1. Environmental Sciences: Towards a Sustainable Future Chapter 15
Environmental Hazards and Human Health

2. Chapter Introduction

3. Avian Flu H5N1 1st appeared in Hong Kong in 1997.
Recently found in migratory birds.
First human case in 2003.
May 22, 2006 a 32 year old man dies after contracting the disease from a family member.
How can this be?

4. Viruses
Viral RNA may mix strands so if someone were to contract avian flu while stricken with another type of flu, the two strands can mix forming a new virulent strand which may be passed from human to human.
38 diseases in the last 25 years have jumped from animal to human.

5. Environmental Health
The study of the connections between hazards in the environment and human disease and death.

6. Links between human health and the environment
Lesson 15.1
Links between human health and the environment

7. Some Definitions
Environment: combination of physical, chemical, and biological factors of where and how people live.
Hazard: anything that can cause
injury, death, disease
damage to personal/public property
or deterioration or destruction of environmental components.
Existence of the hazard doesn’t mean that undesirable consequences will follow.

8. RISK= Hazard x Vulnerability
Vulnerability: some people, especially the poor, are more vulnerable to certain risks than others.
Risk: probability of suffering a loss as a result of exposure to a hazard
RISK= Hazard x Vulnerability

9. Example: Presence of avian flu is the hazard.
This presents a risk to humans contracting the disease.
People who work with poultry are more vulnerable.

10. The CDC Center for Disease Control
In the United States it is the lead federal agency in charge of protecting the health and safety of the public.
Agency under the Department of Health and Human Services.
Other countries: Ministry of Health
Limitations:
Funding and information

11. The WHO World Health Organization
Sub unit of the United Nations (therefore all countries have access to their information)
Located in Geneva (and maintaining 6 other regional offices) it was established in Their mission is to enable “all peoples to attain the highest possible level of health”.

12. The Report
Written in 2002
Entailed: Reducing risks, promoting healthy life, presentation of major risk factors “for which the means to reduce them are unknown”

13. Universal Indicator of Health:
Human life expectancy.
1955-global life expectancy was 48
2008- global life expectancy is 67 By
This progress is a result of social, medical, and economic advances in the latter half of the 20th century.

14. Most lethal Hazards:
Some of the most lethal hazards are the result of voluntary behavior.

15. Two fundamental ways to consider hazards to human health:
Lack of access to necessary resources.
Water
Nutritious food
Exposure to hazards in the environment.
Cultural, biological, physical, chemical,

16. Morbidity: The incidence of disease.
Mortality: The incidence of death.
Epidemiology: The study of the presence, distribution, and control of disease in populations.

17. Causes of Human Mortality
Figure 15-2 page 388

18. Environmental Hazards
Cultural
Biological
Physical
Chemical

19. Cultural Hazards Consequence of choice Risky behavior
Thus we may: eat too much, drive too fast, use addictive drugs, consume alcohol, smoke, sunbathe, etc.

20. Cultural Hazards
Figure 15-3 page 388

21. Smoking-related Diseases

22. Biological Hazards Pathogenic bacteria Fungi Viruses Protozoans Worms
Table 15-1 page 389 gives a list of many infectious diseases and the estimated number of deaths yearly.

23. Infectious Diseases
More prevalent in but not exclusive to developing countries
Contamination of food and water
Lack of resources for sanitation
Lack of education
Ideal climates for transmission of vector-borne (host carried: like the ticks from the chapter intro) diseases like malaria

24. Physical Hazards
Natural disasters, e.g., tornadoes, floods, hurricanes, and wildfires
Avoidance of risk important in prevention, e.g., building homes in flood plains, and living on the coast.
Not all disasters can be avoided

25. Chemical Hazards Result of industrialization
Exposure through ingestion, inhalation, absorption through skin
May be direct use or accidental
Many chemicals are toxic at low levels

26. 188 chemicals are reasonably anticipated to be carcinogenic
Chemical Hazards
188 chemicals are reasonably anticipated to be carcinogenic
Environmental carcinogens initiate mutations in DNA; several mutations lead to a malignancy (cancer).

27. Lesson 15.2
Pathways of Risk

28. Figure 15-9 p. 395 Top 10 leading GLOBAL risk factors.
Underweight, unsafe sex, blood pressure, tobacco use, alcohol use, unsafe water/sanitation/hygeine, cholesterol, indoor smoke from solid fuels, iron deficiency, overweight.
These 10 are responsible for 1/3 of the mortality.

29. Pathways to health hazards
Poverty: developed and developing.
Lack of access to clean water, adequate health care, nutritional foods, healthy air, sanitation and shelter.
The wealthier a nation becomes, the healthier its population.

30. Life spans
65% of developed nation citizens live to full life expectancy and die of “old age” vs. 33% in developing nations.

31. Environmental Health
Factors contributing to the environmental health of a nation include:
Education
Nutrition
Commitment from government
More equitable distribution of wealth

32. Cultural Risk of Smoking
80% of smokers are in developing world.
Synergistic effect: smokers living in polluted areas, higher risk.
Jan 1993-EPA classifies secondhand smoke as a class A carcinogen.
Class A = known human carcinogen

33. In response to being classified “Class A”…
Substantial fallout: smoke free zones in malls, work places, bars restaurants, etc.
2% decrease in second hand smoke = in terms of human exposure to harmful particulates of eliminating all coal-fired power plants in the country.

34. Reasons in developing countries:
Infectious disease
Reasons in developing countries:
Contaminated food
Contaminated water
Inadequate hygiene
Lack of adequate sewage
Back to lack of education, wealth, nutrition!
Developed causes:
Factory like production of food
Inadequate surveillance.

35. Three factors in the developed world
Indoor Air Pollution
Three factors in the developed world
Hazardous fumes from home products
Well-insulated buildings
Long exposure to indoor air (90% time spent indoors)
*Humans breath 30lb of air in each day!

36. Indoor Air Pollution
Developing countries:
Results from burning biofuels (wood, dung) inside homes
Acute respiratory infections in children
Chronic lung diseases
Lung cancer
Birth-related problems

37. Three categories of impact on human health:
Chronic: gradual deterioration over a period of time.
Acute: life-threatening reactions within a matter of hours or days.
Carcinogenic: pollutants initiate changes in cells that lead to uncontrolled growth and division (cancer).

38. Disaster Risk Reduction:
The publication of Living with Risk: A Global Review of Disaster Reduction Initiatives (2004) by the Inter-agency Secretariat of the International Strategy for Disaster Reduction
The UN World Conference on Disaster Reduction (January 2005) by 168 country delegates who met in Kobe, Japan.
Created the Hyogo Framework for Action

39. Hyogo Framework for Action
Make disaster risk reduction a priority.
Know the risks and take action.
Build understanding and awareness.
Reduce risk.
Be prepared and ready to act.

40. Lesson 15.3
Risk Assessment

41. Governmental Stewards
If governments are to be stewards of the health of their people, they need the kind of information a thorough evaluation of health risk can bring them.

42. Risk Assessment
The process of evaluating the risks associated with a particular hazard before taking some action in which the particular hazard is present.

43. The Truth Most people do not make choices based upon risk assessment.
They make them based upon familiarity, control, etc.
Risk assessment is an important process in the development of public policy
Major way of applying sound science to the problems of environmental regulation according to the WHO.

44. Risk assessment
Began in the mid-1970’s by the EPA as a way of addressing the cancer risks associated with pesticides and toxic chemicals.
There are four steps associated with the process (updated in 2005).

45. 4 steps to EPA’s risk analysis.
Hazard assessment (Linking hazard to its effects)
Dose-response assessment (how much, how severe)
Exposure assessment (how long)
Risk characterization (putting it all together to decide the risk and its accompanying uncertainties)

46. Cost-benefit analysis Risk-benefit analysis Public preferences
Risk Management
Usually involves:
Cost-benefit analysis
Risk-benefit analysis
Public preferences

47. Risk Perception: Hazard vs. Outrage
Hazard expresses primarily a concern for fatalities while outrage expresses a number of additional concerns.
Outrage includes:
Lack of familiarity
Extent to which the risk if voluntary
Media attention
Lack of trust in scientists and industry
Morality
Control
Fairness

48. Hazard Assessment
Process of examining evidence linking a potential hazard to its harmful effects.
Sometimes the link is not so clear.
Time delay between the incident and its effect.
In the end hazards assessment tells us we may have a problem.

49. Animal Testing:
Several hundred animals (usually mice). Takes 3 years. Costs $250,000.
If a significant number of animals develop tumors, then the substance is listed as a possible human carcinogen.
Objections:
Rodents and humans may have very different responses.
The dose difference in the animals vs. the human.
Ethics.

50. Dose-response and exposure
Dose-response: the concentration of the chemical with respect to the severity of the response. At this point vulnerability may then be introduced.
Exposure: Identifying humans already exposed to the chemical, how they became exposed and calculating the dose and length of time.

51. Risk characterization:
Pulls together the first three steps (risk assessment, hazard assessment, and dose-response exposure assessment) in order to determine the risk and its accompanying uncertainty.
The limit: analysts must work with the available information, which never seems sufficient.

52. World Health Report WHO, 2002.
Looked at the following criteria with respect to risk assessment:
Potential global impact.
High likelihood of casualty.
Modifiability.
Availability of data.

53. DALY Data must be assessed with a common “currency”.
Disability adjust life year
Represents the loss of one healthy year of a person’s life.

54. Risk Assessment/Management
Some suggest we use distributive justice in making decisions about risk
Ethical process of making certain that everyone receives proper consideration
Should reduce environmental racism/injustice

55. Risk Assessment/Management
Not a perfect system
Precautionary principle
Lack of certainty should not be used as a reason for preventing environmental degradation/hazards