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2. Human Health
7. Health Issues in Highly Developed Countries Leading causes of death in US:
Cardiovascular diseases, cancer, & chronic obstructive pulmonary disease
8. Health Issues in Developing Nations Malnutrition, unsafe water, and poor sanitation
9. Diseases
10. Environmental Pollution & Disease
11. Persistence
Degradation of synthetic pesticides is slow.
Many remain in soil / water for years.
Sometimes the breakdown products are as toxic as the original chemical
12. Bioaccumulation
13. Biomagnification
14. Biomagnification Example: Effect of DDT on bald eagles
15. Endocrine Disruptors
Chemicals that alter hormone production.
Ex: PCBs, dioxins, lead, mercury, DDT
Hormones have their affect at low doses.
Endocrine disruptors act similarly.
16. Endocrine Disruptors Example: American alligators and DDT spill
17. Lake Apopka Alligators Population decline due to “reproductive incompatibility”
DDT and other chemicals came from a spill in 1980
Egg mortality rate was also high during the effected period
18. Determining Health Effects of Environmental Pollution Toxicant –
Chemical that induces adverse response at a certain dose.
Toxicity of a chemical is assessed by determining its LD50
(dose at which 50% of test subjects die due to exposure)
19. Determining Health Effects of Environmental Pollution Lethal Dose-50% (LD50)
20. Determining Health Effects of Environmental Pollution Effective Dose-50% (ED50) –
Dose that induces 50% of test subjects to have some type of effect
Dose response curve –
21. Determining Health Effects of Environmental Pollution
Children and
chemical exposure
22. Determining Health Effects of Environmental Pollution
Identifying Cancer-Causing Substances
Carcinogen –
Environmental agent known to induce cancer.
Chemicals commonly tested with rats but, is the dose equivalent?
Can you extrapolate the results to humans?
23. Health effects of environmental pollution What about mixing chemicals?
synergistic mixtures actually magnify the effects you would expect from those chemicals individually
antagonistic mixtures reduce the effects you would expect
additive mixtures are exactly what you would expect
In order to understand the effects of various mixtures, (like cigarette smoke, for example) that EXACT mixture would have to be tested.
24. Ecotoxicology
Dilution paradigm –
“the solution to pollution is dilution”
Boomerang paradigm –
“what you throw away can come back and hurt you”
25. Decision Making and Uncertainty Risks:
26. Decision Making and Uncertainty Cost-Benefit Analyses