1. Environmental Health 9
CHAPTER
Placeholder opening page, but maybe we can duplicate the look of the SE chapter opener page by using the same fonts and colors (and maybe that Ch 14 icon?)

2. 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.

3. Objectives List the types of environmental health hazards
Compare and contrast epidemiology and toxicology
Describe the reasons why individuals respond differently to the same environmental risks
Discuss risk assessment.

4. Types of Environmental Health Hazards
Lesson 9.1 An Overview of Environmental Health
Types of Environmental Health Hazards
Biological: Viruses, bacteria, and other organisms that cause diseases (ex: Flu, pet dander)
Social: Lifestyle choices that endanger health (ex: smoking)
Chemical: Harmful artificial and natural chemicals in the environment (ex: disinfectants)
Physical: Natural disasters and ongoing natural phenomena, such as UV radiation, that can cause health problems (Ex: earthquake)

5. Epidemiology (Biological Environmental Hazard)
Lesson 9.1 An Overview of Environmental Health
Epidemiology (Biological Environmental Hazard)
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

6. Toxicology (Chemical Environmental Hazard)
Lesson 9.1 An Overview of Environmental Health
Toxicology (Chemical Environmental Hazard)
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.

7. Dose-Response Relationship
Dose – the amount of substance an organism is exposed to. Includes:
Concentration of substance
Time of exposure
Response – effect an organism shows as a result of exposure
Examples:
Exposure to radiation in high doses can result in death
Exposure to radiation in low doses can result in illness
Threshold dose – level of dosage that must be met to bring about a response

8. Determining Dose-Response Relationships
Hard to determine in humans because:
Most people are accidentally exposed to a hazard which is then difficult to determine the dose
People are exposed to different environmental hazards daily
Scientists test effects of hazard on animals which makes it easier to control dosage

9. Lesson 9.1 An Overview of Environmental Health
Individual Responses
Sensitivity to hazards varies with age, sex, weight, and immune system health.
A person’s genes and environment affect chances of suffering from a disease
Image - (Creative Commons licensed)
Geyser info source - National Park Service:
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.

10. Risk Assessment Risk: The probability that a hazard will cause harm
Lesson 9.1 An Overview of Environmental Health
Risk 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 will be exposed to it
How sensitive people are to it

11. 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

12. Objectives Describe how infectious diseases are spread
Explain why emerging diseases are important to monitor and control
Differentiate between social hazards that are lifestyle choices and those that cannot be controlled

13. Infectious Diseases Caused by pathogens (virus, bacteria)
Lesson 9.2 Biological and Social Hazards
Infectious Diseases
Caused by pathogens (virus, bacteria)
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 you’re 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.

14. Infectious Diseases
Human to Human: HIV spread through blood and bodily fluids, TB spread through coughing, sneezing, speaking, spitting
Water or Food: Cholera is spread through contaminated water
Other Organisms: spread by “vectors” who do not suffer from the disease themselves; example is ticks and mosquitoes

15. Lesson 9.2 Biological and Social Hazards
Emerging Diseases
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

16. Emerging Diseases Example is H1N1
Pandemic – an outbreak that becomes widespread and affects a whole region, continent, or world.
Increasing mobility – when people move around the Earth, they may be taking pathogens with them
Antibiotic Resistance – disease becomes resistant to our medicines through natural selection
A Changing Environment – when people cut down forests, they come in contact with new pathogens; climate change allows spread of disease into new, formerly cooler areas

17. Responding to Emerging Diseases
Lesson 9.2 Biological and Social Hazards
Responding to Emerging Diseases
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

18. Social Hazards Some social hazards are easier to avoid than others.
Lesson 9.2 Biological and Social Hazards
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.

19. Objectives Revisited Describe how infectious diseases are spread
Explain why emerging diseases are important to monitor and control
Differentiate between social hazards that are lifestyle choices and those that cannot be controlled

20. 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.”

21. Objectives Explain what makes chemicals hazardous
Discuss how chemical hazards affect human health
List some indoor chemical hazards
Discuss where chemical hazards can be found in the environment
Describe biomagnifications

22. Lesson 9.3 Toxic Substances in the Environment
Chemical Hazards
Any chemical can be harmful in large enough amounts, even water
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.
Poison Ivy is a chemical
hazard but not a pollutant
Oil Pollution

23. Types of Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment
Types 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 (lead, mercury, pesticides)
Endocrine disruptors: Chemicals that interfere with the endocrine system (hormones)
Allergens: Chemicals that over-activate the immune system (Asthma)
Dust mite protein is a common allergen.

24. Indoor Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment
Indoor Chemical Hazards

25. Indoor Chemical Hazards
Asbestos –
used widely in insulation
when disturbed releases fibers into the air, fibers can be inhaled and lodged in lung tissue causing lung cancer
Radon –
colorless, odorless, highly toxic radioactive gas
Made and released naturally when uranium decays
Can cause lung cancer
We live in an area with high radon potential
Volatile Organic Compounds (VOCs)
Released into air from plastic, perfume, pesticide
Usually level of human exposure is low

26. Indoor Chemical Hazards
Carbon Monoxide
Colorless and odorless gas
Unvented stoves, car exhaust, cigarette smoke
Can cause headaches, dizziness, nausea, fatigue, death
Lead –
In air, drinking water (lead pipes), soil, paint, dust, etc.
Causes damage to brain, liver, kidneys, stomach, learning problems, behavior abnormalities, anemia, hearing loss, death

27. Sources of Outdoor Chemical Hazards
Lesson 9.3 Toxic Substances in the Environment
Sources of Outdoor Chemical Hazards
In the air: Natural sources, such as volcanic eruptions, or human sources, such as pesticides
Wind can carry chemicals far away from their original location
Pesticide drift – airborne transport of pesticides
A leaking oil line

28. Sources of Outdoor Chemical Hazards
In the ground:
Pesticide use, improper disposal of electronics, etc.
Humans can inhale them, absorb them by touching contaminated soil, or ingest them through produce
In the water: Chemical runoff from land or direct drainage of toxic substances into water
Amphibians are a good indicator of water quality
Contaminants in streams and rivers can seep into drinking water

29. Bioaccumulation and Biomagnification
Lesson 9.3 Toxic Substances in the Environment
Bioaccumulation and Biomagnification
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 (POPs) are biomagnified and stay in the environment for long periods of time and over long distances.
Example: DDT

30. Objectives Revisited Explain what makes chemicals hazardous
Discuss how chemical hazards affect human health
List some indoor chemical hazards
Discuss where chemical hazards can be found in the environment
Describe biomagnifications

31. 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

32. Objectives
Discuss how earthquakes affect structures on Earth’s surface
Discuss how volcanoes affect human lives and property
Describe tornadoes, hurricanes, and thunderstorms
Discuss the dangers of avalanches

33. Lesson 9.4 Natural Disasters
Earthquakes
Earth’s 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.

34. Earthquakes: Surface Effects
Can cause ground to sink and soil to liquefy
Landslide – occur when rock and soil slide down a slope
Tsunami – large ocean wave that results from an earthquake at the bottom of the ocean

35. Lesson 9.4 Natural Disasters
Volcanoes
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.
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.

36. Lesson 9.4 Natural Disasters
Storms
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.

37. Avalanches Masses of snow that slide down a slope
Lesson 9.4 Natural Disasters
Avalanches
Masses of snow that slide down a slope
Conditions favoring avalanches:
Slope greater than 30 degrees
Unstable snowpack (hard snow on top of weak snow)
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.

38. Objectives Revisited
Discuss how earthquakes affect structures on Earth’s surface
Discuss how volcanoes affect human lives and property
Describe tornadoes, hurricanes, and thunderstorms
Discuss the dangers of avalanches