross-tabulation of Oil Spill against Diarrhea ...... 53 Table 2. Background Characteristics of the Sample Population...... 57 Table 3. Household Water and Sanitation Facilities ...... 59 Table 4. Prevalence of Diarrhea by Background Characteristics ...... 61 Table 5. Prevalence of Diarrhea by Water Source and Sanitation ...... 62 Table 6. Correlation between Infant Diarrhea and Household Characteristics ...... 64

LIST OF FIGURES

Page

Figure 1. Frequency of Oil Spills in Nigeria from 2005 to January 2019 ...... 21 Figure 2. Oil Spill Frequency and Density Map of the Niger Delta...... 22 Figure 3. The Niger Delta Region of Nigeria ...... 36 Figure 4. Location of DHS Clusters and Oil spills in the Niger Delta...... 45 Figure 5. A Spatial Autocorrelation of Oil Spill Incidences in the Niger Delta ...... 48 Figure 6. A Spatial Autocorrelation of Incidences of Infant Diarrhea...... 49 Figure 7. Density Distribution of Infant Diarrhea in the Niger Delta...... 51 Figure 8. Percent Distribution of Infant Diarrhea According to States...... 52 Figure 9. Distance Decay of Child Diarrhea...... 55 Figure 10. Diarrhea Prevalence in Different Regions of Nigeria...... 65

CHAPTER 1: INTRODUCTION

This research examines the spatial distribution and correlation between oil spills and child diarrhea in the Niger Delta region of Nigeria using Geographic Information

Systems (GIS). This study is necessary because little research has examined this relationship especially regarding the Niger Delta. This research undertakes a geospatial analysis of whether variations in child diarrhea prevalence are correlated with oil spills.

Studying the spatial variation and geographic pattern in the prevalence of child diarrhea in the Niger Delta is vital for understanding child mortality across the region. The study could be useful in presenting important insights for informed policy decision making and health resource allocation planning and intervention to address infant diseases and mortality.

Oil spills, the most significant and frequently occurring environmental hazard in the Niger have proliferated over the past few decades. Niger Delta residents depend directly on the natural environment for their food and livelihood and therefore are in constant contact and suffer direct exposure to oil pollutants in their environment. They face prolonged and heightened vulnerability to high concentrations of hydrocarbons and other petroleum chemicals in their neighborhoods, farms, creeks and rivers leading to poor nutrition and adverse health consequences (UNEP, 2011; Atubi, 2015; Nriagu at al.,

2016).

The health effects of oil spills are of special interest to public health professionals and researchers, and agencies as well as researchers in the emerging field of spatial epidemiology. However, only a few studies have been conducted on the health effects of 10 oil spills in the Niger Delta (Nriagu at al., 2011, 2016; Atubi, 2015; Bruederle & Hodler,

2017), and even fewer on those effects on maternal and child health. This study, therefore, seeks to fill this gap by focusing on the implications of oil spills on infant diarrhea in the Niger Delta.

This study proposes that prevalence of infant diarrhea in the Niger Delta could be associated with incidences of oil spills. The study is primarily based on the hypothesis that cases of infant diarrhea are spatially correlated with the distribution of oil spills in the Niger Delta. Furthermore, this study considers demographic and socioeconomic risk factors associated with infant diarrhea in the study area.

1.1. Research Questions and Objectives

The first objective of this research is to examine the spatial distribution of oil spills in the Niger Delta region of Nigeria. Similarly, the second objective will examine the spatial distribution of diarrheal infection among infants in the study area. The first and second objectives involve an investigation of whether oils spills and incidences of infant diarrhea express a dispersed, random, or clustered pattern across different locations in the study area. The third objective examines the spatial correlation between child diarrhea prevalence and oil spill incidences in the Niger Delta. In other words, to determine whether spatial variations of infant diarrhea can be explained by proximity to an oil spill site.

Hypotheses to be tested are:

Ho1: ‘Oils spills are randomly distributed across the Niger Delta of Nigeria’

Ho2: ‘Incidences of infant diarrhea are randomly distributed across the Niger Delta’ 11

Ho3: ‘There is no relationship between oil spills and infant diarrhea in the Niger Delta’

This research, therefore, seeks to find answers to the following research questions:

1. What is the spatial pattern of distribution of oil spills in the Niger Delta?

2. What is the spatial pattern of distribution of infant diarrhea across the Niger

Delta?

3. Is there a spatial relationship between child diarrhea and oil spills in the study

area?

1.2. Presentation of the Research

This paper is organized into six chapters. Chapter one contains the introduction

and lays out the background to the research problem. Chapter two, presents a

summary of the body of literature that have touched on issues of oil spills, the

linkages between environmental hazards and human health outcomes. Chapter two

further explores literature on oil spills in the Niger Delta, diarrhea prevalence, and the

application of Geographic Information Systems (GIS) techniques to environmental

assessment, spatial epidemiology research, and in studying geographic patterns and

spatial relationships.

The third chapter presents an overview of the Niger Delta and describes the

physical and human population characteristics of the study area. Chapter four

discusses the data and methods used to collect and analyze the data. Chapter Four

also covers the limitations of the data. Chapter five outlines the results and research

findings, while Chapter Six contains the conclusion.

CHAPTER 2: CRUDE OIL AND HUMAN HEALTH ASSESSMENT

The history of oil exploration and production is long and complex, dating back to the eighteenth-century industrial revolution. Oil exploration has, since its discovery, become a major actor in shaping world economy, technological advancements, and global energy demands. Crude oil and natural gas are the dominant energy sources all over the world today (Steiner, 2010; Goldstein et al., 2011, Ayuba, 2014). As the world advances toward further development, the demand for fossil fuels, especially petroleum derivatives, continues to increase together with the concomitant hazards. Although the discovery of petroleum reserves might hold significant economic possibilities for local communities, the risks of oil spills and high exposure to hydrocarbon pollution are equally apparent and virtually inevitable.

Environmental hazards related oil fields are a global problem that has persisted since the discovery and extraction of oil resources (Onuoha, 2008; Anifowose, 2008,

Michel & Fingas, 2016). Oil spill is the most common and frequently occurring oil field related environmental hazard. The movement and transportation of petroleum products from oil rigs to the final consumers require extraction and conveyance through various means (pipelines, ocean vessels and tankers, trucks, and by rail). Thus, oil spills can result from accidents, such as operational failures, oil well blow outs, and leakage at any point during exploration, refining, transportation, storage, distribution, and final consumption.

Oil spills vary in terms of magnitude and impact. The magnitude of an oil spill refers to the total amount of oil spilled and its persistence in the environment. The 13 magnitude and impacts are determined by the quantity of the spill, the type of product spilled and its mobility or migratory patterns by air, water, or on land (Chang et al., 2014;

Eykelbosh, 2014). In addition to magnitude, oil spills also vary in terms of the total number of human populations exposed. This is in close relation to the proximity of the oil spill to human settlements. In the case of offshore oil spills that occur far away from coastal settlements the oil may undergo some degree of biodegradation before pollutants reach the coast. On the other hand, onshore oil spills immediately impact the surrounding environment and human population (Eykelbosh, 2014). Similarly, on-shore oil spills that are far away from human settlements, although having the same environmental impacts, may not lead to significant human exposure compared to other on-shore spills that occur within or near settlements.

Surface oil spills can easily be detected because they leave visible traces of oil stains, odors or sometimes a fire outbreak. On the other hand, oil run off to underground is more difficult to detect, but there may be significant problems. Oil may infiltrate the subsoil and may even reach ground water and flow with it. Surface and underground oil spills contaminate soils, sediments, water, and air through the release of several volatile compounds into the atmosphere.

Incidences of oil spills have proliferated over the past few decades and researchers have extensively studied the environmental, socio-economic, and human health impacts. Oil spill impacts are devastating both to the environment and human populations (Michel & Fingas, 2016). For instance, the Deep Horizon Oil spill, an offshore accident in the Gulf of Mexico, had catastrophic impacts on marine and aquatic 14 life, on cleanup workers, and on people living along the coasts. (D’Andrea et al., 2013;

Peres et al., 2016).

Environmental hazards and human health conditions are inextricably linked, as many scholars as well as the World Health Organization (WHO) have widely established and acknowledged. Evidence from the literature suggests that oil spills affect human health through exposure to inherent hazardous chemicals and hydrocarbons present in crude oil. Epidemiological research seeks to evaluate and identify possible risk factors associated with a disease, and researchers have developed and employed a variety of models and statistical tools to determine potential health consequences of human exposure to environmental hazards. they also work to determine whether the risk of experiencing certain symptoms after exposure to an environmental hazard is higher than that of developing the symptoms by random chance.

Numerous researchers have documented the human health implications of oil spills in residents living near oil spill locations and in workers participating in cleanup activities, who, due to the nature of their work, are in direct contact with and have higher exposure to oil pollutants (Cheong et al., 2011; D’Andrea et al., 2013). For instance, following the Braer wreck off the coast of Scotland in 1993, Campbell et al. (1993) reported that residents living within 4.5 km of the spill site experienced a higher prevalence of sore throats and irritated eyes compared to residents living farther away.

Similarly, Lyons et al. (1999) noted a range of acute symptoms on exposed cleanup workers following the Sea Empress accident off the coast of Wales. They collected data on physical symptoms, mental health, perceived health, and anxiety for both exposed and 15 non-exposed populations. The authors observed a statistically significant increase in cases of headaches, nausea, sore eyes and throat, cough, skin infections, shortness of breath and a condition of general weakness among exposed subjects. They found that populations living along the south coast of Wales had significantly higher cases of headaches, skin irritations, anxiety and depression due to proximity to the oil spill than those living on the northern coasts far away from the area of the spill.

Janjua et al. (2013) surveyed people living 0 km, 2 km, or 20 km from the

Tasman Spirit oil spill accident off the coasts of Pakistan. They observed a wide range of adverse health effects, such as acute respiratory infections, neurological, dermatological, and gastrointestinal problems. The authors also reported an elevated risk of sore eyes and throat, irritability, and fatigue among residents, which decreased as distance from the spill site increased. Residents living up to 20 km from the spill were the least likely to experience any of the observed symptoms while residents living along the shorelines near the spill site faced higher risks of exposure and were the most impacted by the accident.

The health impacts of the Exxon Valdez oil spill, considered to be the largest oil spill in the history of the United States (Aguilera et al., 2010; Solomon et al., 2010) have garnered extensive study and publication. Adverse health consequences include dermatological infections, abnormalities in hematological, respiratory, and neurologic functions (Lyons, 1999; Goldstein, 2011; Cheong, 2011; Janjua, 2012). Short-term impacts of sore and irritated throats and eyes, skin rashes, and long-term impacts of cancer, lung and kidney problems were prevalent especially in cleanup workers who were in direct contact and highly exposed to the oil contaminants (Palinkas, 2012; D’Andrea, 16 et al., 2013; Eykelbosh, 2014). D’Andrea et al. (2013) also note that subjects exposed to the oil spill often experienced frequent asthmatic attacks, diarrhea, dizziness, and other symptoms. Gill et al. (2011) provided a comparison between the social and mental health impacts of the Exxon Valdez and BP oil spills and reported post-traumatic stress symptoms, anxiety, and depression.

Compared to the documentation of acute physical and mental health impacts, relatively little has been documented regarding health impacts of oil spills on maternal and child health. However, in general, the literature suggests that exposure to oil spills have significant effects on maternal and child health and is one of the major environmental factors contributing to child morbidity and neonatal mortality. Hurtig &

San Sebastian (2004) submit that leukemia incidences in children in the Amazon Basin of

Ecuador are linked to their proximity to oil fields. They do not find any significant difference between the prevalence of leukemia in male and female children and reported that incidences of childhood leukemia were similar for both sexes. However, through

Relative Risk analysis, they established elevated levels of leukemia in younger infants from 0-4 years. Additionally, the exposed population living in proximity to oil fields reported more cases of childhood leukemia compared to the unexposed people living farther away.

Peres et al. (2016) employed exploratory factor analysis to characterize and examine the association between oil spill exposure and the physical health of adult women in southern Louisiana, following the 2010 Deepwater Horizon oil spill incident.

Results revealed that women exposed to the oil spill had a significantly higher chance of 17 experiencing symptoms like burning sensations in the nose and lungs, sore throat, red eyes, dizziness, and wheezing. The authors, therefore, concluded that proximity and exposure to the Deep Horizon oil spill was associated with an increase in physical health outcomes.

2.1. The Niger Delta of Nigeria

The Niger Delta region of Nigeria provides a highly relevant example of a region cursed by its abundance of natural resources, especially petroleum. Since the discovery of oil in the Niger Delta in the late 1950s, the oil and gas sector has overtaken other sectors to become the backbone of Nigeria’s economy. Nigeria is the largest oil producer in

Africa and among the largest in the world. The nation’s crude oil and natural gas reserves as well as the multiple multinational oil companies that exploit the petroleum resources reside in the Niger Delta.

Once crude oil was discovered in the Niger Delta, the Federal government of

Nigeria embarked on an exploration that was of enormous significance for the collective development of the local communities in the region. Oil production and exploration from the Niger Delta contributes about 95 percent of Nigeria’s export revenues, and 32 percent of gross domestic product (GDP). The oil resource is sometimes referred to as ‘black gold’ (Jike, 2004). However, while oil exploration has contributed immensely to the economic growth and development of the country at large, it has resulted in severe environmental degradation, pollution, and widespread underdevelopment in the oil- producing communities (Adeola, 2000; Amnesty International, 2009; UNEP, 2011).

Sadly, over time, crude oil has developed an entirely different meaning to the people of 18 the Niger Delta. The excitement and expectations following the discovery of crude oil have diminished because the livelihoods and general well-being of the Niger Delta people have not been positively affected. Rather, the reverse has been the case.

Oil spills are common occurrences throughout the region as a result of pipeline corrosion, poor maintenance of infrastructure, operational failures and third-party damage through oil theft and vandalism (Fig. 1 and 2) (Adeola, 2000; Amnesty International,

2009). Studies estimate that at least 9-13 million barrels of oil have been spilled over more than 5 decades of oil exploration in the Niger Delta with an estimated average of about 240,000 barrels spilled annually (Ordinioha & Brisibe, 2013; Balogun, 2015).

Erhun (2015) attributes these unchecked, frequently occurring oil spills to Nigeria’s regulatory failure in environmental governance and to the fact that national interests in economic development are valued over and supersede all concerns for environmental sustainability and the citizenry by extension. Thus, the Niger Delta, popular for its rich biodiversity and delicate ecosystems of mangrove swamps, fresh water swamps, rain forest, and wetlands is threatened by severe environmental degradation, particularly from oil spills. The oil producing communities of the Niger Delta are crisscrossed by thousands of oil and gas pipelines. Atubi (2015) records that the Niger Delta contains about 47,000 km of pipelines and over 1,000 oil wells. As a result, oil spills as direct consequences of oil extraction, transportation, refining, and distribution through these wells and pipelines persist and pose a severe threat to the region (Abi & Nwosu, 2009;

Nwankwoala & Nwaogu, 2009). The Niger Delta region is now characterized by contaminated air, soils, streams and rivers, deforestation and a general loss of 19 biodiversity. It is described as one of the worst oil degraded locations and most severely polluted and endangered ecosystems in the world (Ngobiri et al., 2007; Nwankwoala &

Nwaogu 2009).

Steiner (2010) notes that due to the low standard of operation of oil companies in the Niger Delta, with specific reference to Shell Petroleum Development Company as regards to methods of extraction and infrastructure integrity, the region faces a high risk of oil spills. Additionally, the oil companies continue to misreport causes of oil spills, blaming them on oil theft and vandalism. This action actively releases them from the legal obligations to clean up the reported oil spills and as such, oil spills continue to linger in the environment unattended and continue to pose serious threat to the residents of the Niger Delta. Local communities on the other hand over-estimate and inflate figures to stress their point and blame the oil spills on operational failures, lack of maintenance, and poor quality of oil infrastructure. But regardless of the cause of the oil spills, the natural ecosystem of the Niger Delta remains largely degraded and polluted. Steiner

(2010) also highlights a seemingly outrageous oversight with respect to oil spill incidences in developing countries. He notes that about 4 million tons of oil that spilled over the Gulf of Mexico in the summer of 2010 have received substantial funding and global attention, whereas an estimated 9 – 13 million tons of oil spill and million tons of gas flared over the course of 50 years of oil exploration in the Niger Delta region of

Nigeria have received little attention. The oil companies still operate below minimum standards of operation and their practices are largely left unchecked. Considering that oil facilities, especially pipelines, run through residential areas and sometimes are exposed 20 on the earth’s surface in the Niger Delta, it is essential to consider the proximity of an oil spill to human settlements, the quantity or volume of oil spilled, and the area where the oil spilled (whether on off-shore, on land or on surrounding swamps), as important indicators of human exposure and impact. Furthermore, most of the oil infrastructure is located near human settlements, actively exposing residents to oil pollution of varying scales near their homes, farms and fishing grounds. Oil spills in the Niger Delta are no longer just environmental issues but are also sustainable development issues because they have given rise to a myriad of other socio-economic concerns: security, poverty, food security, human health and the overall quality of life of the local communities.

The growing concern among researchers about the health consequences of oil spill exposure in the Niger Delta attests to the fact that the health effects of this high level of exposure cannot be overemphasized. A United Nations Environment Program (UNEP,

2011) assessment of the Niger Delta reported that both the surface water and ground water in the Ogoniland region contained high concentration of carcinogens. Farm crops, vegetables, and seafood which are the primary food sources for Niger Delta residents are extremely contaminated with hydrocarbons and could cause liver damage, cancer, and reproductive health problems (Nriagu et al., 2011; Ordinioha & Brisibe, 2013).

Frequency of Oil Spills

1754 1601

1095 1032 994 998 962 831 873 683 511 370 406

145 30

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Figure 1: Frequency of Oil Spills in Nigeria from 2005 to January 2019

Figure 2: Oil Spill Frequency and Density Map of the Niger Delta

Research on oil spills in the Niger Delta generally focus on environmental and socioeconomic consequences. Extensive research has been conducted on the environmental impacts of the Niger Delta oil spills, socioeconomic consequences, as well as on the relationship between oil extraction and armed conflicts and violence in the region. While some studies report that the Niger Delta crisis is a direct fallout of the environmental degradation due to oil-related activities (Ehigie, 2005; Ogege, 2009;

Ordinioha & Brisibe, 2013; Ovadia, 2013), others take an environmental justice perspective and submit that the Niger Delta crises has resulted from marginalization and 23 alienation of the region (Obi, 2010). The Niger Delta region of Nigeria has witnessed a remarkable upsurge in violence and conflicts as a result of oil extraction in the area. This increase in violence and unrest has directly led to an escalation of vandalization and attacks, on oil infrastructure and an associated rise in the occurrences of oil spills in the region. The socio-economic impacts on the income and livelihoods of local communities have also gained much attention in the literature. For instance, Ojimba (2011) highlights loss of agricultural land due to oil exploration and its implications on the livelihoods and economic sustainability of farmers in Delta State, Nigeria. Crude oil spills adversely affect crops by reacting with and significantly decreasing soil nutrients (Osuji et al.,

2006; Abi & Nwosu, 2009), invariably leading to stunted growth or death of crops, and a general decrease in crop yield.

Although health problems are cited in a vast majority of these publications, there have only been few systematic health studies with respect to oil spills (Nriagu 2011; Gay et al., 2010). Health and epidemiology research in Sub-Saharan Africa, including Nigeria, have primarily revolved around demographics and socio-economic risk factors and determinants of health. For instance, Kandala & Madise (2004) examined the spatial epidemiology of malaria, diarrhea, and fever among infants in Malawi and Zambia. Their study shows a significant correlation between disease prevalence and family income, parental education, and geographical location. Childhood diseases appeared to be clustered around rural and poorer households while urban and wealthier households showed relatively low risk of disease prevalence. Kandala et al. (2007) observe that high rates of child mortality in Nigeria can be associated with the prevalence of such diseases 24 as diarrhea, malaria, and HIV/AIDS. They suggest that high rates of child morbidity in northern Nigeria could be linked to the persistence of drought, while the prevalence of cough, fever, and diarrhea in the southern region could be linked to oil spills and environmental pollution. The study also revealed, in line with other similar studies, a significant association of infant health problems with socioeconomic factors, such as the age of children and the education and income levels of the parents.

Nwanna-Nzewunwa (2016) studied the spatial epidemiology of child diarrhea in the Niger Delta. Their main goal was to examine the prevalence of diarrhea and determine the geographic patterns of the disease in children under 5 years of age. Their study sample included infants in the pediatrics department of the Niger Delta University

Teaching Hospital (NUDTH), and they used demographic variables such as sex, age, and level of education of the children’s mothers. Their results, in tandem with other similar studies, showed that incidences of child diarrhea are inversely proportional to the child’s age and maternal level of education. Most diarrhea cases occur in younger infants and in children of mothers who only have primary education. Thus, prevalence of child diarrhea decreased as the maternal level of education increased, and vice versa. Fifty-five percent of the cases occurred in children whose mothers had only primary education. Children of mothers with secondary school education accounted for about 23 percent of the cases, while mothers with tertiary education or higher had only 9 percent of the reported infant diarrhea cases. Dairo (2017) surveyed additional personal hygiene factors by mothers, such as washing hands with soap, handling and disposal of child stools, and 25 immunization practices, and found that these were also critical potential risk factors causing high prevalence of child diarrhea.

With respect to the human health impacts of oil spills in the Niger Delta, the

United Nations Environment Program (UNEP) in 2011 carried out a comprehensive environmental impact assessment to determine the level of oil pollution and hydrocarbon concentration in Ogoniland and environs. They reported a significantly high level of contamination in Ogoniland, which poses adverse health hazards. The soils, rivers and dams, farm crops, vegetables, and seafood were extremely contaminated with hydrocarbons, leading to an increase in health problems, such as liver damage, cancer, acute respiratory infections, and reproductive health problems. Over 4,000 samples were drawn and analyzed from drinking water sources in the region, from wells, ground and surface water. Soil samples were extracted from 780 boreholes. In addition, the UNEP project team examined more than 5,000 medical records. The assessment reports that considering the Niger Delta is a high intensity rainfall region, oil spills have the tendency to flow and disperse quickly into farmland and streams and may infiltrate underground water. Ordinioha & Brisibe (2013) buttress this fact by noting that people in the Niger

Delta are directly dependent on the natural environment for food and livelihood and face heightened risks of exposure to contaminants through contact with and consumption of food and water. They presented a review of hydrocarbon concentration on the marine and terrestrial environment of the Niger Delta and potential exposure of human populations to these contaminants. They also analyze health implications of oil spills in the region. Their results showed increased cases of child malnutrition, cancer, kidney diseases, diarrhea, 26 and anemia, all of which are attributable to direct exposure to high levels of hydrocarbon concentration.

Whanda et al. (2016) performed a geospatial analysis of oil spill distribution and assessed potential human exposure pathways and health risks associated with oil spill contamination in the Niger Delta of Nigeria. They employ three GIS techniques: nearest neighbor analysis, Getis-Ord General G test, and the Moran’s I index. While results from the nearest neighbor analysis and Getis-Ord G test indicated that oil spill distribution in the region expressed a spatially clustered pattern, the Moran’s I index indicated that there is a less than 1 percent probability that the clusters are a result of random chance. Using a generic assessment criterion based on the behavior and characteristics of contaminants in different land-use types, Whanda et al. (2018) assessed potential human health risks caused by exposure to petroleum hydrocarbons in the Niger Delta. They found that most significant exposure pathways were associated with rural agricultural land use through inhalation, direct contact with polluted soils and consumption of homegrown produce.

They also suggest that prolonged exposure to hydrocarbon components from oil spills tends to deteriorate the health of the affected and exposed communities.

Bruederle & Hodler (2017) documented an analysis of the impacts of oil spills on neonatal and infant mortality, and on child health in Nigeria. They use information on the birth histories of 2,477 mothers living within 10 km of an oil spill location and compared mortality rates of infants conceived before an oil spill with the mortality rates of infants conceived after the reported oil spill. Their analysis revealed an increased neonatal and infant mortality rate for infants conceived after an oil spill incident. In other words, oil 27 spills that occur prior to conception lead to an increase in neonatal mortality. They also report a significant correlation between the distribution of neonatal mortality and location of oil spills; Neonatal and infant mortality rates were higher in locations close to oil spills than in locations farther away. They provide further evidence to suggest that oil spills prior to conception increased the occurrence of low birthweight especially in the first 12 months of life. Similarly, San Sebastian et al. (2002) reveal that the rate of spontaneous abortion was two times higher for women living in communities surrounded by oil fields in the Ecuadorian Amazon Basin than elsewhere due to high level exposure to oil pollutants. They reveal that the river water in the communities are heavily polluted by hydrocarbons from oil chemicals and note that women living in these communities, though aware of this contamination, often have little or no access to alternative sources of water and thus use the contaminated river water regardless.

Evidently, research on environmental risk factors to child health and mortality associated with oil spills in the Niger Delta is generally lacking and therefore requires further investigation. This study is designed to fill this gap in the literature by investigating the spatial distribution and prevalence of infant diarrhea with respect to oil spills in the Niger Delta. Carrying out this research is critical to understanding the underlying causes of infant mortality in the study area. The Niger Delta, faced with serious environmental and health hazards, is the current focus of many intervention programs from federal and state governments as well as local and foreign aid agencies. It is anticipated that results from this research will provide useful insights into the issues of child health and mortality and provide vital spatial information that could serve as a 28 relevant tool for decision making and planning health intervention programs in the region.

2.2. Infant Diarrhea

The World Health Organization defined diarrhea as the frequent discharge of loose or watery stools, three or more times a day. Diarrhea is one of the most common childhood problems in Nigeria and the world. Evidence from the literature suggests that diarrhea is most prevalent in the first two years of the life of a child and declines as the child grows older (Oloruntoba et al., 2014; Dairo et al., 2017). It is the second most common cause of infant mortality worldwide (WHO, 2013) and the leading cause of death among children under the age of five (Oloruntoba et al., 2014; Omelonye et al.,

2015).

It is not always easy to differentiate normal intestinal problems from diarrhea in infants because bowel movements from breast milk can also be loose and liquid.

Although the disease can be dangerous and deadly, it is preventable and amenable to treatment. Acute diarrhea in infants may generally last for a short period of time, usually

1 or 2 days. Chronic diarrhea on the other hand is long term and may last up to four weeks. Common symptoms of diarrhea include vomiting, abnormal increase in stool weight and liquidity (Omelonye et al., 2015; Hussein, 2017). Other symptoms could include fever, loss of appetite, weight loss, and dehydration. In severe cases, diarrhea may sometimes be accompanied by passage of bloody stools. Most symptoms resolve on their own without treatment. Nonetheless, the World Health Organization (2011) notes 29 that improper or delayed treatment contributes up to 70 percent of all deaths for children under 5 years of age.

Diarrheal infection is generally known to be caused by bacterial and/or viral infections, food intolerance, irritable bowel syndrome, or other forms of bowel disorder.

Several studies have equally cited an association between diarrhea prevalence and demographic, socio-economic, and environmental influences. For instance, Rosenberg

(2007) and Hussein (2017) notes that infant diarrhea appears to be more prevalent in low and middle-income countries due to limited access to potable and improved sources of drinking water, unhealthy toilet facilities, and improper waste management practices.

Environmental and living conditions as well as personal hygiene are also primary risk factors for diarrhea disease. Infant mortality due to diarrhea is still very high in developing countries like Nigeria because of the weak and fragile health care systems.

Additionally, poor and rural households often do not have access or are not able to afford the most basic health care for their children.

There is a global estimate of about 2.5 billion cases of child diarrhea annually, a mortality rate higher than that of AIDS, malaria and measles combined (Boschi et al.,

2009, Akinrotoye, 2018). Africa and South Asia account for most of the mortality and other severe outcomes as a result of diarrhea (Ehiri, 2009; Raji, 2011). The World Health

Organization (WHO) reports that Africa and Southeast Asia account for as much as 7.7 percent and 8.5 percent, respectively, of all deaths. Most of the 25,000 children under 5 years that die daily are concentrated in sub-Saharan Africa and South Asia. Infant 30 mortality rates in these regions are 29 times greater than that in industrialized countries;

175 deaths per 1000 children compared to 6 per 1000 in industrialized countries.

In Nigeria, reports estimate that more than 315,000 child mortality cases annually are as a result of diarrhea (Dairo, 2017; Akinrotoye, 2018). The country falls short of the millennium development Goal 4 (MDG4) in which it was to attain a two-thirds reduction in the under-five mortality rate from 230 deaths per 1000 live births in 1990 to 76 in 2015

(Federal Ministry of Health (FMoH), 2011; Griggs, 2015). The Nigeria Demographic

Health Survey (DHS, 2013) reports that 10 percent of children under the age of 5 have had diarrhea in the two weeks preceding the survey, and 2 percent had diarrhea with blood. The prevalence of child mortality due to diarrhea remains high in Nigeria and is often associated with polluted water sources, inadequate sanitation, poor hygiene practices and contaminated food. Akinrotoye (2018) documents that about 67 percent of the population still does not have access to improved sanitation facilities. Open defecation, indiscriminate and improper disposal of children’s stools and household wastes, lack of sanitary toilets, use of public latrines, and inadequate sewage systems are common problems in Nigeria, and contribute to the risks and prevalence of the diarrhea disease. Additionally, lack of adequate health care services minimizes the possibility of prompt and appropriate treatment of the disease.

Atubi (2015) recorded high rates of diarrhea, asthma, bronchitis, and different forms of skin infection in Delta State, an oil producing state, and suggests that the high prevalence of these observed health problems could be a direct effect of exposure to oil spills. People in these regions hardly visit hospitals, claiming that the services are 31 unaffordable. Therefore, they patronize ‘chemist shops’ or adopt traditional methods and practices to treat illnesses. Atubi (2015) examined the relationship between oil exploration and human health outcomes in Delta State, and documents that gas flaring and air pollution has had adverse health effects, like bronchitis and skin infection.

Despite efforts toward the prevention, control, and management of diarrheal disease, associated mortality remains high in developing countries. Diarrhea is preventable and amenable to treatment, but delayed or improper treatment could easily lead to mortality.

2.3. Geographic Information Systems in Spatial Epidemiology

The relevance of Geographic Information Systems (GIS) techniques for examining spatial distributions, patterns, and relationships is growing in popularity

(Cromley and Mclafferty 2012). One area of increasing interest in GIS is that of spatial epidemiology which seeks to examine spatial relationships between disease prevalence and exposure to environmental elements. The goal of spatial epidemiology is to study disease transmission and identify infection causes by relating the spatial distribution of a disease to spatial variations in human health hazards. GIS underpins disease mapping, area examination, the characterization of populations, and spatial analysis and visualization (Jacquez, 2000).

The analytical capabilities of GIS provide the researcher with the ability to conceptualize and visualize data and enables us to better understand spatial trends and patterns of diseases and epidemics. The capability of GIS in displaying the spatial distribution of health events makes the technology valuable for a wide range of applications (Longley et al., 2005; Shaw, 2017). Dangendorfa et al. (2001) demonstrated 32 the utility of GIS applications for the analysis of diarrheal infections through drinking water in the Rhine-Berg District, Germany. They integrated a wide range of datasets comprising features of water supply structures and epidemiological databases which constitute a surveillance system for waterborne infectious diseases. Their main objective was to investigate whether spatial variation of diarrheal illnesses was associated with different drinking water supply structures. They applied a Poisson probability distribution model to estimate and the Standardized Morbidity Ratio (SMR) to compare observed and expected incidence rates and applied a spatial autocorrelation model to detect clusters of disease incidences. Their geo-statistical and spatial autocorrelation analysis showed spatial clustering of the diarrheal disease. They also found a significant positive correlation between the prevalence of diarrheal illnesses and amount of ground water.

Similarly, Sarkar et al. (2007) explored drinking water epidemiology and reported a uniform distribution of diarrheal diseases throughout the various water supply structures.

However, limited access to sanitary latrines, indiscriminate defecation and poor maintenance of water pipes, among other factors, were found to be major predictors of disease prevalence in the study area. They integrated the epidemiological data and water supply infrastructure data into a GIS to enable spatial mapping of the disease and noted that GIS provides an essential functionality in disease mapping and spatial analysis.

In Nigeria, Ayademo et al. (2015) employed GIS technology to examine the spatial spread of malaria risk and vulnerability in Nigeria. They sought to determine the spatial trends and pattern of malaria epidemics in the country and to employ a spatial model to predict risks of malaria infections in different locations throughout the country. 33

They analyzed and produced a malaria risk map of Osogbo, the capital city of Osun State,

Nigeria. Njemanze et al. (1999) highlight the importance of GIS as a vital tool in water source planning in a community in the Niger Delta as a means of minimizing water source contamination and prevention of diarrheal diseases.

This thesis reinforces the applicability of GIS in disease mapping and spatial epidemiology. It equally contributes to the body of literature using explicit geographic techniques (Moran’s I and CROSSTAB) to identify spatial clustering, visualize the distribution and determine spatial relationships among variables.

CHAPTER 3: THE STUDY AREA

3.1. Physical Geography

Nigeria lies between latitude 4oN and 14oN, and between longitude 3oE and 15oE. It is bordered by Cameroon in the east, Benin Republic in the west, and the Republic of Niger and the Atlantic Ocean in the north and south respectively. Though Nigeria has many rivers, the River Niger and River Benue are the two major river systems in the country

(Kuruk, 2004). These two major rivers converge at Lokoja, Kogi State and flow southwards into the Atlantic Ocean through many distributaries, thus, forming an extensive delta area along the coasts. This explains why the southern part of Nigeria is commonly referred to as the Niger Delta region.

The Niger Delta region is bounded in the west, and southern by the Atlantic Ocean, and in the east by the Imo River. Characteristically, the region is typically marked by meandering and braided channels, beach ridges, sand bars and lagoons, uneven terrain, creeks, shallow saline and brackish water bodies (UNEP, 2011). The Rivers State region is drained by the Bonny and New Calabar rivers as well as several creeks and streams.

Few islands are separated from the continental landmass by creeks and distributaries of the Niger River.

The Niger Delta is considered the second largest delta region in the world, with approximately 28,000 sq. km of land mass and continental shelf stretching about 46,300 sq. km. The region is also considered the largest wetland and mangrove forest in Africa and third largest in the world (Anifowose, 2008; Chinweze & Abiola-Oloke, 2009). The region lies within a dense tropical rainforest consisting of diverse species of flora and 35 fauna. Some scientists have classified the region into four ecological zones, namely, the coastal inland zone, freshwater zone, lowland rainforest and mangrove swamp zones

(FME, 2006; ANEEJ, 2004). The region is warm and humid all year round. The mean annual temperature range is 24-32°C and mean annual rainfall ranges between 1,500-

4,000 mm (Kuruk, 2004). The Niger Delta Basin, popular for its diverse species of flora and fauna, is even more popular for its abundant deposits of petroleum resources. It is the richest part of Nigeria in terms of petroleum resources and natural ecosystems of biodiversity.

3.2. Human Geography of the Niger Delta

The Niger Delta consists of nine states: Abia, Akwa Ibom, Bayelsa, Cross River,

Delta, Edo, Imo, Ondo, and Rivers States, all within the South-East and South-South geopolitical zones of Nigeria (Fig. 3). According to the 2006 population census, over 30 million people from more than 40 different ethnic groups and 250 dialects live in the

Niger Delta. They account for more than 23 percent of the population of Nigeria’s

(Twumasi and Merem, 2006; Uyigue & Agho, 2007). Residents of the Niger Delta engage mainly in primary economic activities like crop and fish farming, forestry, hunting, and gathering. They are largely dependent on natural environmental resources for livelihood.

The region’s abundant natural wealth stands in stark contrast to its widespread underdevelopment. The region lacks essential amenities and services like electricity, clean and potable water, motorable roads, good schools, quality health care services and 36 facilities. The region consistently ranks low on the United Nations indices for development, income, health and gender (UNDP, 2006 in Steiner, 2010).

Fig 3: The Niger Delta Region of Nigeria

CHAPTER 4: DATA AND METHODS

4.1. Data

This study is based on analysis of secondary oil spill data from the Nigerian Oil

Spill Monitor, and spatial health data from the Nigeria National Demographic and Health

Survey (2013). Georeferenced data of oil spill locations are available for download from the Nigerian National Oil Spill Monitor (https://oilspillmonitor.ng/). The website provides public access to official oil spill record collected and managed by the National

Oil Spill Detection and Response Agency (NOSDRA), the Nigerian environmental regulatory agency. The website contains an online interactive map of oil spills in Nigeria that can be queried, extracted, and/or downloaded in table format depending on the needs and requirements of the user. The dataset contains information on the geographic coordinates and location of oil spills, dates of the spills, and estimated quantity spilled.

This study focuses on oil spill data for the Niger Delta from 2008 to 2013.

Until recently, health data were usually collected from hospitals and clinics. One limitation of this data source is that hospital records may not be representative of the overall health condition of a study area given that many patients may not seek medical attention or may visit health facilities located away from their immediate area of residence (Kandala & Madise, 2004). For instance, it is common practice in some developing countries like Nigeria for patients to seek traditional health care because of the belief that traditional medicine is more potent and effective than hospitals or they visit

‘chemist shops’ because they cannot afford professional healthcare from hospitals. For this reason, researchers especially in developing countries have widely adopted health 38 data published by the Demographic and Health Survey (Kandala & Madise, 2004;

Kandala, et al., 2007; Adekanmbi et al., 2016,). The DHS dataset is judged by both national and international health agencies to be the best available data about developing countries where a comprehensive health data is otherwise absent. Thus, this research adapts cases infant of diarrhea collected and published by the Demographic and Health

Survey (DHS, 2013).

The Demographic and Health Survey is a national representative sample survey that provides up-to-date information on population, demographics, socioeconomic characteristics, nutrition and health indicator estimates in developing countries. The DHS dataset also contains information on levels and trends in fertility, nuptiality, early childhood mortality, maternal mortality, maternal and child health, and socio-economic and environmental conditions. The 2013 NDHS contains a sample survey of 33,385 women of reproductive age between 15 and 49 and 15,486 men aged 15 to 59 in randomly selected households across the six geo-political zones in Nigeria. Child health and mortality estimates are based on information from mothers’ birth histories collected through a semi-structured survey questionnaire for women, while infant diarrhea data are collected from questionnaires administered to mothers containing questions about child health in the two weeks preceding the survey. The survey employs a stratified three-stage cluster design consisting of 904 clusters, 372 in urban areas and 532 in rural areas, and provides a comprehensive population-based health data. The sample for this thesis contains 4,060 children under the age of 5 years from 3,384 households located within

206 DHS clusters sampled across the 9 states of the Niger Delta. 39

The instruments and conduct of the Nigeria DHS were approved by the

Institutional Review Board of ICF international (Fairfax, Virginia, U.S.A), and the

Nigeria Health Research Ethics Committee of the Federal Ministry of Health. To the best of my knowledge, the DHS is the only nationally representative dataset available in most developing countries. The DHS has granted permission for the use of this data for this research. Therefore, its use in this study lends credibility to validity of the study.

4.2. Limitations of the data

4.2.1. Health Data

In the DHS (2013) survey, mothers were asked whether any of their children under the age of 5 experienced symptoms of diarrhea any time during the two weeks preceding the survey. As such, there is no information on cases of diarrhea prior to the 2 weeks before the survey. It is generally assumed that mothers can tell when their child has diarrhea and are able to distinguish diarrhea from other forms of bowel movements.

Thus, the validity of the DHS data on infant diarrhea is affected by each mother’s perception of diarrhea as an illness and her ability to recollect past events.

The DHS GPS latitude/longitude data have been randomly displaced for reasons of confidentiality. Urban clusters are displaced up to 2 kilometers and rural clusters are displaced up to 5 kilometers. This affects the spatial context in which relationships between individual households and proximity to oil spill locations are analyzed.

Secondly, the method of collecting the aggregated DHS data is such that a single point feature represents a cluster of households rather than individual households. This restricts 40 the spatial autocorrelation to a cluster level analysis whereas a finer spatial scale at individual household level is presumed to provide more detailed results.

4.2.2. Oil Spill Data

In general, obtaining accurate oil spill data can be problematic and data should be viewed with caution. As Michel and Fingas, (2016) note, spill quantity or volume is the most difficult to estimate. Sometimes it is also difficult to estimate the quantity of oil spill cleaned up, and the final quantity lost to the environment.

It is likely that the estimated quantity of oil spill recorded in many cases are incorrect. Oil spill data in Nigeria are collected by different agencies, like the oil companies, SPDC, and NOSDRA, and members of the local communities are equally encouraged to report any incidence of oil spills either to the government or to NOSDRA.

There are noticeable discrepancies between various oil spill data from different sources and databases. For instance, the Shell Petroleum Development Company (SPDC) oil spill data differs from that of NOSDRA and from figures reported by individuals or private investigators. The oil spill investigation process, commonly known as the Joint

Investigation Visit (JIV) is carried out with the oil companies as the primary investigators and there are several potential abuses and deficiencies within the procedure that would make the report less valuable. Oil company employees might underreport spill events, size, and impacts or misreport causes as suits their purpose while incidents reported by members of the local communities might overestimate and inflate values. Thus, it is sometimes misleading to directly compare oil spill statistics because of the different methods and sources of the data (Steiner, 2010; Whanda, 2014). 41

Furthermore, the oil spill data from the Nigerian Oil Spill Monitor contains some missing information on absolute location and geographic coordinates, quantity of oil spill, quantity cleaned up, and quantity lost to the environment. To reduce error and misrepresentation of data, oil spill incidences with missing information were excluded from the study. Offshore spills were also excluded from the study due to the inability to document their exact locations and migratory capacity. This study, therefore, consider only on-shore oil spills complete with their geographic coordinates and other relevant information, such as quantity of oil spilled, date of the incident, and estimated area affected. This study assumes that onshore oil spills will have a more direct impact on the study area since most of the onshore oil facilities and pipelines are located within and around residential neighborhoods.

4.3. Methods

First, oil spill data were extracted for 2008 to 2013 from the Nigeria Oil Spill

Monitor database. The data were preprocessed using Microsoft Excel 2016 and checked for completeness. Furthermore, the data was sorted and incidences with missing values

(missing geographic coordinates, oil spill quantities, or date of oil spill) were excluded.

MS Excel was also employed to construct histograms of the frequency of oil spills and calculate frequencies averages and percentages. The children’s recode file was downloaded from the DHS online spatial health data repository in SPSS format.

Descriptive statistics of the data were computed to characterize the variables, and calculate frequencies, averages, and percentages, and to produce histograms of distribution. 42

After cleaning the oil spill and DHS health data, they were imported into ESRI’s

ArcMap V10.6 to enable overlay and visualize, and to facilitate a spatial autocorrelation analysis. Spatial autocorrelation is an inferential statistic tool that measures the spatial distribution of phenomena by computing frequencies, means, and standard deviation of the variable to determine whether the pattern expressed is clustered, dispersed, or random. The results are always interpreted within the context of null hypotheses which in this case are (Ho1): Incidences of oil spill are randomly distributed across the Niger Delta, and (Ho2): Incidences of infant diarrhea are randomly distributed across the Niger Delta.

The spatial autocorrelation tool determines the spatial cluster or otherwise of the feature using the Global Moran’s I Index. A positive Moran’s I index indicates a tendency towards spatial clustering while a negative Moran’s I index value indicates dispersion.

The Moran’s I index is given by:

Where N = number of observations, x̅ = mean of the variable,

Xi = Variable value at a location

Xj = variable value at another location

Wij = Wight index location of i relative to j

In addition to the Moran's I Index, spatial autocorrelation calculates a z-score and a p-value to evaluate the significance of the Index. When the p-value is statistically 43 significant, the null hypothesis can be rejected which will mean that cases of infant diarrhea in the Niger Delta are clustered, but if the p-value is not statistically significant, the null hypothesis is accepted. The Z-score measures the distribution of high and low values, i.e. the cluster of high values of oil spills or infant diarrhea.

To assess the level of association and test the null hypothesis (Ho3): ‘there is no significant relationship between oil spills and infant diarrhea in the Niger Delta’, a

CROSSTAB (crosstabulation) operation was performed using IDRISI Selva V17.0. A

Crosstabulation function basically measures the level of association between two or more classified images and calculates an overall as well as per-category indices.

For this analysis, oil spills were classified into 5 categories in raster format using the Jenk’s natural breaks classification scheme. Category 1 represents the least quantities of oil spill, and category 5 represents the highest quantities of oil spill. Similarly, incidences of infant diarrhea were placed into 5 categories with class 1 and class 5 representing the least and highest prevalence rates, respectively. The CROSSTAB operation, therefore, overlays and compares categories of the oil spill raster with those of the infant diarrhea, records the number of cells in each combination and renders three outputs indicating the level and strength of association between the two raster images.

The first output measure of association is the Cramer’s V, a correlation coefficient that ranges from 0.0 indicating no correlation, to 1.0 which indicates a perfect correlation.

The Cramer’s V is defined by: 44

Where: χ2 = chi-square, k = the number of rows or columns in the table.

Secondly, the CROSSTAB operation outputs a Chi-Square value which tests the significance of the correlation (Cramer’s V). If the Chi-Square is significant, then

Cramer’s V will equally be significant. A third output is another measure of association called the Kappa Index of Agreement (KIA).

Kappa Index is given by:

Where: K = Kappa Index of Agreement;

r = number of matrix lines;

th th Xii = number of observations in i row and i column;

th th Xi+ and X+I = total of i row and i column, respectively

N = total number of observations (cells)

The Kappa Index ranges from 0.0 to 1.0 indicating no agreement to perfect agreement, respectively. The Kappa Index is often applied when the images being compared have the same number of classes. This analysis was performed using a 45 classified raster image of oil spills and another image of infant diarrhea with five classes each.

In addition, buffers were created at 5 km, 10 km and 20 km around oil spill locations and selected DHS clusters within the specified distance buffers. The buffers were used to examine the effect of distance from location of an oil spill on the prevalence of infant diarrhea. It was expected that households within 5 km of an oil spill would report a higher rate of infant diarrhea and that the prevalence rate would decrease as distance from the oil spill location increased.

Fig. 4: Location of DHS Clusters and Oil spills in the Niger Delta 46

In line with other studies that have examined socioeconomic predictors of diarrhea prevalence, this study has considered the relationship between demographic and socioeconomic characteristics and infant diarrhea prevalence in the Niger Delta.

Demographic and socioeconomic predictors considered are, household place of residence, mother’s age and education, household wealth, household source of drinking water and toilet facility, and number of children under 5 years of age in the household.

CHAPTER 5: RESULTS AND DISCUSSION

Oil spills are virtually inevitable accidents associated with oil exploration, transportation and distribution and usually occur in areas of damaged oil facilities. The geospatial analysis of the distribution of oil spills in the Niger Delta using the spatial autocorrelation function in ArcMap, revealed a clustered pattern as shown in Fig. 4.

The calculated p-value of ≈0.0004 and a z-score of ≈3.53 indicate that incidences if oil spills express a clustered pattern. In other words, it is very unlikely that the observed spatial clustering is a result of some random process. Therefore, we reject the null hypothesis (Ho1) that ‘oil spills are randomly distributed in the Niger Delta’, and conclude that there is spatial clustering of oil spills in the Niger Delta. This result is consistent with reports from Whanda et al. (2016) who revealed, using multiple geospatial techniques, a spatial cluster of oil spills in the Niger Delta. 48

Fig 5: A Spatial Autocorrelation of Oil Spill Incidences in the Niger Delta

A spatial autocorrelation analysis of infant diarrhea cases in the Niger Delta showed a significantly clustered pattern. Our results revealed a z-score of 2.27 and a p- value of 0.02 indicating that there is less than 5 percent likelihood that incidences of infant diarrhea across the Niger Delta are a result of some random process. Hence, null hypothesis (Ho2) that ‘incidences of infant diarrhea are randomly distributed in the Niger 49

Delta’ is rejected, and it is concluded that cases of infant diarrhea express a spatially clustered pattern in the Niger Delta.

Fig. 6: A Spatial Autocorrelation of Incidences of Infant Diarrhea

A notable problem in the Niger Delta is the fact that most oil pipelines traverse residential neighborhoods and at times are located and exposed on the surface.

Furthermore, residents in the study area engage mostly in primary economic activities like farming, logging, forestry, and fishing, and are also highly dependent on surface water, boreholes, and wells as their main sources of drinking water. These living 50 conditions amplify the likelihood of direct contact with and exposure to oil pollution.

Whanda et al. (2018) observed that most significant exposure pathways in the Niger

Delta were associated with rural agricultural land use through direct contact with polluted soils and consumption of homegrown produce. They also suggest that residents experience prolonged exposure to hydrocarbon components from oil spills due to the persistent nature of some oil pollutants in the environment and due to the land use types and economic activities they engage in.

Imo State appeared to have the highest percentage (12.2 percent) of infant diarrhea and on the other extreme, Bayelsa and Edo States with a sample size 220 and

387 children accounted for 1.8 percent and 2 percent, respectively, of total cases of infant diarrhea in the Niger Delta. Akwa Ibom State appeared to be an outlier where cases of diarrhea were relatively high regardless of the comparatively low incidences of oil spills.

In the case of Akwa Ibom, incidences of infant diarrhea may be attributed to other environmental, demographic or socio-economic factors. 51

Fig 7: Density Distribution of Infant Diarrhea in the Niger Delta

Fig 8: Percent Distribution of Infant Diarrhea According to States

The third objective of this study is to determine the correlation and level of association between oil spills and incidences of infant diarrhea. In other words, whether the spatial clustering of infant diarrhea is due to its proximity to the location of oil spills.

Table 1 below shows a crosstabulation output table of the classified images indicating the level and significance of correlation between oil spills and infant diarrhea.

Table 1:

Crosstabulation of Oil Spills and Diarrhea

Oil Spills 1 2 3 4 5 | Total

Diarrhea

1 547 854 245 144 118 | 3463

2 1160 1079 531 489 760 | 9351

3 137 745 313 344 302 | 5220

4 51 242 139 154 205 | 2283

5 0 250 57 5 0 | 548

Total 2593 5468 1864 1252 1387 | 288600

Chi Square = 97800.92969 df = 25

P-Level = 0.0000

Cramer's V = 0.2603

The CROSSTAB output table shows the overlap/intersect of the different classes of oil spills and infant diarrhea. Oil spills are tabulated along the columns while incidences of infant diarrhea are tabulated along rows. The CROSSTAB calculates a Chi-

Square, Cramer’s V value, and a p-value.

Using the crosstabulation operation in IDRISI Selva V17.0, a positive correlation was found between oil spills and infant diarrhea. the CROSSTAB reported a Cramer’s V value of 0.26, indicated a weak correlation between oil spills and infant diarrhea. A p- 54 value less than 0.001 indicates a statistically significant association at 0.95 level of confidence. Therefore, the null hypothesis (Ho3) which states that ‘there is no significant relationship between oil spills and infant diarrhea’ is rejected, and it is concluded that there is a relationship between oil spill and infant diarrhea in the Niger Delta. There is 26 percent chance of agreement between the two variables. In other words, there is 26 percent likelihood that the prevalence of infant diarrhea in the Niger Delta is correlated with incidences of oil spills.

Using the Buffer geoprocessing tool in ArcMap V10.6, and 5 km, 10 km and 20 km distance buffers around reported oil spill locations, the impact of proximity to an oil spill location, and the rate of diarrhea prevalence was assessed. Rates of infant diarrhea in the DHS clusters were compared based on proximity to oil spill locations. Results showed that incidences of infant diarrhea were inversely proportional to distance to oil spills. In other words, infant diarrhea decreased as distance from an oil spill location increased. Households within 5 km of a reported oil spill location had about 19 percent prevalence rate while households 10 km and 20 km from an oil spill site recorded 13 percent and 10 percent of infant diarrhea, respectively (Fig. 8). This further strengthens and validates the results from the CROSSTAB operation which showed a correlation between the oil spills and infant diarrhea. This finding is in tandem with previous studies that have established that adverse health outcomes diminish with distance from the point of pollution (Lyons, 1999; Janjua et al. 2013; Bruederle and Hodler, 2017). 55

DISTANCE DECAY OF CHILD DIARRHEA Distance (km) Diarrhea Percent Diarrhea 50 25

40 20 Percent Diarrhea

30 15

Frequency 25

20 10 ( percent) 15

10 5

0 0 5 10 20 Distance (km)

Fig. 9: Distance Decay of Child Diarrhea

Researchers have widely documented and acknowledged that demographic and socioeconomic factors are strongly associated with incidences of diarrhea. In this study, an assessment of demographics and socio-economic characteristics of the sample population as reported by the Nigeria DHS (2013) shows that household characteristics, such as mothers’ age and education, household economic status, type of place of residence, and access to improved water and toilet facilities are major contributing factors to diarrheal diseases prevalence in the study area.

To this effect, this study further explores associated demographics and socioeconomic risk factors that could contribute to diarrheal disease in the study area.

Mothers’ age and level of education, the household’s place of residence (rural or urban), 56 household wealth index, household source of drinking water, and type of toilet facility were considered.

This study includes a sample of 4,060 children under 5 years from 3,384 households in the 206 DHS clusters within the Niger Delta region. A computation of the descriptive statistics of our sample population using their demographic and socioeconomic characteristics was done with Microsoft Excel 2016 and R statistical package.

The mean age of mothers in the sample was 3.7 representing mothers between 25-29 years old. The number of mothers 24 years and younger in the sample was relatively low and the number of children in their households were equally low. Thus, this group may have been underrepresented, leading to the small number of cases of diarrhea reported for that age range.

Majority of the respondents (67 percent) resided in rural areas while 34 percent lived in the urban areas. On level of education, only 10 percent of the subjects have attained education beyond secondary school level (Table 2). A household wealth index was constructed using household asset data via a principal component analysis. It considers household income as well as possession of things such as cars, televisions and radios, and refrigerators, among other essential household asset. Results show that most of the sample respondents were relatively wealthy (Table 2).

Table 2:

Background Characteristics of the Sample Population

Background Characteristics Niger Delta National

N=3,384 (%) N=40,680 (%)

Residence: Urban 1,134 (33.5) 10,403 (9.2)

Rural 2,250 (66.5) 18,547 (10.8)

Mother’s age: 15-19 170 (5.0) 1,531 (3.8)

20-24 566 (16.7) 6,083 (15.0)

25-34 1,628 (48.1) 15,698 (38.6)

35-49 1,020 (30.1) 8,170 (20.1)

Maternal Education: No Education 226 (6.7) 13,945 (11.7)

Primary 925 (27.3) 5,563 (9.9)

Secondary 1,883 (55.6) 7,697 (8.8)

Higher 350 (10.3) 1,744 (5.6)

Wealth Status: Poorest 24 (0.7) 7,076 (17.4)

Poorer 389 (11.5) 7,386 (18.2)

Middle 914 (27.0) 6,272 (12.1)

Richer 1,150 (34.0) 5,806 (14.3)

Richest 907 (60.8) 4,942 (12.1)

An assessment of the sources of drinking water sources showed that about 59 per cent of Niger Delta residents have access to potable water by DHS standards. Boreholes were the main source of household drinking water, and about 41 percent of households get their water supply from boreholes (Table 3). Only very few, less than 2 percent of the respondents, had access to pipe-borne water in their homes while about 7 percent used public taps.

It is generally believed that ground and surface water provide safe sources of drinking water. This general belief may not hold true for Niger Delta where several reports indicate that both ground and surface water in the region are heavily polluted with hydrocarbon contaminants from oil spills. The United Nations Environmental

Assessment report (2011) reports high level of hydrocarbon contamination of subsurface soil and underground water. The report reveals that oil pollutants have permeated through the soil, reaching and polluting both surface and ground water. Therefore, ground and surface water in the Niger Delta region cannot be considered completely safe for drinking unless properly treated. However, residents still consider water from boreholes safe for drinking and that provides an explanation why many households do not treat water before use. Rivers and dams on the other hand, are highly susceptible to oil contamination are considered unimproved sources of water in this study. Reports suggest that many of the rivers in the Niger Delta communities are heavily polluted with hydrocarbons from oil chemicals and although some residents may be aware of this contamination, they often have little or no access to alternative sources of water and thus use the contaminated river water regardless. 59

On the other hand, 64 percent of residents lacked access to improved toilet facilities. About 29 percent of the population reported having no toilet facilities.

Table 3:

Household Water and Sanitation Facilities

Household Water and Sanitation

Source of Drinking Water Type of Toilet Facility

N (%) N (%)

Piped 49 (1.4) Flush 897 (26.5)

Public tap 225 (6.6) Pit latrine 996 (29.4)

Borehole 1394 (41.1) No facility 985 (29.1)

River/Dam 887 (26.2) Other 506 (15.0)

Other 747 (24.5)

Improved 2,007 (59.3) 1,194 (35.3)

Unimproved 1,377 (40.7) 2,190 (64.7)

The survey returned a total of 231 cases of child diarrhea. 154 cases of the diarrhea occurred in rural households while urban households reported 77 cases, representing 67 percent and 33 percent of total infant diarrhea, respectively (Table 4).

Urban households were also observed to be associated with more educated mothers, improved water sources and toilet facilities, and generally among the upper class in terms 60 of household wealth. Thus, the likelihood of diarrhea prevalence in the urban households was relatively low.

Children of mothers 25-29 years of age had higher likelihood of experiencing symptoms of diarrhea and the rate of diarrhea decreased as the age of the mothers increased. Similarly, infant diarrhea was highest among children in poorer households, and as household wealth increased, cases of infant diarrhea decreased.

As expected, households with pipe borne water and access to public taps, which are generally considered improved and safe sources of household water, had the least diarrhea prevalence rates of 1 percent and 5 percent, respectively (Table 4). A 38 percent rate of diarrhea disease occurred among households that drew water from boreholes.

Households that use river/dam water accounted for roughly 28 percent diarrhea incidence.

Similarly, as most of the Niger Delta Residents (64 percent) have limited access to improved toilet facilities. These households that have unimproved toilet facilities accounted for 71 percent of total child diarrhea. Of the 3,384 households included in the survey, 985 households representing approximately 29 percent of the survey population had no toilet facilities at all and alternatively practiced open defecation in surrounding fields or bushes. It is therefore not surprising that these households reported a high (37 percent) rate of diarrhea. On the contrary, households with improved toilet facilities like flush toilets, reported roughly 19 percent of the total diarrhea.

Table 4:

Prevalence of Diarrhea by Background Characteristics

Background Characteristics All Diarrhea N (%)

Residence

Urban 1,134 (33.5) 77 (33.3)

Rural 2,250 (66.5) 154 (66.7)

Mother’s age

15-19 170 (5.0) 10 (4.3)

20-24 566 (16.7) 44 (19.1)

25-29 1,628 (48.1) 49 (21.2)

30-34 777 (22.96) 49 (21.2)

35-49 1,020 (30.1) 79 (34.2)

Wealth Status

Poorest 24 (0.7) 6 (2.6)

Poorer 389 (11.5) 36 (15.6)

Middle 914 (27.0) 55 (23.8)

Richer 1,150 (34.0) 83 (35.9)

Richest 907 (60.8) 51 (22.1)

Table 5:

Prevalence of Diarrhea by Water Source and Sanitation

Household Characteristics All Diarrhea N (%)

Source of Drinking Water N (%)

Piped 49 (1.45) 3 (1.3)

Public tap 225 (6.65) 11 (4.8)

Borehole 1,394 (41.2) 88 (38.1)

Rainwater 76 (2.3) 6 (2.6)

River/dam 887 (26.2) 63 (27.3)

Well 388 (11.5) 30 (13)

Spring 92 (2.7) 14 (6.1)

Other 273 (8.0) 16 (7.0)

Improved 2,007 (59.3) 53 (22.9)

Unimproved 1,377 (40.7) 178 (77.1)

Type of Toilet Facility

Flush 897 (26.5) 45 (19.5)

Improved pit latrine 996 (29.4) 82 (35.5)

No facility 985 (29.1) 85 (36.8)

Other 506 (14.95) 19 (8.3)

Improved 1,194 (35.3) 67 (29.0)

Unimproved 2,190 (64.5) 164 (71.0)

Infant diarrhea is inversely proportional to maternal age (r = 0.16) and education

(r = -0.02) (Table 6). In other words, older mothers reported lower diarrhea rate, while diarrhea prevalence was found to be higher in younger mothers. Similarly, as mother’s level of education increased, the rate of diarrhea prevalence decreased. An inverse relationship also exists between infant diarrhea and household characteristics like place of residence, household wealth, drinking water source and toilet facility. In general, as household

Results show that there is a weak positive correlation (r = 0.16) between household wealth and source of drinking water, and a strong positive correlation (r =

0.51) between household wealth and type of toilet facility (Table 6). Wealthier families tend to live in the urban areas, with access to better and improved sources of drinking water and improved toilet facilities. Poorer households on the other hand tend to live more in rural areas and have limited access to improved water supply and toilet facilities and had a higher rate of diarrhea prevalence. This provides better insight and elucidates the differences in disease prevalence between the two groups.

Table 6:

Correlation between Infant Diarrhea and Household Characteristics

1 2 3 4 5 6 7 8

1 Diarrhea

2 Mother's Age -0.016

3 Maternal Education -0.002 -0.016

4 Children under 5 years 0.061 0.006 -0.108

5 Type of Residence 0.003 -0.001 -0.221 0.004

6 Household Wealth -0.048 0.033 0.443 -0.056 -0.413

7 Toilet Facility -0.038 0.019 0.302 -0.04 -0.347 0.51

8 Water Source -0.004 0.012 0.049 -0.038 -0.147 0.16 0.07

In the general DHS data collected for the entire country, diarrhea was most common among children 12-23 months old and declined among children 48-59 months.

The DHS (2013) reports that 10 percent of children under the age of 5 have had diarrhea in the two weeks preceding the survey, and 2 percent had diarrhea with blood. Children of mothers with no education were twice as likely as children of mothers with more than a secondary education to have had diarrhea. There is also a direct relationship between family wealth and diarrhea prevalence with children from wealthier households being less likely to have diarrhea. In other words, urban households with higher income, educated parents, improved drinking water, and improved toilet facilities reported a 65 relatively lower prevalence of diarrhea than the less educated, low income residents with unimproved sources of drinking water and little or no access to improved toilet facilities.

Nonetheless, when compared to the national average, prevalence of child diarrheal disease in the Niger Delta falls below the national average. The national average of diarrhea prevalence is 9.96 percent whereas the Niger Delta average is 5.12 percent. The

North East region records the highest rate of child diarrhea in Nigeria at 21 (Fig. 9) percent with about 3.6 percent experiencing diarrhea with blood (DHS, 2013). Kandala et al. (2007) attribute the high rate of child diarrhea in the North East to lack of clean potable water and limited access to quality health care. The North East region of Nigeria is in the southern part of the Sahara, which has little rainfall and limited access to improved alternative sources of household water.

Diarrhea Prevalence in Nigeria by Regions

12000 25

10000 20 % Diarrhea 8000 15 6000 10 4000

5 No. ofChildrenNo. 2000

0 0 Niger Delta North North East North West South East South West Central

No. of Children % of Diarrhea

Fig. 9: Diarrhea Prevalence in Different Regions of Nigeria 66

CHAPTER 6: CONCLUSION

Oil spill is undoubtedly the most common environmental hazard plaguing the

Niger Delta. Marked by numerous oil wells, pipelines and other infrastructure traversing residential areas and neighborhoods, residents face elevated risk of exposure to oil pollution of varying scales near their homes, farms and fishing grounds. The low standard of operation of oil companies in the Niger Delta region of Nigeria, as regards to methods of extraction and infrastructure integrity, amplifies the risk of oil spills (Steiner, 2010).

Furthermore, residents in the study area engage mostly in primary economic activities like farming, logging, forestry, and fishing. Residents are also highly dependent on surface water, boreholes, and wells, which are polluted with oil chemicals, as their main sources of drinking water.

This high level of exposure to oil pollution increases the tendency of adverse health conditions for the local communities, providing a highly relevant context to examine spatial relationships between environmental elements and human health conditions. Researchers have suggested that infant diarrhea, among other adverse health effects, could be associated with oil spills. Therefore, this thesis has presented an understanding of the spatial patterns and relationship between oil spills and the prevalence of childhood diarrhea. The study reveals a spatial clustering of oil spills and infant diarrhea disease in the study area, and it is very unlikely that the observed spatial clustering is a result of some random process. The study also reveals a 26 percent chance that infant diarrhea in the Niger Delta is associated with oil spills. The distance buffer analysis to further determine the effects of distance for an oil spill location on the 67 prevalence rate of infant diarrhea revealed that distance from an oil spill is inversely proportional to rate of diarrhea. A higher rate of child diarrhea was observed in households nearer to an oil spill than households farther away. This conclusion is in tandem with findings from similar studies (Lyons, 1999; San Sebastian, 2002; Janjua et al., 2013; Bruederle and Hodler, 2017) that have concluded that adverse health outcomes diminish with increasing distance from the point of pollution.

Background characteristics and living conditions are also critical factors predicting disease prevalence. Rural, low-income households with limited access to improved water sources and sanitation facilities reported a higher rate of diarrhea than the wealthier urban households. Similarly, maternal age and education predict diarrhea as older and more educated mothers report a relatively low rate of diarrhea among their children. In general, as household socioeconomic status and living conditions improved, the rate of diarrhea prevalence declined.

The inextricable relationship between environmental hazards and human health conditions remains an important theme among public health professionals, agencies, and researchers in the emerging field of spatial epidemiology. Equipped with the ability to conceptualize, visualize, and overlay data, Geographic Information Systems (GIS) technology has proved relevant in investigating spatial patterns and relationships of environmental and public health risks (Cromley and Mclafferty, 2012).

The validity of the results presented here supports the application of a geospatial technique to the examination of spatial variations and relationships between environmental components and human health conditions. This case study is nevertheless 68 subject to intrinsic subjective errors of the GIS, derived from the interpolation of the data.

However, it is important to recognize that the training of the parameters for classification is arbitrary and subjective, and represents the current state of the study area, which may change over time. Changes in household socioeconomic characteristics and living conditions are generally more rapid than those in environmental parameters.

The application of GIS in spatial epidemiology research represent an essential step in the development of integrated environmental management approach primarily about the identification of environmental variables that cause significant adverse health impacts. It is hoped that the findings from this study will provide guidance to policymakers in formulating strategies to address oil spills and improve child health in the Niger Delta region of Nigeria.

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