Environmental Health and Toxicology
How safe is it to live on Planet Earth?
Chapter 8
Terms
Risk – possibility of suffering harm from a hazard
1.
1. Expressed as the probability of the event happening
2. Risk assessment
3.
Hazard – something that causes injury, disease, economic
loss or environmental damage
Major types of Hazards
Cultural Hazards – unsafe working conditions, smoking, poor
diet, etc.
5.
Chemical Hazards – chemicals that affect air,water, soil,or
food
6.
Physical Hazards – tornadoes, hurricanes, earthquakes,
ionizing radiation, etc.
7.
Biological Hazards – pathogens, pollen, animals
4.
Health
8.
State or complete physical, mental, and social well-being.
Disease
1.
Deleterious change in the body’s condition in response to an
environmental factor that could be:
1.
2.
3.
4.
Nutritional
Chemical
Biological
Psycological
Morbidity – factors of illness
Mortality – factors of death
5.
6.
Biological Hazards
1.
Nontransmissible diseases
1.
2.
3.
4.
5.
6.
7.
Is not caused by living organisms, does not spread from one person to another.
Cardiovascular disease
Cancer
Diabetes
Emphysema
Malnutrition
Transmissible Diseases
8.
9.
10.
11.
12.
13.
Caused by living organisms, can be spread
Pathogens – infectious agents
Vectors – non-human carriers
Bacterium
Virus
Waterborne infectious disease, diarrhea, hepatitis, typhoid fever, cholera
Infectious organisms
14. Pathogenic – disease-causing
15. Virulent – extremely severe or infectious
16.Ebola
17.Tuberculosis
18.Cholera
Viral Diseases
19. Influenza or Flu – bodily fluids and airborne emissions
20. Ebola – blood and other bodily fluid transmission
21. Rabies – transmitted by dogs, coyotes, raccoons, skunks, and
bats
22. HIV/AIDS – STD, shared needles, mother to child at birth,
blood and bodily fluids
1998 – World’s seven deadliest infectious diseases were:
23. Acute respiratory infections – pneumonia and flu (bacteria and virus)3.7 million/yr.
24. HIV/AIDS (virus) – 2.5 million/yr
25. Diarrheal disease (bacteria and virus) – 2.5 million/yr.
26. Malaria (parasitic protozoa) – 1.5 to 2.7 million/yr.
27. Tuberculosis (bacteria) – 2 million/yr
28. Measles (virus) – 1 million/yr.
29. Hepatitis B (viral) – 1 million/yr.
Silent Global Epidemic
Factors that affect the spread of transmissible
diseases
30. Migration of people, migration of vector
31. Destruction of forest areas, destroy or reduce predators of the
vectors
32. Increase of breeding grounds for vectors
33. Climate changes
34. Natural disasters
Malaria
Outbreaks
Emergent Disease
35.
36.
37.
38.
Disease that has never been known
One that has been absent for at least 20 years
AIDS
Ebola
Quality of Life
39. Disability-Adjusted Life Years – (DALY)
40.Measure of the disruption to quality of life and economic productivity
caused by illness or disability
41.40% communicable diseases
42.90% DALY loss in poorest nations
Ecological Diseases
43. Distemper in seals of western Europe
44.Pollution induced?
45. Chronic wasting disease (CWD)
46.Deer and Elk populations
47.Neurological disease – transmissible spongiform encephalopathies
(TSE)
48.
49.
50.
Mad Cow in cattle
Scrapie in sheep
Creutzfelt-Jacob disease in humans
Diseases in Developed countries
51.
Epidemiological transition
52. Childhood diseases less important, chronic diseases of adulthood become more
important
53. Heart disease, stroke, cancer, respiratory conditions
54. U.S. Deaths 1996
1. Heart attacks and strokes = 39%
2. Cancer = 24%
3. Infectious diseases = 5%
4. Accidents = 4%
Toxicology Terms:
5.
Toxicity – measure of how harmful a substance is
6. Dose: the amount of a potentially harmful substance
7. Size of dose
8. Frequency of dose
9. Who is exposed
10.
How effective is the body’s ability to detoxify
11. Response: type and amount of health damage as a result of the exposure
12.
13.
Acute effects – immediate and rapid
Chronic effect – permanent or long-lasting
Bioaccumulation
Poison
14. Legally is chemical that has a LD50 of 50 milligrams or less
per kilogram of body weight
Median lethal dose = LD50
15.
16.The amount of a chemical received in one dose that kills exactly 50%
of the animals in a test population within a 14-day period.
Levels of toxicity
How is toxicity determined
17. Case reports – reports from physicians as to the adverse health effects
or death after exposure
18. Laboratory investigations – animal testing, determine toxicity,
residence time, where the chemical affects
19. Epidemiology – study of populations of humans exposed to certain
chemical or diseases
Dose-Response curve
Dose Effect
20. Acute effect
21.Single exposure causes an immediate health crisis of some sort
22.Effects are reversible
23. Chronic effect
24.Single exposure or multiple exposures
25.Permanent effect
26. Detection limits
Chemical Hazards
27.
Toxic Chemicals – substance that is fatal to 50% of the test animals.
28.
Hazardous Chemicals – cause harm by:
1. Flammable or explosive
2. Irritating or damaging the skin or lungs (acidic or alkaline)
3. Interfering with or preventing oxygen uptake and distribution (asphyxiates, CO, H 2S)
4. Inducing allergic reactions of the immune system (allergens)
Chemical Agents
Mutagens – chemicals or radiation that causes random mutations or
changes in the DNA found in a cell
6.
Teratogens – chemicals, radiation, or viruses that cause birth defects
while the human embryo is growing
5.
7. Fetal Alcohol Syndrome
Carcinogens – chemicals, radiation or viruses that cause or promote
the growth of a malignant (cancerous) tumor, cells multiply
uncontrollably.
9. Metastasis – travel in body fluids to other parts of the body
10. Allergens
8.
11. Substances that activate the immune system
12. Antigens – recognized at a foreign substance by white blood cells, produce the
production of antibodies
13. Sick Building Syndrome – poor indoor air quality
14.
Neurotoxins
15. Attack nerve cells
16. Lead and Mercury
17. Organophosphates (Malathion, Parathion)
18.
Endocrine Hormone Disrupters
19. Chemicals that disrupt normal endocrine hormone functions
20. DDT and PCB’s
21. Sexual dysfunction
Chemical response in various organ systems
22.
Immune System
23. Ionizing radiation
24. Malnutrition
25. Viruses
26. Synthetic chemicals
27.
Nervous System
28.
29.
30.
31.
32.
33.
Neurotoxins – attack nerve cells
Chlorinated hydrocarbons (DDT, PCB’s, dioxins)
Organophosphate pesticides
Formaldehyde
Various compounds of arsenic, mercury, lead, and cadmium
Widely used industrial solvents trichloroethylene (TCE), toluene, and xylene
Reasons for so many harmful chemicals on the
market.
34. 72,000 commercial chemicals, ~1,000 new ones per year
35.Chemicals are considered harmless until proven guilty.
36.Not enough funds, personnel, facilities, test animals to prove
chemicals are harmful
37.To costly to determine interactions, or multiple exposure effects
Distribution of toxins
38. Solubility
39.Water-soluble
40.
Flushable from the system
41.Fat-soluble
42.
Life long
43. Sensitivity
44. Persistence
45.Time in the ecosystem
46.Persistent organic pollutants (POP’s)
47.PBDE polybrominated diphenyl ethers
48.Chromated copper arsenates (CCA) pressure treated lumber
49.Perflurooctane sulfonate (PFOS)
50.Atrazine – herbicide
51. Synergism
52.Chemical interaction
53.Synergistic effect
Precautionary Principle
54. pollution prevention
55. When uncertain about potential serious harm err on
precautionary side than lenient
56. Better safe than sorry.
Risk Analysis
57.
Risk Assessment –identifying hazards and evaluating their associated risks
58. Determine the types of hazards
59. Estimate the probability that each hazard will occur
60. Estimate how many people are likely to be exposed and suffer serious harm
61.
Comparative risk analysis – ranking risks
62.
Risk management – determining options and making decisions about reducing or
eliminating risks
63.
Risk communications – informing decision makers and the public about risks
Risk Assessment
Risks people face
Comparison of Risk analysis