1. Human Health and Environmental Risks

2. physical Biological chemical Many risk factors Natural disasters
Excessive UV radiation
physical
Diseases
Biological
Natural and synthetic
Ex: pesticides, arsenic
chemical

3. Diseases Acute Chronic Impair body rapidly short in duration
Ebola, pneumonia
Chronic
Slowly impair body over decades
Heart disease, cancer, lung disease, HIV/AIDS

4. toxicology Neurotoxins – EX: insecticides on insects, lead, mercury
Carcinogens – cause cell damage and cause uncontrolled growth of these cells EX: asbestos, radon, formaldehyde, PCBs, vinyl chloride, chemicals in tobacco
Teratogens – interfere with embryo/fetal development EX: thalidomide, alcohol
Allergens – high response of immune system EX: peanuts, milk, penicillin, mold
Endocrine disruptors – interfere with hormones EX: hormones from birth control pills/animal-rearing places in sewage, low sperm count in male fish and amphibians, DDT

5. Chronic disease risk factors
Differ between LDC and HDC. HOW?
LDC associated with poverty: unsafe drinking water, poor sanitation, malnutrition
½ children under 5 that die from pneumonia is because of poor nutrition
¾ children who die from diarrhea suffer from poor nutrition
HDC: tobacco, less active lifestyles, poor nutrition, overeating

6. Historically important infectious diseases
Plague – bacteria transmitted by fleas
Malaria – protists transmitted by mosquito; eradicated in US due to DDT
Tuberculosis – bacterial infection of lungs; medicines not available/affordable in LDC
Drug-resistant strains

7. Emergent Infectious Diseases
Ability of many pathogens to mutate and be able to infect humans
HIV/AIDS – combination antiviral drugs reduce virus gaining resistant ($$, but changing)
Ebola hemorragic fever – virus, central Africa, 50-90% death rate, no drugs, death in 2 weeks)
Mad Cow Disease – prions (proteins turned pathogens)
Bird Flu – not typically transmitted person to person, typically only infects birds, but mutated
West Nile Virus – kills some birds, transmitted by mosquitoes, causes brain inflammation, infect humans and horses

8. **All countries: continued education to reduce spread of HIV and TB
Future?
HDC: promotion of healthier lifestyle: increased physical activity, balanced diet, limit excess food consumption, and tobacco use
LDC : improve nutrition, wider availability of clean drinking water, proper sanitation
**All countries: continued education to reduce spread of HIV and TB

9. Determining the concentration of a chemical that is harmful
LD50 – dose that kills 50% of test subjects
Unethical on humans; use mice/rats
Used to compare toxicity of different chemicals
ED50 - dose that effects 50% of test subjects

10. challenges Kids vs adults
Synergistic interactions of chemicals – 2 risks together cause more harm than one would expect based on their individual risks
Health impact of a carcinogen, like asbestos, can be much higher if an individual also smokes tobacco.

11. Risk analysis Typically 3 steps: Risk assessment Risk acceptance
Identify hazard and determine extent of exposure
Risk acceptance
Determine acceptable level of risk
Risk management
Determine policy (with input from citizens, industry, interest groups)

12. Risk analysis put into action…
Maker of electrical components dumped PCBs into Hudson River
PCBs in air, soil, water and persist
EPA identified at what concentration PCB caused cancer (LD50/dose-response)
Greater chance of getting cancer from eating contaminated fish  put up signs to minimize exposure

14. Perceived risk vs. actual risk
Perceived (qualitative) / actual (quantitative)
Ex: someone afraid to fly in airplane, but will drive car all the time.
Death in US:
1. heart disease (1 in 5)
2. cancer (1 in 7)
3. COPD

15. ECONOMIC IMPACTS OF POLLUTION
COST-BENEFIT ANALYSIS
EXTERNALITIES
MARGINAL COSTS
SUSTAINABILITY

16. Economic activity generally harms the environment
Cost to environment not included in cost to buyer
External costs (externalities) are harmful social or environmental effects caused by the production or consumption of economic goods
Buy cotton t-shirt at a price that doesn’t reflect possible eutrophication due to fertilizer run-off or poor working conditions in “sweat shops.”
Ex: paper manufacturer dumps wastes into local river (public goods)  negative impacts on fish that depend on water, decrease quality of water used for recreation, extensive treatment of water to drink downstream

17. Cost-benefit analysis
Cost-benefit analysis looks at the social benefits (health/environmental) that can be derived from pollution reduction vs the cost of achieving that reduction.
There is a limit to how much money can be spent before the budgets of other important public services (police, fire, parks departments) are negatively impacted.
As hazards become more known, perceived benefits derived from pollution reduction may increase.
Problem with analysis: assumes all benefits have a price tag. Aesthetic benefits cannot be prices and are important (beauty of a clear-running stream and quiet solitude of a wilderness)

18. Marginal costs
The change to the total cost when the quantity produced changes by one unit.
Marginal cost of pollution abatement: Initial clean-up of a polluted site is cheap, but gets increasingly more costly

19. Sustainability
Seek to proved best outcomes for both human societies and natural ecosystems.
Conservation of biodiversity and ecological integrity
Integration of environmental, social, and economic goals in policies and activities
Need for good governance
Unlimited economic and population growth puts many demands on natural resources.