1. Apes Ch 11 Risk, Toxicology, and Human Healthy
Student Guide to Notes
May 2007

2. Risk Risk is the possibility of suffering harm for a hazard
Risk = exposure X harm
1 in 1M or 1 in 1B

3. Risk Assessment
How is risk (probability) determined?

4. Risk Assessment Three components (229)
Contrast biological, physical, and chemical hazards
Contrast to risk management – why is this more difficult than risk assessment?
Key components of risk management

5. Risk and Probability
Fig p. 229

6. Toxicity What factors determine whether a chemical is harmful?
Are all people at equal risk for a given dose and time of exposure?
Explain your answer
Should the regulatory levels be set for “average” sensitivity or most sensitive
Discuss pros of cons of each approach

7. © 2004 Brooks/Cole – Thomson Learning
Figure 11-3 Page 230
© 2004 Brooks/Cole – Thomson Learning
Number of individuals affected
Very
sensitive
Majority
of population
Very
insensitive 20 40 60 80
Dose (hypothetical units)

8. How much is concerning? Chemical Concentration
What has happened to our ability to determine concentration levels?
Can all substances be harmful?
Why are some different than others?
Levels of detection – can now identify much lower amounts – how does this affect risk management?

9. Degree of a Substances Harm
Solubility
Persistence
Bioaccumulation
Biomagnification
Chemical interactions
Antagonistic interaction
Synergistic interaction

10. Figure 11-4 Page 231 DDT in fish-eating birds (ospreys) 25 ppm
DDT in large
fish (needle fish)
2 ppm
DDT in small
fish (minnows)
0.5 ppm
DDT in
zooplankton
0.04 ppm
DDT in water
ppm,
Or 3 ppt
Figure 11-4 Page 231

11. Threshold Levels (231-232) Define
Why do some chemicals have threshold and some do not?
How does body deal with some toxins?

12. 100 75 50 25 2 4 6 8 10 12 14 16
Percentage of population killed by a given dose
Dose (hypothetical units) LD
© 2004 Brooks/Cole – Thomson Learning
Figure 11-5 Page 231

13. What is a Poison? Discuss LD50
Using animals to determine toxicity and LD50
Advantages
Disadvantages
Why use acute levels of exposure when humans generally exposed to chronic levels?
Alternatives to animal testing

14. Toxicity Ratings and Average Lethal Doses
Study and discuss Table 11-1
How is toxicity estimated (232)?
Animal tests
Alternatives: tissue and cel cultures
Chick egg membranes

15. Dose-Response Curve
Acute toxicity levels

16. © 2004 Brooks/Cole – Thomson Learning
Nonlinear
dose-response
Nonlinear
dose-response
Linear
dose-response
Linear
dose-response
Effect
Effect
Threshold
level
Dose
Dose
Threshold – many carcinogens and teratogens
No threshold
Figure 11-6 Page 233

17. Hazardous Substances and Wastes Toxic or poisons
Mutagenic
Teratogenic
Carcinogenic
Harmful to immune, endocrine or nervous systems
Examples of each of above

18. Other Hazardous Materials and Wastes (233 and 527)
Flammable or explosive
Reactive (with other substances)
Corrosive
To humans and materials

19. Regulation and testing of hazardous substances
“Toxicologists know a great deal about a few chemicals, a little about many, and next to nothing about most.”
Explain why this is the case
Apply precautionary approach – relate directly to hazardous chemicals

20. Biological Hazards (236) Non-transmissible diseases
Discuss those related to environmental issues
Transmissible diseases
Name pathogens
Name vectors
Relate several to environmental issues as discussed this year ( )
Focus on malaria & relate to environmental issues

21. Risk Analysis
Fig p. 247
Contrast to risk management – why is this more difficult than risk assessment?

22. © 2004 Brooks/Cole – Thomson Learning
Risk
probability
Risk
assessment
Risk
severity
Acceptability of a Risk
Is the risk acceptable?
Expressed
preferences
Cost–benefit
Acceptable if
benefits
outweigh costs
Acceptable if
people agree to
accept the risks
Natural
standards
Revealed
preferences
Acceptable if
risk is not
greater than
those created by
natural hazard
Acceptable if
risk is not
greater than
those currently
tolerated
Figure Page 247

23. Figure 11-15 Page 246 Scientists (Not in rank order in each category)
Citizens
(In rank order)
High-Risk Health Problems
• Indoor air pollution
• Outdoor air pollution
• Worker exposure to industrial
or farm chemicals
• 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 and destruction
• Species extinction and loss of biodiversity
High-Risk Problems
• Hazardous waste sites
• Industrial water pollution
• Occupational exposure
to chemicals
• Oil spills
• Stratospheric ozone depletion
• Nuclear power-plant accidents
• Industrial accidents releasing
pollutants
• Radioactive wastes
• Air pollution from factories
• Leaking underground tanks
Medium-Risk Problems
• Coastal water contamination
• Solid waste and litter
• Pesticide risks to farm workers
• Water pollution from
sewage plants
Medium-Risk Ecological Problems
• Acid deposition
• Pesticides
• Airborne toxic chemicals
• Toxic chemicals, nutrients, and
sediment in surface waters
Figure Page 246
Low-Risk Ecological Problems
• Oil spills
• Groundwater pollution
• Radioactive isotopes
• Acid runoff to surface waters
• Thermal pollution
Low-Risk Problems
• Air pollution from vehicles
• Pesticide residues in foods
• Global climate change
• Drinking water contamination