MILLER/SPOOLMAN 17 TH LIVING IN THE ENVIRONMENT. Chapter 17 Environmental Hazards and Human Health

Transcription

1 MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT 17 TH Chapter 17 Environmental Hazards and Human Health

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 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 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 Baby Drinking from BPA Bottle Fig. 17-1, p. 436

6 17-1 What Major Health Hazards Do We Face? Concept 17-1 We face health hazards from biological, chemical, physical, and cultural factors, and from the lifestyle choices they make.

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

8 Science: Risk Assessment and Risk Management Fig. 17-2, p. 437

9 Risk Assessment Hazard identification What is the hazard? Risk Management Comparative risk analysis How does it compare with other risks? Probability of risk How likely is the event? Risk reduction How much should it be reduced? Risk reduction strategy How will the risk be reduced? Consequences of risk What is the likely damage? Financial commitment How much money should be spent? Fig. 17-2, p. 437

10 We Face Many Types of Hazards 1. Biological: Pathogen: an organism that causes disease in other organisms 2. Chemical 3. Physical 4. Cultural 5. Lifestyle choices

11 17-2 What Types of Biological Hazards Do We Face? Concept 17-2 The most serious biological hazards we fade are infectious diseases such as flu, AIDS, tuberculosis, diarrheal diseases, and malaria.

12 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

13 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

14 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

15 Science: Pathways for Infectious Diseases in Humans Fig. 17-3, p. 439

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

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

18 Major Causes of Death from Infectious Diseases in the World, 2007 Fig. 17-4, p. 439

19 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 Hepatitis B (virus) 1 million Malaria (protozoa) 900,000 Measles (virus) 800,000 Fig. 17-4, p. 439

20 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) Malaria (protozoa) 1 million 1.7 million Hepatitis B (virus) Measles (virus) 1 million 800,000 Stepped Art Fig. 17-4, p. 439

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

22 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?

23 Case Study: The Growing Global Threat from Tuberculosis One in ten will become sick with TB 1.8 million deaths each year, primarily in lessdeveloped 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

24 Lung Tissue Destroyed by Tuberculosis Fig. 17-5, p. 440

25 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

26 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

27 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: 1.Wash your hands 2.Avoid touching your face 3.Avoid sick people

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

29 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

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

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

32 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

33 Global Outlook: Distribution of Malaria Fig. 17-6, p. 444

34 A Boy in Brazil s Amazon Sleeps Under an Insecticide-Treated Mosquito Net Fig. 17-7, p. 445

35 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

36 Solutions: Infectious Diseases Fig. 17-8, p. 445

37 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 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

38 17-3 What Types of Chemical Hazards Do We Face? Concept 17-3 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.

39 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

40 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

41 Potential Pathways on Which Toxic Chemicals Move Through the Environment Fig. 17-9, p. 447

42 Atmosphere Crops Vegetation Surface water Humans Animals Vegetation Fig. 17-9, p. 447

43 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

44 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

45 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

46 Solutions: Mercury Pollution Fig , p. 449

47 Solutions Mercury Pollution Prevention Phase out waste incineration Remove mercury from coal before it is burned Control Sharply reduce mercury emissions from coal-burning plants and incinerators Label all products containing mercury Switch from coal to natural gas and renewable energy resources Collect and recycle batteries and other products containing mercury Fig , p. 449

48 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

49 Hormones and Hormones Mimics or Blockers Fig , p. 449

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

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

52 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.

53 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

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

55 Science: Estimating Human Exposure to Chemicals and Measuring Their Effects Fig , p. 452

56 Food pesticide levels Soil/dust levels Water pollutant levels Air pollutant levels Nutritional health Overall health Scientific measurements and modeling? Lifestyle Personal habits Predicted level of toxicant in people Genetic predisposition Metabolism Accumulation Excretion Lung, intestine, and skin absorption rates Fig , p. 452

57 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

58 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

59 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?

60 Hypothetical Dose-Response Curve Showing Determination of the LD50 Fig , p. 453

61 Percentage of population killed by a given dose LD Dose (hypothetical units) Fig , p. 453

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

63 Science: Two Types of Dose-Response Curves Fig , p. 454

64 Effect Nonlinear doseresponse Linear doseresponse Dose No threshold Fig a, p. 454

65 Effect Threshold level Threshold Dose Fig b, p. 454

66 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

67 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?

68 Some Potentially Harmful Chemicals Found in Most Homes Fig , p. 455

69 Nail polish Perfluorochemicals and phthalates 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 Perfume Phthalates Mattress Flame retardants in stuffing Hairspray Phthalates Food Some food contains bisphenol A Milk Fat contains dioxins and flame retardants Frying pan Nonstick coating contains perfluorochemicals Carpet Padding and carpet fibers contain flame retardants, perfluorochemicals, and pesticides TV Wiring and plastic casing contain flame retardants Sofa Foam padding contains flame retardants and 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

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

71 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

72 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

73 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

74 17-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them? Concept 17-5 We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices.

75 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

76 Global Outlook: Number of Deaths per Year in the World from Various Causes Fig , p. 458

77 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) 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

78 Comparison of Risks People Face in Terms of Shorter Average Life Span Fig , p. 459

79 Hazard Poverty Born male Smoking Overweight (35%) Unmarried Overweight (15%) Spouse smoking Driving Air pollution Alcohol Drug abuse Flu AIDS Drowning Pesticides Fire Natural radiation Medical X rays Oral contraceptives Toxic waste Flying Hurricanes, tornadoes Living lifetime near nuclear plant 1 year 7 months 5 months 5 months 4 months 4 months 3 months 1 month 1 month 1 month 8 days 5 days 5 days 4 days 1 day 1 day 10 hours Shortens average life span in the United States by 2 years 5 years 6 10 years 6 years 7 10 years 7.5 years Fig , p. 459

80 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)

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

82 Normal Lung and Emphysema Lung Fig , p. 459

83 Stepped Art Fig , p. 459

84 Annual Deaths in the U.S. from Tobacco Use and Other Causes Fig , p. 460

85 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 Suicides 30,600 Homicides 20,622 Illegal drug use 17,000 Fig , p. 460

86 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

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

88 Most People Do a Poor Job of Evaluating 1. Fear Risks 2. Degree of control 3. Whether a risk is catastrophic or chronic 4. Optimism bias 5. Want instant gratification without thinking of future harm

89 Several Principles Can Help Us to Evaluate 1. Compare risks and Reduce Risk 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

90 Three Big Ideas 1. 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.

91 Three Big Ideas 3. Becoming informed, thinking critically about risks, and making careful choices can reduce the major risks we face.