powerpoint chapter 9 - staff web sites @...

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9 Environmental HealthC

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The Rise and Fall—and Rise?—of DDTThe Rise and Fall—and 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.

• 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.

Talk About It Evidence shows that DDT damages ecosystems but helps eradicate malaria in areas where millions of people die of the disease each year. Should DDT be used in malaria-stricken areas? Why or why not?

Talk About It Evidence shows that DDT damages ecosystems but helps eradicate malaria in areas where millions of people die of the disease each year. Should DDT be used in malaria-stricken areas? Why or why not?

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Lesson 9.1 An Overview of Environmental HealthLesson 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.

Types of EnvironmentalHealth Hazards

Types of EnvironmentalHealth Hazards

• 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

• 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

Lesson 9.1 An Overview of Environmental Health

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EpidemiologyEpidemiology

• The study of disease in human populations—how 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 can’t prove the hazards actually caused the effects


ToxicologyToxicology

• The study of how poisonous substances affect an organism’s health

• Toxicity is a measure of how harmful a substance is.

• Toxicologists look at toxicity by determining dose-response relationships.

• The study of how poisonous substances affect an organism’s 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 ResponsesIndividual Responses

• Sensitivity to hazards varies with age, sex, weight, and immune system health.

• Many diseases have genetic as well asenvironmental factors.

• Sensitivity to hazards varies with age, sex, weight, and immune system health.

• Many diseases have genetic as well asenvironmental 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.

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.

Risk AssessmentRisk Assessment

• 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 willbe exposed to it

• How sensitive people are to it


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Lesson 9.2 Biological and Social HazardsLesson 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

Infectious DiseasesInfectious Diseases

Lesson 9.2 Biological and Social Hazards

Did You Know? In 2002, AIDS killed about 2 million people worldwide—almost equal to the entire population of Arkansas.

Did You Know? In 2002, AIDS killed about 2 million people worldwide—almost equal to the entire population of Arkansas.

• Caused by pathogens

• Spread by human and animalcontact and through contaminatedfood 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 you’re sick help prevent thespread of infectious disease.

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Emerging DiseasesEmerging Diseases

• Diseases appearing in the human population for the first timeor suddenly beginning to spread rapidly

• Humans have little or no resistance, and no vaccines have been developed.

• Facilitated byincreasing humanmobility, growingantibioticresistance, andenvironmentalchanges

• Diseases appearing in the human population for the first timeor suddenly beginning to spread rapidly

• Humans have little or no resistance, and no vaccines have been developed.

• Facilitated byincreasing humanmobility, growingantibioticresistance, andenvironmentalchanges


Responding to Emerging DiseasesResponding to Emerging Diseases

• World Health Organization (WHO):Monitors health events worldwide andcoordinates international responses toemerging diseases

• Centers for Disease Control andPrevention (CDC): Responds to emerging diseases in the United States; the CDC developed pandemic plans to deal with the spread of the H1N1 flu virus.

• World Health Organization (WHO):Monitors health events worldwide andcoordinates international responses toemerging diseases

• Centers for Disease Control andPrevention (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 HazardsSocial Hazards


• Some social hazards areeasier to avoid than others.

• Examples of social hazardsinclude smoking, beingexposed to secondhandsmoke, living near an old toxic waste site, workingwith harmful chemicals, and eating fatty foods.

Lesson 9.3 Toxic Substances in the EnvironmentLesson 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 HazardsChemical Hazards• 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.

• 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.

Lesson 9.3 Toxic Substances in the Environment

Oil Pollution

Types of Chemical HazardsTypes of Chemical Hazards• 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

• 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


Sources of Outdoor Chemical HazardsSources of Outdoor Chemical Hazards

• In the air: Natural sources, such as volcanic eruptions, or human sources, such as pesticides

• In the ground: Pesticide use, improper disposal ofelectronics, etc.

• In the water: Chemical runoff from land or direct drainage of toxic substances into water

• In the air: Natural sources, such as volcanic eruptions, or human sources, such as pesticides

• In the ground: Pesticide use, improper disposal ofelectronics, 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

Bioaccumulation and Biomagnification

• Bioaccumulation: The buildup oftoxic substances in the bodies oforganisms

• 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.

• Bioaccumulation: The buildup oftoxic substances in the bodies oforganisms

• 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.


Lesson 9.4 Natural DisastersLesson 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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EarthquakesEarthquakes

Lesson 9.4 Natural Disasters

• Earth’s crust is broken into large pieces called tectonic plates, which float on a layer of molten rock.

• Earthquakes tend tooccur along active plate boundaries.

• Earthquakes can damage structures and triggerlandslides and tsunamis.

• Earth’s crust is broken into large pieces called tectonic plates, which float on a layer of molten rock.

• Earthquakes tend tooccur along active plate boundaries.

• Earthquakes can damage structures and triggerlandslides and tsunamis.

• Openings in Earth’s 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.

• Openings in Earth’s 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.

VolcanoesVolcanoes


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.

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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StormsStorms

• 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

• 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.

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

AvalanchesAvalanches

• 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 snow—about the equivalent of 20 football fields filled with snow 3 m (10 ft) deep.

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

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