- 1. 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.
- 2. There is no vaccine for HIV if you get AIDS, you will
eventually die from it.
3. Drugs help some infected people live longer, but only a tiny
fraction can afford them. 4. Core Case Study: The Global HIV/AIDS
Epidemic
- AIDS has reduced the life expectancy of sub-Saharan Africa from
62 to 47 years 40 years in the seven countries most severely
affected by AIDS.
Projected age structure of Botswana's population in 2020. Figure
18-2 5. RISKS AND HAZARDS
- Risk is a measure of the likelihood that you will suffer harm
from a hazard.
6. We can suffer from:
-
- Biological hazards : from more than 1,400 pathogens.
- 7. Chemical hazards : in air, water, soil, and food.
8. Physical hazards : such as fire, earthquake, volcanic
eruption 9. Cultural hazards : such as smoking, poor diet, unsafe
sex, drugs, unsafe working conditions, and poverty. 10. BIOLOGICAL
HAZARDS:DISEASE IN DEVELOPED AND DEVELOPING COUNTRIES
- Diseases not caused by living organisms cannot spread from one
person to another ( nontransmissible disease ), while those caused
by living organisms such as bacteria and viruses can spread from
person to person ( transmissibleorinfectious )
11. Transmissible Disease
- Pathway for infectious disease in humans.
Figure 18-4 12. Transmissible Disease
- WHO estimates that each year the worlds seven deadliest
infections kill 13.6 million people most of them the poor in
developing countries.
Figure 18-5 13. Case Study: Growing Germ Resistance to
Antibiotics
- Rabidly producing infectious bacteria are becoming genetically
resistant to widely used antibiotics due to:
-
- Genetic resistance : Spread of bacteria around the globe by
humans, overuse of pesticides which produce pesticide resistant
insects that carry bacteria.
- 14. Overuse of antibiotics : A 2000 study found that half of
the antibiotics used to treat humans were prescribed
unnecessarily.
15. 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.
-
-
- 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.
16. 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.
- 17. Concentrate on groups in a society that are likely to
spread the disease.
18. Provide free HIV testing and pressure people to get tested.
19. Implement educational programs. 20. Provide free or low-cost
drugs to slow disease progress. 21. 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 22.
- 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.
Case Study:Malaria Death by Mosquito 23. Ecological Medicine
andInfectious Diseases
- Mostly because of human activities, infectious diseases are
moving at increasing rates from one animal species to another
(including humans).
24. Ecological (or conservation) medicine is devoted to tracking
down these connections between wildlife and humans to determine
ways to slow and prevent disease spread. 25. CHEMICAL HAZARDS
- A toxic chemical can cause temporary or permanent harm or
death.
-
- Mutagensare chemicals or forms of radiation that cause or
increase the frequency of mutations in DNA.
- 26. Teratogensare chemicals that cause harm or birth defects to
a fetus or embryo.
27. Carcinogensare chemicals or types of radiation that can
cause or promote cancer. 28. CHEMICAL HAZARDS
- A hazardous chemical can harm humans or other animals because
it:
30. An irritant 31. Interferes with oxygen uptake 32. Induce
allergic reactions. 33. Effects of Chemicals on the Immune,
Nervous, and Endocrine Systems
- Long-term exposure to some chemicals at low doses may disrupt
the bodys:
-
- Immune system : specialized cells and tissues that protect the
body against disease and harmful substances.
- 34. Nervous system : brain, spinal cord, and peripheral
nerves.
35. Endocrine system : complex network of glands that release
minute amounts of hormones into the bloodstream. 36. Effects of
Chemicals on the Immune, Nervous, and Endocrine Systems
- Molecules of certain synthetic chemicals have shapes similar to
those of natural hormones and can adversely affect the endocrine
system.
Figure 18-9 37. Case Study:A Black Day in Bhopal, India
- The worlds 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.
- 38. 15,000-22,000 people died
39. Indian officials claim that simple upgrades could have
prevented the tragedy. 40. TOXICOLOGY: ASSESSING CHEMICAL
HAZARDS
- Factors determining the harm caused by exposure to a chemical
include:
-
- The amount of exposure (dose).
- 41. The frequency of exposure.
42. The person who is exposed. 43. The effectiveness of the
bodys detoxification systems. 44. Ones genetic makeup. 45.
TOXICOLOGY: ASSESSING CHEMICAL HAZARDS
- Typical variations in sensitivity to a toxic chemical within a
population, mostly because of genetic variation.
Figure 18-10 46. 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.
Figure 18-11 47. 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 48. 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.
- 49. They are exposed to toxins when they put their fingers or
other objects in their mouths.
50. Children usually have less well-developed immune systems and
detoxification processes than adults. 51. TOXICOLOGY: ASSESSING
CHEMICAL HAZARDS
- Under existing laws, most chemicals are consideredinnocent
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.
52. 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.
53. Some health scientists contend that regulators should assume
children at a risk 100 times that of adults. 54. 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 ).
55. Manufacturers contend that wide-spread application of the
precautionary principle would make it too expensive to introduce
new chemicals and technologies. 56. How Would You Vote? Should we
rely more on the precautionary principle as a way to reduce the
risks from chemicals and technologies?
-
- a. No. Assuming that every chemical or technology is a serious
health or environmental threat will lead to wasteful
over-regulation, high costs and hinder the development of
critically needed pesticides, plastics, and other commercial
products.
- 57. b. Yes. Preventing the commercialization of harmful
chemicals and technologies is better than dealing with the high
costs of medical treatments and environmental damage.
58. RISK ANALYSIS
- Scientists have developed ways to evaluate and compare risks,
decide how much risk is acceptable, and find affordable ways to
reduce it.
Figure 18-12 59. Fig. 18-12, p. 433 Comparative Risk Analysis
Most Serious Ecological and Health ProblemsHigh-Risk Health
Problems Indoor air pollution Outdoor air pollution Worker chemical
exposurePollutants 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 insurface waters Low-Risk Ecological Problems Oil spills
Groundwater pollution Radioactive isotopes Acid runoff to surface
waters Thermal pollution 60. 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%.
61. RISK ANALYSIS
- Annual deaths in the U.S. from tobacco use and other causes in
2003.
Figure 18-A 62. 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.
Figure 18-13 63. Fig. 18-13, p. 435 Cause of death Annual deaths
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) 64. Perceiving Risk
- Most individuals evaluate the relative risk they face based
on:
66. Whether we voluntarily take the risk. 67. Whether risk is
catastrophic. 68. Unfair distribution of risk. Sometimes misleading
information, denial, and irrational fears can cloud judgment. 69.
RISK ANALYSIS
- Comparisons of risks people face expressed in terms of shorter
average life span.
Figure 18-14 70. Fig. 18-14, p. 436 Shortens average life span
in the U.S. by Hazard Poverty Born male 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 710 years 71. Becoming Better at
Managing Risk
- We can carefully evaluate or tune out of the barrage of bad
news covered in the media, compare risks, and concentrate on
reducing personal risks over which we have some control.
Figure 18-3