Risks, Hazards and Toxicity

How do we know what's dangerous?
• RISK: Probable Causes of Death
    r = (births + immigrations) - (deaths + emigrations)     example: female mortality
• HAZARD: Causes of Harm
• TOXICITY: How Harmful is it?

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Risk (probable cause of death)

Heart Disease 29.0%
Cancer 22.9%              SMOKING
Stroke 6.8%                 RELATED
Emphysema 5.1%        $157 billion/yr 2009
Accidents 4.2%
Diabetes 3.0%               vs. Global x
Influenza 2.6%
Alzheimer's 2.2%           vs.20-24 yr old
Kidney disease 1.6%
Bacterial infections 1.3%
Other (uncategorized) 21.3% (CDC Data for USA, 2001)

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Hazards: (causes of harm)

(categories)
Cultural: sanitation, poverty
Chemical: in food, water, soil→
Physical: autos, natural disasters
Biological: disease, poor sanitation

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Toxicity: (how harmful a substance is)
(mostly chemical hazards) (cocaine heroin)

1. size of the dose
2. length (time) of exposure
3. age of victim
4. health of victim
5. genetic predisposition of victim

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Bioaccumulation: toxins concentrated in tissues 800:1

Biomagnification: concentration of toxins in higher levels of food chain 202,368:1

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Poison: lethal in small quantities

Dosage
100 cups of coffee in 2 hours lethal
1 liter 200 proof alcohol 2 hrs lethal
Poison: 50 mg / kg body weight lethal to 50% of victims 150 lbs = 68 kg (3.4g dose)
LD₅₀ death to 1/2 of the victims
(60-200 lab animals, in 14 days)



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Hazardous Chemicals: can be lethal

Mutagens: change genetic code (DNA) - organic solvents CCl₄
Teratogens: cause birth defects - thalidomide, arsenic
Carcinogens: cancer causing - tobacco

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Reducing risk

• don't smoke
• avoid excess sunlight
• drink in moderation
• reduce cholesterol
• eat fruits and vegetables
• exercise regularly
• maintain healthy weight
• drive safely

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