Download Chapter 18: Environmental Hazards and Human Health

February 26, 2014
Chapter 18: Environmental Hazards and Human
Health
February 26, 2014
Types of Hazards
1. Biological
2. Chemical
3. Physical
4. Cultural
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Biological Hazards
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Bacterial infections:
• TB
• Diarrheal diseases (Cholera)
• Antibiotic resistance
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Viral Diseases
• Influenza
• HIV
• Hepatitis
• Measles
• Diarrheal diseases (Rotavirus)
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Protozoa
• Malaria
• Diarrheal disease (Giardia)
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Ecological Medicine
*track infectious disease that potentially cross from
animals to humans
• HIV-bushmeat
• Nipah virus-clearing forests + pig farms
• Malaria-clearing forest increase range of
mosquitos
• Lyme disease-suburbs
• E.coli-factory farming
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Chemical hazards
• Mutagens
• Teratogens
• Carcinogens
• Disrupts:
> immune system
> nervous system (neurotoxin)
> endocrine system (hormonally active agents
(HAA)
– Mimic and blockers
– BPA
– Phthalates
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Chemical Hazards
• 7 factors that affect extent of harm:
> dose
> genetics
> solubility
> persistence
> bioaccumulation
> biomagnification
> chemical interactions (antagonistic or synergistic)
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Toxicity Assay:
LD50 = median lethal dose
• Relative indicator of how toxic or how dangerous
chemical is
• Dose that kills 50% of animals in a test population
within certain period of time (18-days).
> Usually measured in amount/kg of body
weight
– "amount" = g, mg, ng, etc depending on
substance
What is more toxic? Something with LD50
0f 50 or 5?
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Toxicity Assay:
LC50 = median lethal concentration
• Relative indicator of how toxic or how dangerous
chemical is
• Concentration not dose
> Sometimes difficult to measure exposure by
dose so use concentration instead
> ex: Fish in water--can't make fish ingest a
certain amount of toxin.
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Bioassay done with live animals
What animals would you use?
Ethical?
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Brine Shrimp Toxicity Assay
-Find out lethal concentration of common household
cleaners.
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