1. Chapter 17 Managing Risk In the 21 st Century Environmental Hazards and Human Health

2. Chapter Overview Questions  What types of hazards do people face? Biological- bacteria, viruses, protists, fungi, animal parasites Biological- bacteria, viruses, protists, fungi, animal parasites Chemical- toxins, mutagens, teratogens, carcinogens Chemical- toxins, mutagens, teratogens, carcinogens Physical- fires, earthquakes, weather Physical- fires, earthquakes, weather Cultural- driving, smoking, poor diet, crime, poverty, unsafe sex Cultural- driving, smoking, poor diet, crime, poverty, unsafe sex  What types of disease (biological hazards) threaten people in developing countries and developed countries?

3. Chapter Overview Questions  How can risks be estimated and recognized? Risk analysis (a potential career!): Risk analysis (a potential career!): Risk assessmentRisk assessment Comparative risk analysis (ranking risks)Comparative risk analysis (ranking risks) Risk management (making decisions)Risk management (making decisions) Risk communication (informing politicians & the public)Risk communication (informing politicians & the public)

4. Core Case Study: The Global HIV/AIDS Epidemic  According to the World Health Organization (WHO), in 2005 about 42 million people worldwide (1.1 million in the U.S.) were infected with HIV.  There is no vaccine for HIV – if you get AIDS, you will eventually die from it.  Drugs help some infected people live longer, but only a tiny fraction can afford them.  Costs are starting to come down a bit

5. Core Case Study: The Global HIV/AIDS Epidemic  AIDS has reduced the life expectancy of sub- Saharan Africa from 62 to 40– 47 years in the seven countries most severely affected by AIDS. Projected age structure of Botswana's population in 2020. Figure 18-2

6. Core Case Study: The Global HIV/AIDS Epidemic HIV Positive AIDS Becoming Infected Developing AIDS Dying 4.9 million per year 7-10 yrs 3 million per year (13,400 per day) Year 2005 data 42 million Eventually, “all”

7. Core Case Study: The Global HIV/AIDS Epidemic  The virus itself is not deadly, but it cripples the immune system, leaving the body susceptible to infections such as Kaposi’s sarcoma (above). Figure 18-1

8. Viral Diseases  HIV is the second biggest killer virus worldwide. Five major priorities to slow the spread of the disease are: Quickly reduce the number of new infections to prevent further spread. Quickly reduce the number of new infections to prevent further spread. Concentrate on groups in a society that are likely to spread the disease. Concentrate on groups in a society that are likely to spread the disease. Provide free HIV testing and pressure people to get tested. Provide free HIV testing and pressure people to get tested. Implement educational programs. Implement educational programs. Provide free or low-cost drugs to slow disease progress. Provide free or low-cost drugs to slow disease progress.

9. RISKS AND HAZARDS  Risk is a measure of the likelihood that you will suffer harm from a hazard.  We can suffer from: Biological hazards: from more than 1,400 pathogens (disease-causing organisms) Biological hazards: from more than 1,400 pathogens (disease-causing organisms) Chemical hazards: in air, water, soil, and food. Chemical hazards: in air, water, soil, and food. Physical hazards: such as fire, earthquake, volcanic eruption… Physical hazards: such as fire, earthquake, volcanic eruption… Cultural hazards: such as smoking, poor diet, unsafe sex, drugs, unsafe working conditions, and poverty. Cultural hazards: such as smoking, poor diet, unsafe sex, drugs, unsafe working conditions, and poverty.

10. BIOLOGICAL HAZARDS: DISEASE IN DEVELOPED AND DEVELOPING COUNTRIES  Nontransmissible Diseases- not caused by living organisms cannot spread from one person to another cannot spread from one person to another  Transmissible a.k.a. Infectious Diseases- caused by living organisms such as bacteria and viruses can spread from person to person… “contagious” can spread from person to person… “contagious”

11. Transmissible Disease  Vectors: Pathways for infectious disease in humans. Next

12. Fig. 18-4, p. 420 Pets Livestock Wild animals MosquitoesFood Water Air Fetus and babies Other humansHumans Vectors of Transmissible Diseases Baby, I’m A-L-L-L Clean! Yeah……. keep talkin’……

13. Transmissible Disease  WHO estimates that each year the world’s seven deadliest infections kill 13.6 million people – most of them the poor in developing countries. Next

14. Fig. 18-5, p. 420 Disease (type of agent) Deaths per year Flu and pneumonia (viruses & bacteria) 3.2 million HIV/AIDS (virus) 3.0 million Malaria (protozoa) 2.0 million Diarrheal diseases (viruses, bacteria, protozoa) 1.9 million Tuberculosis (bacteria) 1.7 million Hepatitis B (virus) 1 million Measles (virus) 800,000

15. Case Study: Growing Germ Resistance to Antibiotics  Rapidly reproducing infectious bacteria are becoming genetically resistant to widely used antibiotics due to: Overuse of antibiotics: A 2000 study found that half of the antibiotics used to treat humans were prescribed unnecessarily (also, MOST are used in animal feed to hasten growth) Overuse of antibiotics: A 2000 study found that half of the antibiotics used to treat humans were prescribed unnecessarily (also, MOST are used in animal feed to hasten growth) Genetic resistance: Spread of bacteria around the globe by humans; overuse of pesticides which produce pesticide resistant insects that carry bacteria. Genetic resistance: Spread of bacteria around the globe by humans; overuse of pesticides which produce pesticide resistant insects that carry bacteria.

16. Case Study: The Growing Global Threat from Tuberculosis  The highly infectious tuberculosis bacterium (TB) kills 1.7 million people per year and could kill 25 million (total) people by 2020.  Recent increases in TB are due to: Lack of TB screening and control programs especially in developing countries due to expenses (half do not known they are infected) Lack of TB screening and control programs especially in developing countries due to expenses (half do not known they are infected) Drugs must be taken every day for 6-8 months Drugs must be taken every day for 6-8 months Genetic resistance to the most effective antibiotics (symptoms disappear in in a few weeks, patients stop taking their medicine) Genetic resistance to the most effective antibiotics (symptoms disappear in in a few weeks, patients stop taking their medicine)

17. Viral Diseases  Flu, HIV, and hepatitis B viruses infect and kill many more people each year then highly publicized West Nile and SARS viruses. The influenza virus is the biggest killer virus worldwide. The influenza virus is the biggest killer virus worldwide. Pigs, chickens, ducks, and geese are the major reservoirs of flu.Pigs, chickens, ducks, and geese are the major reservoirs of flu. As they move from one species to another, they can mutate and exchange genetic material with other viruses, hastening viral evolutionAs they move from one species to another, they can mutate and exchange genetic material with other viruses, hastening viral evolution

18. Case Study- Flu Pandemics  Common flu kills about 2% of those infected.  Occasionally, flu strains develop that kill 80% of those infected. 1918- Spanish Flu- killed 20-50 million worldwide 1918- Spanish Flu- killed 20-50 million worldwide 500,000 deaths in USA500,000 deaths in USA People woke up healthy, died by nightfallPeople woke up healthy, died by nightfall 1957- Asian Flu- killed 1-4 million people 1957- Asian Flu- killed 1-4 million people 1968- Hong Kong Flu- killed 1-4 million people 1968- Hong Kong Flu- killed 1-4 million people

19. Case Study- Flu Pandemics  Many health scientists believe that sooner or later, a potent flu pandemic will sweep the world again. Hastened by global air travel Hastened by global air travel Could infect 25% of the world’s people and kill between 2 and 360 million people worldwide Could infect 25% of the world’s people and kill between 2 and 360 million people worldwide Worst-case, USA: 1.9 million dead, 8.5 million hospitalized, $450 billion in economic losses, massive social & economic disruption. Worst-case, USA: 1.9 million dead, 8.5 million hospitalized, $450 billion in economic losses, massive social & economic disruption. H5N1- “bird flu”- deadly new strain of avian flu, related to 1918 flu H5N1- “bird flu”- deadly new strain of avian flu, related to 1918 flu So far, has not developed the ability to spread from humans to humansSo far, has not developed the ability to spread from humans to humans

20. Case Study: Malaria – Death by Mosquito  Malaria kills about 2 million people per year and has probably killed more than all of the wars ever fought. Figure 18-7

21. Sporozoites penetrate liver and develop into merozoites Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes Merozoites enter blood-stream and develop into gametocytes causing malaria and making infected person a new reservoir Female mosquito injects Plasmodium sporozoites into human host Plasmodium develops in Anopheles mosquito Fig. 18-7, p. 423 Stepped Art Plasmodium is an infectious protozoan

22. Case Study: Malaria – Death by Mosquito  Economists estimate that spending $2-3 billion on malaria treatment may save more than 1 million lives per year. Figure 18-6

23. Case Study: Malaria – Death by Mosquito  Columbia University economist Jeffrey Sachs- preventing malaria for one person costs 25 cents to $2.40 per year- “This is probably the best bargain on the planet” Figure 18-6

24.  Spraying insides of homes with low concentrations of the pesticide DDT greatly reduces the number of malaria cases. Under international treaty enacted in 2002, DDT is being phased out in developing countries. Under international treaty enacted in 2002, DDT is being phased out in developing countries.  Window screens & bed nets  Clear vegetation around houses  Plant trees to soak up water in marshes  Zinc & Vitamin A supplements to increase resistance to malaria Case Study: Malaria – Death by Mosquito

25.  Good news- According to the WHO: Global death rate from infectious diseases has dropped by 2/3 between 1970 & 2000 Global death rate from infectious diseases has dropped by 2/3 between 1970 & 2000 Projected to continue to decreaseProjected to continue to decrease Global immunizations of children have increased from 10% to 84% between 1971 & 2000 Global immunizations of children have increased from 10% to 84% between 1971 & 2000 Saves about 10 million lives per yearSaves about 10 million lives per year Good News/ Bad News

26.  Bad news- According to the WHO: Only 10% of global medical research & development money goes toward preventing infectious disease in developing countries Only 10% of global medical research & development money goes toward preventing infectious disease in developing countries Even though more people worldwide suffer from these diseases than all other diseases combined Even though more people worldwide suffer from these diseases than all other diseases combined Good News/ Bad News

27. Fig. 18-8, p. 424 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 Careful hand washing by all medical personnel Immunize children against major viral diseases Oral rehydration for diarrhea victims Global campaign to reduce HIV/AIDS

28. Ecological Medicine and Infectious Diseases  Mostly because of human activities, infectious diseases are moving at increasing rates from one animal species to another (including humans).  Ecological (or conservation) medicine is devoted to tracking down these connections between wildlife and humans to determine ways to slow and prevent disease spread.

29. Case Study: Ecological Medicine Fruit Bats, Pig Farms, and Japanese Encephalitis (Nipah Virus)

30. Case Study: Ecological Medicine  Malaysia, mid-1990s- clear forests for pig farms Outbreak contained: 8 pig farms closed, 1 million pigs slaughtered & disposed of Outbreak contained: 8 pig farms closed, 1 million pigs slaughtered & disposed of Virus spreads from pigs to keepers, Virus spreads from pigs to keepers, killing 40% of human victims Bat droppings infected with Nipah Virus (Japanese encephalitis) drop into pig drinking water Bat droppings infected with Nipah Virus (Japanese encephalitis) drop into pig drinking water Displaced fruit bats a.k.a. “flying foxes” move into rafters of pig barns Displaced fruit bats a.k.a. “flying foxes” move into rafters of pig barns

31. CHEMICAL RISKS  Toxic Chemicals vs Hazardous Chemicals: What is the difference? What is the difference?  Toxic means “poisonous”, e.g. too much Tylenol damages your liver.  Hazardous means “harmful”, e.g. fires & floods are hazardous, but not toxic.

32. CHEMICAL RISKS  A toxic (a.k.a. “poisonous”) chemical can cause temporary or permanent harm, or death Mutagens are chemicals or forms of radiation that cause or increase the frequency of mutations in DNA. Mutagens are chemicals or forms of radiation that cause or increase the frequency of mutations in DNA. Teratogens are chemicals that cause harm or birth defects to a fetus or embryo. Teratogens are chemicals that cause harm or birth defects to a fetus or embryo. Carcinogens are chemicals or types of radiation that can cause or promote cancer. Carcinogens are chemicals or types of radiation that can cause or promote cancer.

33. CHEMICAL RISKS  A hazardous chemical can harm humans or other animals because it: Is flammable Is flammable Is explosive Is explosive An irritant An irritant Interferes with oxygen uptake, like CO (carbon monoxide) Interferes with oxygen uptake, like CO (carbon monoxide) Induce allergic reactions. Induce allergic reactions.

34. Effects of Chemicals on the Immune, Nervous, and Endocrine Systems  Long-term exposure to some chemicals at low doses may disrupt the body’s: Immune system: specialized cells and tissues that protect the body against disease and harmful substances. Immune system: specialized cells and tissues that protect the body against disease and harmful substances. Nervous system: brain, spinal cord, and peripheral nerves. Nervous system: brain, spinal cord, and peripheral nerves. Endocrine system: complex network of glands that release minute amounts of hormones into the bloodstream. Endocrine system: complex network of glands that release minute amounts of hormones into the bloodstream.

35. HAAs: Hormonally Active Agents  Molecules of certain synthetic chemicals have shapes similar to those of natural hormones and can adversely affect the endocrine system. Next

36. Fig. 18-9, p. 427 Hormone Estrogenlike chemical Antiandrogen chemical Receptor Normal Hormone ProcessHormone MimicHormone Blocker Cell Hormonally Active Agents (HAAs) a.k.a. “gender benders” Feminization Smaller penises Lower sperm counts Hermaphroditism Aluminum DDT Mercury PCBs Phthlates Bisphenol A (BPA) Atrazine & other herbicides

37. Case Study: A Black Day in Bhopal, India  The world’s worst industrial accident occurred in 1984 at a pesticide plant in Bhopal, India. An explosion at Union Carbide pesticide plant in an underground storage tank released a large quantity of highly toxic methyl isocyanate (MIC) gas. An explosion at Union Carbide pesticide plant in an underground storage tank released a large quantity of highly toxic methyl isocyanate (MIC) gas. 15,000-22,000 people died 15,000-22,000 people died Indian officials claim that simple upgrades could have prevented the tragedy. Indian officials claim that simple upgrades could have prevented the tragedy.

38. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Typical variations in sensitivity to a toxic chemical within a population, mostly because of genetic variation. Typical variations in sensitivity to a toxic chemical within a population, mostly because of genetic variation. Figure 18-10

39. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS  Factors determining the harm caused by exposure to a chemical include: The amount of exposure (dose). The amount of exposure (dose). The frequency of exposure. The frequency of exposure. The person who is exposed (age, size, gender, etc.) The person who is exposed (age, size, gender, etc.) The effectiveness of the body’s detoxification systems. The effectiveness of the body’s detoxification systems. One’s genetic makeup. One’s genetic makeup.

40. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS  Estimating human exposure to chemicals and their effects is very difficult because of the many and often poorly understood variables involved. Next

41. Fig. 18-11, p. 431 Water pollutant levels Air pollutant levels Soil/dust levels Food pesticide levels Nutritional health Overall health Mathematical measurements & modeling ? Lifestyle Predicted level of toxicant in people Personal habits Genetic predisposition Metabolism Accumulation Excretion Lung, intestine & skin absorption rates

42. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS  Risk assessment expert Joseph V. Rodricks: “Toxicologists know a great deal about a few chemicals, a little about many, and next to nothing about most”

43. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS  Children are more susceptible to the effects of toxic substances because: Children breathe more air, drink more water, and eat more food per unit of body weight than adults. Children breathe more air, drink more water, and eat more food per unit of body weight than adults. They are exposed to toxins when they put their fingers or other objects in their mouths. They are exposed to toxins when they put their fingers or other objects in their mouths. Children usually have less well-developed immune systems and detoxification processes than adults. Children usually have less well-developed immune systems and detoxification processes than adults.

44. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS  Under existing laws, most chemicals are considered innocent until proven guilty, and estimating their toxicity is difficult, uncertain, and expensive.  Federal and state governments do not regulate about 99.5% of the commercially used chemicals in the U.S.

45. Protecting Children from Toxic Chemicals  The U.S. Environmental Protection Agency proposed that regulators should assume children have 10 times the exposure risk of adults to cancer-causing chemicals.  Some health scientists contend that regulators should assume a risk 100 times that of adults.

46. TOXICOLOGY: ASSESSING CHEMICAL HAZARDS  Some scientists and health officials say that preliminary but not conclusive evidence that a chemical causes significant harm should spur preventive action (precautionary principle).  Manufacturers contend that wide-spread application of the precautionary principle would make it too expensive to introduce new chemicals and technologies.

47. Risk analysis

48. RISK ANALYSIS  Scientists have developed ways to Evaluate and compare risks Evaluate and compare risks Decide how much risk is acceptable Decide how much risk is acceptable Find affordable ways to reduce it. Find affordable ways to reduce it. Next

49. Risk analysis Risk assessment (evaluating individual risks)Risk assessment (evaluating individual risks) Comparative risk analysis (ranking risks)Comparative risk analysis (ranking risks) Risk management (making decisions)Risk management (making decisions) Risk communication (informing politicians & the public)Risk communication (informing politicians & the public)

50. Fig. 18-12, p. 433 Comparative AVERAGE Risk Analysis Most Serious Ecological and Health Problems High-Risk Health Problems Indoor air pollution Outdoor air pollution Worker chemical exposure Pollutants in drinking water Pesticide residues on food Toxic chemicals in consumer products High-Risk Ecological Problems Global climate change Stratospheric ozone depletion Wildlife habitat alteration & destruction Species extinction, loss of biodiversity Medium-Risk Ecological Problems Acid deposition Pesticides Airborne toxic chemicals Toxic chemicals, nutrients, and sediment in surface waters Low-Risk Ecological Problems Oil spills Groundwater pollution Radioactive isotopes Acid runoff to surface waters Thermal pollution

51. RISK ANALYSIS  Estimating risks from using many technologies is difficult due to unpredictability of human behavior, chance, and sabotage.  Reliability of a system is multiplicative: If a nuclear power plant is 95% reliable and human reliability is 75%, then the overall reliability is (0.95 X 0.75 = 0.71) 71%. If a nuclear power plant is 95% reliable and human reliability is 75%, then the overall reliability is (0.95 X 0.75 = 0.71) 71%.

52. RISK ANALYSIS Figure 18-A 2003 data

53. RISK ANALYSIS  Number of deaths per year in the world from various causes. Parentheses show deaths in terms of the number of fully loaded 400-passenger jumbo jets crashing every day of the year with no survivors. Next

54. Fig. 18-13, p. 435 Cause of deathAnnual deaths (Global) Poverty/malnutrition/ disease cycle 11 million (75) Tobacco 5 million (34) Pneumonia and flu 3.2 million (22) Air pollution 3 million (21) HIV/AIDS Malaria 2 million (14) Diarrhea 1.9 million (13) Tuberculosis 1.7 million (12) Car accidents 1.2 million (8) Work-related injury & disease 1.1 million (8) Hepatitis B 1 million (7) Measles 800,000 (5) 3 million (21)

55. Perceiving Risk  Most of us are not good at evaluating risk!  Most individuals evaluate the relative risk they face based on: Fear Fear Degree of control Degree of control Optimism bias Optimism bias Whether risk is catastrophic. Whether risk is catastrophic. Instant gratification Instant gratification Unfair distribution of risk (NIMBY) Unfair distribution of risk (NIMBY)  Sometimes misleading information, denial, and irrational fears can cloud judgment.

56. RISK ANALYSIS  Comparisons of risks people face expressed in terms of shorter average life span. Figure 18-14

57. Fig. 18-14, p. 436 Shortens average life span in the U.S. byHazard Poverty xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Smoking Overweight (35%) 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 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 Lifetime near nuclear plant 10 hours 6 years 6–10 years 7.5 years 7–10 years also, Born Male

58. Becoming Better at Risk Analysis We can:  Carefully evaluate or tune out of the barrage of bad news covered in the media  Compare risks  Concentrate on reducing personal risks over which we have some control. Figure 18-3

59. Becoming Better at Risk Analysis  Read p. 464-465 “Most People Do Not Know How…” and “Several Principles…”  Write one example of each of the “five factors” that cause people to mis-evaluate risk; try to make at least two of your examples original.  Briefly describe one personal risk that you probably overestimate and one that you probably underestimate. Figure 18-3

60. Fig. 18-3, p. 419 Risk AssessmentRisk Management Hazard identification Comparative risk analysis What is the hazard? How does it compare with other risks? How much should it be reduced? Risk reduction Probability of risk How likely is the event? Risk reduction strategy How will the risk be reduced? Consequences of risk Financial commitment What is the likely damage? How much money should be spent?