Principles and Practice of Environmental Health in Nigeria PDF

Principles and Practice of Environmental Health in Nigeria 1 Principles and Practice of Environmental Health in Nigeria PRINCIPLES AND PRACTICE OF ENVIRONMENTAL HEALTH IN NIGERIA Dr. BEST ORD...

Principles and Practice of Environmental Health in Nigeria 1 Principles and Practice of Environmental Health in Nigeria PRINCIPLES AND PRACTICE OF ENVIRONMENTAL HEALTH IN NIGERIA Dr. BEST ORDINIOHA FMCPH Consultant Community Physician, University of Port Harcourt Teaching Hospital, Senior Lecturer Department of Preventive and Social Medicine, University of Port Harcourt, Port Harcourt RURAL HEALTH FORUM, Port Harcourt, 2010 2 Principles and Practice of Environmental Health in Nigeria DEDICATION This book is dedicated to the POWER OF THE INTERNET especially the website of the WORLD HEALTH ORGANIZATION (www.who.int) that provided access to numerous full-length publications of the organization at no charge. The book is also dedicated to Dr. SBS AFIESIMAMA for his support and encouragement throughout the period of my residency training in public health medicine. First printed, August 2006. Revised, November, 2010. ISBN 978 – 30380 – 20 - 87 Published by: RURAL HEALTH FORUM P.O.BOX 162 OMOKU ONELGA – RIVERS STATE E-mail: [email protected]. Tel: 234-8053837699, 234-8085601355 This book is sold with a CD that contains a richly illustrated version. They are however not to be sold separately. Printed by: Alenibe (Nig.) Company, Port Harcourt 3 Principles and Practice of Environmental Health in Nigeria PREFACE The practice of public health in Nigeria is perhaps at the lowest ebb. Practitioners are seriously constrained by the lack of political support for public health programmes, blamed on the worsening economic situation of the country. In this idle state, the development of the specialty has stagnated, such that the principles and practice taught in classrooms and read in the few available textbooks are often reflective of the past glory days of the specialty, when the miasmic theory was current. This has resulted in situations where students find the specialty irrelevant to modern day medical practice. But thank God for the World Health Organization, other international organizations, donor agencies and practitioners of public health, especially those in developed countries, public health has continued to develop, evolving to keep pace with the changing world. Knowledge generated by these torchbearers luckily can now be accessed through the internet, especially as most of the organizations grant free access to full-length publications to users in the developing world. This book is a product of my preparation for the Part II examination of the National Postgraduate Medical College of Nigeria. Its publication is my desire to share with other practitioners and students what I consider a mine of valuable information for public health practice in Nigeria. Through out this book I have highlighted the two principles of public health practice – namely the identification of the root cause or causes of health problems, and the utilization of the resources of the 4 Principles and Practice of Environmental Health in Nigeria community, nation and the world to achieve a lasting, but affordable solution to the health problems. I have also emphasized the need to see health as a fundamental human right so that practitioners of public health in Nigeria would have the locus standi to, if possible blackmail the political office holders into giving the issue of public health the priority it deserves. Public health programmes are often the first to be axed in periods of economic depression, especially in governments whose officials are more interested in how much they can get from the public coffers. The presentation of the book differs markedly from the common public health textbooks in Nigeria. I hope you would not find it too awkward. The sections of the book captioned “A walk around the community” and “At the health center” that provide the situation analysis, were so named to emphasize the link between the cases seen in health facilities, and the environmental condition of the community. It becomes imperative because the contributions of environmental factors to the health burden of Nigerians are rarely acknowledged in the increasingly machinistic Nigerian medical community. This book is voluminous, because of the need to provide a comprehensive, practical and up-to-date textbook for students and practitioners of public health in Nigeria. As earlier stated, I didn’t write the book because of my experience or perfect understanding, I wrote it to fulfill a need, and hope that the good Lord who knows my intentions and the desire of my heart will grant me success and sustain me according to my purpose, not according to my gifts and abilities. To continue to borrow the words of Saadyna Gaon (892 – 942), let any 5 Principles and Practice of Environmental Health in Nigeria learned man who read the book and find any mistake in it, correct it. They should not be prevented from doing so because the book is not theirs, for the wise has compassion on wisdom and feel kindness for it as members of one family feel kindly towards each other, as is said “say unto wisdom thou art my sister; and call understanding thy kinswoman” (Proverbs 7:4). Dr. BEST ORDINIOHA, PORT HARCOURT, 2006 6 Principles and Practice of Environmental Health in Nigeria Acknowledgement Keeping tract of all the copyright owners of the materials used to write a book that started as a personal study material is almost impossible. This book was written with information drawn from several sources, very much like how the bees gather nectar for honey. Unfortunately, some of these sources I cannot specifically acknowledge, because of poor book keeping. I plead with the authors and publishers that the omission is not deliberate. I lay claim to the book only because honey is called the bee’s honey, not the nectar of the various plants it is made from. In spite of the my constraints I still have on record the following publishers 1. The World Health Organization for its various publications freely downloaded from its website www.who.int. 2. Oxford University Press for Oxford textbook of public health 3. University Press PLC, Ibadan for The principles and practice of public health in Africa. 4. United States Agency for International Development especially for projects such as FANTA, SARA, and BASICS 5. WEDC/DFID 7 Principles and Practice of Environmental Health in Nigeria 6. Hodder and Stoughton for A short textbook of preventive medicine for the tropics I would also like to use this opportunity to thank all those that assisted in the course of writing and printing this book, especially my colleagues in the department of Preventive and Social Medicine of the University of Port Harcourt Medical School, and students whose desire for practical information in environmental health swiveled me into undertaking the project. I also owe a big gratitude to my wife JOYCE and our four young children, BLEST, TREASURE, BEST II, SOLOMON for letting me have the extra time required for this project; and to my parents Chief and Mrs Sunday Nwalor Ordinioha who despite all odds were able to give education to their children. The final thanks however is reserved to GOD ALMIGHTY the giver of all inspirations Dr. BEST ORDINIOHA PORT HARCOURT, 2010 8 Principles and Practice of Environmental Health in Nigeria Content Chapter One: Introduction 1.0. Definitions, concepts and history 11 Chapter Two: Health Impact Assessment 2.1 Introduction: ……………………………….. 16 2.2 The conduct of Health Impact Assessment: ….. 17 2.2.1 Project description: ………………………… 18 2.2.2. Screening: ………………………………… 19 2.2.3. Scoping: …………………………………… 19 2.2.4. Profiling: …………………………………… 21 2.2.5. Assessing the health impact: ………………. 21 2.2.6. Managing the health impact: ………………. 22 2.2.7. Health impact statement: …………………… 22 2.2.8. Decision making: …………………………… 23 2.2.9. Monitoring and evaluation: ………………… 23 Chapter Three: Legislations 3.1 Introduction: ………………………………….. 24 3.2. EIA legislations: ……………………………… 25 3.3. The control of nuisance: …………………….. 26 3.3. Legislations regulating food and drugs: ……… 28 Chapter Four: Water Supply 4.1.Water supply (introduction): ……………. 30 4.2. A walk around the community: ………… 31 4.3. Water related diseases: ………………… 33 4.4. Interventions: ………………………….. 34 4.4.1. Rainwater:……………………. 35 4.4.2. Well water: ………………….. 36 9 Principles and Practice of Environmental Health in Nigeria 4.4.3. Water from borehole: ………. 37 4.4.4. Spring water: ………………… 38 4.4.5. Surface water: ………………... 39 4.4.6. Household water treatment: ….. 43 4.4.7. Household storage of drinking water: 46 4.4.8. Evaluation: …………………… 46 4.4.8.1.Sanitary inspection: ….. 47 4.4.8.2.Water quality analysis: 48 Chapter Five: Disposal of excreta (sewage) 5.1.Introduction: ……………………………… 52 5.2.A walk around the community: …………… 52 5.3. At the health center (Excreta related diseases) 56 5.4.Interventions: ……………………………. 59 5.4.1. Technical considerations: ……………….. 59 5.4.2. Felt needs of community members: …….. 61 5.4.3. Options of sanitation facilities: …………. 62 5.4.3.1. Pit latrine: ……………………………… 64 5.4.3.2.VIP latrine: …………………………... 65 5.4.3.3.Borehole latrine: ………………………. 67 5.4.3.4.Aqua privy: ……………………………. 68 5.4.3.5.Ecological sanitation: ………………… 69 5.4.3.6.Pour-flush toilet: …………………….. 72 5.4.3.7.Facilities with septic tank: ……………. 74 5.4.3.8.The sewerage system: ………………… 75 5.4.4. The final disposal of sludge: …………….. 76 Chapter Six: Vector Control 6.1.Introduction: …………………………. 78 6.2.Control of Anopheles mosquitoes: ……. 81 6.3.Control of culex mosquitoes: …………... 97 6.4.Control of Aedes mosquitoes: ………….. 99 10 Principles and Practice of Environmental Health in Nigeria 6.5.Control of tsetse flies: ………………… 100 6.6.Control of simulimum blackflies: ………. 104 6.7.Control of Cyclops: ……………………… 106 6.8.Control of freshwater snails: …………….. 108 Chapter Seven: Disposal of solid waste 7.1.Introduction: ……………………………….. 112 7.2.A walk around the community: ……………. 113 7.3.At the health center: ………………………. 115 7.4.Interventions for safe refuse disposal: ……. 118 7.5.Safe management of health care waste: ……. 124 Chapter Eight: Healthy housing 8.1.Introduction: ……………………………….. 144 8.2.The housing situation in Nigeria: ………….. 146 8.3.At the health center: ……………………….. 149 8.4.Intervention: …………………………… ….. 151 Chapter Nine: Food Safety 9.1.Introduction: …………………………… 155 9.2.A walk around the community: …………….. 158 9.3.At the health center: ………………………… 166 9.3.1. Food poisoning: ………………………… 166 9.3.2. Chemical hazards in food: ……………. 169 9.3.3. Investigations of food poisoning: …….. 173 9.3.4. Food-borne infections: ……………….. 176 9.3.5. Emerging food-borne infections: ……… 178 9.4.Interventions: …………………………….. 179 9.5.Technologies to improve food quality: ….. 185 11 Principles and Practice of Environmental Health in Nigeria Chapter Ten: Air Pollution 10.1.Introduction: ……………………………….. 192 10.2.Indoor air pollution: ………………………… 192 10.3.Outdoor air pollution: ……………………… 204 Chapter Eleven: Climate change and health 11.0.Introduction: ………………………… 214 11.1.Climatic variation and social disruption 215 11.2.Climate change and desertification: 216 11.3.Climate change and flooding: … 217 11.4.Climate change and epidemics of CSM 218 11.5.Climate change and vectors: …….. 219 11.6.Mitigation measures: …………….. 221 Chapter Twelve: Disaster management 12.1.Introduction: ……………………………. 225 12.2.Vulnerability Assessment: ……………… 229 12.3.Disaster prevention and mitigation: ……. 240 12.4.Emergency preparedness: ……………… 247 Chapter Twelve: Noise 13.1.Introduction: …………………………….. 264 13.2.The measurement of sound: ………………. 265 13.3.A walk around the community: …………. 269 13.4.Diseases associated with noise: …………. 272 13.5.Interventions: ……………………………. 276 12 Principles and Practice of Environmental Health in Nigeria CHAPTER ONE INTRODUCTION 1.1 Definitions, concepts and history The environment contains elements essential for life, and the maintenance of good health, as well as potential hazards. Most of the deleterious environmental conditions are caused by human activity. As the first country to industrialize, Britain was the first country to be confronted by the grim effects of the deteriorating environment on health. The slums that accommodated the working class in nineteen century Britain were noted for their narrow alleys and tenement housing, the total inadequacy of the water supplies and sewerage systems, and the squalor and violence of the streets. The noxious air and vapours generated by the filth in these slums were said to have made the slums fever dens, while the inhabitants were feared as agents of infection. Fig. 1.1: Amulet used for protection against cholera in France 13 Principles and Practice of Environmental Health in Nigeria In 1842, the ubiquitous Victorian civil servant and lawyer, Edwin Chadwick published his investigation on “the sanitary condition of the labouring poor” facilitated by his job as the secretary to the first British Board of Health. In this report, he emphasized the crucial link between dirt due to unsanitary conditions and overcrowding, and disease; and stressed the need for a central administrative structure to oversee health issues. These triggered not only government action, but also the response of reformers including middle and upper class women who wanted to escape the narrow bounds of domestic responsibilities. These women saw sanitary reform activity as “municipal housekeeping” a natural extension of women’s training and experience as the “housekeepers of the world”. Fig.1.2: Edwin Chadwick Government to champion the reformation course established city health offices in the United States, and local boards of health in Britain. These establishments 14 Principles and Practice of Environmental Health in Nigeria were administered by the local governments, perhaps borne out of the recognition that effective action is better at the community level. Public health activities were more like police function designed for the enforcement of the good health laws. Medical Officers for Health were appointed in Britain to oversee public health activities in the local councils. The main duties of the Medical Officers of Health (MOsH) were two fold, involving first the duties of sanitary inspection and improvement (which were to earn the MOsH the derogatory title of “drain doctors”) and second, disease control, emphasizing primarily isolation and removal to hospital of infected persons, and the tracing of the foci of infection during epidemic. Fig. 1.3: The many responsibilities of the Medical Officer of Health The appointment of an inspector of nuisances was made for Lagos as early as 1887; while by 1897, Lagos had 15 Principles and Practice of Environmental Health in Nigeria both a medical and sanitary departments, headed respectively by Dr. H. Strachan as Chief Medical Officer, and WM Mackison as Sanitary Engineer, with WF Lumpkin as Inspector of Nuisances. The pioneer public health staff helped draw up ordinances and rules for the meat markets, slaughterhouses, hospitals, sanitaria, and housing. Sites and plans of new buildings were to be approved by the medical officer, while a written approval must be obtained for any sanitary service; notification of smallpox was also made mandatory. Dr. Isaac Ladipo Oluwole became the first African Medical Officer for Health in Nigeria when he was appointed first, as Assistant Medical Officer for Health in 1925, and then Medical Officer for Health in 1935. He was credited to have established the school health service in Lagos, and the medical inspection of school children in Ibadan in 1929. He reclaimed swampy islands in Lagos to aid malaria control, and supported measures to control smallpox, rabies and plague. He was given an OBE in 1940 for his efforts, and recognized as the father of public health in Nigeria. The Medical Officers of Health were mainly concerned with environmental sanitation. The WHO defined environment sanitation as the control of factors in the environment that exercises, or may exercise a deleterious effect on the physical development, health and survival of humans. It includes the following: Provision of a safe and adequate water supply Proper disposal of solid waste Proper sewage disposal, and treatment Safe guarding of food. 16 Principles and Practice of Environmental Health in Nigeria Provision of good housing Control of atmospheric pollution (air hygiene) Control of insect vectors, and other pests Control of animal reservoir of infection. Disinfection Elimination of other hazards e.g. noise, radiation etc. Environmental sanitation was very important at the inception of the work of the Medical Officer of Health, because all diseases were then considered to be from filth. To effectively perform his responsibilities, the MOH had sanitary inspectors as foot soldiers, and the services of public health engineers who provided engineering solutions to the environmental hazards. Now, the traditional environmental hazards have been controlled in the developed countries, but still cause havoc in developing countries. According to the 2002 World Health Report, 5.5% of the global disease burden is due to inadequate water and sanitation. However, the whole world (both developed and developing countries) now faces additional environmental hazards, resulting from the huge human population; rapid development, without health and environmental safeguards, and the unsustainable consumption of the earth’s natural resources. When the world’s population was only about a billion at the start of the industrial age, the ocean and air were still sufficient to dilute and absorb wastes, and the consumption of the world’s renewable resources was not beyond its capacity for regeneration. Now that the world’s population is more than six billion, the wastes generated by human activities are so much that there are genuine fears of a 17 Principles and Practice of Environmental Health in Nigeria possible end of the world, especially with climate change and stratospheric ozone depletion. These have forced the United Nations (UN) to promote the concept of sustainable development. Sustainable development is defined as development that meets the needs of the present generation, without compromising the ability of the future generation to meet their own needs. The new environmental hazards also forced several governments to establish another agency to deal with the threats. The new agencies include Federal Environmental Protection Agency (FEPA) in the United States, and the Ministry of Environment in Nigeria. To help promote sustainable development, Nigeria in 1989 formulated a national policy on the environment. The national policy called for the establishment of adequate environmental standards, monitoring and evaluation of changes in the environment, and the conduct of an Environmental Impact Assessment of any proposed activities that may affect the environment, or the use of a natural resource. Environmental Impact Assessment according to the International Association for Impact Assessment (IAIA) is the process of identifying, predicting, evaluating, and mitigating the biophysical, social, and other relevant effects of development proposals, prior to major decisions being taken and commitments being made. The modus operandi prescribed by the national policy on the environment are different from those used for the traditional environmental hazards; mainly because of the difference in the time the hazards take to cause ill health. The traditional environmental hazards rapidly result in ill 18 Principles and Practice of Environmental Health in Nigeria health, such as a diarrhoeal disease resulting from the drinking of contaminated water. Whereas it typically takes months and years before the exposure to a modern environmental hazard would manifest as disease, often as cancer. The effective control of the new environmental hazards as outlined in the policy on the environment requires the establishment of environmental standards for all the hazards, and ensuring that industries and processes that produce the hazards comply with the standards. These require greater expertise and more sophisticated equipment that might be very expensive to have at the level of the community. This perhaps explains why the ministry of environment is only at the State and federal level in Nigeria. Fig. 1.4: Chicken fed with dioxin contaminated feed might be the cause of a cancer years later 19 Principles and Practice of Environmental Health in Nigeria CHAPTER TWO HEALTH IMPACT ASSESSMENT 2.1 Introduction There is overwhelming evidence that developmental projects can have a beneficial effect on health and wellbeing, through the creation of employment, promotion of economic advancement, and the engenderment of circumstances that improve living standards. Developmental projects can also have adverse effects, through problems such as noise, water and air pollution, and increased risks of injury and disease that often follow such projects. These adverse effects often disproportionately affect susceptible persons like children and the elderly, and other members of the community that are not direct beneficiaries of the project or policy. Thus, the prevention of the adverse effects is not only equitable and good economics. Health Impact Assessment (HIA) is a process that systematically identifies and examines in a balanced way, both the potential positive and negative health impact of an activity. It has been defined by different agencies, in different ways, but the one given by the “Gothenburg Consensus paper” published by the WHO Regional office for Europe is considered one of the best definitions. It defined HIA as a combination of procedures or methods by which a policy, programme or project may be judged as to the effects it may have on the health of a population. These effects may be direct and immediate, or indirect or delayed. 20 Principles and Practice of Environmental Health in Nigeria The purpose of HIA is to seek the health impact of a policy, project or programme, usually before implementation, and ideally early in the planning stage, as to facilitate the reduction or avoidance of negative impacts on human health, and enhancement of the positive impacts, and in so doing promote sustainable development. HIA can be carried out even on policies and projects that do not overtly have health objectives. Although the EIA Decree No. 86 of 1992 did not give much prominence to HIA in the EIA process in Nigeria, it has since become a key chapter of all EIA reports in Nigeria. This is because HIA has been found to have a lot of uses in Nigeria, the least being a baseline data for the long term follow up of the impact of the project or policy. Fig. 2.1: If an impact assessment had been conducted before the ban on the use of motorcycles for commercial transportation, it could have revealed the massive traffic holdups, and the huge inconveniences suffered by certain commuters. 21 Principles and Practice of Environmental Health in Nigeria 2.2. The conduct of health Impact Assessment The ideal method for the conduct of HIA is still in development. Several models exist, but most can be described in terms of two fundamental categories: Broad-focus HIA and tight-focus HIA, depending on the scope of the activity under scrutiny, and the approaches used to assess the impact. Broad-focus HIA considers health according to the WHO’s definition of health which considers health as a state of complete physical, mental and social wellbeing, and not merely the absence of disease or infirmity. Broad focus HIA therefore uses qualitative methods in assessing the likely health impacts at various stages of a project’s life cycle. It rarely attempts to calculate risk, but uses the inputs of lay and professional advice. By contrast, tight-focus HIA also called environmental HIA is closely linked to risk assessment. It focuses its attention on the influence of the policy or project on the physical environment, and through this, the likely effect on health is extrapolated. However, most HIA are carried out according to the following steps: 1. Project description 2. Screening 3. Scoping 4. Profiling 5. Assessment of health impact 6. managing the health impact 7. Health impact statement 8. decision making; and 9. Monitoring and Evaluation 22 Principles and Practice of Environmental Health in Nigeria Fig. 2.2: Flow chart of the Health Impact Assessment process 2.2.1. Project Description This involves giving a detail description of the project so that the reader, who is not familiar with the project, could clearly understand what the intentions of the project are, and what in general terms, the health impact might be. It is prepared by those carrying out the project (proponent). 23 Principles and Practice of Environmental Health in Nigeria 2.2.2. Screening Screening is the process of determining whether or not a proposed project warrants a HIA. This is based on the information provided in the project description. In Nigeria, the screening of the projects are currently carried out by officials of the Ministry of Environment, though inputs from officials of the Ministry of Health should ideally be sought, especially when policy issues are to be subjected to a HIA. Screening is firstly a process of filtering out those projects that do not require HIA because: their health impacts are expected to be negligible, or; that their health effects are well known, and readily controllable; through measures that are well understood, and routinely applied, and so require no specific investigation or analysis Identifying these early in the HIA process prevents wastage of resources. 2.2.3. Scoping Scoping is the process of prioritization that reduces the long list of issues raised in the project description, to a short list of potentially significant ones, to be addressed in the HIA study. It improves the efficiency and effectiveness of the HIA study, by ensuring that more attention is focused on issues deemed important by the public and experts. The set boundaries must be appropriate. Broad boundaries such as those used in broad focus HIA are 24 Principles and Practice of Environmental Health in Nigeria difficult to assess and require a lot of resources to carry out. If the project is scoped narrowly as in the tight focus HIA, the HIA study can miss some potential effects which can upset some sections of the host community. Criteria used to determine the scope of a HIA include: the size and nature of the project; the health impact of already existing projects in the host community which in combination with the proposed project, would suggest that cumulative effects could occur; the availability and feasibility of existing data on the host community; and the characteristics of the environment in which the project will take place (e.g. land use, riverine). For example, the Niger delta is considered a delicate ecosystem, and therefore treated with care. Sometimes, the scope of an HIA is determined by a rapid assessment study of the magnitude and severity of the potential effects of the project. This is often carried out through the review of literature, and key informant interviews of certain members of the affected communities. This is sometimes called desktop HIA study. The inputs of the experts and stakeholders in the scoping process are often articulated in brainstorming meetings. In Nigeria, there is often a meeting between the proponent of the project with key stakeholders in the 25 Principles and Practice of Environmental Health in Nigeria host communities, and several meetings with officials of the Ministry of Environment. A suitable scoping process should decide on: The methodology of the study, and the required details Sources for reliable health and demographic data The significant stakeholders to be consulted, and involved in the HIA study; and The ways of monitoring the health effects of the project, from its construction to its completion. Fig. 2.3: A newspaper publication for an EIA in Nigeria 26 Principles and Practice of Environmental Health in Nigeria 2.2.4. Profiling Once issues of concern have been identified through scoping, baseline health status of the affected communities must be obtained. The baseline health status is needed to provide reference values against which future comparisons can be made, when the project begins operation. Profiling is a description of the baseline health status of the affected communities. The type of information provided in profiling depends on the scoping, particularly the definition of health used. When the WHO’s definition of health is used, as subscribed to by the broad focus HIA, the baseline information provided in the profiling would include information on a large number of health determinants including the health, social and environmental conditions of the affected communities. For tight focus HIA (environmental HIA), the information provided in the profiling might just include the demographic characteristics of the affected communities, and the baseline values of relevant environmental conditions, especially air, soil, and water quality. 2.2.5. Assessing the health impact This step of the HIA process involves carrying out studies to predict the effect of the potential health impact of the project on the affected communities. This assessment can be carried out using quantitative, qualitative, or a combination of the methods. Quantitative method of assessment is commonly used for tight-focus HIA (environmental HIA), where a risk 27 Principles and Practice of Environmental Health in Nigeria assessment is carried out; while qualitative methods are often used in broad-focus HIA because of the difficulties in measuring a lot of the health determinants. The use of qualitative assessment methods also allow for the input of non-experts, especially members of the affected communities, as demanded by the relevant legislations in Nigeria. 2.2.6. Managing the health impact This step considers the results of the HIA studies, and proffers ways of mitigating the negative impacts of the project, even as the positive impacts are further strengthened. Mitigation has been defined as the elimination, reduction, or control of a project’s adverse environmental effects, including the restitution for any damage to the environment caused by such effects. The WHO has identified three main categories of mitigation measures for health effects: Mitigation through control of sources (e.g. pollution standards, safety standards) Mitigation through control of exposure (e.g. planning requirements, public health measures); and Mitigation through health services development (e.g. health education, provision of medical services) Providing compensation or restitution is an additional option. Monetary payments or compensation do not reduce the environmental impacts, but serve to 28 Principles and Practice of Environmental Health in Nigeria financially compensate the individual(s) for tolerating the negative impact. 2.2.7. Health impact statement This is a summary of the previous steps in the HIA. It is prepared by the proponent, and often presented to the general public for their final comments, before the submission to the regulatory authorities. In Nigeria, the general public is often invited through the mass media to view and pass comment on the issues raised in the health impact statement. The health impact statement is displayed at various public places for this purpose. Allowing different perspectives and views through this public display ensures that important aspects are not overlooked in the final draft. 29 Principles and Practice of Environmental Health in Nigeria 30 Principles and Practice of Environmental Health in Nigeria Fig. 2.5: A provisional approval given by the Federal Ministry of Environment to SPDC for a project. Assessed from www.shell.com.ng 2.2.8. Decision making After the final input of the general public, the updated version of the health impact statement is sent to the Ministry of Environment who has the responsibility to decide whether or not the project should be allowed to proceed, and if so, what conditions should be attached to the approval. The conditions can include mitigation measures, requirements for follow-up activities, modifications to operative procedures etc. 31 Principles and Practice of Environmental Health in Nigeria 2.2.9. Monitoring and evaluation It is important to ensure that any mitigation measures for potential effects on health recommended are implemented and monitored as to their effectiveness; and to verify that there are no unanticipated effects on health and wellbeing. This is important because HIA is basically an intelligent guess, extra safety measures are therefore needed to be double sure that potential negative impacts of the project/ policy do not go undetected. Further reading 1. Health Canada. Canadian handbook on Health Impact assessment. Ontario. Health Canada. 2004. 2. Scot-Samuel A, Birley M, Arden K. The Merseyside guidelines for health impact assessment. Second edition. Liverpool. 2001. 32 Principles and Practice of Environmental Health in Nigeria CHAPTER THREE ENVIRONMENTAL HEALTH LEGISLATIONS 3.1. Introduction Environmental health problems led to the emergence of public health in the 19th century. Legislation formed an important part of the all out war against filth. Most of the legislations for the control of such traditional environmental health concerns as solid waste disposal, water quality, sewage disposal, and housing are contained in the sanitary manual – the book form of the public health ordinance Cap 56 of 1917 which has been variously revised, without a significant change in the terminology and concept. The only recognizable activities in public health legislation in Nigeria are the comprehensive legislations establishing government agencies like NAFDAC and FEPA. These organizations have been able to use the powers conferred on them by their Establishment Acts to make regulations that are consistent with international standards. Unfortunately, not all aspects of public health have so benefited. The maintenance of the traditional aspects of environmental health is currently the responsibility of the Local Government Councils, who are empowered to make byelaws and regulations within the framework of the parent public health law. Environmental health issues have changed with the growth of industrialism, throwing up issues like excessive noise, air quality control, control of toxic substances in industry and the community, and the 33 Principles and Practice of Environmental Health in Nigeria regulation of the use of pesticides in agriculture. These issues are typically handled by a Federal Environmental Protection Agency (FEPA), which is constitutionally empowered to help control, these new threats in the environment. The Nigerian Federal Environmental Protection Authority was established by decree No. 58 of 1988, but since June 1999, the new Ministry of Environment has taken it up. Legislations for the control of these fallouts of industrialism aim to strike a balance between the interest in a healthy environment, and the need for employment and industrial development. Thus, the major interest of the regulating body is not to completely eliminate the hazards, which would drive the industries out of business, but to ensure that the hazards are kept within a safe limit. Fig. 3.1: Equity is a key component of all legislations 34 Principles and Practice of Environmental Health in Nigeria 3.2. The Environmental Impact Assessment (EIA) legislation Sustainable development concedes that whereas the present generation has the right to exploit the earth for equitable economic growth, and for the eradication of poverty, it should be able to bequeath the environment in a state that the future generation won’t find it difficult to meet their own developmental aspirations. The EIA legislation is designed to achieve sustainable development. Environmental Impact Assessment according to the International Association for Impact Assessment (IAIA) is the process of identifying, predicting, evaluating, and mitigating the biophysical, social, and other relevant effects of development proposals prior to major decisions being taken, and commitments being made. EIA is entrenched in Nigeria through the EIA Decree No. 86 of 1992. The decree made EIA mandatory for all major development projects in Nigeria, except those needed in emergency situations, and those seen to have minimal effects on the environment. The EIA Decree No. 86 gave prominence to assessing the impact on the physical environment. The cursory attention given to the assessment of the health impact of development projects in the EIA Decree has since been abandoned by every major stakeholder, wishing to carry out an EIA of international standard. The EIA Decree gave some guidelines on how EIAs is to be carried out in Nigeria. This is further elucidated by the Federal Ministry of Environment’s regulation The Procedural and Sectoral Guidelines for Environmental 35 Principles and Practice of Environmental Health in Nigeria Impact Assessment. However, the general principles follow the international standard. 3.3. The control of nuisances In the colonial and immediate postcolonial periods in Nigeria, the practice of environmental health was essentially the finding and abatement of nuisance. This is reflected in the stated duties of the quintessential public health practitioner of the period. Section 4 of the public health law (Rivers State) mentioned the duties of the Medical officer of Health as: “…inspect the area to which he is appointed, and to abate nuisances, and otherwise to enforce the powers vested in him relating to public health” Nuisance has been defined as anything which annoys, gives trouble or cause vexation. This can extend to everything that endangers life or health, gives offense to the senses, violates the law of decency, or obstructs the reasonable and comfortable use of property. Nuisance has also been defined as the wrong done to a man by unlawfully disturbing him in the enjoyment of his property, or, in some cases, in the exercise of a common right. This definition flows from the Latin maxim sic uteri tuo non alienum laedas, which translates that every person is entitled to a reasonable enjoyment of life and property, but he must so use his own as not to injure others. Section 5 of the public health law (Rivers State) listed various nuisances. But, public health authorities in Nigeria are often besieged with numerous complaints 36 Principles and Practice of Environmental Health in Nigeria and demands for action over nuisances that are unrelated to public health. However, the jurisdiction of public health authorities over nuisances extends only to those matters that have been legally identified as capable of endangering health, as enumerated in this section of the Public Health law. A nuisance may be public, private or mixed. A public nuisance is one that affects more than one individual or family, or one that annoys or injures the people as a whole. Private nuisance affects only one person, and often does not fall under the jurisdiction of a public health agency, but the affected individual can personally obtain legal redress. Mixed nuisance occurs when a public nuisance also causes special and peculiar damage to an individual, as can occur when a factory emits harmful chemical fumes that disturb and endanger an entire area, and also cause particular damage to individual households in the immediate vicinity of the factory. To look out for nuisance, the Medical Officer of Health and his support staff (the sanitary inspectors, now Environmental Health Officers) are empowered by the Public Health Law to enter any premises, at a reasonable time. This is called the right of entry. Once a nuisance is found in any part of the LGA in which the Medical Officer of Health has jurisdiction over, Sections 6, 7 and 8 of the Public Health Law (Rivers State) clearly spelt out the steps to be taken by the Medical Officer of Health: First, an abatement notice is served the person by whose act, default, or sufferance, the nuisance arises or continues. The notice specifies the jobs 37 Principles and Practice of Environmental Health in Nigeria to be carried out within a stipulated time, to reduce the nuisance to an acceptable level. When the person fails to carry out the recommended jobs, or when the MOH feels that the nuisance is likely to recur even after it has been abated following the notice, he/she takes the offender to court, who issues a nuisance order. The nuisance order can be another abatement notice giving the offender another chance, a prohibition order, prohibiting the recurrence of the nuisance, a closing order prohibiting the use of the property for human habitation, or a combination of all. If the offender defaults the nuisance order, he is liable to a fine, and the health officer is empowered to enter the premises to carry out all measures necessary to abate or remove the nuisance, at full cost to the offender. The cost of cleaning up a nuisance, as well as the cost of prosecution is borne entirely by the offender, according to the polluter pays principle. The administration of these orders is more often than not, a question of encountering recalcitrant defaulters whose attitudes in public towards the abatement of the nuisance have been highly uncooperative, and whose influence in the community is feared might constitute a serious deterrent to effective control. This is unlike the current situation where touts, working as staff of environmental sanitation authority, literally trick and 38 Principles and Practice of Environmental Health in Nigeria immediately fine people for contravening an environmental byelaw. Fig. 3.1: Plantain is one of the plants considered to be favourable to the breeding of mosquitoes, and therefore should not be planted close to residential quarters (Mosquito Destruction law Cap 103 LFN 1948). 3.4. Legislations regulating food and drugs Concern for food safety dates back to pre-colonial times; Olaudah Equiano – a freed Nigerian slave, writing in the 18th century described how the seller of a food item would have to kiss round the food to convince the buyer that the food is not poisoned. In colonial Nigeria, health workers were empowered by law to seek out and destroy any unsafe food displayed for sale. This is still found in Section 12 of the subsisting public health law (Rivers State). 39 Principles and Practice of Environmental Health in Nigeria Presently, the consumption of commercially produced food items has grown, and some of these foods are produced and imported from far-flung places. This has expanded the scope of the measures required to ensure food safety, hence the establishment of the National Agency for Food and Drug Control (NAFDAC) under Decree No. 15 of 1993. NAFDAC under this establishment Decree, and as amended by Decree No. 20 of 1999, is empowered to take any necessary measure to ensure the safety of foods in Nigeria. Most of the food standards set by NAFDAC are consistent with the international standards set by the Codex Alimentarius Commission. These standards are designed not only to ensure food safety, but also to encourage the citizens to eat a healthy diet. The enforcement of the standards is carried out through inspections of the manufacturing process, recall or seizure of defective products, civil and criminal penalties for violations of the standards, and injunctions to prevent marketing of food and drugs found to be unsafe or unsanitary. Further Reading 1. Sosan OO. Health legislation in Africa: the example of Nigeria. In Sofoluwe GO, Schram R, Ogunmekan DA (edited). Principles and Practice of Public Health. Ibadan. University Press PLC. 1998. 40 Principles and Practice of Environmental Health in Nigeria CHAPTER FOUR WATER SUPPLY 4.1. Introduction Domestic water supply is one of the fundamental requirements for human life; without water, life cannot be sustained beyond a few days. It plays a vital role in nearly every function of the body, protecting the immune system, and helping remove waste matter Yet much of the ill health that affects humanity, especially in the developing countries can be traced to lack of safe water supply. The WHO estimates that water related diseases are responsible for 5.8% of all deaths and 5.5% of DALYs in high mortality developing countries like Nigeria. Fig. 4.1: Burden of disease attributable to unsafe water according to % of DALYs in each subregion. 41 Principles and Practice of Environmental Health in Nigeria The importance of water in the maintenance of life and health made it an essential human need that as a matter of right should be provided to all human being, irrespective of class or residence. The quest to realize this all over the world has led to several international conventions, including the International Drinking Water Supply and Sanitation Decade, declared in 1980 by the United Nations General Assembly, and target 10, goal 7 of the Millennium Development Goal. This MDG sets a 2015 target of halving the proportion of people without access to safe water supply. Like all fundamental needs, the quest to grant universal access to adequate potable water often attracts international assistance and cooperation. Therefore, governments of poor countries have no reason for not providing its citizens with this fluid of life. The Romans more than two thousand years ago, had felt that a place is not civilized, unless it is able to offer a water supply system with house connections, public fountains and public baths, to both the poor and the rich 4.2. A Walk around the community The steps involved in ascertaining the water situation of a community include: 1. The identification of the sources of the community’s water supply. Emphasis is given to sources that provide most of the water needs of members of the community, at most times of the year. These sources could be Rain water Surface water, including rivers, ponds, lakes and sea; and 42 Principles and Practice of Environmental Health in Nigeria Under ground water, including wells, bore holes and springs Fig. 4.2: Women digging for water in a dry river bed in northern Nigeria. 2. The quantity of water available to each member of the community. This is assessed by estimating the volume of water collected by a household in a day, for the domestic and sanitation needs of its members. It does not however include water used for gardening, or used in watering animals. Quantity of water Total volume of water (in liters) collected for used per capita = domestic use by all the households per day Total number of persons in the household 43 Principles and Practice of Environmental Health in Nigeria The WHO and World Bank recommend that each individual in a community should have 20 – 40 liters of water for his/her domestic and sanitation needs, and at least two liters for his/her drinking water needs (per capita water requirement). Calculating the per capita water use, using the formula given above can be time consuming. This burden is lifted by the use of an indirect method that makes use of the distance to the water source; especially as studies have shown that the closer the water source is to the household, the greater the water use. Based on this, the WHO recommends that households in urban centers should have a public stand pipe within 200 meters of their residence; while rural dwellers should not spend a disproportionate part of their day collecting water. The to and fro journey from the house to the source of drinking water should not take more than 15 minutes. Fig. 4.3: Fetching water from the public tap should not take more than 15 minutes 44 Principles and Practice of Environmental Health in Nigeria 3. The quality of water from the water source The desire is to make potable water available to all members of the community, at all time. Potable water is defined as water that is safe and acceptable for drinking. For any water to be said to be potable, it must have its constituents within the drinking water quality guideline values. These values represent the concentration of constituents that do not result in any significant health risk to the consumer over a lifetime of consumption. The standard for drinking water quality is assessed by considering the physical, chemical, microbiological and radiological aspects of the water. The physical/aesthetic aspect often determines the acceptability of the water to the people; its determinants include the turbidity, colour, taste and odour of the water. Fig. 4.4: “Pure water” forms a part of most meals eaten in Nigeria due to poor quality community water supply. 45 Principles and Practice of Environmental Health in Nigeria The chemical aspect considers the chemical content of the water. It often takes a massive chemical contamination of water to cause an acute health problem. Experiences have shown that such excessive contamination often renders the water undrinkable, owing to its unacceptable taste, odour and appearance. The main public health fear of chemicals in drinking water is the long term drinking of water contaminated with certain chemicals like arsenic and fluorides that are easily found in underground water. The radiological aspect considers the radioactivity of drinking water. Water can gain radioactivity from natural sources, as well as wastes from establishments that use nuclear energy. It has to be noted that nuclear energy is commonly used in hospitals and in the oil industry. Where funds are limited, the microbiological aspect is about the only consideration given to drinking water. Ideally, drinking water should not contain any microorganism known to be a pathogen, but the WHO advocates that all drinking water should at least be tested for E.coli, whose presence is indicative of definite faecal pollution. 46 Principles and Practice of Environmental Health in Nigeria Fig. 4.5: The stream is a source of water supply to several communities in Nigeria, but is often polluted with faeces, and even with sacrificial items. 4.3 At the health center (Water related diseases) The water situation in the community can reflect in the pattern of diseases seen in the health center. These diseases can be broadly classified as: 1. Water borne infections – These are infections acquired through the drinking of contaminated water. They include viral infections like poliomyelitis and infective hepatitis; potentially epidemic causing diseases like typhoid fever and 47 Principles and Practice of Environmental Health in Nigeria cholera, and parasitic diseases like amoebic dysentery. An increase in the incidence of any of the water borne diseases points to contaminated water supply that should be investigated and corrected. Fig. 4.6: Water from sources like this is often very contaminated, and a source of several water-borne infections 2. Water shortage diseases - arise due to poor availability of water, such that little water is available for bathing and other sanitation purposes. Examples of such diseases include trachoma and skin infections. 48 Principles and Practice of Environmental Health in Nigeria Fig. 4.7: Inadequate access to water makes the observation of personal hygiene difficult as shown by the boy in the picture Fig. 4.8: A lack of water has left many people blind with trachoma. 49 Principles and Practice of Environmental Health in Nigeria 3. Water impounding diseases - are diseases contracted through repeated contact with impounded water sources such as ponds, wells and flooded areas of irrigation schemes. Examples of such diseases include schistosomiasis and guinea worm. Fig. 4.9: Fetching water from a pond places one at risk of water impounding diseases 4. Water – arthropod diseases are diseases caused by arthropods that breed in water. Examples include such mosquito-borne diseases such malaria, yellow fever and filariasis, and the simulimum (black fly) borne onchocerciasis. 50 Principles and Practice of Environmental Health in Nigeria Fig. 4.10: Onchocerciasis is a common cause of blindness in Nigeria Fig. 4.11: A guinea worm, another water-related disease, emerging from the foot of a patient 51 Principles and Practice of Environmental Health in Nigeria 5. Water chemical diseases – These diseases can arise due to excess or lack of certain chemicals in water. Examples include methaemoglobinaemia in bottle-fed infants whose infant formula is constituted with water containing high concentration of nitrates, skeletal fluorosis caused by drinking water high in fluoride. Studies have noted saline intrusion of groundwater in several communities in the Niger delta, due mainly to over-abstraction. The groundwater in the Niger delta have also been found to have high iron and manganese content, a situation that is probably also indicative of high arsenic content, as found in the Bengal delta of Bangladesh. The granite rocks and sedimentary basins of north-eastern Nigeria are believed to cause high groundwater fluoride concentrations, with samples taken in Maiduguri containing up to 5.6 ppm of fluoride. Indeed, dental fluorosis was noted in school children and adults in north-east Nigeria, as early as 1954. 4.4. Interventions: Solving the water problem of the community. The prevention of water related diseases often requires that the per capita water needs of the community is met, and that the water is of good quality, from source to the point of use. Meeting the per capita water need requires the exploitation of water from the various water sources; while the quality of the water is assured by using various 52 Principles and Practice of Environmental Health in Nigeria purification methods, according to the requirements of the source of water. Fig. 4.12: Access to adequate drinking water is a fundamental human right that should not be denied any individual irrespective of his/her place of residence. Fig. 4.13: Water tanker is a major source of drinking water in some communities in Nigeria. How clean is the water supplied to the communities? 53 Principles and Practice of Environmental Health in Nigeria 4.4.1 Rainwater – Rainwater is often of good quality except that it can pick up impurities from the atmosphere, roofs, roof gutterings and the storage tank. Fig. 4.14: Collection system for rainwater When these sources of contamination are taken care of, rainwater can be a source of good quality drinking water for the household, at least during the rainy season. A collection system can be put in place to divert the rainwater from the roof to a completely covered storage tank, with filtering meshes installed at various parts of the collection system to filter out solid impurities. To doubly ensure the quality of the rainwater, chlorine tablets can be added into the storage tank to disinfect it. Communities in the arid region of the Middle East have perfected the strategies of collecting and storing rainwater in huge reservoirs that can be used for several months, by thousands of people. 54 Principles and Practice of Environmental Health in Nigeria Fig. 4.15: A rain water collecting system Fig. 4.16: Gas flaring in the Niger delta often contaminates rainwater 55 Principles and Practice of Environmental Health in Nigeria Fig. 4.17: A communal filtration unit made with oil drum being used to collect rain water in a Niger delta community 4.4.2 WELL – The hand dug well is the most common source of drinking water, especially in the rural areas of the country. Unfortunately, it is often of very poor quality, because it is easily contaminated by nearby latrines and septic tanks. Efforts aimed at preventing the contamination of hand- dug wells include: 1. Putting at least, 30 meters distance between the well and the latrine/septic tank. 2. The construction of a concrete lining and parapet. These involve the plastering of the upper part of 56 Principles and Practice of Environmental Health in Nigeria the well with cement, down to the dry season water level; creating a two feet high parapet, and the construction of at least, a two meter concrete drain around the well head, to keep out the often contaminated surface water. These ensure that spilled water do not enter the well directly, but have to be filtered through the soil. 3. The use of a windlass, and a single bucket, in lifting water from the well. A better improvement is when a hand pump is installed, and the open hand-dug well completely covered with a concrete stab. Fig. 4.18: Unprotected hand-dug well 57 Principles and Practice of Environmental Health in Nigeria Fig 4.19: Types of hand dug wells 58 Principles and Practice of Environmental Health in Nigeria Fig. 4.20: A man scooping water from a swallow well Fig. 4.21: A protected well 59 Principles and Practice of Environmental Health in Nigeria 4. Pot chlorination can be used to further improve the quality of the water, particularly when the faecal contamination persists, even after applying the measures above. Fig. 4.22: Multiple buckets being used in a well. Please the sticks and other objects inside the well 60 Principles and Practice of Environmental Health in Nigeria 4.4.2.2.Water from a borehole The drilling of a borehole for water has become a common feature in Nigeria, especially in urban areas. Water from these deep boreholes is normally free from microbiological contamination, and therefore might not require further treatment to make them potable. This is because the water is from a source below the first impervious layer of the soil. Fig. 4.23: A typical protected dug well installation 61 Principles and Practice of Environmental Health in Nigeria However, certain structural precautions are essential when the well and the associated pumps are installed. The pump casing should extend approximately 30cm above ground, and down wards to the parent rock. Other precautions observed with the shallow wells should also be installed. The fig. 4.23 shows the sanitary protection of the pump of a deep borehole. Fig. 4.24: Non-functional water boreholes are common in Nigeria because of lack of maintenance Although, water from a borehole often has good microbiological qualities, it might however contain certain chemicals, arising from intervening rocks and sediments. Water from boreholes drilled in some communities the Niger delta have been found to contain a lot of sodium (due to saline intrusion from the sea), iron, manganese and arsenic. 62 Principles and Practice of Environmental Health in Nigeria Fig. 4.25: A water treatment plant in a Niger delta community with high content of iron in its ground water Fig. 4.26: A solar-powered water borehole in a rural community in Nigeria. 63  Principles and Practice of Environmental Health in Nigeria 4.4.3. Spring water: – is derived from a source below the first imperious layer of the soil, but has tracked its way to the surface. It is often of very good quality, except that it can be contaminated by the various sources of pollution located adjacent to it. Efforts made to preserve the quality of spring water are as illustrated below (Fig. 4.5), and include: Preventing rain runoffs from contaminating the spring water The construction of a fence to prevent livestock from contaminating the water; and The construction of a spring encasement, to collect, store and distribute the water from the spring. Water from a protected spring may be supplied to small community either directly or via a distribution system. Fig. 4.27: Protected gravity spring 64 Principles and Practice of Environmental Health in Nigeria 4.4.4 Surface water – surface water sources are often very contaminated. It is therefore better to supply the water needs of small communities with a ground water source, that require little or no treatment, than to bring the highly contaminated surface water to the required standard. The use of surface water for community water supply is only cost effective for urban centers, with high water requirement. Fig. 4.28: Typical multistage treatment system for surface water Fig. 4.29: Surface water are often heavily contaminated, like this one that has an overhung toilet and filled with refuse 65 Principles and Practice of Environmental Health in Nigeria The purification process of surface water for the use of the community includes: 1. Abstraction and storage – screened intake channels are usually constructed to channel water into storage facilities. This is to ensure that solids are not sucked into the storage tank. The time the water spends in the storage facility might be long enough for the death of certain pathogens. However, very long retention time might encourage the growth of algae and the breeding of mosquitoes Fig 4.30: Protected water intake system in a river 2. Plain sedimentation (primary sedimentation) – Water from the preliminary storage facility is 66 Principles and Practice of Environmental Health in Nigeria passed slowly through a sedimentation tank, to allow time for the settling of suspended solids. Fig. 4.31: Plain sedimentation tank 3. Slow sand filtration – This improves the physical, chemical and microbiological quality of the water. It consists of an upper sand bed, and a lower bed of gravel. A thin, slimy mat known as the schmutzdecke or filter skin forms at the upper surface of the filter. This is said to be rich in organic matter, and has the ability to trap and destroy microorganisms, with up to 99% efficiency. Fig. 4.32: Slow sand filter 67 Principles and Practice of Environmental Health in Nigeria 4. Coagulation, flocculation and secondary sedimentation. Slow sand filtration is able to remove all, but the smallest of solids; these solids are however taken care of in this stage of purification. First, coagulants are added to react with the suspended solids to form settleable flocs, in the process called flocculation. These flocs aggregate into bigger macroflocs, as more time is spent in the secondary sedimentation tank, and then eventually filtered out. Fig. 4.33: Coagulation, mixing and flocculation tank 5. Rapid sand filtration – Rapid sand filtration involves the passage of water under pressure through a sand filter. 6. Aeration – Aeration is used to reduce taste and odour, and to alter the concentrations of dissolved gases in the water. It involves passing a thin film of water over surfaces, to maximize the transfer of oxygen into the water from the surrounding air. 68 Principles and Practice of Environmental Health in Nigeria 7. Disinfection – Disinfection serves as a backup for slow sand filtration, for the removal of micro- organisms in water. Disinfection methods may be physical or chemical. Physical methods include ultraviolet (UV) irradiation; while chemical methods include the addition of ozone, or most commonly chlorine, or its derivatives. Chlorine is preferred because it is not only capable of killing most pathogens within the contact time, but also has residual effect, to deal with small possible recontamination. Fig. 4.34: Water guard, a proprietary formulation of chlorine and coagulant, sold in a patent medicine store in Nigeria Chlorine is an oxidizing agent that reacts rapidly with organic and inorganic matter present in water. If 69 Principles and Practice of Environmental Health in Nigeria adequate disinfection is to be achieved, due allowance must be made for the chlorine consumed in these reactions, in addition to that needed for disinfection, which is present as free residual chlorine. The amount of chlorine required to react with compounds in the water is termed the chlorine demand of the water. The more polluted the water, the higher its chlorine demand. This explains the numerous filtration processes the heavily polluted surface water had to pass through, to get to the disinfection stage. The amount of chlorine used to disinfect the water must be sufficient both to satisfy the chlorine demand of the water, and to produce the unreacted excess required for disinfection (free residual). The point at which the free residual chlorine begins to appear is called the breaking point. A minimum free residual of 0.5ppm (parts per million) is recommended, together with a minimum contact time of 30 minutes. Fig. 4.35: Collecting water from a broken pipe 70 Principles and Practice of Environmental Health in Nigeria 4.4.5. Household water treatment Because most community water supply in Nigeria is intermittent, water is often stored in the home to ensure that enough is available when it is needed. Water supplied at the well or public stand post, may be microbiologically safe, but can become grossly contaminated with faecal material before consumption, in the course of its transportation and storage at home. Fig. 4.36: A woman using a monofilament cloth filter for water filtration (Dr. CM Adeiyongo, UniJos) Most recontamination is the result of behavioural patterns that can be changed through hygiene education, especially for women and children, who are mostly 71 Principles and Practice of Environmental Health in Nigeria involved in water collection and storage. Failing this, the following technical interventions can be used to bring the contaminated water back to the required standard: Boiling Filtration Chemical disinfection Cloth filtration (to prevent dracunculiasis Fig. 4.37: Nomadic Fulani using a straw filter to drink directly from a pond (Dr. CM Adeiyongo, UniJos) 4.5.1. Boiling Boiling is a simple way of killing all the microorganisms in the water. For it to be effective, the water needs to be brought to a “rolling boil” for one minute. Rolling boil occurs when large bubbles come continuously to the surface of the water. Boiling as a household purification 72 Principles and Practice of Environmental Health in Nigeria method is not highly recommended, because of the following reasons: The cost of buying fuel to bring the water to rolling boil might be beyond the reach of the poor. Boiling can give an unpleasant taste to the water Very hot water is a source of accident in the home; Boiled water can become recontaminated once it has cooled. 4.5.2. Simple household filters They are of many types, and most have the ability to remove solids, silt, and larger microorganisms like ova, cysts and most bacteria, but not viruses like hepatitis A virus. The common types of simple household filters are candle, stone and sand filters. Candle filters are often commercially produced and involve filtering contaminated water slowly, through a porous ceramic material. The filtered microorganisms are left on the outer layer of the filter material, and therefore had to be periodically cleaned, by gently scrubbing the filter under clean, running water. The candle filter is often designed to minimize the risk of recontamination of water after filtering. Most consist of two inter locking containers; the upper container has the candle(s) and receives the raw water, while the lower container receives the filtered water. 73 Principles and Practice of Environmental Health in Nigeria Fig. 4.38: The common household candle filter Sand filters can be locally made, and consist of fine sand at the top and gravels at the base. It should not be confused with slow sand filters, which requires a continuous and constant flow of water to function effectively. The household sand filter, though not as efficient as the slow sand filters in removing micro- organism, is still capable of removing ova, larva, cysts and cyclops, but not most bacteria and viruses. Therefore, disinfection might be required to bring the quality of sand filtered water to the required standard. The household sand filter should not be used to filter water of high turbidity, because the pores of the filter are 74 Principles and Practice of Environmental Health in Nigeria easily blocked by the suspended solids. It is therefore advised that highly turbid water be left to settle for several hours e.g. over night before being filtered. 4.5.3. Chemical disinfection Disinfection is ideally carried out with clear water. When carried out on turbid or cloudy water, the disinfectant is largely consumed by the suspended particles in the water. These particulates also provide protection for microorganisms against the actions of the disinfectant. Therefore turbid water should be allowed to settle, or should have coagulants like alum added, before disinfectants are added to them. The most common disinfectant for household use is chlorine, in the form of bleach and chlorine tablets. Three drops of bleach have been found to be enough disinfection for one liter of water. Water-guard, a mixture of chlorine and coagulants is being socially marketed in Nigeria. It is probably an ideal disinfectant for use in most communities in Nigeria. Fig. 4.39: Water Guard 75 Principles and Practice of Environmental Health in Nigeria 4.6. Household storage of drinking water Storage of drinking water is very important if recontamination won’t occur. The location of the storage vessel should be above ground level, to restrict access to children and animals. It should be placed in a shaded place, preferable in an earthenware jar, or pot to keep the water cool. The storage vessel should have a secure, tight fitting cover. Fig. 4.40: Earthen pots fitted with tap can be a very good storage container for drinking water Water should be removed from the container hygienically, with no contact between the hands and the water. Since it is very difficult to do this with a cup, a ladle should be permanently kept inside the container for the transfer of water from the container to a cup. The ladle should be held only by the top of its handle, and not by the scoop, or any part that is immersed in the water during storage. Fitting a tap to the container 76 Principles and Practice of Environmental Health in Nigeria minimizes contact with the water, and is the most hygienic method of withdrawing water. Fig. 4.41: Earthen pots fitted with tap prevent contamination even when used by a child Fig. 4.42: Jerry can is a very hygienic way of storing drinking water Presently jerry cans are becoming very common water storage containers. They can prevent recontamination since contaminated cups cannot be dipped into them. The use of jerry can for the storage of 77 Principles and Practice of Environmental Health in Nigeria the household’s drinking water can reduce the risk of diarrheal disease in the household by up to 75%. 78 Principles and Practice of Environmental Health in Nigeria 79 Principles and Practice of Environmental Health in Nigeria 80 Principles and Practice of Environmental Health in Nigeria Fig. 4.43: Water storage containers with which the above study was carried out (Ogutu P, Garrett V, Barasa P, Ombeki S, Mwaki A, Quick RE Seeking Safe Storage: A Comparison of Drinking Water Quality in Clay and Plastic Vessels. American Journal of Public Health 2001; (91) 10: 1610 – 1611.) 4.7. Evaluation The assessment of the water situation of the community is done by comparing the community with the various international indicators mentioned earlier. The assessment of the quality of the community’s water supply is one of the most important water related public health activities. It is not a one-off activity, but a continuous process designed to ensure that drinking water does not constitute a danger to the health of members of the community. The assessment involves two principal activities; sanitary inspection and water quality analysis. These are 81 Principles and Practice of Environmental Health in Nigeria complementary activities. Sanitary inspection identifies potential hazards, while water quality analysis indicates whether contamination is occurring and if so, its intensity. Fig. 4.44: Burst pipe across a drain is a common cause of contamination of pipe-borne water in Nigeria. 4.7.1. Sanitary inspection Sanitation inspection is an on-site inspection and evaluation of all conditions, devices and practices in the water supply system that pose an actual, or potential danger to the health and well being of the community. For a piped supply, the inspection starts from the water pumping station, down to the distribution network, and ending in the public tap. The inspection of unpiped 82 Principles and Practice of Environmental Health in Nigeria sources involves looking for likely sources of contamination around the water source. Fig. 4.45: Procedural steps for carrying out a sanitary survey 4.7.2 Water quality analysis The principal risk to human health derives from faecal contamination. Though, there may also be hazards associated with specific chemical contaminants, such as fluoride and arsenic, the levels of these chemical contaminants are unlikely to change significantly with 83 Principles and Practice of Environmental Health in Nigeria time. Thus, if a full range of chemical analyses is undertaken on new water sources, and repeated thereafter at fairly long intervals, chemical contaminants are unlikely to present an unrecognized hazard. In contrast, the potential for faecal contamination in untreated or inadequately treated community supplies is always present, hence the need to test the water regularly for faecal contamination. One of the major objectives of testing the community’s water supply is to determine if there is any significant difference between the quality of water at source, and the quality at the point of use. This would help establish if there has been contamination within the distribution system. Carrying out a water analysis to detect possible faecal contamination requires that the sample be collected with the thoroughness of a surgical operation, with the observation of similar aseptic precautions; and that the collected sample be appropriately stored in a dark, lightproof insulated box containing melting ice. Fig. 4.46: Transport boxes for water samples Despite the numerous bacteria found in faeces, the coliform organisms (total coliform) are specifically used during water analysis, to indicate the likelihood of 84 Principles and Practice of Environmental Health in Nigeria faecal contamination. This is because the bacteria are easily detected and enumerated. The term “coliform organisms” refers to gram-negative, rod-shaped bacteria capable of growing in the presence of bile salts, and able to ferment lactose at 35 – 37 oc, within 24 – 48 hours, and with the production of acid, gas, and aldehyde. The principal analytical techniques used in the isolation of the indicator organisms in the sample water include: The membrane-filtration method and The multiple-tube or probable number method 4.7.2.1. Membrane-filtration method This method involves: 1. Measuring out a given volume of the water to be tested, and instilling it aseptically into a sterile membrane filter, with a nominal pore size 0.2 or 0.45um. 2. This membrane filter is then transferred to a suitable selective culture medium, in a petri dish. The commonly used media are the Lactose TTC Tergitol agar, and the membrane lauryl sulphate lactose broth. 3. Following a period of resuscitation, during which any bacteria contained in the water sample would become acclimatized to the new conditions, the petri dish is transferred to an incubator for culturing, at the appropriate selective temperature that allows for the maximum replication of the indicator organisms. 85 Principles and Practice of Environmental Health in Nigeria 4. The culture results are read after about two days. This involves counting the visually identifiable colonies. The results are expressed in the numbers of “colony-forming units” (CFU) per 100ml of original sample. This is calculated as follows: Thermo-tolerant coliform = No. of coliform colonies counted x 100 per 100ml No. of ml of sample filtered The result of this calculation can be presented according to the classification below Classification and colour-code scheme for indicator organisms in water supplies Count per Category and Remark 100ml colour code 0 A (blue) In conformity with WHO guidelines 1 – 10 B (green) Low risk 10 – 100 C(yellow) Intermediate risk 100 – D (orange) High risk 1000 >1000 E (red) Very high risk The membrane-filtration technique is not ideal for testing water of high turbidity, because of the likelihood of blocking the filter, before an adequate volume of it has passed through. To solve this problem, smaller sample volume of the highly turbid water is used, with an adequate volume of sterile diluent added to flush the sample through the membrane filter. 86 Principles and Practice of Environmental Health in Nigeria 4.7.2.2.Multiple-tube Method This is ideal for highly turbid water samples. It is more sensitive, but more time-consuming to perform, and requires more equipment, glassware and consumables than the membrane-filtration method. It is said to be an indirect method, because statistical tables are used to determine the most probable number of microorganisms present in the original sample. It is carried out by aseptically adding a known quantity of water to tubes containing sterile nutrient medium, in a mixture ratio of one ml of sample water to 10ml of single strength medium. The commonly used media are Mac-conkey broth and improved formate lactose glutamate medium. Growth in the medium is confirmed by visible turbidity and/or a colour change. A small inverted glass tube called Durham tube is often placed inside the big tube containing the medium, to facilitate the detection of gas production. The number of positive reactions found in the tubes after 24 and/or 48 hours is recorded. These positive reactions are called “Presumptive Positive” because they are sometimes further validated as truly formed by the indicator bacteria (coliform) by a confirmatory test, also called Presumptive test. The confirmation test is performed by inoculating a selective media for coliforms (usually the Lauryl tryptose and the Brilliant green lactose (bile) broth) with material taken from the positive tubes. After an appropriate incubation time, the tubes are examined for positive signs of bacterial growth, as previously done. 87 Principles and Practice of Environmental Health in Nigeria The concentration of microorganisms in the original water sample is estimated from the pattern of the positive results, using statistical tables that give the “most probable number” per ml of the original sample. Further reading 1. WHO. Guidelines for drinking water quality. Second edition. Geneva. WHO. 1993. 2. British Geological Society. Groundwater quality: Nigeria. WaterAid. 2003. 3. Water and Environmental health at London and Loughborough (WELL). Guidance manual on water supply and sanitation programmes. London. LSHTM/WEDC. 1998. A single scoop of snails along the dam wall of a heavily snail infested reservoir (Lougourougoumbo, Mali). 88 Principles and Practice of Environmental Health in Nigeria CHAPTER FIVE SEWAGE DISPOSAL 1.1.Introduction Safe disposal of excreta is the less glamorous cousin of safe water supply; while many people hail water as the fountain of water, only very few are willing to be associated with excreta disposal. Yet, the two must work together to achieve most of the envisaged health goals. In a review of several studies, it was for instance found that whereas improvements in the quantity and quality of water alone were able to reduce the morbidity due to diarrhoeal diseases by just 17%; combinations of water and sanitation projects have the capacity to reduce the morbidity by as much as 30%. This synergy stems from the fact that both work together to reduce the pathogen load in the ambient environment, and in the interruption of the transmission of the pathogens. The WHO estimates that 5.5% of the global disease burden is due to inadequate water and sanitation, while the duo is believed to be responsible for 88% of the four billion diarrhoeal cases, and the resultant 1.8 million deaths that occur in the world annually. The WHO further estimates that 94% of the diarrhoeal cases are preventable, through increased availability of clean water; and improved sanitation and hygiene. The importance of safe water and improved sanitation is further reflected in their inclusion as one of the millennium development goals, a framework that has been widely accepted for the worldwide improvement of health and welfare. 89 Principles and Practice of Environmental Health in Nigeria Fig. 5.1: Percentage of the world’s population using improved sanitation facilities in 2000. Fig. 5.2: 2.4 billion people were without access to improved sanitation in the year 2000 90  Principles and Practice of Environmental Health in Nigeria 5.2. A Walk around the community Even as efforts are being made to meet the MDG on access to sanitation, three billion people are still without proper sanitation, and only about half of the over one million tons of human faeces produced each day are properly disposed, according to a 1997 WHO estimate. The WHO recommends that each household should have a sanitation facility within 50 meters of their residence. It also recommends that the number of households that share a sanitation facility should not exceed five, to ensure that facility is able to effectively prevent excreta-related diseases. It is believed that a 75% use of sanitation facility is able to control most of the excreta-related diseases in a community, but universal access is being advocated as easily achievable in several communities in Nigeria. Fig. 5.3: The bush behind the house is a common toilet used by many households in Nigeria. 91 Principles and Practice of Environmental Health in Nigeria Fig. 5.4: Open defecation The zest for universal access to sanitation facility might require the construction of public toilets, in public facilities, to ensure that patrons of the facilities are not forced to open defecation. It however does not mean that public toilets should be built for households who “cannot afford’ to build their own facility, because such toilets are often misused, or not used at all. An unhygienic toilet does not have much health benefits, while public toilets 92 Principles and Practice of Environmental Health in Nigeria are often not used in Nigeria, because defecation is considered a private matter that should be carried out without the knowledge of others. Fig. 5.5: The type of toilet used in ancient Rome Access to sanitation facility is improving in Nigeria. In the north, where the purdah system is practiced, the provision of sanitation facilities is almost a religious duty; while increased efforts are being made to encourage householders in the rural communities of the south to built their own sanitation facility, and move away from open defecation. 93 Principles and Practice of Environmental Health in Nigeria Fig. 5.6: A toilet in northern Nigeria However, the efforts in the rural riverine communities of the Niger Delta region are being hampered by high groundwater level that makes the construction of the sanitation facility very difficult. This encouraged the people to make use of the jetty-type latrine (over hung latrine). This involves constructing a platform of variable, but conducive distance from one’s house into the river, where a super structure is often built to provide privacy for the user. A squat hole is provided to allow faeces to be passed into the river, which is then carried away by the current of the river. Considering the fact that the life of the inhabitants of these riverine communities revolve round the river, the health implications of this practice can best be imagined. 94 Principles and Practice of Environmental Health in Nigeria However, Wagner and Lanoxi (1958) suggested that such latrines might be acceptable in areas that are continuously or seasonally covered with water, if the following conditions are met. If the structures are safe for adults and children. If the receiving water is salt water, and not used for drinking purposes. If the latrine is installed over water that is sufficiently deep to ensure that the bed is never exposed during low tide, or the dry season. If it is sited downstream from the village; and If the water is not used for recreation or fishing Fig. 5.7: The jetty-type toilet 95 Principles and Practice of Environmental Health in Nigeria The use of bucket latrine was common in most houses built during the colonial period in Nigeria. It involves defecating into a bucket, while squatting on a platform constructed over the bucket. The bucket latrine is not only unsanitary - often involving the handling of fresh stool, but also very expensive to run. It requires the hiring of a labourer to empty the bucket containing the excreta, every one to three days; and in our society where this type of work is considered demeaning, the labourer definitely needs to be well paid to do his work enough to halt the transmission of excreta-related diseases in the community. Without this, the bucket system presents a continuous health hazard from spillage, direct contact with faeces, and the breeding of flies, mosquitoes and rats; from the collection point, to the site of final disposal. Fig. 5.8: Bucket Latrine 96 Principles and Practice of Environmental Health in Nigeria Fig. 5.9: Containers used in transporting night soil in a Nigerian city in the 21st century (Oloruntoba EO) Fig. 5.10: The water-closet toilet uses about 10 liters of water per flush. More may be needed to completely dislodge faeces 97 Principles and Practice of Environmental Health in Nigeria Fig. 5.11: Poorly maintained squat toilet, not too effective against excreta-related disease Fig. 5.12: Children should be encouraged to use the toilet, instead of defecating indiscriminately 98 Principles and Practice of Environmental Health in Nigeria Hand washing practices: Studies have shown that the provision of toilet facilities alone is not enough to halt the transmission of excreta related diseases in a community. A classical study carried out in Bangladesh showed that the simple practice of washing hands with soap and water after defecation can reduce the transmission of dysentery, within a household, by as much as 85%. Appropriate hand washing behaviour has two dimensions to it: Washing at critical times; and The use of the right hand washing technique Critical time for hand washing includes: After defecation After cleaning babies bottoms Before food preparation Before eating; and Before feeding children. Fig. 5.13: Hand washing Good hand washing techniques include - The use of water for hand washing - The use of soap or ash 99 Principles and Practice of Environmental Health in Nigeria - Washing of both hands, rubbing hands together at least three times - Drying the hands hygienically by air, or using a clean cloth. Fig. 5.14: Hand washing is vital for the prevention of faeco-oral diseases 100 Principles and Practice of Environmental Health in Nigeria 5.3.At the health center Inadequate and/or inappropriately used toilet facilities could lead to an increase in certain diseases described as excreta-related. These diseases according to Cairncross and Feachem (1998) can be classified as follows: 1. Faecal – Oral diseases These are the diseases transmitted as shown in the F- diagram (Fig. 5.3) below. They basically involve the ingestion of faecal matter through fluid, fingers, flies, food, and the foot. The diseases include bacterial infections such as cholera that require large infective doses for their transmission, a