MILLER/SPOOLMAN    LIVING IN THE ENVIRONMENT          17TH                  Chapter 17                  Environmental Haza...
Core Case Study: Are Baby Bottles and Food Cans     Safe To Use? The BPA Controversy (1) • Some synthetic chemicals act as...
Core Case Study: Are Baby Bottles and Food Cans     Safe To Use? The BPA Controversy (2) • BPA (bisphenol A)    • Estrogen...
Core Case Study: Are Baby Bottles and Food Cans     Safe To Use? The BPA Controversy (3) • BPA leaches into foods and drin...
Baby Drinking from BPA Bottle                                Fig. 17-1, p. 436
Risks Are Usually Expressed as Probabilities  • Risk    • Probability of suffering harm from a hazard    • Probability vs....
Science: Risk Assessment and Risk Management                                          Fig. 17-2, p. 437
We Face Many Types of Hazards1. Biological:  •   Pathogen: an organism that causes disease in other      organisms2. Chemi...
Some Diseases Can Spread from One       Person to Another (1)• Infectious disease   • Pathogen invades the body and multip...
Some Diseases Can Spread from One       Person to Another (2)• Nontransmissible disease   • Not caused by living organisms...
Infectious Diseases Are Still Major             Health Threats• Infectious diseases spread through   •   Air   •   Water  ...
Science: Pathways for Infectious Diseases              in Humans                                     Fig. 17-3, p. 439
Major Causes of Death from Infectious Diseases             in the World, 2007                                         Fig....
Science Focus: Genetic Resistance to      Antibiotics Is Increasing (1)• Bacteria: rapid reproduction, easily spread• Over...
Viral Diseases and Parasites Kill Large        Numbers of People (1)• Influenza or flu virus   • #1 Killer• HIV   • #2 Kil...
Viral Diseases and Parasites Kill Large        Numbers of People (2)• Viruses that move form animals to humans   • West Ni...
Case Study: Malaria — The Spread of a         Deadly Parasite (1)• Malaria  • Caused by Plasmodium sp. carried by Anophele...
Case Study: Malaria — The Spread of a         Deadly Parasite (2)• Malaria on the rise since 1970   •   Drug resistant Pla...
Global Outlook: Distribution of Malaria                                    Fig. 17-6, p. 444
A Boy in Brazil’s Amazon Sleeps Under an   Insecticide-Treated Mosquito Net                                      Fig. 17-7...
Solutions: Infectious Diseases                                 Fig. 17-8, p. 445
Some Chemicals Can Cause Cancers,    Mutations, and Birth Defects• Toxic chemicals  • Carcinogens     • Chemicals, types o...
Potential Pathways on Which Toxic Chemicals      Move Through the Environment                                       Fig. 1...
Some Chemicals May Affect Our Immune        and Nervous Systems• Some natural and synthetic chemicals in the  environment ...
Science Focus: Mercury’s Toxic                 Effects (1)• Hg: teratogen and potent neurotoxin   •   Once airborne, persi...
Science Focus: Mercury’s Toxic               Effects (2)• Effects of Hg on humans   • Damage nervous system, kidneys, lung...
Solutions: Mercury Pollution                               Fig. 17-10, p. 449
Some Chemicals Affect the Human          Endocrine System• Glands that release hormones that regulate bodily  systems and ...
Hormones and Hormones Mimics or           Blockers                             Fig. 17-11, p. 449
Many Factors Determine the Harmful   Health Effects of a Chemical (1)• Toxicology• Toxicity dependent on  •   Dose  •   Ag...
Many Factors Determine the Harmful  Health Effects of a Chemical (2)• Response  • Acute effect: immediate or rapid  • Chro...
Science: Estimating Human Exposure toChemicals and Measuring Their Effects                                   Fig. 17-12, p...
Case Study: Protecting Children from Toxic                Chemicals • Infants and children more susceptible    • Eat, drin...
Scientists Use Live Lab Animals and Nonanimal           Tests to Estimate Toxicity (1)• Mice and rats   • Systems are simi...
Scientists Use Live Lab Animals and Nonanimal          Tests to Estimate Toxicity (2) • More humane methods using animals ...
Toxicity Ratings and Average Lethal Doses                for Humans                                    Table 17-1, p. 453
Are Trace Levels of Toxic Chemicals               Harmful?• Insufficient data for most chemicals• We are all exposed to to...
Why Do We Know So Little about the   Harmful Effects of Chemicals?• Severe limitations estimating toxicity levels and risk...
Pollution Prevention and the Precautionary                 Principle  • Those introducing a new chemical or new    technol...
The Greatest Health Risks Come fromPoverty, Gender, and Lifestyle Choices• Risk analysis   • Risk assessment   • Risk mana...
Global Outlook: Number of Deaths per      Year in the World from Various CausesNumbers in parentheses represent death toll...
Comparison of Risks People Face in Terms of        Shorter Average Life Span                                       Fig. 17...
Most People Do a Poor Job of Evaluating                Risks1. Fear2. Degree of control3. Whether a risk is catastrophic o...
Several Principles Can Help Us to Evaluate             and Reduce Risk 1. Compare risks 2. Determine how much you are will...
Three Big Ideas1. We face significant hazards from infectious diseases,   malaria, and tuberculosis, and from exposure to ...
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Bio 105 Chapter 17

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  • 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.
  • Figure 17.2: S cience. 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?
  • Figure 17.3: S cience. 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?
  • 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 )
  • 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 )
  • 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 www.Malaria N oMore.or g .
  • 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?
  • Figure 17.9: PCBs and other persistent toxic chemicals can move through the living and nonliving environment on a number of pathways.
  • 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?
  • 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.
  • Figure 17.12: S cience. 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?
  • 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)
  • 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)
  • Bio 105 Chapter 17

    1. 1. MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17TH Chapter 17 Environmental Hazards and Human Health
    2. 2. 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
    3. 3. 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
    4. 4. 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
    5. 5. Baby Drinking from BPA Bottle Fig. 17-1, p. 436
    6. 6. Risks Are Usually Expressed as Probabilities • Risk • Probability of suffering harm from a hazard • Probability vs. possibility • Risk Assessment • Risk Management
    7. 7. Science: Risk Assessment and Risk Management Fig. 17-2, p. 437
    8. 8. We Face Many Types of Hazards1. Biological: • Pathogen: an organism that causes disease in other organisms2. Chemical3. Physical4. Cultural5. Lifestyle choices
    9. 9. 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
    10. 10. 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
    11. 11. 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
    12. 12. Science: Pathways for Infectious Diseases in Humans Fig. 17-3, p. 439
    13. 13. Major Causes of Death from Infectious Diseases in the World, 2007 Fig. 17-4, p. 439
    14. 14. Science Focus: Genetic Resistance to Antibiotics Is Increasing (1)• Bacteria: rapid reproduction, easily spread• Overuse of antibiotics• Overuse of pesticides
    15. 15. 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
    16. 16. Viral Diseases and Parasites Kill Large Numbers of People (2)• Viruses that move form animals to humans • West Nile virus • Swine flu (H1N1) • Bird flu• Reduce chances of infection: 1. Wash your hands 2. Avoid touching your face 3. Avoid sick people
    17. 17. Case Study: Malaria — The Spread of a Deadly Parasite (1)• Malaria • Caused by Plasmodium sp. carried by Anopheles mosquitoes • Tropical and subtropical regions • Malarial cycle
    18. 18. 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
    19. 19. Global Outlook: Distribution of Malaria Fig. 17-6, p. 444
    20. 20. A Boy in Brazil’s Amazon Sleeps Under an Insecticide-Treated Mosquito Net Fig. 17-7, p. 445
    21. 21. Solutions: Infectious Diseases Fig. 17-8, p. 445
    22. 22. 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
    23. 23. Potential Pathways on Which Toxic Chemicals Move Through the Environment Fig. 17-9, p. 447
    24. 24. 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
    25. 25. 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? 1. Inhalation: vaporized Hg or particulates 2. Eating fish with high levels of methylmercury 3. Eating high-fructose corn syrup
    26. 26. 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
    27. 27. Solutions: Mercury Pollution Fig. 17-10, p. 449
    28. 28. 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-increase plastic flexibility
    29. 29. Hormones and Hormones Mimics or Blockers Fig. 17-11, p. 449
    30. 30. Many Factors Determine the Harmful Health Effects of a Chemical (1)• Toxicology• Toxicity dependent on • Dose • Age • Genetic makeup • Solubility • Persistence • Biomagnification
    31. 31. Many Factors Determine the Harmful Health Effects of a Chemical (2)• Response • Acute effect: immediate or rapid • Chronic effect: permanent or long-lasting
    32. 32. Science: Estimating Human Exposure toChemicals and Measuring Their Effects Fig. 17-12, p. 452
    33. 33. Case Study: Protecting Children from Toxic Chemicals • 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
    34. 34. 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
    35. 35. 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?
    36. 36. Toxicity Ratings and Average Lethal Doses for Humans Table 17-1, p. 453
    37. 37. 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?
    38. 38. 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
    39. 39. 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
    40. 40. The Greatest Health Risks Come fromPoverty, Gender, and Lifestyle Choices• Risk analysis • Risk assessment • Risk management • Risk communication• Greatest health risks • Poverty • Gender • Lifestyle choices
    41. 41. Global Outlook: Number of Deaths per Year in the World from Various CausesNumbers 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. Fig. 17-16, p. 458
    42. 42. Comparison of Risks People Face in Terms of Shorter Average Life Span Fig. 17-17, p. 459
    43. 43. Most People Do a Poor Job of Evaluating Risks1. Fear2. Degree of control3. Whether a risk is catastrophic or chronic4. Optimism bias5. Want instant gratification without thinking of future harm
    44. 44. Several Principles Can Help Us to Evaluate and Reduce Risk 1. Compare risks 2. Determine how much you are willing to accept 3. Determine the actual risk involved 4. Concentrate on evaluating and carefully making important lifestyle choices
    45. 45. Three Big Ideas1. 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.2. Because of the difficulty in evaluating the harm caused by exposure to chemicals, many health scientists call for much greater emphasis on pollution prevention.3. Becoming informed, thinking critically about risks, and making careful choices can reduce the major risks we face.

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