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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? 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

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Chapter 17 Environmental Hazards and Human Health

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  1. 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 Risk Management Comparative risk analysis Hazard identification 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? Financial commitment How much money should be spent? Consequences of risk What is the likely damage? Fig. 17-2, p. 437

  10. We Face Many Types of Hazards • Biological: • Pathogen: an organism that causes disease in other organisms • Chemical • Physical • Cultural • 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 insectsto 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. 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 Disease (type of agent) Deaths per year 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 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

  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: • Wash your hands • Avoid touching your face • 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 (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

  31. Case Study: Malaria — The Spread of a Deadly Parasite (1) • Malaria • 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 Vegetation Crops Surface water Humans Animals Surface water Water table Groundwater Fish Vegetation Groundwater Soil Water table Rock Rock 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? • Inhalation: vaporized Hg or particulates • Eating fish with high levels of methylmercury • 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. 17-10, p. 449

  47. 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 Switch from coal to natural gas and renewable energy resources Collect and recycle batteries and other products containing mercury Fig. 17-10, 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. 17-11, p. 449

  50. Hormone Estrogen-like chemical Antiandrogen chemical Receptor Cell Hormone Mimic Normal Hormone Process Hormone Blocker Fig. 17-11, p. 449

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