Chapter 13

Environment and health / Ecohealthissues, and think, together with teachers, about what can be done to maintain and improve the health andquality of people’s lives in Cambodia as well as other countries.
What makes it important to address environmental health? According to WHO estimates, anunhealthy or unsanitary environment was responsible for as much as 23% of total global mortality or
12.6 million deaths worldwide, and for 26% of deaths in children younger than 5 years in 2012, whichindicates that the environment has a large impact on human health.2 Of the environmental factors,

Learning objectives

environmental pollution is the largest environmental cause of diseases and premature deaths. Diseases

You will be able to gain proper understanding and explain:caused by environmental pollution were responsible for an estimated 9 million premature deaths or 16%- What makes environment important for health of humans and survival of life.

of all deaths worldwide in 2015; this is estimated to be three times more deaths than from AIDS,- What effects each has on the health and lives of humans with several examples each of physical,

tuberculosis, and malaria combined, and 15 times more than from all wars and other forms of violence.2

chemical, biological, and cultural/psychosocial environments.
- The relationship between an environmental factor and human health based on its dose-response
relationship.

It is evident that polluted environments significantly affect human health.
Among the different forms of environmental pollution, those of particular concern are outdoor andindoor air pollution, water pollution, soil and food contamination by pesticides and other chemicals,- Through group work, and giving presentations, what impacts Cambodia’s social and economic

and toxic/hazardous occupational exposure. It should be noted that, compared to high-income

development has on the health of ecosystems, people’s lives and main occupations (livelihood),

countries, pollutants cause greater harm to the environment and human health in low- and middle-

and human health.

income countries, particularly pregnant women, fetuses, and infants, poor and minority populations, andresidents of rural areas who make a living from agriculture and fisheries.2 As a result of globalization,

This chapter will discuss the effects environment has on human health, focusing on each of the following:

foreign capital seeking to secure food is making inroads into the agricultural and fishery industries ofcategories of environmental factors as health risks; health effects of environmental pollution; thelow- and middle-income countries, causing pollution of soil and waterways/groundwater through coastal

relationship between exposure levels and biological reaction; and environmental health issues ofdevelopment, deforestation, and use of pesticides/insecticides. In recent years, many countries are

Cambodia addressed using an ecological health approach (loss of mangroves, deforestation and declining

experiencing a concentration of population in cities, bringing global attention to the deterioration of

biodiversity, soil degradation, water pollution, vulnerability to climate change and natural disasters,

urban environments such as vehicular exhaust and greenhouse gas emissions, domestic sewage pollution

landmines and unexploded ordnance, and deteriorating urban environment).

of rivers, and treatment of large quantities of waste. Cambodia is no exception. Though different
countries and regions may face different pollutants, environmental pollution presents a major risk to the

1. Importance of environmental healthhealth of humans.
In low- and middle-income countries, including Cambodia, however, environmental monitoring
systems are not well established yet, and few data are available on environmental pollution and otherFirst, we will look at what environmental health is and why it is important for human health. There areenvironmental issues. Building a system to gather and analyze environmental data is an undertaking thatdifferent definitions of “environmental health;” according to WHO:1

is necessary to promote effective environmental health measures. In the context of school health,providing environmental health education and Ecohealth education is a key to ensure understanding“Environmental health comprises those aspects of human health, including quality of life, that areof the relationship between environment and ecosystems, human health, and social development.

determined by physical, chemical, biological, social, and psychosocial factors in the environment. It also
refers to the theory and practices of assessing, correcting, controlling, and preventing those factors in theenvironment that can potentially affect the health of present and future generations adversely.”

2. What is an environment?

Human health and quality of life are determined by physical, chemical, social, and psychosocial

What does environment refer to, exactly? Living organisms are surrounded by many different conditions,factors that are present in the environment. The prevention of illnesses and disabilities, therefore, calls

objects, or circumstances of the external world, which are what constitutes the environment.3 For thefor theories and practices to assess, correct, and control these environmental factors.

purpose of this chapter, “environment” refers to that for humans, namely the conditions, objects,

This means that, in the context of school health, environmental health provides educationalorganisms, and circumstances of the external world that surround humans. While the external world that

opportunities for children to gain a deeper understanding about the environment, learn about risk factors

surrounds humankind is a limitless expanse, like outer space, we primarily discuss the biosphere (i.e.,in the environment that cause human illnesses and disabilities and about present-day environmental

the life-supporting parts that extend around the Earth including the layers on and under the ground, the244

Chapter 13

Environment and health / Ecohealth245

atmosphere, and the hydrosphere; a sum of ecosystems where living and non-living things interact), andlimit our discussion at most to the extent to which humankind has thus far reached into outer space. That

Column: Environmental pollution of methylmercury and the health of people

being said, we may need to take certain other things into consideration, such as the sun and meteorites;

Minamata disease describes the poisoning from methylmercury compounds that affected thehumankind has not reached the sun, and yet it has tremendous influence over the Earth, while a meteorite

Minamata area along the coast of the Yatsushiro Sea in Kumamoto Prefecture, Japan. The cause of

can cause major climate or environmental change or disasters if it hits the Earth, which makes meteorites

the environmental pollution was the release into the sea of methylmercury compounds, a by-productsomething that we may not be able to ignore for their influence over our environment and health.

that occurs during the production of acetaldehyde, in the industrial wastewater from a factory owned

Of the biosphere that is the Earth’s environment, environments and ecosystems relevant to theby the Japan Nitrogenous Fertilizer Company. The methylmercury compounds polluted thequality of life and well-being of human will be discussed in this chapter (see Chapter 1 for a definition ofenvironment of the Yatsushiro Sea, where fish and shellfish consumed the methylmercury compounds

health).

and passed them along the food chain in the ecosystem. This led to bioaccumulation of thepollutant, bringing about central nervous system disorders among humans and cats that ate polluted

3. Human survival and the Earth’s environment

fish and shellfish due to mercury poisoning (see the Dose-Response Relationship section in thischapter to learn more about these symptoms).
The first patient identified was a young child who, in April 1956, exhibited severe symptoms,

Now, why is the Earth’s environment important for us? As we all know, it is because it is the environment

including difficulty speaking, walking, or eating. It was not until twelve years later in 1968 that thethat possesses all the conditions that have made it possible for life (including humans) to begin, evolve,

national government finally officially recognized Minamata disease as a pollution disease. During thisand prosper as humankind does today. These conditions, for instance, include at the very least: thetwelve-year period, the nation experienced a plethora of social issues: various different theories andatmosphere; water; food; stable climates; protective layers that shield against harmful cosmic rays andmisunderstandings concerning the cause of the disease; counterarguments made by the company;

radiation; biological diversity; and adequate supply of thermal energy from the sun. These are theprejudice, discrimination, and stigma against the patients and the local communities; lawsuits overconditions that are indispensable for life activities of organisms, which means that if these conditions ofpatient certification; medical researchers making judgments in favor of the government and thethe Earth’s environment are disrupted, it poses a threat to the health, or even the survival, of humans.

company, and so on. It surfaced only recently that people inland had also suffered central nervous

One grave issue that have faced in recent years is the fact that human activities can cause environmental

system disorders due to mercury poisoning after eating fish and shellfish from Minamata Bay, yet

destruction, which threatens human health and survival. In particular, it is our short-sighted activities inheld back from seeking patient recognition for fear of discrimination, and that such inland sufferers

pursuing immediate economic interest and social utility. In fact, it has been pointed out that some ancient

had not received relief as the government would only certify coastal residents as Minamata diseasecivilizations collapsed as a result of serious environmental issues. One example is Easter Island, known

patients. More than 60 years on, Minamata disease is still an issue.

for its giant stone statues. It has been established that the civilization on the island collapsed because its

Environmental pollution of mercury has raised concerns not only in Japan but in many countries.

inhabitants harvested its scarce forest resources to build roads to transport the stone statues to various

For instance, pollution of metallic mercury used for the refining of gold has been detected in theritual platforms across the island, which resulted in soil sliding and erosion, making it impossible to

Brazilian Amazon basin, the Philippines, Tanzania, and Indonesia. In Cambodia, too, mercury was

4produce enough food to sustain its population. Japan, in its effort to bounce back from its defeat infound at high concentrations in the hair of people who were living in fishery villages and who

World War II, pursued a ten-year plan to double its national income starting in 1961 and promoted rapid

consumed large quantities of fish and shellfish, or those who were sorting waste at landfill sites.6

industrialization, ultimately achieving spectacular economic growth. Behind these accomplishments,

Increasing environmental pollution and resulting health hazards caused by mercury are of great

however, the nation suffered a tragedy; hazardous substances spewed from factories and polluted theconcern in Cambodia.

environments and ecosystems, which destroyed the health of people in the communities, as represented
by what are known as the four big pollution diseases of Japan, namely Minamata disease, Yokkaichi
asthma, Itai-itai disease, and Niigata Minamata disease.5
What conditions, circumstances, or substances that are present in environments affect human health,including our quality of life and well-being? And what human or social behaviors cause what forms of

4. Health and environment1) Host-environment interaction

ecosystem degradation and again affect human health, including our quality of life and well-being? Weneed to learn about these issues and consider what we can do to achieve ecological health, where

Broadly speaking, there are two ways to understand the relationship between our health and theenvironments/ecosystems are in harmony with human and social behaviors and human health (seeenvironment. One is to find out what kinds of health issues and diseases occur as a result of exposure to

Chapter 1 to learn more about ecological health approaches).

the conditions, objects, or circumstances in the environment. The purpose is to identify hazardous
substances or conditions in the environment and eliminate or improve them in order to secure health and246

Chapter 13

Environment and health / Ecohealth247

safety. This is an important and fundamental approach in environmental health and hygiene for thetheir work site had COVID-19, they would have a higher likelihood of catching the virus, which is a

purpose of protecting the safety and health of workers, especially in work settings where workers arebiological environmental factor, as a close contact. Furthermore, at their workplace they may be

exposed to substances and environmental conditions that are different from those they are faced with ininfluenced by cultural/psychosocial environmental factors, including working conditions (such as long

their everyday lives. This approach concerns the relationship between environmental exposure andworking hours, working at high places, and uncertain employment contacts), stress from work

human health.

relationships, and social norms of the employee population. Such diverse working environments are

For instance, the WHO Regional Office for the Western Pacific (where Cambodia is one of the nonPacific Islands Countries and Areas) regarded unsafe water, poor sanitation, air pollution, hazardous
chemicals and poisons, occupational hazards, and extreme weather as being examples of environmental
determinants of health.7
With this approach, the relationship between humans and the environment may be understood as
Biological environment

Cultural/psychosocial environment

environments, such as physical, chemical, biological, and cultural/psychosocial environments (Table

constitution as its internal environment, namely a human (i.e., host), comes in contact, through their

y (h

beh

ost/huma vio rs (l

a

ife

st

Physical/chemical environment

lifestyle behaviors, with environments (physical/chemical, biological, and/or cultural/psychosocial) of
by the results of such interactions.

yle

e

st

lifestyle activities and environment, in which an entity that has certain genetic characteristics andthe external world, and as the two influence each other, the health condition of the human is determined

tit

En

Lif

such (Figure 13.1). Figure 13.1 shows a model that illustrates the relationship between humans and their)

they form the environment in combination and exert influence over the health and lives of humans ases13.1). In the real world, these environmental factors do not exist independently from one another; rather,

n)

Gene/
constitution
Internal
environmentylhost-environment interaction, with environmental factors organized according to a category of the

Figure 13.1 Model for the relationship between humans and their lifestyle behaviors andenvironment

Take a working environment at a building construction site as an example. A worker who has certain
genetic characteristics, constitution, and lifestyle would be exposed to physical factors such as vibrations,noise, high temperatures, ultraviolet light, and dust from building construction work. They may also be
exposed to chemical factors such as organic solvents used for painting and adhesion, and if they smoked
during a break, they would inhale various chemicals contained in the cigarettes, as well. If someone at

Category of environment

PhysicalVibrations, noise, electromagnetic waves, high temperatures, lowtemperatures, high voltage, humidity, radiation, ultraviolet, airborne
particulate matter

ChemicalDioxins, asbestos, organic solvents, mercury, lead, arsenic, pesticides/
insecticides, food additives, pharmaceuticals, cosmetics, cigarettes andalcohols, illicit drugs, and other synthetic chemicals

Biological

Pathogenic microorganisms and parasites such as Escherichia coli O157,
SARS, HIV (AIDS), and SARS-CoV-2, venomous snakes, wild animals,
hygiene pests, mosquitos, plants

Cultural/psychosocial

Social systems and social organizations, political regimes, social norms,
legal systems, values, discrimination/stigma, human relationships(including violence/abuse and bullying), overcrowding, family/kinships,
religions, working conditions, financial situation, science and technology,
academia, art

Gene/Constitution
Internal environment
Hostaviors (L
ife
beh
le

248

Life
st
y

Examples of environmental factors

Cultural/psychosocial
environment

)
yle
st

Table 13.1 Categories of environment and examples of environmental factors as health risks

Biologicalenvironment

Physical/chemical
environment

Figure 13.2 Human-environment relationships. A case of construction workers
Chapter 13

Environment and health / Ecohealth249

believed to interact with a worker’s biological and psychosocial characteristics, defining the health of

poisoning, such as impairment of sensory functions, including seeing, hearing, smelling, tasting, andthe worker (Figure 13.2).

touching, and impaired ability to control the movements of limbs. In a case of a chemical used as a

In a school environment, children’s physical, mental, and social health is influenced by physicaltreatment, ED50 (effective dose 50) is used instead as an indicator of its efficacy, referring to the dose

environment (e.g., light, sound, electricity, and temperature), chemical environment (water, air, andthat produces a therapeutic effect in half of the population. In either case, the dose-response relationshipdisinfectants), and biological environment (bacteria, viruses, and animals), which are explained insuch as the one illustrated in Figure 13.3 is used to evaluate levels of harm, therapeutic effect, and safety.

Chapter 4 in the discussion of school environmental health, as well as cultural/psychosocial environment,
including children’s relationships among themselves and with teachers, and classroom culture, which
may involve issues such as bullying.

Column: Environmental risk factors in low-middle income countries

In the category of cultural/psychosocial environment, psychosocial stress has become an important

The disability-adjusted life year (DALY) is a summary measure of the overall impact of disease on

issue as a factor that damages health. The health effects of life stress that people experience in their

the health of a human population. This measure is used to assess the impact of a disease on

working, family, or school environment are addressed in Chapter 12 in the discussion of mental health.

humans in a population level, based on the number of years of life lost due to premature mortality
caused by the disease and the number of lost years of healthy life due to disabilities caused by thedisease. The number of years “lost” used to be calculated using the life expectancy (i.e., the average2) Dose-response relationshipnumber of additional years that a person of a given age is expected to live) of the Japanese as thestandard, as Japan has historically had the longest life expectancy in the world. Recently, however,

One of the ways to determine what kinds of health issues or diseases humans may develop as a result ofdifferent approaches have sometimes been taken, such as the use of national life tables for individual

exposure to a condition, object, or circumstance in the environment is to analyze its dose-response

countries.

relationship (Figure 13.3) and show the related levels of harm and margin of safety. These provide abasis for establishing environmental safety standards or permitted levels for it.
This is a method to assess what kinds of health effects may result from what amount of exposure toa physical factor in the environment, such as radiation, or by taking in what amount of a chemical factor,

Note that one DALY represents one year of healthy life lost in life expectancy because of adisease. A higher DALY value indicates a greater burden posed on human health and life by theparticular disease or health risk.
Using DALYs as a measure, the Global Burden of Disease Study 2019 estimated the 20 leadingrisk factors for countries grouped according to the levels of their social and economic development.8

such as organic mercury.

Percentage of individuals responding

Thanks to its recent economic progress, Cambodia was now included in the group of low-middleincome countries.

100%

For the group of these development levels, the leading environmental risk factors to health forfemales were8:
Household air pollution (5th);50%

Ambient particulate matter (7th);
TD50 (toxic dose 50; dose that produces
toxic reactions in half of population) or ED50
(effective dose 50; dose that produces
effects of medication in half of population)

Unsafe water (8th);
Unsafe sanitation (14th); andHandwashing (17th).
For males:
Ambient particulate matter (6th);0%
Dose of hazardous or therapeutic

Figure 13.3 Sample dose-response curveHousehold air pollution (8th);
Unsafe water (12th);
Unsafe sanitation (14th);
Occupational injury (16th); andFigure 13.3 illustrates how this may look using TD50 (toxic dose 50). Take methylmercury poisoning

as an example. It is a form of health hazard caused by mercury contamination of the environment/
ecosystem that is represented not only by Japan’s Minamata disease but seen widely across the globe. Its

Handwashing (18th).
These data show that environmental pollution represents a significant health risk and that males,in particular, are exposed to occupational risk factors.

TD50 refers to the dose at which half of the population exhibit the symptoms of methylmercury
250

Chapter 13

Environment and health / Ecohealth2515. Ecosystem health and human healthAs an approach to understand the relationship between health and the environment, we discussed theapproach of looking at exposure to environmental factors and human health in the previous section.

have been seen in the Philippines, Mexico,11 and Ecuador.12

1) What is an ecosystem? What is an ecological health approach?

Another approach is that of environmental health, focusing on impacts of economic development on
ecosystems based on the development-ecosystem-life or main occupation (livelihood)-healthAn ecosystem is a concept of seeing all the organisms that live within a certain area, together with therelationships. To help understand the social and economic development-ecosystem-life and main

abiotic environment, as one cohesive system, focusing on energy flows, food chains, and geochemical

occupation (livelihood)-health relationships, we use examples of banana plantations in the column

cycles (cycles of earth materials). Multiple layers of micro-ecosystems form one large ecosystem that is

below.

the Earth.
In the case of humans, for instance, ecosystems exist at multiple levels, from individual to family,
neighborhood, school, and workplace, municipality, county, and province, nation, and the world; acrossColumn: Truth behind banana plantations

these levels are cycles or flows of energy, materials, information, cultures, politics, and economy. In

It is believed that over a thousand kinds of bananas of different colors, shapes, and sizes areother words, all these levels, from individual to global, are linked together and influence one anotherproduced and consumed around the world. However, the Cavendish type makes up 47% of global

through such cycles and flows.

production and 99% of exports. Cavendish bananas are all genetically identical clones, andApplying the concept of ecosystems to human health is known as the ecological health approach.

overdependence on a single cultivar, or monoculture, poses the risk of disease spreading globally

According to these approaches, the health and healthy behaviors of humans are influenced by factors at

and causing tremendous damage to crops.9

various different ecological levels, while the behaviors and lives of humans exert influence over andWhile it is difficult to cite exact statistics on annual banana production, records show it was 114

bring about changes to ecosystems at various different levels. This means that the health and healthy

million tonnes in 2017. The world’s largest producer of bananas is India (29 million tonnes produced

behaviors of children who live in a given area of Cambodia are influenced by, and have influence over,annually), followed by China (11 million tonnes) and the Philippines (7.5 million tonnes), with Ecuador

ecosystems at different levels on a global scale, albeit to varying degrees.

and Brazil tying for 4th place (7 million tonnes). A majority of bananas produced in India and China

When it comes to defining different levels of ecosystems, an article titled Adolescent health in theare for domestic consumption with very little left for export; Ecuador, the Philippines, Costa Rica,

21st century, for instance, suggests the following levels (from smaller to larger): individual adolescents;

Colombia, and Guatemala are the large exporters. India and China have seen expansions in domestic

school/friends; family; neighborhood; and macro-level society.13 The US Centers for Disease Control

demand as a result of population growth, and between 2000 and 2015, they had an increase in

and Prevention (CDC), meanwhile, as a framework for the prevention of violence, presents a social-

9

ecological model, which comprises the following levels: individual; relationship; community (schools,

production by 48% and 83%, respectively.

Issues that surround banana plantations include the use of large quantities of chemicals, including

workplaces, and neighborhoods), and societal (i.e., a larger society that forms norms and cultures

pesticides, insecticides, and chemical fertilizers, to prevent diseases in banana crops and increase

concerning violence, or a society that has common politics, social policies, economy, and educational

productivity, which can create soil and water pollution, exposing workers and residents tosystems in it), which surround the lower levels.14

environmental pollution. In addition, the development of plantations may result in deforestation orland acquisition or leasing, which causes farmers to lose their land.
In Laos, for instance, many Chinese companies began arriving around 2010 and started operatingbanana plantations in the mountainous northern parts of the country, such as the provinces ofUsing an ecological health approach, we can rearrange the health risk factors in the environment thatare shown in Table 13.1; they exist in each level of an ecosystem, and they influence one another withina given level as well as across different levels, determining the health, healthy behaviors, and lives ofindividuals.

Oudomxay and Luang Namtha. Bananas produced there were all for export to China. While thesebanana plantations generated jobs and income for the poor areas, they also brought about pollutionof the local ecosystems and health hazards. Pollution of nearby rivers also killed large quantities offood fish, causing fisherfolk to lose work.10

A system is a dynamic and complex whole, within which different elements influence one another.

In the summer of 2016, flooding led to massive spills of chemicals, polluting the ecosystems andAn ecosystem is a typical system where cycles or flows of energy, information, and materials occur

environment of the region, and affecting the lives and health of the residents. This forced the Laoamong various elements that constitute the ecosystem. Systems thinking that is based on an

10

government to issue a ban on Chinese-owned banana plantations.

252

Column: Ecohealth and systems thinking

ecological health approach is a concept that holds that, in an ecosystem which comprises multiple

Similar cases of soil and waterways/groundwater pollution and health hazards to residents

levels, different elements influence one another within or across levels, thereby defining the health ofcaused by large-scale pesticide spraying and extensive use of insecticides and chemical fertilizers

the ecosystem and that of humans. In cases of health issues such as dizziness, headaches, andChapter 13

Environment and health / Ecohealth253

diarrhea among residents living near a banana plantation, for instance, issues of ecosystems andeconomic growth and social development, and they arise in a complex, interconnected manner. If suchthose of human health may be rising out of a complex web of elements influencing one another,

an impact exceeds ecosystem resilience, even if economic growth and social development bringincluding: the decisions made by the local authority to accept the company; standard of living, state

economic wealth to people’s lives in the short term, ecosystem degradation will produce health hazards,of employment, and land use in the area; background factors for the company’s entry into the area;

which ultimately makes any such growth or development not worthwhile in the long term for people

operating policy and safety and health measures at the plantation; amounts of fertilizers andwho live in the ecosystem. In other words, we cannot call it sustainable development.

pesticides/insecticides used for banana plants and their levels of harm; geographical conditions of
the rivers as sources of water; ways of life and main occupations of local residents; and levels of(1) Coastal development and loss of mangrovesfinancial hardships of the residents. Ecohealth employs systems thinking to analyze and map such

Mangroves are communities of plants that grow in intertidal zones (i.e., brackish water where freshwater

relationship, clear up complex issues, and find solutions.

and seawater mix, primarily in coastal areas or estuaries) in the tropics and subtropics. In addition toabsorbing CO2, mangroves help protect fishing grounds and biological diversity, and mitigate damage
from cyclones and high tides. Cambodia’s coastline (443 km), which makes up 14.7% of the country’s2) Economic growth and social development in Cambodia

borders, is on the Gulf of Thailand. A large portion of the coastline is found in the province of Koh Kong,which used to be the country’s largest home to mangroves, accounting for 75% of all mangroves in

Cambodia is one of the more natural resource-rich countries in Southeast Asia, with resources including

Cambodia in 1992. However, illegal logging of mangroves by local inhabitants for the purpose of

farmland, water/fishery/forest resources, minerals, oil, and natural gas. Putting these resources to good

charcoal production destroyed the mangrove forests over a vast area. Over the course of around 30 years

use promotes economic progress; in fact, the country has achieved steady economic growth over the past

between 1973 and 2002, 40% of the mangrove areas were lost. Although reforestation efforts through20 years at an annual rate of 7.6%. Further economic progress may potentially reduce poverty.15

replanting of mangroves have been made since 2000, the loss of mangroves has not been curbed, with

Cambodia is a country of great opportunities.

as much as 45% of the mangroves lost by 2016/2017 compared to 1973.

What we need to take into consideration here is that a prerequisite for economic progress based on

Shrimp farms, which were introduced in 1989 and started expanding in 1991, also stimulated

natural resources is social development. Depending on the kind of development that is carried out, it canmangrove deforestation. Shrimp farming is practiced in four provinces, namely Kampot, Kep, Preah

produce impacts not only on economic progress but also on the environment and ecosystems where theSihanouk Ville, and Koh Kong, where large ponds were created close to or within mangrove forests.17

resources exist. It is therefore important to continuously monitor any impacts on the natural environment

For that purpose, large swaths of mangrove forests were cut down. In Cambodia, the rapid destructionand ecosystems produced by development that is made for the sake of economic progress, because someof mangrove forests has caused soil and water degradation, adversely affecting the lives of residentsof these impacts may have negative effects on the lives and health of people (see Column: Truth behindliving on coastal fishing (i.e., livelihood). Furthermore, organic matter and chemicals, phytoplankton,

banana plantations). In addition, whether or not economic progress leads to a reduction in poverty also

and bacteria that are present in the effluent from shrimp farms may potentially degrade the ecosystems

depends on social systems, such as redistribution of wealth and social security, as well as the national

along the coast.17 If these issues cause the yields of fish to decrease and lead to declines in fisheries, it

political system that is in place. Poor people and rural and remote areas where poverty rates are high andmay result in food problems for Cambodia.15,17

building an economic base is challenging are also the people and areas that are more vulnerable to issues
related to natural environment and ecosystems.

In addition, there are concerns that large-scale port development projects, offshore oil and natural
gas drilling, and other development projects by the hotel business and tourism may also lead to mangrove
deforestation.15(2) Deforestation

3) Environmental issues in Cambodia

Forests provide people with a place to preserve their traditional culture and gather food and fuelwood.
What kinds of environmental issues face Cambodia today? We will address this by referring to two
15

In the context of the environment, forests help regulate climate at local levels, filtrate water, retain water

reports, one by the University of Gothenburg in Sweden, and the other by the Ministry of Environment

to control river volumes, or prevent floods or mudslide disasters.16,18 Degradation of such forests is one

of Cambodia, titled Cambodia Environment Outlook.16

of the environmental issues facing Cambodia.

The primary environmental issues in Cambodia identified by the two reports include: loss of

The percentage of Cambodia’s total land area covered by forest (forest area) was 75% in the latemangroves; deforestation and declining biodiversity; soil degradation; water pollution;

1960s, but it declined to 60% in 1993, 59% in 2006, and was down to 47% in 2018. It has been pointed

vulnerability to natural disasters (floods, droughts, and windstorms); climate change; land minesout that this rate of reduction in forest area in Cambodia is considered to be greater than those in its

and other unexploded ordnance; waste pollution; and deteriorating urban environment.

15,16

These

issues represent impacts on the ecosystems that are produced in ways that are connected to Cambodia’s
254neighboring countries or international standards.16
Causes for deforestation include rubber tree plantations and logging for timber or charcoal
Chapter 13

Environment and health / Ecohealth255

production.18 They also include constructing roads or securing land for residential use to accommodate

damage and health hazards. Mudslides caused by soil degradation/erosion can deprive people of theiran increasing population. Illegal logging is thought to account for 90% of deforestation, attributable tohouses or farmland, which may force them to relocate.15

the lack of a forest management system, absence of rules and laws on land ownership, and the corruption
15,16,18

In addition, if global warming brings about sea-level rises and mangrove forests are no longer inbrackish water, it may also affect the ecosystems in the coastal areas.15

that surrounds logging.

Health effects of concern produced by climate change or extreme weather events that are not natural(3) Soil degradation

disasters include vector-borne diseases (e.g., malaria, dengue fever), food security (malnutrition,

Cambodian soil tends to be of low fertility, and land productivity is low. According to 2001 statistics,

famine), water-borne infection, food poisoning, rodent-borne infection, and non-communicableagriculture accounts for only 21% of the total land area.16 To make matters worse, deforestation promotes

diseases.21

soil erosion, while excessive use of pesticides to increase crop yields creates pollution of soil, water, andcrops. These forms of pollution can ultimately threaten the safety of food and the health of humans.
Agricultural practice that involves excessive use of pesticides is not sustainable.

Column: Community-based tourism and ecotourism

The annual sum of pesticides imported to Cambodia was around 37,500 metric tonnes in 2019. It

Tourism is a growing industry globally. In 2014, it generated revenues of US$7.6 trillion, which

was approximately 3,300 metric tonnes for Laos, one of its neighbors; this means that, while theiraccounts for 10% of global GDP, and 277 million jobs. In the past, however, tours would be organizedpopulations and land areas differ widely, Cambodia is importing, and presumably using, approximatelyby travel agents both small and large, and such companies would take most of the profits, leaving

ten times more pesticides than Laos. The sum was approximately 48,000 metric tonnes for Myanmar,

very little to local communities. Tourism has also been responsible for environmental issues. As an

19alternative to such traditional tours, various types of community-based tourism (CBT) recently

while it was approximately 199,000 metric tonnes for Vietnam, which makes it a large importer.

emerged in many countries, including Cambodia. With CBT, tours are organized and operated by(4) Water pollution and water shortages

members of the community. This makes their tours more aligned to the preservation of the local

Cambodia is generally considered a water-rich country. However, around 3.4 million people, many of

natural environment, society, and culture, while profits are given back to the community, which helps

whom live in rural areas, lack access to safe water, and 5 million people have no access to improved

raise the standard of living of community members and empower the community. Compared towater (see Column: Drinking water situation in Cambodia in Chapter 4). In five of thirteen provinces,conventional styles of travel, CBT may also minimize damage to the local environment, society, andnaturally occurring arsenic has been detected in 9% of the groundwater sources at levels above the WHO

culture.

15

standards, which makes the water hazardous for drinking. Furthermore, pesticides, when used in large

Community-based ecotourism that utilizes Cambodia’s nature as an environmental resource

volumes as mentioned earlier, are released not only into soil but into groundwater and rivers as well,

may help improve the well-being and economic life of people while protecting the society and culture

polluting the water sources. Securing safe water in sufficient quantities is a challenge for Cambodia.

of the community as well as the well-being of ecosystems. People of the local community can earn

Meanwhile, the construction of impounding dams upstream in the Mekong River may have impacts

income, which allows them to live in a manner that helps protect forest resources and valuable

on the flood pulse, fish resources and fisheries, agriculture, and downstream water supply. So far, theecosystems such as mangrove forests. Tourists, meanwhile, can experience the true Cambodian

15

nature, society, and culture. Hopes are high that community-based ecotourism will grow into a new

impacts of industrial effluents on water quality have been small, owing to slow industrial development.

(5) Climate change and natural disasters
Cambodia is not yet highly industrialized and therefore has very low emissions of CO2 and otherstyle of tourism that is in keeping with the philosophy of Ecohealth, which promotes a harmonious
balance among development, ecosystem health, life, the main occupations of people, and theirhealth.

greenhouse gases, which are contributing factors to climate change, with a per capita CO2 emission of
0.97 metric tonnes in 2019,20 compared to 4.14 metric tonnes for Thailand, 4.58 metric tonnes for Laos,
0.49 metric ton for Myanmar, and 2.57 metric tonnes for Vietnam.

(6) Land mines and unexploded ordnance (UXO) (Figure 13.4)

The country has been less affected by climate change so far. Potential future increase in volume and

It is estimated that there are 100 million mines buriel in the ground globally. As a result of the Vietnam

frequency of rainfall and intensity of windstorm as a result of climate change, however, may lead to

War followed by a civil war that went on for around 20 years, Cambodia may have four to six million

unseasonal floods, which, combined with soil degradation/erosion due to deforestation, may produce

mines and over 2.4 million pieces of unexploded ordnance (UXO),22 leaving 40% of arable land

mudslide disasters. Such events may well produce extensive damage, given Cambodia is not highly

inaccessible (see Column: Measures related to land mines in Cambodia in Chapter 14).

resilient to natural disasters. Flooding itself has served to make the soil more fertile and produce benefits,

Between 1979 and 2015, land mines and UXO caused approximately 65,000 casualties. The number

and people have adjusted to dealing with seasonal flooding over the ages. Floods that come at unexpected

has been on the decline; according to the Cambodian Mine Action and Victim Assistance Authority,

times of the year due to climate change are difficult to respond to, however, potentially causing flood

Cambodia recorded 111 casualties (18 killed; 93 injured) of mines and UXO in 2015. According to the256

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Environment and health / Ecohealth257

(7) Urban environment and health issues
As a result of population growth, many countries are seeing a migration of population from rural tourban areas, which is creating a concentration of people in cities, thus giving rise to various environmental
and health issues that are unique to cities.
In Cambodia, population was growing at an annual rate of 2.2% up until 1970, when it reached 6.8
million. It then saw a sharp drop due to genocide under the Khmer Rouge. The population then recovered
to its pre-genocide levels, and from 2010 onward, it grew at a rate of around 1.5% to reach 16.25 million
in 2019. People in rural areas would depend on the use of natural resources in the environment for their
Photos provided by NGO JMAS (Japan Mine Action Service)

Figure 13.4 Mines and unexploded ordnance (UXO) in Cambodia

livelihood; as a result of resource decline, however, there arose a trend of migration to urban areas tosearch for employment.15,16 According to estimates in World Urbanization Prospects,26 the rate ofurbanization (i.e., percentage of people living in urban areas) in Cambodia was 22.0% in 2020,
compared to 78% of the population living in rural areas. The rate is estimated to reach only 36% byrecorded cumulative total of casualties, 30% were killed, 56% were injured, and 14% had legs amputated.

2050. For reference, the 2020 estimate was 36% and 31% for Laos and Myanmar, respectively. Japan’sCasualties are unevenly distributed across the country, with Battambang being most heavily affected,

rate of urbanization is approximately 92%.

23

followed by Bantey, Meanchey, and Siem Reap.

While the advancement of urbanization is slow in Cambodia as a whole, Phnom Penh does have

The effects of land mines and UXO span a broad range, from local economic activities such as

some concentration, with a population of 2.13 million (2019), which accounts for 14% of the overall

agriculture and tourism to people’s everyday lives, access to medical treatment, mental and physicalpopulation of the country. This is even higher than the proportion of Japan’s national population living

health, and burden on families caring for victims. Specifically, mine injuries leave the victims and theirin metropolitan Tokyo (9%). The urbanization of Phnom Penh brings about levels of concentration offamilies emotionally traumatized, negatively affecting their mental health; people who live in the area

population that are comparable to those of capitals in European and North American countries. Phnom

cannot feel safe; and mines and UXO restrict access to land that may be used for food production

Penh’s social infrastructure, however, is said to be not adequate to accommodate such a large population.

through farming or stockbreeding, other facilities, services or markets, or safe drinking water. These

The city’s unemployment rate is twice as high as that of rural areas, at 9.2% versus 4.7%.15 The

constraints, in turn, give rise to issues such as the following: food production, distribution, and supply

vulnerability and insufficiency of infrastructure in Phnom Penh is reflected in issues of waste treatment,

are affected, causing food shortages and ultimately malnutrition; as the number of injured people

drinking water, and wastewater treatment discussed in Chapter 4.

increases, medical care, which is poor to begin with, becomes even more strained; financial burdens

Urban environmental issues, unlike those of rural areas which concern natural environment andbecome greater due to medical fees for the treatment of casualties and a loss of earnings because theynatural ecosystems, are issues of the built environment (Figure 13.5), which is created by people; it

are unable to work; municipal governments have to divert funds for clearance of mines and UXO awayfrom other local public services, including healthcare and education.23 On the flip side, clearance ofmines and UXO will resolve these issues; this is why international cooperation and aid for clearance ofmines and UXO are important.
However, the area of land that was cleared of land mines and UXO during a five-year period between
2014 and 2018 was 190.52 km2, compared to 890 km2 of remaining contamination, which is 4.7 times
as large as that of the cleared area.24 At this rate, it will require another 25 years to rid Cambodia ofmines and UXO.
In order to help keep people from falling victim to land mines and UXO, it is important to provide
mine risk education in school health.24 According to statistics, youth under 18 account for 11% of
casualties, and a majority are boys (9%). What should we teach? A Japan-based international NGO25 thatis active in Myanmar, Afghanistan, and Uganda teaches the following:(i)

The colors, shapes, and sizes of mines and UXO(ii) The typical locations where mines and UXO are found(iii) What to do if one encounters a mine or UXO
258

Figure 13.5 The urban environment in Phnom Penh
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Environment and health / Ecohealth259

involves many elements, including buildings, neighborhoods, streets, parks, transportation systems

3

Merriam-Webster Dictionary online. environment. https://www.merriam-webster.com/dictionary/environment(including cars), housing, water supply and sewage disposal, energy grids, recreational facilities,

4

Diamond J. Collapse: How Societies Choose to Fail or Succeed. Penguin Books. 2011.

5

Asakura T, Mallee H, Tomokawa S, Moji K, Kobayashi J. The ecosystem approach to health is a promising strategy in international

distribution systems, information systems, industrial facilities, and commercial facilities (Figure 13.4).27

development: lessons from Japan and Laos. Globalization and Health. 11: 3. 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/

Built environments, therefore, have large impacts on the urban ecology and human health. Human
health may be determined by the following dichotomies, for instance: if one’s physical activity is
promoted or hindered; whether or not one can obtain health-promoting food; if one enjoys good or poor
indoor or outdoor air quality; if one is socially excluded or isolated, or has smooth social relationships;
whether or not one has access to safe water; whether or not there is a safe transportation system; whether
or not one can get a job; whether or not one has elevated opportunities to become infected due to
crowding, and so on.27 It is necessary to monitor how Phnom Penh’s built environments affect humanhealth.

PMC4340288/
6

Honda S, Kamiya M. Environmental issues in Cambodia -with Field survey of mercury in biological samples-, Research reports of
the Kogakuin University, 108: 37-43, 2010.

7

WHO Regional Office For the Western Pacific Bureau. Environmental Health. https://apps.who.int/iris/bitstream/
handle/10665/259292/WPR-RC067-07-Environmental-health-2016-en.pdf?sequence=1&isAllowed=y8

Supplementary appendix 2a (Part 1 of 2) (GBD 2019 Risk Factors Collaborators. Global burden of 87 risk factors in 204 countries
and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet 396: 1223–49, 2020).
https://ars.els-cdn.com/content/image/1-s2.0-S0140673620307522-mmc2a.pdf

9Food and Agriculture Organization of the United Nations. Banana facts and figures. http://www.fao.org/economic/est/estcommodities/bananas/bananafacts/en/

10 Cash and chemicals: Chinese banana boom a blessing and curse in Laos. The Straits Times MAY 16, 2017. https://www.straitstimes.
com/lifestyle/food/cash-and-chemicals-chinese-banana-boom-a-blessing-and-curse-in-laos

Exercises for further thought and research[13-1] Name environments that are important for the health of humans and survival of life and discuss
why they are important.
[13-2] Give one example each of physical, chemical, biological, cultural/psychosocial environments,and look into how they are related to human health.
[13-3] Look for a case where Cambodia’s social and economic development produces impacts on thehealth of ecosystems, people’s lives and main occupations (livelihood), and human health.
Review the case and draw a chart that illustrates what links lead to health issues.
[13-4] Pick up one issue associated with urban built environments in Phnom Penh and look into how it
is related to lives and health of humans.
[13.5] Have a group discussion about which of the SDG 17 goals (Cambodia Sustainable Development
Goal: https://csdgs.org/km/) the environmental health and ecological health issues correspond to.
[13-6] Do research on organizations that are engaged in the protection of the environment or ecosystems
and report the results.

11 Geissen V, Ramos FQ, Bastidas-Bastidas PJ, Dı´az-Gonza´lez G, Bello-Mendoza R. et al., Soil and Water Pollution in a Banana
Production Region in Tropical Mexico. Bulletin of Environmental Contamination and Toxicology, 85:407-13, 2010.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952104/
12 Svensson O, Bellamy AS, den Brink PJV, Tedengren M, Gunnarsson JS. Assessing the ecological impact of banana farms on water
quality using aquatic macroinvertebrate community composition, Environmental Science and Pollution Research. 25:13373-13381,
2018. https://link.springer.com/article/10.1007/s11356-016-8248-y
13 Blum RW, Bastos FIPM, Kabiru CW, Le LC. Adolescent health in the 21st century. 379: 1567-1568, 2012. https://www.thelancet.
com/journals/lancet/article/PIIS0140-6736(12)60407-3/fulltext
14 CDC. The Social-Ecological Model: A Framework for Prevention. https://www.cdc.gov/violenceprevention/about/socialecologicalmodel.html
15 Wingqvist GÖ. Cambodia Environmental and Climate Change Policy Brief. 2009 University of Gothenburg. https://sidaenvironmenthelpdesk.se/digitalAssets/1683/1683319_cambodia-env-and-climate-change-policy-brief-2009.pdf
16 Ministry of Environment. Cambodia Environment Outlook, 2009. https://wedocs.unep.org/handle/20.500.11822/8689
17 Lang O, Sothea M. Current Status of Shrimp Farming and Diseases in Cambodia. Addressing acute hepatopancreatic necrosis
disease (AHPND) and other transboundary diseases for improved aquatic animal health in Southeast Asia. 33-36. 2016.
https://repository.seafdec.org.ph/handle/10862/3086
18 Kajiyama T. Forest Resources and Their Transformations. In Waragai T Ed. Study on Cambodia: Its Nature, Culture, Society,
Politics, and Economy. 111-131, Bunshin-do, 2019.
19 Food and Agriculture Organization of The United Nations. Fertilizers indicators. http://www.fao.org/faostat/en/#data/EF/visualize
20 Ritchie H, Roser M. CO2 and Greenhouse Gas Emissions. Published online at OurWorldInData.org. 2020. https://ourworldindata.
org/co2-and-other-greenhouse-gas-emissions
21 WHO. Climate Change and Health in Cambodia: A Vulnerability and Adaptation Assessment. 2010.
https://www.who.int/globalchange/mediacentre/events/2010/costa_rica_consultation_200710/CAMBODIA_va.pdf
22 JICA. What is Cambodia Mine Action Centre? https://www.jica.go.jp/project/cambodia/0701732/outline/ku57pq0000231j8w-att/
cmac_01.pdf
23 Geneva International Center for Humanitarian Demining. ‘Finishing the Job’ An Independent Review of the Mine Action Sector in
Cambodia. 2016. https://www.gichd.org/fileadmin/GICHD-resources/rec-documents/Cambodia-Sector-Review-Final-ReportGICHD.pdf
24 Landmine and Cluster Munition Monitor. Landmine monitor 2019. http://www.the-monitor.org/media/3074086/Landmine-Monitor-

References

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25 AAR Japan. Mine Action. https://www.aarjapan.gr.jp/english/what_we_do/landmine/

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Skolnik R. Global Health 101 4th Edition, pp.189-218, Jones & Bartlett Learning, Burlington, MA, 2020.

26 United Nations. World Urbanization Prospects 2018. https://population.un.org/wup/Country-Profiles/

2

Landrigan PL, Fuller R, Acosta NJR, Adeyi O, Arnold R, et al. The Lancet Commission on pollution and health, Lancet, 391:

27 Dannenberg A, Capon AG. Healthy Communities. In Frumkin H Ed. Environmental Health-From Global to Local. Third edition.

462–512, 2018.

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377-411, Jossey-Bass, San Francisco, 2016.

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