Environmental Health

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Environmental Health
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CHAPTER
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The Rise and Falland Rise?of DDT

• DDT is the least expensive way of killing the
  mosquitoes that cause malaria.
• DDT harms fish and birds, and can cause liver
  damage, cancer, and convulsions in humans.
• In the 1970s many countries banned the use of
  DDT, but some African countries have resumed its
  use to control malaria.

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Lesson 9.1 An Overview of Environmental Health

• One third of death and disease in the least
  developed nations is a direct result of
  environmental causes.

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Types of Environmental Health Hazards
Lesson 9.1 An Overview of Environmental Health

• Biological Viruses, bacteria, and other
  organisms that cause disease
• Social Lifestyle choices that endanger health
• Chemical Harmful artificial and natural
  chemicals in the environment
• Physical Natural disasters and ongoing natural
  phenomena, such as UV radiation, that can cause
  health problems

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Epidemiology
Lesson 9.1 An Overview of Environmental Health

• The study of disease in human populationshow and
  where they occur and how they can be controlled
• Often involves studying large groups over long
  periods
• Can determine statistical associations between
  health hazards and effects, but cant prove the
  hazards actually caused the effects

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Toxicology
Lesson 9.1 An Overview of Environmental Health

• The study of how poisonous substances affect an
  organisms health
• Toxicity is a measure of how harmful a substance
  is.
• Toxicologists look at toxicity by determining
  dose-response relationships.

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Individual Responses

Lesson 9.1 An Overview of Environmental Health

• Sensitivity to hazards varies with age, sex,
  weight, and immune system health.
• Many diseases have genetic as well as
  environmental factors.

Did You Know? Thalidomide, a drug that currently
shows promise for treatment of Alzheimer's, AIDS,
and some cancers, caused thousands of severe
birth defects when it was used as an anti-nauseal
in the 1950s and 60s.
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Risk Assessment
Lesson 9.1 An Overview of Environmental Health

• Risk The probability that a hazard will cause
  harm
• Risk assessment The process of measuring risk
• Takes into account
• The type of hazard
• How frequently humans will be exposed to it
• How sensitive people are to it

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Lesson 9.2 Biological and Social Hazards

• Three quarters of infectious disease deaths are
  caused by five types of diseases respiratory
  infections, AIDS, diarrheal diseases,
  tuberculosis, and malaria.

Tuberculosis-causing bacteria
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Infectious Diseases
Lesson 9.2 Biological and Social Hazards

• Caused by pathogens
• Spread by human and animal contact and through
  contaminated food and water
• Cause of almost half of all deaths in developing
  nations
• Covering your mouth when you cough, washing your
  hands often, and staying home from school if
  youre sick help prevent the spread of
  infectious disease.

Did You Know? In 2002, AIDS killed about 2
million people worldwide almost equal to the
entire population of Arkansas.
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Emerging Diseases
Lesson 9.2 Biological and Social Hazards

• Diseases appearing in the human population for
  the first time or suddenly beginning to spread
  rapidly
• Humans have little or no resistance, and no
  vaccines have been developed.
• Facilitated by increasing human mobility,
  growing antibiotic resistance, and
  environmental changes

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Responding to Emerging Diseases
Lesson 9.2 Biological and Social Hazards

• World Health Organization (WHO) Monitors health
  events worldwide and coordinates international
  responses to emerging diseases
• Centers for Disease Control and Prevention
  (CDC) Responds to emerging diseases in the
  United States the CDC developed pandemic plans
  to deal with the spread of the H1N1 flu virus.

H1N1 Virus
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Social Hazards
Lesson 9.2 Biological and Social Hazards

• Some social hazards are easier to avoid than
  others.
• Examples of social hazards include smoking, being
  exposed to secondhand smoke, living near an old
  toxic waste site, working with harmful chemicals,
  and eating fatty foods.

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Lesson 9.3 Toxic Substances in the Environment

• Chemicals are all around us, and all of them can
  be harmful to our health in large enough amounts.
  In other words, The dose makes the poison.

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Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment

• Any chemical can be harmful in large enough
  amounts.
• A pollutant is something released into the
  environment that has some harmful impact on
  people and other organisms.
• Chemical hazards are not necessarily pollutants,
  and pollutants are not necessarily chemical
  hazards.

Oil Pollution
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Types of Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment

• Carcinogens Cancer-causing chemicals
• Chemical mutagens Chemicals that cause genetic
  mutations
• Teratogens Chemicals that harm embryos and
  fetuses
• Neurotoxins Chemicals that affect the nervous
  system
• Endocrine disruptors Chemicals that interfere
  with the endocrine system
• Allergens Chemicals that over-activate the
  immune system

Dust mite protein is a common allergen.
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Indoor Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment
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Sources of Outdoor Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment

• In the air Natural sources, such as volcanic
  eruptions, or human sources, such as pesticides
• In the ground Pesticide use, improper disposal
  of electronics, etc.
• In the water Chemical runoff from land or direct
  drainage of toxic substances into water

A leaking oil line
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Bioaccumulation and Biomagnification
Lesson 9.3 Toxic Substances in the Environment

• Bioaccumulation The buildup of toxic substances
  in the bodies of organisms
• Biomagnification The increased concentration of
  toxic substances with each step in a food chain
• Persistent organic pollutants are biomagnified
  and stay in the environment for long periods of
  time and over long distances.

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Lesson 9.4 Natural Disasters

• Although we cannot prevent most natural
  disasters, there are steps that scientists,
  engineers, governments, and citizens can take to
  resist damage and deal with the aftermath.

A landslide caused by the Great Sichuan
Earthquake in Sichuan Province, China
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Earthquakes
Lesson 9.4 Natural Disasters

• Earths crust is broken into large pieces called
  tectonic plates, which float on a layer of molten
  rock.
• Earthquakes tend to occur along active plate
  boundaries.
• Earthquakes can damage structures and trigger
  landslides and tsunamis.

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Volcanoes
Lesson 9.4 Natural Disasters

• Openings in Earths crust that eject molten lava
  and other materials
• Ash and gases from volcanic eruptions can block
  sunlight, causing temperatures to drop.
• Eruptions can trigger landslides and mudflows.
• Molten lava can cover and destroy surrounding
  land.

Did You Know? In 1991, Mount Pinatubo erupted in
the Philippines, covering the area around the
volcano with a layer of volcanic materials up to
180 m (600 ft) thick.
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Storms
Lesson 9.4 Natural Disasters

• Tornadoes Rotating funnels of air that can
  travel over 400 km (250 mi) per hr
• Hurricanes Storms that form over tropical
  oceans, with winds over 119 km(74 mi) per hour
• Thunderstorms Produce lightning and thunder,
  usually with heavy rain

Did You Know? Hurricane Katrina, which struck New
Orleans in 2005, caused more than 80 billion in
damage and killed 1800 people.
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Avalanches
Lesson 9.4 Natural Disasters

• Masses of snow that slide down a slope
• Conditions favoring avalanches
• Slope greater than 30 degrees
• Unstable snowpack
• Heavy snowfall
• Warm temperatures

Did You Know? A big North American avalanche can
contain 230,000 m3 of snowabout the equivalent
of 20 football fields filled with snow 3 m (10
ft) deep.