1. Advances in Environmental Health For MPH students.pptx

Advances in Environmental Health (PbEH5101)
Credit hours: 2
By
Simachew Dires
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Course Contents
1. Introduction
• Definition of terms
• Brief Historical Overview of Environmental Health
2. Hazard, exposure and risk
• Biological Hazards
• Chemical Hazards
• Physical hazards
• Methods for monitoring and control of environmental hazards
3. Principles of pollution prevention
4. Concepts and principles in hygiene and environmental Health
• Environmental intervention models
• The role of environmental health in public health
• Promoting Environmental conditions that enhance health of humans and other
species.
5. Essential Services of Environmental Health
6. Vector Control
7. Housing and institutional health 2

Course Contents
8. Food safety and human health
• Historical review on situation of food hygiene in Ethiopia
• Public health importance of food
• Factors of food-associated diseases
• Food hygiene intervention
• HACCP Principles
• Standard criteria
• Regulatory Mechanisms and Agencies in Ethiopia to Prevent and
Control Food Safety
• GMO
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Methods of instruction
• Lecture (power point presentation)
• Classroom discussion
• Individual home work
• Group work/Term paper presentation
• Reading assignments
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Definitions of Environment
• The word environment is derived from a French word “ environ”
which means surrounding or enveloping.
• Environment: the total of our surroundings
• All the things around us with which we interact:
Living things- Animals, plants, forests, fungi, etc.
Non-living things - Continents, oceans, clouds, soil, rocks
Our built environment - Buildings, human-created living centres
Social relationships and institutions
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What is the environment?
The trees, air, & soil
around us
Our fields, farms &
the food we grow
Our oceans, lakes, and rivers
ALL the places we live, work &
play

• Scope of Environment: The environment consists of four segments:
1. Atmosphere - implies the protective blanket of gases, surrounding
the earth;
• it sustains life on the earth;
• the atmosphere is composed of nitrogen and oxygen besides, argon, carbon
dioxide, and trace gases.
2. Hydrosphere: The Hydrosphere comprises all types of water
resources oceans, seas, lakes, rivers, streams, reservoir, polar
icecaps, glaciers, and ground water.
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3. Lithosphere: Lithosphere is the outer mantle of the solid earth. It
consists of minerals occurring in the earth’s crusts and the soil e.g.
minerals, organic matter, air and water.
4. Biosphere: Biosphere indicates the realm of living organisms and
their interactions with environment, viz atmosphere, hydrosphere
and lithosphere.
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Environmental science
• Environmental science is the study of the interaction of humans with
the natural environment.
• It is the study of how humans interact with their environment.
• Devoted to studying the impacts humans have on the environment.
• Environmental science (or studies) - interdisciplinary studies in
natural sciences, including geology, climatology, hydrology,
ecology, and their interaction with social sciences such as
economics, political science, sociology, anthropology, geography.
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Environmental science and the issues
that it studies are complex and
interdisciplinary.
• Includes concepts and ideas from
multiple fields of study.
• By combining aspects of the natural
sciences, social sciences, and the
humanities, the field of
environmental science can cover
more concepts and also examine
problems and topics from many
different points of view.
Environmental science cont’d..
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• A community decides to use coal for electricity, as it is the cheapest source
available. (Economics)
• The coal must be mined from under the soil. (Geology)
• The coal must be transported to the population center by road or rail.
(Engineering)
• When it is burned at a power plant, air pollution is released. Some of that
pollution is converted to acid in the atmosphere. (Chemistry)
• This falls as acid rain somewhere downwind. (Meteorology)
• The acid stresses plants by affecting their nutrient absorption. (Ecology)
• Laws are passed requiring the plant to install pollution scrubbers. (Politics)
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Goal of environment science: To understand and solve environmental
problems
• Ecosystem functions
• Air Pollution
• Water Pollution
• Toxic Chemicals
• Climate Change
• Resource usage
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• Environmental science helps us understand our relationship with the
environment and informs our attempts to solve and prevent problems.
• Solving environmental problems can move us towards health, longevity,
peace and prosperity
• Environmental science can help us find balanced solutions to
environmental problems.
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Major environmental problems
1. Resource Depletion
• A great deal of resources are needed to support the human population (~7
billion).
Natural Resources are any natural materials that are used by humans
water, petroleum, minerals, forests, & animals
Said to be depleted when most of the resource has been used up
Either renewable or nonrenewable resources
Nonrenewable resources take millions of years to be replaced if depleted.
(Oil)
Renewable resources can be replaced relatively quickly by natural process.
(Trees)
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2. Pollution
Pollution is an undesirable change in the natural environment that is caused
by the introduction of substances that are harmful to living organisms.
Can also be excessive wastes, heat, noise, or radiation
Much of the pollution that troubles us today is produced by human activities
& the accumulation of wastes.
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2 main types of pollutants:
Biodegradable pollutants
Can be broken down by natural processes over time
Example: newspaper
Only a problem if they accumulate faster than they can be broken down
Nonbiodegradable pollutants
can’t be broken down by natural processes
Example: mercury
Can build up to dangerous levels in the environment
• Pollution, whether in air or water, can move and affect ecosystems far away
from the source.

3. Loss of Biodiversity
Biodiversity is the variety of organisms in a given area (in one specific
ecosystem).
There is:
genetic variation within a population
A variety of species in a community
A variety of communities in an ecosystem
Humans need to understand & preserve biodiversity for
our own survival.

The organisms that share the world with us can be considered natural
resources.
We depend on them for: food, the oxygen we breathe, & for their
potential economic, scientific, aesthetic, & recreational value.
Scientists think that species extinction may cause problems for the
human population.

Current Extinctions
• Extinction, or the complete loss of a species, is a natural event that can be
accelerated by human actions.
• Assuming no catastrophic events occur, extinctions normally occur at a pretty
slow rate, called the background rate. Normal background extinction rate for
mammals is 1 every 200 years.
• Scientists believe we may be in the midst of the next major extinction event,
due to human influences.
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• The rate of extinctions is estimated to have increased by a multiple of 50
since 1800, with up to 25 percent of all species on Earth becoming extinct
between 1800 and 2100.
• Australia has experienced 27 mammal extinctions since 1788, primarily due
to the influence of European settlers
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Species Prone to Extinction
• Species that are especially at risk of extinction are those that migrate, those
that need large or special habitats, & those that are exploited by humans.
• Endangered species-has been identified to be in danger of extinction
throughout all or a significant part of its range, & that is thus under
protection by regulations or conservation measures
• Threatened species-has been identified to be likely to become endangered
in the future
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Biodiversity Loss and Species Extinction: Remember HIPPO
• The major causes of extinction today are:
• H for habitat destruction and degradation
• I for invasive species
• P for pollution
• P for human population growth
• O for overexploitation

Population and Consumption
• Developed countries on average have higher incomes, longer life spans,
slower growth rate, diverse industrial economies, & stronger social support.
• These countries are more economically stable, educated, and have more
environmental protections
• Developed countries, while smaller in size and growth, consume resources at
a greater rate.
• About 20% of the world’s population uses 75% of its resources.
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• This rate of consumption creates more waste & pollution per person than in
developing countries.
• Developing countries have lower average incomes, simple agriculture-based
economies, & rapid population growth.
Almost all environmental problems can be traced back to 2 root causes:
• The human population in some areas is growing too quickly for the local
environment to support.
• People are using up, wasting, or polluting many natural resources faster
than they can be renewed, replaced, or cleaned up.

Local Population Pressures
When the population in an area grows rapidly, there may not be enough
natural resources for the everyone to live a healthy, productive life.
In severely overpopulated regions, forests are stripped bare, topsoil is
exhausted, & animals are driven to extinction.
In these areas, malnutrition, starvation, & disease can be constant
threats.

Ecological footprint
• An ecological footprint is one measurement of a person’s resource use.
• Ecological footprints are calculations that show the productive area of Earth
needed to support one person in a particular country.
Estimates land used for crops, grazing, forest products, & housing
Includes the ocean area used to harvest seafood & the forest area needed to
absorb the air pollution caused by fossil fuels.
• Developed countries have a much larger footprint, reflecting a much larger use
of resources.
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An ecological footprint is one
way to express the differences
in consumption between
nations.

Ecological footprints are not all
equal
• The ecological footprints of countries vary
greatly.
• The U.S. footprint is much greater than
the world’s average.
• Developing countries have much smaller
footprints than developed countries.
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Environmental Impact (I) = (P)(A)(T)
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Health
• Health: “Health is a state of complete physical, mental, social and
spiritual well-being and not merely the absence of disease or
infirmity.”
• In recent years the statement is amplified to include,
“The ability to lead a socially and economically productive life.”
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Integrated Environmental Health Middle
School Project • University of
Washington © 2005
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What is health?
Nutritious foods help us stay
healthy.
Doctors, hospitals & medicines help
us get healthy if we’re sick.
Regular exercise helps keep us
strong and healthy.

Definitions of Environmental Health
Environmental health has been defined in many ways:
• Some definitions make reference to the relationship between people and
the environment, evoking an ecosystem concept, and
• others focus more narrowly on addressing particular environmental
conditions.
• Some focus on abating hazards, and others focus on promoting health-
enhancing environments.
• Some focus on physical and chemical hazards, and others extend more
broadly to aspects of the social and built environments.

• Environmental health is the branch of public health that is concerned with all
aspects of the natural and built environment that may affect human health.
• Public Health is defined as “the art and science of preventing disease,
prolonging life and promoting health through the organized efforts of society”
(Acheson, 1988; WHO).
• Other terms referring to or concerning environmental health are environmental
public health, and public health protection / environmental health protection.

• “Environmental health - comprises those aspects of human health,
including quality of life, that are determined by physical, chemical,
biological, social and psychosocial factors in the environment.
• It also refers to the theory and practice of assessing, correcting,
controlling, and preventing those factors in the environment that can
potentially affect adversely the health of present and future
generations” (World Health Organization [WHO], 2004).
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• “Environmental health is the discipline that focuses on the
interrelationships between people and their environment, promotes
human health and wellbeing, and fosters a safe and healthful
environment” (National Center for Environmental Health).

Environmental Health…
• Environmental health and protection refers to protection against
environmental factors that may adversely impact human health or the
ecological balances essential to long-term human health and
environmental quality, whether in the natural or man-made
environment. – National Environmental Health Association
• Environmental Health is the field of science that studies how the
environment influences human health and disease.
• In the aggregate the definitions make it clear that environmental
health is many things: an interdisciplinary academic field, an area of
research, and an area of applied public health practice.

Washington © 2005
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Environmental Health?
The study of how the environment
affects your health.
Food
Air
Water
Sunlight
Noise
Soil

Washington © 2005
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Good Things Around Us
There are many things around us that help us stay healthy.
Family &
friends
Beautiful
scenery to look
at
Medicine &
vitamins
Oxygen in the
air
Nutrients in
food

Environmental health vs Environmental science
• Environmental health - it is the branch of public health which covers
all the aspects of natural and built environment that affects the
human health,
• both environmental science and health are very much related
because the environmental health deals with the natural
environments that benefits the human health where as
• science is focused on protecting the natural environment for the
benefit of human health and ecosystem.
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Environmental health vs Environmental protection
• Environmental Health is focused on protecting public health by
managing environmental conditions e.g. housing conditions, food &
beverage safety, water & sewage, workplace safety, hazardous
substances, etc.
• Environmental Protection is focused on preserving the health of the
environment and managing the natural resources .
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Universal human rights:
• “All people have the right to a standard of living adequate for health
and well being of themselves and their family, including food,
clothing, housing, health care, and the necessary social services”
(Article 25, UN Dec 10,1948 universal declaration of human rights).
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Equivalent in Ethiopian Constitution:
• Article 44: (env right) All Persons have the right to live in a clean
and healthy environment.
• Article 90.1: the right to access to PH, education, clean water,
housing, food, security
• Article 92 (1-4):92.1: Government shall endeavor to ensure that
all Ethiopians live in a clean and healthy environment.
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Why Is Environmental Health Important?
• Maintaining a healthy environment is central to increasing quality of life
and years of healthy life.
• Globally, 23% of all deaths and 26% of deaths among children under age 5
are due to preventable environmental factors.
• Environmental factors are diverse and far reaching.
• They include:
• Exposure to hazardous substances in the air, water, soil, and food
• Natural and technological disasters
• Climate change
• Occupational hazards
• The built environment
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Update of the global burden of disease attributable to the environment - Prüss-
Ustün et al 2016
• 23% (95% CI: 13–34%) of global deaths and 22% (95% CI: 13–32%) of global
disability adjusted life years (DALYs) were attributable to environmental risks in
2012.
• The global disease burden attributable to the environment is now dominated by
noncommunicable diseases.
• Susceptible ages are children under five and adults between 50 and 75 years.
• Nearly a quarter of global disease burden could be prevented by reducing
environmental risks.
• Eliminating hazards and reducing environmental risks will greatly benefit our
health, will contribute to attaining the recently agreed Sustainable Development
Goals and will systematically require intersectoral collaboration to be successful.
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The Evolution of Environmental Health
ENVIRONMENTAL HEALTH From Global to Local (Frumkin, Howard, 2005)
• The history of and the development of Environmental Health are unique and
complex in every country of the world.
• It is not possible to assign a specific date from which problems relating to
environment started.
• However, human concern for environmental health dates from ancient times, and
it has evolved and expanded over the centuries.
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ENVIRONMENTAL HEALTH From Global to Local (Frumkin, Howard, 2005)
1. Ancient Origins
• The notion that the environment could have an impact on comfort and
wellbeing—the core idea of environmental health—must have been
evident in the early days of human existence.
• Our ancestors sought shelter in caves or under trees or in crude shelters
they built.
• Food safety - there must have been procedures for preserving food, and
people must have fallen ill and died from eating spoiled food.
• Dietary restrictions in ancient Jewish and Islamic law, such as bans on eating
pork, presumably evolved from the recognition that certain foods could cause
disease.
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• Excreta Disposal- Around 2000 B.C., Israel provided guidelines as to
how to manage wastes; instructions for the mgt of human waste are
provided in the Bible (Deuteronomy 23:12–13).
• Clean water- we can assume that early peoples learned not to
defecate near or otherwise soil their water sources.
• In the ruins of ancient civilizations from India to Rome, from Greece to Egypt
to South America, archaeologists have found the remains of water pipes,
toilets, and sewage lines, some dating back more than 4,000 years.
• Polluted air - there is evidence in the release of high levels of smoke
from ancient cave dwellers
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• Mold in buildings- in the biblical book of Leviticus (14:33–45) may
refer to an environmental health problem well recognized today
• Rodents - European history was changed forever when infestations of
rats in fourteenth century cities led to the Black Death.
• The Black Death (Plague) was one of the most devastating pandemics
in human history, resulting in the deaths of an estimated 75 to 200
million people in Eurasia and peaking in Europe from 1346 to 1353.
• Plague is caused by the bacteria Yersinia pestis, a Gram-negative,
rod-shaped coccobacillus.
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2. Industrial Awakenings
• Modern environmental health further took form during the age of
industrialization.
• With the rapid growth of cities in the seventeenth and eighteenth centuries, the
urban environment fostered
 the spread of diseases with crowded, dark, unventilated housing;
unpaved streets mired in horse manure and littered with refuse;
inadequate or non existing water supplies;
privy vaults unemptied from one year to the next;
stagnant pools of water;
ill-functioning open sewers;
noises from clacking horse hooves, wooden wagon wheels, street railways, and unmuffled
industrial machinery.
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• The provision of clean water became an ever more pressing need, as
greater concentrations of people increased both the probability of water
contamination and the impact of disease outbreaks.
• Regular outbreaks of cholera and yellow fever in the eighteenth and
nineteenth centuries occurred.
• Similarly, sewage management became a pressing need.
• The industrial workplace — a place of danger and even horror—gave
additional impetus to early environmental health.
• Technology advanced rapidly during the late eighteenth and nineteenth
centuries, new and often dangerous machines were deployed in industry
after industry, and mass production became common.
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• A key development in the seventeenth through nineteenth centuries was
the quantitative observation of population health—the beginnings of
epidemiology.
• With the tools of epidemiology, observers could systematically attribute
certain diseases to certain environmental exposures.
• John Graunt (1620–1674), an English merchant and haberdasher, analyzed
London’s weekly death records—the bills of mortality—and published his
findings in 1662 as Natural and Political Observations Upon the Bills of
Mortality;
• This was one of the first formal analyses of this data source and a
pioneering example of demography.
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• William Farr (1807–1883) made the link between vital statistics and
environmental health.
• Farr made observations about fertility and mortality patterns,
identifying rural-urban differences, variations between acute and
chronic illnesses, and seasonal trends, and implicating certain
environmental conditions in illness and death.
• Farr’s 1843 analysis of mortality in Liverpool led Parliament to pass
the Liverpool Sanitary Act of 1846, which created a sanitary code for
Liverpool and a public health infrastructure to enforce it.
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• Edwin Chadwick (1800–1890) was a pioneer in combining social
epidemiology with environmental health.
• Social epidemiology is a branch of epidemiology that focuses particularly on the
effects of social-structural factors on states of health.
• Five years later, following epidemics of typhoid fever and influenza, he was
asked by the British government to investigate sanitation.
• His classic report, Sanitary Conditions of the Labouring Population (1842),
drew a clear link between living conditions—in particular overcrowded,
filthy homes, open cesspools and privies, impure water, and miasmas—and
health, and made a strong case for public health reform.
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• The physician John Snow (1813–1858) was, like William Farr, a
founding member of the London Epidemiological Society- father
environmental epidemiology study.
• During an 1854 outbreak of cholera in London, he observed a far
higher incidence of disease among people who lived near or drank
from the Broad Street pump than among people with other sources
of water.
• He persuaded local authorities to remove the pump handle, and the
epidemic in that part of the city soon abated.
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3. The Modern Era
• The modern field of environmental health dates from the mid-
twentieth century.
• Rachel Carson published a book in 1962 entitled Silent Spring about
the effects of pesticides on large predatory birds, particularly the bald
eagle. The 1962 publication of Rachel Carson’s Silent Spring was the
best landmark.
• Silent Spring focused on DDT, an organochlorine pesticide that had
seen increasingly wide use since the Second World War.
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• Carson had become alarmed at the ecosystem effects of DDT;
• She described how it entered the food chain and accumulated in the
fatty tissues of animals, how it indiscriminately killed both target
species and other creatures, and how its effects persisted for long
periods after it was applied.
• She also made the link to human health, describing how DDT might
increase the risk of cancer and birth defects.
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• One of Carson’s lasting contributions was to place human health in the
context of larger environmental processes.
“Man’s attitude toward nature,” she declared in 1964, “is today critically
important simply because we have now acquired a fateful power to alter and
destroy nature. But man is a part of nature, and his war against nature is
inevitably a war against himself. . . . [We are] challenged as mankind has
never been challenged before to prove our maturity and our mastery, not of
nature, but of ourselves”.
• The recognition of chemical hazards was perhaps the most direct legacy of
Silent Spring.
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• Irving Selikoff (1915–1992) and his colleagues intensively studied
insulators and other occupational groups and showed that asbestos could
cause a fibrosing lung disease, lung cancer, mesothelioma, and other
neoplasms.
• Outbreaks of cancer in industrial workplaces- lung cancer in a chemical
plant were underlined as the risk of carcinogenic chemicals.
• Following these, cancer research was expanded, the American Cancer
Society was made, and as a result environmental and occupational
carcinogens became a focus of public, scientific, and regulatory attention.
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• Herbert Needleman (December 13, 1927 – July 18, 2017 ), studying children in
Boston, Philadelphia, and Pittsburgh, showed that lead was toxic to the
developing nervous system, causing cognitive and behavioural deficits at levels
far lower than had been appreciated.
• Resulted in the removal of lead from gasoline, and as a result population blood
lead levels plummeted.
• Research also suggested that chemical exposures could threaten reproductive
function, can result in decrease in sperm counts, and certain persistent,
bioaccumulative chemicals (persistent organic pollutants, or POPs) could affect
reproduction, perhaps by interfering with hormonal function.
• Emerging evidence showed that chemicals could damage the kidneys, liver, and
cardiovascular system and immune function and organ development.
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• Bhopal disaster- isocyanate release killed hundreds and sickened thousands in
Bhopal, India, in 1984, made it clear that industrialization posed real threats of
chemical toxicity.
• The use of herbicides in Vietnam war - Agent Orange was a powerful herbicide
used by U.S. military forces during the Vietnam War to eliminate forest cover and
crops for North Vietnamese and Viet Cong troops.
• Chernobyl nuclear reactor accident - On April 26, 1986, Ukraine, in the former
Soviet Union. The accident and the fire that followed released massive amounts
of radioactive material into the environment. Resulted in displacement, death
and chronic diseases.
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• Even as the awareness of chemical hazards grew, supported by
advances in toxicology and epidemiology, environmental health
during the second half of the twentieth century was developing in a
different direction altogether: environmental psychology.
• Further development in modern environmental health was the
continued integration of ecology with human health; the
understanding of ecosystem function advanced greatly.
• the role of humans in the context of ecosystems was better and
better delineated.
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• Clinical services related to environmental exposures expanded.
• Occupational medicine and nursing had been specialties in their
respective professions since the early twentieth century, incorporated
a public health paradigm, drawing on toxicological and
epidemiological data, using industrial hygiene and other primary
prevention approaches, and engaging in worker education.
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• Environmental health policy also emerged rapidly. With the promulgation
of environmental laws beginning in the 1960s, legislators at the federal and
state levels created agencies and assigned them new regulatory
responsibilities.
• These agencies issued rules that aimed to reduce emissions
• At the dawn of the twenty-first century, then, the environmental health
field had moved well beyond its traditional sanitarian functions.
• Awareness of chemical toxicity had advanced rapidly, fuelled by
discoveries in toxicology and epidemiology.
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4. Emerging Issues
• Environmental health is a dynamic, evolving field.
• As the twenty-first century unfolds, traditional sanitarian functions
remain critically important, and chemical hazards will continue to be a
focus of scientific and regulatory attention.
• Looking ahead, we can identify at least five trends that will further
shape environmental health: environmental justice, a focus on
susceptible groups, scientific advances, global change, and moves
toward sustainability.
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UN CONFERENCES & PROTOCOLS ON ENVIRONMENT, SUSTAINABLE DEVELOPMENT , CLIMATE CHANGE
• UN Conference on Human Environment, Stockholm (1972)- (Effect of
Environmental degradation on Quality of Human Life)
• Vienna Convention (1985)-(Protection of Ozone Layer)
• Montreal Protocol (1989)-(Total Elimination of Ozone Depleting Substances)
• Basal Convention (1989)-(Control of Trans-boundary Movements of Hazardous
waste)
• Geneva Convention (1990)-(Technology and financial help to Developing
Countries)
• UN Convention on Climate Change, New York (1992)-Economic Development and
Environmental Protection
• Bio-diversity Convention, Nairobi (1992)-(Preservation of Earth’s Bio-diversity)
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UN CONFERENCES & PROTOCOLS ON ENVIRONMENT, SUSTAINABLE DEVELOPMENT , CLIMATE CHANGE
• UN Conference on Environment and Development (Earth Summit) Rio de Janeiro, Brazil
(1992)-(Environment and Sustainable Development)
• Kyoto Protocol (1997)-(Stabilization of Green House Gases)
• World Summit on Sustainable Development, Johannesburg (2002)-(International
Solidarity on Environmental Issues)
• Copenhagen Summit (2009)-(Road map for Post-Kyoto treaties)
• Bali, Indonesia (2007)-Ad Hoc Working Group on Long-term Cooperative Action under
the Convention(AWG-LCA) established
• United Nations Climate Change Conference, Doha, Qatar (2012)-(The Doha Climate
Gateway)
• Paris Agreement (2016)-(Targets for everyone)
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Hygiene and environmental health development in Ethiopia
• Historical information about hygiene practice among the Ethiopian
population is sparse.
1. A formal health service was organized in the Ministry of the
Interior in 1908. Hygiene and sanitation in public health was a
single service.
2. The Ministry of the Interior had a Proclamation and Legal Notices
to exercise sanitation (urine handling, refuse and excreta
management, street sweeping) in 1942–1943.
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3. The Ministry of Public Health was created in 1947. It organized
Municipal and Provincial Public Health services to run both
curative and public health.
Hygiene and sanitation were the focus of these organizations.
4. Late in the 1970s, safe water supply and sanitation became
components of primary healthcare.
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5. In the 1990s, the new Constitution in 1995 and a new Health
Policy in 1993 were designed to reflect the social and health needs
of the Ethiopian population.
• Hygiene, sanitation and environmental matters are stated aims.
6. In early 2000 the Health Extension Program was designed and
integrated into the Health Sector Development Program as a tool
to enhance hygiene and sanitation in rural and urban areas.
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Historical review of Environmental health training in Ethiopia
• Organized sanitary inspectors training in Ethiopia can be traced to around
1942 when the New Ethiopian government was re-established after the
1941 victory of the Italian invasion.
• After the liberation, a medical directorate was established in 1942 under
the Ministry of Interior for carrying out medical and health services in the
country.
• Available records indicate that there was no Ethiopia personnel trained in
the field of environmental sanitation during that time, hence, the
directorate appointed a Sudanese health inspector to handle matters
pertaining to environmental sanitation.
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Historical review of Environmental health training …
• In order to overcome lack of environmental health professionals, the
United Nations Relief and Rehabilitation Administration (UNRRA) which
was then assisting the country during the first phase of reconstruction
initiated the first organized training of sanitary personnel in 1946.
• Under this program the first class of 15 students completed their course
in December 1946. Unfortunately, the sanitary inspector‘s training was
discontinued during 1947-1949 due to withdrawal of external assistance
for the program.
• Some Ethiopians continued the training abroad getting fellowships from
WHO.
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• Therefore, three young men were sent to the school of Hygiene, Mbale,
Uganda in 1950.
• Another three were also sent to the American University of Beirut,
Lebanon in 1952.
• The training of sanitarians in a diploma program resumed in 1956 in
Ethiopia. The duration of the course was one-year theory and practice in
the college and one-year internship period with the other team members
in rural Training Health Centre.
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• Until 1964, the candidates were recruited after completion of eighth
grade.
• After 1964, the entrance requirement was raised to the completion of
10th grade and the training was extended to three years.
• Average enrolment was around 30 students per year. The entrance
requirement was further trained to a completion of 12th grade since
1978.
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• From 1956 up to 1987/88, Gondar was the only School for the
training of Sanitarians in the country. However, in 1988, another
environmental health school was opened at diploma level in Jimma.
Based on the current and anticipated environmental related health
problems in the country, the professional training in the field was
further upgraded to a degree level since 1984.
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Hazard, exposure and risk
• How an environmental factor can affect human health could be
described in terms of hazard, exposure and risk.
• A hazard is defined as a factor that may adversely affect health; it is
basically a source of danger.
• A hazard is a qualitative term expressing the potential of an
environmental agent to harm the health of certain individuals if the
exposure level is high enough and/or other conditions apply.
• Exposure describes both the amount of, and the frequency with
which, a substance reaches a person, group of people or the
environment.
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Washington © 2005
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Hazards
A hazard is anything in the environment that can hurt you or
make you sick.
Bacteria &
viruses
Harmful
chemicals
Loud noises
Tobacco smoke
Stress

Hazard, exposure and risk
• Human exposure can occur through several routes, most importantly,
inhalation, ingestion and skin contact.
• A risk is defined as the probability that a harmful event will occur,
e.g., that an individual will become ill or die within a stated period of
time; the probability of an unfavourable outcome.
• It is the quantitative probability that a health effect will occur after an
individual has been exposed to a specified amount of a hazard.
• A hazard results a risk if there has been exposure.
82

Environmental Hazards
• Environmental hazards may be biological, chemical, physical,
psychological, sociological, or site and location hazards.
83

I: Biological Hazards
• These are living organisms or their products that are harmful to humans
A. Water-borne diseases are diseases that are transmitted through drinking
water
• Examples are polio virus, hepatitis A virus, Salmonella, Shigella, cholera,
amoebic dysentery, Giardia, and Cryptosporidium.
• These disease organisms are shed into the water in feces, and can produce
illness in those who consume untreated, contaminated water
• Our municipal water treatment facilities are usually able to purify water by
removing these agents or killing them by disinfecting the water.
84

I: Biological Hazards…
B. Food borne Diseases
• are diseases transmitted in or on food
1. Examples of food-borne agents are the bacteria Salmonella, serotype
enteritidis, Escherichia coli 0157:H7, as well as other agents.
2. To protect against food-borne diseases, sanitarians from local health
departments routinely inspect food service establishments
(restaurants) and retail food outlets (supermarkets) to verify that food
is being stored and handled properly.
85

I: Biological Hazards…
C. Vector-borne diseases
• Vector borne diseases are those transmitted by insects or other arthropods
• Examples are St. Louis encephalitis and La Crosse encephalitis transmitted by
mosquitoes, and plague and murine typhus transmitted by fleas.
• Improper environmental management can cause vector-borne disease outbreaks.
86

Humans
Fetus and babies
Other humans
Water Air
Insects
Wild animals
Livestock
Pets Food
Ways infectious disease organisms can enter the human body
87

II: Chemical Hazards
• A toxic chemical is one that can cause temporary or permanent harm
or death to humans and animals.
• In 2004, the EPA listed arsenic, lead, mercury, vinyl chloride (used to
make PVC plastics), and polychlorinated biphenyls (PCBs) as the top five
toxic substances in terms of human and environmental health.
• There are three major types of potentially toxic agents.
• Carcinogens are chemicals, types of radiation, or certain viruses that can cause or
promote cancer.
• Mutagens are chemicals or forms of radiation that cause mutations, or changes,
in the DNA molecules found in cells, or that increase the frequency of such
changes.
• Teratogens are chemicals that cause harm or birth defects to a fetus or embryo.
88

II: Chemical Hazards
• Result from mismanagement or misuse of chemicals resulting in an
unacceptable risk to human health.
Pesticides
• that have been manufactured for the purpose of reducing populations of
undesirable organisms (pests)
• Examples of categories of pesticides are herbicides and insecticides.
• Most pesticides kill non-target organisms as well as the target, or pest species.
• The wise use of pesticides can protect human health and agricultural crops.
89

Environmental tobacco smoke (ETS)
• is an environmental hazard produced by millions that smoke
• Diseases associated with ETS include lung cancer and perhaps heart disease.
• ETS contains 4, 000 substances.
• The US EPA has classified ETS as a Class A carcinogen.
• Smoking has been increasingly restricted from public buildings and from many
private work sites,
• Ethiopia has also banned smoking cigarettes in public places, but not known
about its practicability.
• Regulation of smoking seems to be the best approach to controlling this
pollutant
II: Chemical Hazards---
90

Lead
• is a naturally occurring element that is used in the manufacturing of many
industrial and domestic products
• Health problems associated with the over exposure to lead are anemia, birth
defects, bone damage, neurological damage, kidney damage, and others.
• Exposure is by ingestion and inhalation.
• Children are particularly at risk from eating peeling lead paint.
• The prevalence of very high blood lead levels among young children declined
significantly between 1984 and 1994 primarily because the removal of lead from
gasoline.
• Occupational exposure is a major source of lead intake for adults.
II: Chemical Hazards---
91

III. Physical hazards
• A physical hazard is an agent, factor or circumstance that can cause harm
with or without contact.
• They can be classified as type of occupational hazard or environmental
hazard.
• Physical hazards include ergonomic hazards, radiation, heat and cold stress,
vibration hazards, and noise hazards
92

IV. Psychological hazards
• A psychological hazard is any hazard that affects the mental well-
being or mental health of the worker by overwhelming individual
coping mechanisms and impacting the worker's ability to work in a
healthy and safe manner.
• are environmental factors that produce psychological changes
expressed as stress, depression, hysteria.
93

V. Sociological hazards
• Are those that result from living in a society where one experiences
noise, lack of privacy and overcrowding.
• Population growth may be a sociological hazard
• When environmental resources can support no further growth, the
population has reached the equilibrium phase and the environment is
said to be at its carrying capacity
94

VI. Site and Location Hazards
• Natural disasters are geographical and meteorological events of such
magnitude and proximity to communities that they produce
significant damage and injuries.
• Examples are cyclones, earthquakes, floods, hurricanes, tornadoes,
typhoons, and volcanic eruptions.
• Biological, psychological and sociological hazards may increase
following a natural disaster.
95

Methods for monitoring and control of
environmental hazards
96

Introduction
• The monitoring and control of environmental hazards to health entails a
wide range of actions, each tailored to the particular hazard or form of
public health concern.
• Monitoring implies use of routine measurements to detect changes in
the environment or health, and can be based on data from a wide variety
of sources.
• The control of environmental hazards depends on defining acceptable
levels of exposure and hence health risk and determining the levels of
control needed to keep exposure below specified thresholds.
97

Bio-marker Substances (molecules) used as indicators of a biologic state – i.e. as an
indicator of normal or pathogenic processes or of biological response to
an external agent. Examples include: an antibody to indicate infection, a
DNA adduct to indicate modification of genetic material or a protein
that correlates with the risk or progression of disease.
Bio-monitoring
(human)
Monitoring in human beings, using biomarkers, that focus on
environmental exposures, diseases and/or disorders and genetic
susceptibility, activities and their potential relationships.
Disease cluster An unusual aggregation of health events that are grouped in space and
time.
HACCP Hazard Analysis and Critical Control Points – a systematic preventive
approach to food and pharmaceutical safety that addresses physical,
chemical, and biological hazards as a means of prevention rather than
finished product inspection.
Key definitions and terms
98

Monitoring The performance and analysis of routine measurements aimed at detecting
changes in the environment or health status of populations.
May also imply intervention as indicated by monitoring data.
Surveillance Ongoing scrutiny, generally using methods distinguished by their
practicability, uniformity, and frequently their rapidity, rather than by
complete accuracy.
Its main purpose is to detect changes in trend or distribution in order to
initiate investigative or control measures.
Key definitions and terms
99

Principles
Approaches to monitoring and control
• For any potential environmental hazard one of the main principles for
monitoring and control is to identify the critical agents, pathways and
populations at risk.
• Such considerations will guide the methods to be used for monitoring
and surveillance.
100

Monitoring data
Monitoring can use data from a range of sources, including:
• Emissions inventories (records of the permitted or actual level of
emissions from specified sources);
• Environmental data (measurements of the concentrations of
pollutants in the environment);
• Bio-monitoring data (measurements of specific agents or their
metabolic products in biological samples);
• Health data
⁻ Routine (surveillance) data;
⁻ Clinical surveillance (relevant to specific exposed populations);
101

Monitoring data…
Relevant health data might include:
oinfectious disease monitoring data;
ohealth care utilization data (hospital admissions, primary care
consultations);
obirths, congenital anomalies and related data;
ocancer registrations;
omortality statistics;
oepidemiological surveys.
102

Monitoring data…
• Epidemiological surveys are usually undertaken for research
purposes rather than as part of monitoring, but periodic surveys
may provide useful evidence about biological uptake and effects
(bio-markers from clinical specimens, indicator diseases states).
103

Monitoring data…
• In general, the control of environmental hazards depends on:
1. defining acceptable levels of exposure and hence health risk
2. determining the levels of control needed to keep exposure below
the specified thresholds.
• Such assessment usually takes account of toxicological and
epidemiological evidence, and evidence on exposure pathways,
environmental persistence, bio-accumulation etc.
104

Control measures
A range of methods of control may be applied, including:
• Licensing / banning specific substances (e.g. CFCs);
• Setting of emissions controls (e.g. vehicles exhausts, industrial emissions);
• Enforcement of concentrations or exposure limits for specific target groups (e.g.
radiation workers);
• Enforcement of health and safety protection (e.g. for workers handling
biological agents).
• Setting of guidelines/standards relating to environmental levels (e.g. air
pollution monitoring)
105

Control of specific environmental hazards-Water and food
• Quality standards are set for the physical, chemical and biological
characteristics of drinking water and monitored throughout the water
treatment and distribution network through to the household
tap.
106

Control of specific environmental hazards-Water and food
• Biological and chemical testing is also carried out in the food
industry, with water safety,
• the approach is typically based on the principles of the Hazard
Analysis and Critical Control Points (HACCP), which seeks to identify
potential hazard points, so that key actions, known as Critical
Control Points (CCP's) can be taken to reduce or eliminate the risk of
the hazards being realized.
• The system is used at all stages of food production and preparation
processes including packaging, distribution, etc.
107

Control of specific environmental hazards-Air pollution
• periodically to review and assess the current, and likely future, air
quality against national air quality objectives.
108

Control of specific environmental hazards-Noise
• Noise is a complex exposure, as its effects on health and
well-being are function of multiple parameters, including:
• its intensity, its duration, its intermittency, its nature and quality,
and its origin.
109

Ionizing and electro-magnetic radiation
• Monitoring and protection against radiation risks covers a number
of important areas:
• Radon monitoring of households in high radon areas
• Workers in the nuclear industry, or in other fields where there is
exposure to ionizing radiation (e.g. medical imaging), are required
to wear radiation badges to monitor personal exposure.
110

Principles of hazard management
• Establish the context and identify the hazard: These are the first steps.
• You should identify the type of the hazard in as much detail as you can.
• You should also describe the exposure conditions and try to answer the
following questions:
• What is the source of the hazard?
• Who is exposed?
• What are the pathways or activities that expose a person?
• What part of the environment is involved in the transfer of the hazard to humans?
111

Principles of hazard management…
• Hazard/risk analysis and evaluation: analyse the risk and evaluate
the potential of the hazard to cause damage to health. The
evaluation may require appropriate design, sampling and laboratory
investigation.
• Communicate and consult: When the hazards and risks have been
determined, advice can be communicated on the interventions or
control measures that are needed to control the hazard. There can
also be consultations with relevant people and organizations.
112

• Treat the hazard/risk: The interventions or control measures are
carried out by the person or people responsible for the hazard or risk.
• Monitoring and reviewing: The implementation of interventions or
control measures for the hazard must be followed up in order to
determine whether they are successful. Correction measures can be
applied if there is any failure. Identifying appropriate indicators for
monitoring is critical and must be done formally.
113

• Record keeping: Keeping records and reports on hazard management
is always important. These records must contain the type of hazard,
exposures and what control measures were taken.
114

Figure. The hazard management process.
115

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