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Environmental Science: Toward a
Sustainable Future
Richard T. Wright
Chapter 15
Environmental Hazards and
Human Health
PPT by Clark E. Adams
Environmental Hazards and Human Health
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Links between human health and the
environment
Pathways of risk
Risk assessment
Some Definitions
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Environment: combination of physical, chemical,
and biological factors
Hazard: anything that can cause injury, death,
disease, damage to personal/public property, or
deterioration or destruction of environmental
components
Risk: probability of suffering a loss as a result of
exposure to a hazard
Links between Human Health and the
Environment
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The picture of health
Environmental hazards
The Picture of Health: Some Terms
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Morbidity: incidence of disease in a
population
Mortality: incidence of death in a
population
Epidemiology: study of presence,
distribution, and control of disease in a
population
Causes of Human Mortality
Environmental Hazards
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Cultural
Biological
Physical
Chemical
Cultural Hazards
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Consequence of choice
Risky behavior
To what cultural hazards do college
students commonly subject themselves?
Deaths from Various Cultural Hazards
Biological Hazards
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Pathogenic bacteria
Fungi
Viruses
Protozoans
Worms
Global Map of Tuberculosis, 2001
Infectious Diseases
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More prevalent in, but not exclusive to,
developing countries
Contamination of food and water
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Lack of resources for sanitation
Lack of education
Ideal climates for transmission of
vector-borne diseases like malaria
Malarial Parasite Life Cycle
Physical Hazards
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Natural disasters, e.g., tornadoes, floods,
hurricanes, and wildfires
Avoidance of risk important in prevention,
e.g., building homes in floodplains, and
living on the coast
Climate change: consequences of
elevated greenhouse gases
Chemical Hazards
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Result of industrialization
Exposure through ingestion, inhalation,
absorption through skin
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May be direct use or accidental
Many chemicals are toxic at low levels
Chemical Hazards
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74 chemicals are known to be
carcinogenic (Table 15-2)
Environmental carcinogens initiate
mutations in DNA; several mutations lead
to a malignancy
Pathways of Risk
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The risk of being poor
The cultural risk of tobacco use
Risk and infectious diseases
Toxic risk pathways
The Risk of Being Poor
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One major pathway for hazards is poverty
No money for health insurance
Higher probability of exposure to
environmental hazards
The 10 Leading Global Risk Factors
Fig. 15-9 here
Environmental Health
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Factors contributing to the environmental
health of a nation include:
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Education
Nutrition
Commitment from government
More equitable distribution of wealth
The Cultural Risk of Tobacco Use
Regulation of Smoking
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Warning labels
Smoke-free zones in public places
FDA regulations
Lawsuits against the tobacco industry
Risk and Infectious Diseases
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One major pathway of risk is
contamination of food and water
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Inadequate hygiene
Inferior sewage treatment
Control of Infectious Disease
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Genome sequencing
of the Anopheles
mosquito
Bed nets
Change in land use
practices: wetland
development
New effective
antimalarial drugs
Worldwide Distribution of Malaria
Toxic Risk Pathways
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Categories of impact of airborne pollutants
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Chronic: effect takes place over a period of
years
Acute: life-threatening reaction within a period
of hours or days
Carcinogenic: pollutants initiate cellular
change leading to cancer
Indoor Air Pollution: Developed Countries
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Hazardous fumes
from home
products
Well-insulated
buildings
Long exposure to
indoor air
Indoor Air Pollution: Developing Countries
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Results from burning biofuels (wood,
dung) inside homes
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Acute respiratory infections in children
Chronic lung diseases
Lung cancer
Birth-related problems
Risk Assessment
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Environmental risk assessment by the
EPA
Public-health risk assessment
Risk management
Risk perception
Definition of Risk Assessment
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The process of evaluating the risks
associated with a particular hazard before
taking some action in which the particular
hazard is present
Loss of Life Expectancy from Various Risks:
Top Five (see Fig. 15-16)
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Alcoholic
Poverty
Smoking – male
Poor social connections
Heart disease
Loss of Life Expectancy from Various Risks
Environmental Risk Assessment by the EPA
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Hazard assessment (What chemicals
cause cancer?)
Dose-response assessment (How much?)
Exposure assessment (How long?)
Risk characterization (How many will die?)
Public-Health Risk Assessment
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Potential global impact
High likelihood of causality
Modifiability
Availability of data (see Table 15-4)
Risk Management
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Usually involves:
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Cost–benefit analysis
Risk–benefit analysis
Public preferences
Risk Perception: Hazard vs. Outrage
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Hazard: expresses primarily a concern
for fatalities only
Risk Perception: Hazard vs. Outrage
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Outrage includes:
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Lack of familiarity with technology
Extent to which the risk is voluntary
Public impressions of hazards
Overselling safety
Morality
Control
Fairness
Risk Assessment/Management
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Some suggest we use distributive justice
in making decisions about risk
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Ethical process of making certain that
everyone receives proper consideration
Should reduce environmental racism/injustice
Risk Assessment/Management
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Not a perfect system
Precautionary principle
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Lack of certainty should not be used as a
reason for preventing environmental
degradation/hazards
End of Chapter 15