Environmental Sciences: Towards a Sustainable Future Chapter 15

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. 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. 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 1948. 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 2025- 73 • 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. Figure 15-3 page 388 Cultural Hazards

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. 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. 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. 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. Risk Analysis • 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. 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.