Chapter 17 Environmental Hazards and Human Health

Chapter 17 Environmental Hazards and Human Health

Core Case Study: Are Baby Bottles and Food Cans Safe To Use
Core Case Study: Are Baby Bottles and Food Cans Safe To Use? The BPA Controversy (1) Some synthetic chemicals act as hormone mimics and disrupt the human endocrine system Excess estrogen effects on males Feminization Smaller penis Lower sperm counts Presence of both male and female sex organs

Core Case Study: Are Baby Bottles and Food Cans Safe To Use? The BPA Controversy (2) BPA (bisphenol A) Estrogen mimic In polycarbonates and other hardened plastics Baby bottles and sipping cups Reusable water bottles Sports drink and juice bottles Microwave dishes Food storage containers Liners of most food and soft drink cans

Core Case Study: Are Baby Bottles and Food Cans Safe To Use? The BPA Controversy (3) BPA leaches into foods and drinks Even when containers not heated 93% of Americans older than 6 have BPA levels above the threshold level set by the EPA Higher in children and adolescents Risks for infants, children, adults

Baby Drinking from BPA Bottle
Figure 17.1: There is concern that bisphenol A (BPA), an estrogen mimic, can leach out of polycarbonate baby bottles, especially when they are warmed, microwaved, or used to hold acidic juices. In 2008, Canada became the first country to classify BPA as a toxic substance and announced that it would ban its use in baby bottles. Some manufacturers are no longer using polycarbonate plastic in baby bottles, in sipping cups, or in the plastic lining of baby formula cans. But almost all food and soft drink cans are lined with a plastic resin that some researchers believe can release BPA into the contents of the cans. Fig. 17-1, p. 436

17-1 What Major Health Hazards Do We Face?
Concept We face health hazards from biological, chemical, physical, and cultural factors, and from the lifestyle choices they make.

Risks Are Usually Expressed as Probabilities
Probability of suffering harm from a hazard Probability vs. possibility Risk Assessment Risk Management

Science: Risk Assessment and Risk Management
Figure 17.2: Science. Risk assessment and risk management are used to estimate the seriousness of various risks and how to reduce such risks. Question: What is an example of how you have applied this process in your daily living? Fig. 17-2, p. 437

Risk Assessment Risk Management Comparative risk analysis
Hazard identification Comparative risk analysis How does it compare with other risks? What is the hazard? Risk reduction How much should it be reduced? Probability of risk How likely is the event? Risk reduction strategy How will the risk be reduced? Figure 17.2: Science. Risk assessment and risk management are used to estimate the seriousness of various risks and how to reduce such risks. Question: What is an example of how you have applied this process in your daily living? Consequences of risk What is the likely damage? Financial commitment How much money should be spent? Fig. 17-2, p. 437

We Face Many Types of Hazards
Biological: Pathogen: an organism that causes disease in other organisms Chemical Physical Cultural Lifestyle choices

17-2 What Types of Biological Hazards Do We Face?
Concept The most serious biological hazards we fade are infectious diseases such as flu, AIDS, tuberculosis, diarrheal diseases, and malaria.

Some Diseases Can Spread from One Person to Another (1)
Infectious disease Pathogen invades the body and multiplies Transmissible disease Contagious or communicable disease Infectious disease transmitted between people Flu, tuberculosis, measles

Some Diseases Can Spread from One Person to Another (2)
Nontransmissible disease Not caused by living organisms Heart disease, most cancers, diabetes Since 1950, death from infectious diseases have declined due to Better health care Better sanitation Antibiotics Vaccines

Infectious Diseases Are Still Major Health Threats
Infectious diseases spread through Air Water Food Body fluids Epidemics and pandemics Resistance of bacteria and insects to drugs and pesticides

Science: Pathways for Infectious Diseases in Humans
Figure 17.3: Science. There are a number of pathways on which infectious disease organisms can enter the human body. Question: Can you think of other pathways not shown here? Fig. 17-3, p. 439

Pets Livestock Wild animals Insects Food Water Air Fetus and babies
Figure 17.3: Science. There are a number of pathways on which infectious disease organisms can enter the human body. Question: Can you think of other pathways not shown here? Fetus and babies Other humans Humans Fig. 17-3, p. 439

Pets Livestock Wild animals Insects Food Water Air Fetus and babies
Other humans Humans Stepped Art Fig. 17-3, p. 439

Major Causes of Death from Infectious Diseases in the World, 2007
Figure 17.4: Global outlook: The World Health Organization estimates that each year, the world’s seven deadliest infectious diseases kill 11.3 million people—most of them poor people in less-developed countries (Concept 17-2). This averages about 31,000 mostly preventable deaths every day—roughly the same as wiping out everyone in the U.S. states of Massachusetts and Alabama or all the people in Delhi, India, each year. Question: How many people, on average, die prematurely from these diseases every hour? (Data from the World Health Organization, 2007) Fig. 17-4, p. 439

Pneumonia and flu (bacteria and viruses) 3.2 million
Disease (type of agent) Deaths per year Pneumonia and flu (bacteria and viruses) 3.2 million HIV/AIDS (virus) 2.0 million Tuberculosis (bacteria) 1.8 million Diarrheal diseases (bacteria and viruses) 1.6 million Figure 17.4: Global outlook: The World Health Organization estimates that each year, the world’s seven deadliest infectious diseases kill 11.3 million people—most of them poor people in less-developed countries (Concept 17-2). This averages about 31,000 mostly preventable deaths every day—roughly the same as wiping out everyone in the U.S. states of Massachusetts and Alabama or all the people in Delhi, India, each year. Question: How many people, on average, die prematurely from these diseases every hour? (Data from the World Health Organization, 2007) Hepatitis B (virus) 1 million Malaria (protozoa) 900,000 Measles (virus) 800,000 Fig. 17-4, p. 439

(bacteria and viruses) 3.2 million
Disease (type of agent) Deaths per year Pneumonia and flu (bacteria and viruses) 3.2 million HIV/AIDS (virus) 2.1 million Diarrheal diseases (bacteria and viruses) 1.9 million Tuberculosis (bacteria) 1.7 million Malaria (protozoa) 1 million Hepatitis B (virus) 1 million Measles (virus) 800,000 Stepped Art Fig. 17-4, p. 439

Science Focus: Genetic Resistance to Antibiotics Is Increasing (1)
Bacteria: rapid reproduction, easily spread Overuse of antibiotics Overuse of pesticides

Science Focus: Genetic Resistance to Antibiotics Is Increasing (2)
Methicillin-resistant Staphylococcus aureus (MRSA) Resistant to most antibiotics Symptoms of MRSA How will it be controlled?

Case Study: The Growing Global Threat from Tuberculosis
One in ten will become sick with TB 1.8 million deaths each year, primarily in less-developed countries Why is tuberculosis on the rise? Not enough screening and control programs Genetic resistance to a majority of effective antibiotics Person-to-person contact has increased AIDS individuals are very susceptible to TB

Lung Tissue Destroyed by Tuberculosis
Figure 17.5: The colorized red areas in this chest X-ray show where TB bacteria have destroyed lung tissue. Fig. 17-5, p. 440

Individuals Matter: Three College Students Have Saved Thousands of Lives
North Carolina State seniors Developed a device that can detect TB bacteria on a slide Very useful in less-developed countries

Viral Diseases and Parasites Kill Large Numbers of People (1)
Influenza or flu virus #1 Killer HIV #2 Killer Hepatitis B virus (HBV) #3 Killer Emergent diseases: West Nile virus

Viral Diseases and Parasites Kill Large Numbers of People (2)
Viruses that move form animals to humans West Nile virus Ecological medicine Reduce chances of infection: Wash your hands Avoid touching your face Avoid sick people

Science Focus: Ecological Medicine: How Humans Get Infectious Diseases from Animals
Human practices that encourage the spread of diseases from animals to humans Emerging infections HIV Avian flu Hepatitis B Lyme virus

Case Study: Global HIV/AIDS Epidemic (1)
Acquired immune deficiency syndrome (AIDS) caused by human immunodeficiency virus (HIV) Many secondary infections No vaccine to prevent or cure AIDS Expensive drugs—live longer

Case Study: Global HIV/AIDS Epidemic (2)
25 million deaths, so far #1 killer globally of women 15-49 Most prevalent in sub-Saharan Africa Life expectancy dropped from 62 to 47 Alters age structure of population

Case Study: Malaria — The Spread of a Deadly Parasite (1)
Caused by Plasmodium sp. carried by Anopheles mosquitoes Tropical and subtropical regions Spread Symptoms Malarial cycle

Case Study: Malaria — The Spread of a Deadly Parasite (2)
Malaria on the rise since 1970 Drug resistant Plasmodium Insecticide resistant mosquitoes Clearing of tropical forests AIDS patients particularly vulnerable Prevention of spread and current research

Global Outlook: Distribution of Malaria
Figure 17.6: Global outlook: About 40% of the world’s population lives in areas in which malaria is prevalent. Malaria kills at least 1 million people a year or about 2 people every minute. More than 80% of these victims live in sub-Saharan Africa and most of them are children younger than age 5. According to the WHO, every 45 seconds, a child in Africa dies of malaria. (Data from the World Health Organization and U.S. Centers for Disease Control and Prevention) Fig. 17-6, p. 444

A Boy in Brazil’s Amazon Sleeps Under an Insecticide-Treated Mosquito Net
Figure 17.7: This boy, who lives in Brazil’s Amazon Basin, is sleeping under an insecticide-treated mosquito net to reduce his risk of being bitten by malaria-carrying mosquitoes. Such nets cost about $5 each and can be donated through groups such as Fig. 17-7, p. 445

We Can Reduce the Incidence of Infectious Diseases
Good news Vaccinations on the rise Oral rehydration therapy Bad news More money needed for medical research in developing countries

Solutions: Infectious Diseases
Figure 17.8: There are a number of ways to prevent or reduce the incidence of infectious diseases, especially in less-developed countries. Question: Which three of these approaches do you think are the most important? Fig. 17-8, p. 445

Solutions Infectious Diseases
Increase research on tropical diseases and vaccines Reduce poverty Decrease malnutrition Improve drinking water quality Reduce unnecessary use of antibiotics Educate people to take all of an antibiotic prescription Reduce antibiotic use to promote livestock growth Figure 17.8: There are a number of ways to prevent or reduce the incidence of infectious diseases, especially in less-developed countries. Question: Which three of these approaches do you think are the most important? Require careful hand washing by all medical personnel Immunize children against major viral diseases Provide oral rehydration for diarrhea victims Conduct global campaign to reduce HIV/AIDS Fig. 17-8, p. 445

17-3 What Types of Chemical Hazards Do We Face?
Concept There is growing concern about chemicals in the environment that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine system.

Some Chemicals Can Cause Cancers, Mutations, and Birth Defects
Toxic chemicals Carcinogens Chemicals, types of radiation, or certain viruses the cause or promote cancer Mutagens Chemicals or radiation that cause mutations or increase their frequency Teratogens Chemicals that cause harm or birth defects to a fetus or embryo

Case Study: PCBs Are Everywhere—A Legacy from the Past
Class of chlorine-containing compounds Very stable Nonflammable Break down slowly in the environment Travel long distances in the air Fat soluble Biomagnification Food chains and webs Banned, but found everywhere

Potential Pathways on Which Toxic Chemicals Move Through the Environment
Figure 17.9: PCBs and other persistent toxic chemicals can move through the living and nonliving environment on a number of pathways. Fig. 17-9, p. 447

Water table Fish Soil Water table
Atmosphere Vegetation Crops Surface water Humans Animals Surface water Groundwater Water table Fish Vegetation Figure 17.9: PCBs and other persistent toxic chemicals can move through the living and nonliving environment on a number of pathways. Soil Groundwater Water table Rock Rock Fig. 17-9, p. 447

Some Chemicals May Affect Our Immune and Nervous Systems
Some natural and synthetic chemicals in the environment can weaken and harm Immune system Nervous system Neurotoxins: PCBs, arsenic, lead, some pesticides Endocrine system

Science Focus: Mercury’s Toxic Effects (1)
Hg: teratogen and potent neurotoxin Once airborne, persistent and not degradable 1/3 from natural sources 2/3 from human activities Enters the food chain: biomagnification How are humans exposed? Inhalation: vaporized Hg or particulates Eating fish with high levels of methylmercury Eating high-fructose corn syrup

Science Focus: Mercury’s Toxic Effects (2)
Effects of Hg on humans Damage nervous system, kidneys, lungs Harm fetuses and cause birth defects Who is most at risk? Pregnant women 75% of exposure comes from eating fish

Solutions: Mercury Pollution
Figure 17.10: There are a number of ways to prevent or control inputs of mercury into the environment from human sources—mostly coal-burning power plants and incinerators. Question: Which four of these solutions do you think are the most important? Fig , p. 449

Phase out waste incineration
Solutions Mercury Pollution Prevention Control Phase out waste incineration Sharply reduce mercury emissions from coal-burning plants and incinerators Remove mercury from coal before it is burned Label all products containing mercury Figure 17.10: There are a number of ways to prevent or control inputs of mercury into the environment from human sources—mostly coal-burning power plants and incinerators. Question: Which four of these solutions do you think are the most important? Switch from coal to natural gas and renewable energy resources Collect and recycle batteries and other products containing mercury Fig , p. 449

Some Chemicals Affect the Human Endocrine System
Glands that release hormones that regulate bodily systems and control sexual reproduction, growth, development, learning, behavior Hormonally active agents have similar shapes and bind to hormone receptors Gender benders Thyroid disruptors BPA? Phthalates in plastics

Hormones and Hormones Mimics or Blockers
Figure 17.11: Hormones are molecules that act as messengers in the endocrine system to regulate various bodily processes, including reproduction, growth, and development. Each type of hormone has a unique molecular shape that allows it to attach to specially shaped receptors on the surface of, or inside, cells and to transmit its chemical message (left). Molecules of certain pesticides and other synthetic chemicals have shapes similar to those of natural hormones, allowing them to attach to the hormone molecules and disrupt the endocrine system in people and various other animals. These molecules are called hormonally active agents (HAAs). Because of the difficulty in determining the harmful effects of long-term exposure to low levels of HAAs, there is uncertainty about their effects on human health. Fig , p. 449

Normal Hormone Process
Estrogen-like chemical Antiandrogen chemical Receptor Cell Figure 17.11: Hormones are molecules that act as messengers in the endocrine system to regulate various bodily processes, including reproduction, growth, and development. Each type of hormone has a unique molecular shape that allows it to attach to specially shaped receptors on the surface of, or inside, cells and to transmit its chemical message (left). Molecules of certain pesticides and other synthetic chemicals have shapes similar to those of natural hormones, allowing them to attach to the hormone molecules and disrupt the endocrine system in people and various other animals. These molecules are called hormonally active agents (HAAs). Because of the difficulty in determining the harmful effects of long-term exposure to low levels of HAAs, there is uncertainty about their effects on human health. Normal Hormone Process Hormone Mimic Hormone Blocker Fig , p. 449

Normal Hormone Process Hormone Mimic Hormone Blocker
Estrogen-like chemical Antiandrogen chemical Receptor Cell Normal Hormone Process Hormone Mimic Hormone Blocker Stepped Art Fig , p. 449

17-4 How Can We Evaluate and Deal with Chemical Hazards?
Concept 17-4A Scientists use live laboratory animals, case reports of poisonings, and epidemiological studies to estimate the toxicity of chemicals, but these methods have limitations. Concept 17-4B Many health scientists call for much greater emphasis on pollution prevention to reduce our exposure to potentially harmful chemicals.

Many Factors Determine the Harmful Health Effects of a Chemical (1)
Toxicology Toxicity dependent on Dose Age Genetic makeup Multiple chemical sensitivity (MCS) Solubility Persistence Biomagnification

Many Factors Determine the Harmful Health Effects of a Chemical (2)
Response Acute effect: immediate or rapid Chronic effect: permanent or long-lasting

Science: Estimating Human Exposure to Chemicals and Measuring Their Effects
Figure 17.12: Science. Estimating human exposure to chemicals and measuring the effects of that exposure are very difficult because of the many and often poorly understood variables involved. Question: Which of these factors, if any, might make you more vulnerable to the harmful effects of chemicals? Fig , p. 452

Scientific measurements and modeling
Water pollutant levels Soil/dust levels Air pollutant levels Food pesticide levels Nutritional health ? Overall health Scientific measurements and modeling Lifestyle Figure 17.12: Science. Estimating human exposure to chemicals and measuring the effects of that exposure are very difficult because of the many and often poorly understood variables involved. Question: Which of these factors, if any, might make you more vulnerable to the harmful effects of chemicals? Predicted level of toxicant in people Personal habits Metabolism Genetic predisposition Accumulation Excretion Lung, intestine, and skin absorption rates Fig , p. 452

Case Study: Protecting Children from Toxic Chemicals
Analysis of umbilical cord blood: significance Infants and children more susceptible Eat, drink water, and breathe more per unit of body weight than adults Put their fingers in their mouths Less well-developed immune systems and body detoxification processes Fetal exposure may increase risk of autism, asthma, learning disorders

Scientists Use Live Lab Animals and Nonanimal Tests to Estimate Toxicity (1)
Mice and rats Systems are similar to humans Small, and reproduce rapidly Is extrapolation to humans valid? Dose-response curve: median lethal dose (LD50) Nonthreshold dose-response model Threshold dose-response model

Scientists Use Live Lab Animals and Nonanimal Tests to Estimate Toxicity (2)
More humane methods using animals Replace animals with other models Computer simulations Tissue culture and individual animal cells Chicken egg membranes What are the effects of mixtures of potentially toxic chemicals?

Hypothetical Dose-Response Curve Showing Determination of the LD50
Figure 17.13: Science. This hypothetical dose-response curve illustrates how scientists can estimate the LD50, the dosage of a specific chemical that kills 50% of the animals in a test group. Toxicologists use this method to compare the toxicities of different chemicals. Fig , p. 453

Percentage of population killed by a given dose
100 75 50 Percentage of population killed by a given dose 25 Figure 17.13: Science. This hypothetical dose-response curve illustrates how scientists can estimate the LD50, the dosage of a specific chemical that kills 50% of the animals in a test group. Toxicologists use this method to compare the toxicities of different chemicals. LD50 2 4 6 8 10 12 14 16 Dose (hypothetical units) Fig , p. 453

Toxicity Ratings and Average Lethal Doses for Humans
Table 17-1, p. 453

Science: Two Types of Dose-Response Curves
Figure 17.14: Science. Scientist use two types of dose-response curves to help them estimate the toxicity of various chemicals. The linear and nonlinear curves in the left graph apply if even the smallest dosage of a chemical has a harmful effect that increases with the dosage. The curve on the right applies if a harmful effect occurs only when the dosage exceeds a certain threshold level. Which model is better for measuring the effects of a specific harmful agent is uncertain and controversial because of the difficulty in estimating the responses to very low dosages. Fig , p. 454

Nonlinear dose-response
Effect Figure 17.14: Science. Scientist use two types of dose-response curves to help them estimate the toxicity of various chemicals. The linear and nonlinear curves in the left graph apply if even the smallest dosage of a chemical has a harmful effect that increases with the dosage. The curve on the right applies if a harmful effect occurs only when the dosage exceeds a certain threshold level. Which model is better for measuring the effects of a specific harmful agent is uncertain and controversial because of the difficulty in estimating the responses to very low dosages. Dose No threshold Fig a, p. 454

Effect Threshold level Dose Threshold Figure 17.14: Science.
Scientist use two types of dose-response curves to help them estimate the toxicity of various chemicals. The linear and nonlinear curves in the left graph apply if even the smallest dosage of a chemical has a harmful effect that increases with the dosage. The curve on the right applies if a harmful effect occurs only when the dosage exceeds a certain threshold level. Which model is better for measuring the effects of a specific harmful agent is uncertain and controversial because of the difficulty in estimating the responses to very low dosages. Threshold level Dose Threshold Fig b, p. 454

There Are Other Ways to Estimate the Harmful Effects of Chemicals
Case reports and epidemiological studies Limitations of epidemiological studies Too few people tested Length of time Can you link the result with the chemical? Cannot be used for new hazards

Are Trace Levels of Toxic Chemicals Harmful?
Insufficient data for most chemicals We are all exposed to toxic chemicals Are the dangers increasing or are the tests just more sensitive?

Some Potentially Harmful Chemicals Found in Most Homes
Figure 17.15: A number of potentially harmful chemicals are found in many homes. Most people have traces of these chemicals in their blood and body tissues. We do not know the long-term effects of exposure to low levels of such chemicals. (Data from U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, and New York State Department of Health) Questions: Does the fact that we do not know much about the long-term harmful effects of these chemicals make you more likely or less likely to minimize your exposure to them? Why? Fig , p. 455

Perfluorochemicals to add shine Teddy bear
Shampoo Perfluorochemicals to add shine Teddy bear Some stuffed animals made overseas contain flame retardants and/or pesticides Clothing Can contain perfluorochemicals Baby bottle Can contain bisphenol A Nail polish Perfluorochemicals and phthalates Mattress Flame retardants in stuffing Perfume Phthalates Hairspray Phthalates Carpet Padding and carpet fibers contain flame retardants, perfluorochemicals, and pesticides Food Some food contains bisphenol A TV Wiring and plastic casing contain flame retardants Milk Fat contains dioxins and flame retardants Figure 17.15: A number of potentially harmful chemicals are found in many homes. Most people have traces of these chemicals in their blood and body tissues. We do not know the long-term effects of exposure to low levels of such chemicals. (Data from U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, and New York State Department of Health) Questions: Does the fact that we do not know much about the long-term harmful effects of these chemicals make you more likely or less likely to minimize your exposure to them? Why? Sofa Foam padding contains flame retardants and perfluorochemicals Frying pan Nonstick coating contains perfluorochemicals Tile floor Contains perfluorochemicals, phthalates, and pesticides Fruit Imported fruit may contain pesticides banned in the U. S. Water bottle Can contain bisphenol A Computer Flame retardant coatings of plastic casing and wiring Toys Vinyl toys contain phthalates Tennis shoes Can contain phthalates Fig , p. 455

Stepped Art Fig. 17-15, p. 455 Chloroform
Source: Chlorine-treated water in hot showers Possible threat: Cancer Para-dichlorobenzene Source: Air fresheners, mothball crystals Threat: Cancer Tetrachloroethylene Source: Dry-cleaning fluid fumes on clothes Threat: Nerve disorders, damage to liver and kidneys, possible cancer Formaldehyde Source: Furniture stuffing, paneling, particleboard, foam insulation Threat: Irritation of eyes, throat, skin, and lungs; nausea; dizziness 1,1,1-Trichloroethane Source: Aerosol sprays Threat: Dizziness, irregular breathing Styrene Source: Carpets, plastic products Threat: Kidney and liver damage Nitrogen oxides Source: Unvented gas stoves and kerosene heaters, woodstoves Threat: Irritated lungs, children's colds, headaches Carbon monoxide Source: Faulty furnaces, unvented gas stoves and kerosene heaters, woodstoves Threat: Headaches, drowsiness, irregular heartbeat, death Benzo-α-pyrene Source: Tobacco smoke, woodstoves Threat: Lung cancer Particulates Source: Pollen, pet dander, dust mites, cooking smoke particles Threat: Irritated lungs, asthma attacks, itchy eyes, runny nose, lung disease Tobacco smoke Source: Cigarettes Threat: Lung cancer, respiratory ailments, heart disease Radon-222 Source: Radioactive soil and rock surrounding foundation, water supply Threat: Lung cancer Asbestos Source: Pipe insulation, vinyl ceiling and floor tiles Threat: Lung disease, lung cancer Methylene chloride Source: Paint strippers and thinners Threat: Nerve disorders, diabetes Stepped Art Fig , p. 455

Why Do We Know So Little about the Harmful Effects of Chemicals?
Severe limitations estimating toxicity levels and risks Only 2% of 100,000 chemicals have been adequately tested 99.5% of chemicals used in the United States are not supervised by government

Pollution Prevention and the Precautionary Principle
Those introducing a new chemical or new technology would have to follow new strategies A new product is considered harmful until it can be proved to be safe Existing chemicals and technologies that appear to cause significant harm must be removed 2000: global treaty to ban or phase out the dirty dozen persistent organic pollutants (POPs) 2007 REACH program in the European Union

Individuals Matter: Ray Turner and His Refrigerator
1974: Ozone layer being depleted by chlorofluorocarbons (CFCs) 1992: International agreement to phase out CFCs and other ozone-destroying chemicals Ray Turner: citrus-based solvents to clean circuit boards

17-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them?
Concept We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices.

The Greatest Health Risks Come from Poverty, Gender, and Lifestyle Choices
Risk analysis Risk assessment Risk management Risk communication Greatest health risks Poverty Gender Lifestyle choices

Global Outlook: Number of Deaths per Year in the World from Various Causes
Figure 17.16: Global outlook: Scientists have estimated the number of deaths per year in the world from various causes. Numbers in parentheses represent death tolls in terms of the number of fully loaded 200-passenger jet airplanes crashing every day of the year with no survivors. Because of the lack of media coverage of the largest annual causes of death and its sensational coverage of other causes of death, most people are misinformed and guided by irrational fears about the comparative levels of risk. Question: Which three of these items are most likely to shorten your life span? (Data from World Health Organization, 2007) Fig , p. 458

Cause of death Annual deaths Poverty/malnutrition/ disease cycle 11 million (150) Tobacco 5.4 million (74) Pneumonia and ﬂu 3.2 million (44) Air pollution 2.4 million (33) HIV/AIDS 2 million (27) Diarrhea 1.6 million (22) Tuberculosis 1.5 million (21) Automobile accidents 1.2 million (16) Figure 17.16: Global outlook: Scientists have estimated the number of deaths per year in the world from various causes. Numbers in parentheses represent death tolls in terms of the number of fully loaded 200-passenger jet airplanes crashing every day of the year with no survivors. Because of the lack of media coverage of the largest annual causes of death and its sensational coverage of other causes of death, most people are misinformed and guided by irrational fears about the comparative levels of risk. Question: Which three of these items are most likely to shorten your life span? (Data from World Health Organization, 2007) Work-related injury and disease 1.1 million (15) Malaria 1 million (14) Hepatitis B 1 million (14) Measles 800,000 (11) Fig , p. 458

Comparison of Risks People Face in Terms of Shorter Average Life Span
Figure 17.17: Global outlook: This figure compares key risks that people can face, expressed in terms of an estimated shorter average life span (Concept 17-5). Excepting poverty and gender, the greatest risks people face come mostly from the lifestyle choices they make. These are merely generalized relative estimates. Individual responses to these risks differ because of factors such as genetic variation, family medical history, emotional makeup, stress, and social ties and support. Question: Which three of these factors are most likely to shorten your life span? (Data from Bernard L. Cohen) Fig , p. 459

Shortens average life span
Hazard Shortens average life span in the United States by Poverty 7–10 years Born male 7.5 years Smoking 6–10 years Overweight (35%) 6 years Unmarried 5 years Overweight (15%) 2 years Spouse smoking 1 year Driving 7 months Air pollution 5 months Alcohol 5 months Drug abuse 4 months Flu 4 months AIDS 3 months Drowning 1 month Pesticides 1 month Figure 17.17: Global outlook: This figure compares key risks that people can face, expressed in terms of an estimated shorter average life span (Concept 17-5). Excepting poverty and gender, the greatest risks people face come mostly from the lifestyle choices they make. These are merely generalized relative estimates. Individual responses to these risks differ because of factors such as genetic variation, family medical history, emotional makeup, stress, and social ties and support. Question: Which three of these factors are most likely to shorten your life span? (Data from Bernard L. Cohen) Fire 1 month Natural radiation 8 days Medical X rays 5 days Oral contraceptives 5 days Toxic waste 4 days Flying 1 day Hurricanes, tornadoes 1 day Living lifetime near nuclear plant 10 hours Fig , p. 459

Case Study: Death from Smoking (1)
Most preventable major cause of suffering and premature death Premature death of 5.4 million per year globally and 442,000 in the United States Could be linked to increased dementia and Alzheimer’s disease Nicotine: additive Effects of passive smoking (secondhand smoke)

Case Study: Death from Smoking (2)
How to reduce smoking Taxes Classify and regulate nicotine Bans on smoking in public places Education

Normal Lung and Emphysema Lung
Figure 17.18: There is a startling difference between normal human lungs (left) and the lungs of a person who died of emphysema (right). The major cause is prolonged smoking and exposure to air pollutants. Fig , p. 459

Stepped Art Fig , p. 459

Annual Deaths in the U.S. from Tobacco Use and Other Causes
Figure 17.19: Smoking is by far the nation’s leading cause of preventable death, causing more premature deaths each year than all the other categories in this figure combined. (Data from U.S. National Center for Health Statistics, Centers for Disease Control and Prevention, and U.S. Surgeon General) Fig , p. 460

Cause of Death Deaths per Year Tobacco use 442,000 Accidents
101,500 (33,960 auto) Alcohol use 85,000 Infectious diseases 75,000 (15,000 from AIDS) Pollutants/toxins 55,000 Figure 17.19: Smoking is by far the nation’s leading cause of preventable death, causing more premature deaths each year than all the other categories in this figure combined. (Data from U.S. National Center for Health Statistics, Centers for Disease Control and Prevention, and U.S. Surgeon General) Suicides 30,600 Homicides 20,622 Illegal drug use 17,000 Fig , p. 460

Coal-fired electricity 286%
Synthetic oil and gas produced from coal 150% Coal 100% Tar sand 92% Oil 86% Natural gas 58% Nuclear power fuel cycle 17% Geothermal 10% Stepped Art Fig , p. 460

Estimating Risks from Technologies Is Not Easy
System reliability (%) = Technological reliability (%) x Human reliability (%) To err is human…

Most People Do a Poor Job of Evaluating Risks
Fear Degree of control Whether a risk is catastrophic or chronic Optimism bias Want instant gratification without thinking of future harm

Several Principles Can Help Us to Evaluate and Reduce Risk
Compare risks Determine how much you are willing to accept Determine the actual risk involved Concentrate on evaluating and carefully making important lifestyle choices

Three Big Ideas We face significant hazards from infectious diseases, malaria, and tuberculosis, and from exposure to chemicals that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine systems. Because of the difficulty in evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution prevention.

Three Big Ideas Becoming informed, thinking critically about risks, and making careful choices can reduce the major risks we face.

Chapter 17 Environmental Hazards and Human Health

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