Presentation on theme: "Environmental Health 9 CHAPTER"— Presentation transcript:
1Environmental Health9CHAPTERPlaceholder 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?)
2The 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.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?
3Lesson 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.
4Types of Environmental Health Hazards Lesson 9.1 An Overview of Environmental HealthTypes of Environmental Health HazardsBiological: Viruses, bacteria, and other organisms that cause diseaseSocial: Lifestyle choices that endanger healthChemical: Harmful artificial and natural chemicals in the environmentPhysical: Natural disasters and ongoing natural phenomena, such as UV radiation, that can cause health problems
5Lesson 9.1 An Overview of Environmental Health EpidemiologyThe study of disease in human populations—how and where they occur and how they can be controlledOften involves studying large groups over long periodsCan determine statistical associations between health hazards and effects, but can’t prove the hazards actually caused the effects
6Lesson 9.1 An Overview of Environmental Health ToxicologyThe study of how poisonous substances affect an organism’s healthToxicity is a measure of how harmful a substance is.Toxicologists look at toxicity by determining dose-response relationships.
7Lesson 9.1 An Overview of Environmental Health Individual ResponsesSensitivity to hazards varies with age, sex, weight, and immune system health.Many diseases have genetic as well as environmental factors.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.
8Risk Assessment Risk: The probability that a hazard will cause harm Lesson 9.1 An Overview of Environmental HealthRisk AssessmentRisk: The probability that a hazard will cause harmRisk assessment: The process of measuring riskTakes into account:The type of hazardHow frequently humans will be exposed to itHow sensitive people are to it
9Lesson 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
10Infectious Diseases Caused by pathogens Lesson 9.2 Biological and Social HazardsInfectious DiseasesCaused by pathogensSpread by human and animal contact and through contaminated food and waterCause of almost half of all deaths in developing nationsCovering 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.
11Lesson 9.2 Biological and Social Hazards Emerging DiseasesDiseases appearing in the human population for the first time or suddenly beginning to spread rapidlyHumans have little or no resistance, and no vaccines have been developed.Facilitated by increasing human mobility, growing antibiotic resistance, and environmental changes
12Responding to Emerging Diseases Lesson 9.2 Biological and Social HazardsResponding to Emerging DiseasesWorld Health Organization (WHO): Monitors health events worldwide and coordinates international responses to emerging diseasesCenters 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
13Social Hazards Some social hazards are easier to avoid than others. Lesson 9.2 Biological and Social HazardsSocial HazardsSome 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.
14Lesson 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.”
15Chemical Hazards Any chemical can be harmful in large enough amounts. Lesson 9.3 Toxic Substances in the EnvironmentChemical HazardsAny 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
16Types of Chemical Hazards Lesson 9.3 Toxic Substances in the EnvironmentTypes of Chemical HazardsCarcinogens: Cancer-causing chemicalsChemical mutagens: Chemicals that cause genetic mutationsTeratogens: Chemicals that harm embryos and fetusesNeurotoxins: Chemicals that affect the nervous systemEndocrine disruptors: Chemicals that interfere with the endocrine systemAllergens: Chemicals that over-activate the immune systemDust mite protein is a common allergen.
17Indoor Chemical Hazards Lesson 9.3 Toxic Substances in the EnvironmentIndoor Chemical Hazards
18Sources of Outdoor Chemical Hazards Lesson 9.3 Toxic Substances in the EnvironmentSources of Outdoor Chemical HazardsIn the air: Natural sources, such as volcanic eruptions, or human sources, such as pesticidesIn the ground: Pesticide use, improper disposal of electronics, etc.In the water: Chemical runoff from land or direct drainage of toxic substances into waterA leaking oil line
19Bioaccumulation and Biomagnification Lesson 9.3 Toxic Substances in the EnvironmentBioaccumulation and BiomagnificationBioaccumulation: The buildup of toxic substances in the bodies of organismsBiomagnification: The increased concentration of toxic substances with each step in a food chainPersistent organic pollutants are biomagnified and stay in the environment for long periods of time and over long distances.
20Lesson 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
21Lesson 9.4 Natural Disasters EarthquakesEarth’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.
22Lesson 9.4 Natural Disasters VolcanoesOpenings in Earth’s crust that eject molten lava and other materialsAsh 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.
23Lesson 9.4 Natural Disasters StormsTornadoes: Rotating funnels of air that can travel over 400 km (250 mi) per hrHurricanes: Storms that form over tropical oceans, with winds over 119 km (74 mi) per hourThunderstorms: Produce lightning and thunder, usually with heavy rainDid You Know? Hurricane Katrina, which struck New Orleans in 2005, caused more than $80 billion in damage and killed 1800 people.
24Avalanches Masses of snow that slide down a slope Lesson 9.4 Natural DisastersAvalanchesMasses of snow that slide down a slopeConditions favoring avalanches:Slope greater than 30 degreesUnstable snowpackHeavy snowfallWarm temperaturesDid 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.