Human Healthand

Risk Assessment

Protecting Human HealthEfficient Use of Limited Resources

Causes of death:• Disease• Lifestyle Factors• Toxins

Symptoms and Causes

Laboratory Studies

Epidemiological Studies

Should we protect people from themselves?

Environmentally-Based Health IssuesToxins and Exposure

50 years later, victims of Minamata Disease still fight for justiceNew America Media, Commentary, Christopher Reed,

Apr 26, 2006

Environmental Racism

Asbestos

Microscopic view of lung tissue with asbestosis.

Asbestos fibers lodged in the lungs. Asbestos-related conditions affect the

lungs and surrounding tissues

Effects

• Carcinogens• Mutagens• Teratogens• Toxins

• Synergisms • Antagonisms• Multiple Effects

Differences in Effect:Sensitive Receptors

• Children– Longer exposure– Developing tissues– Higher exposures?

• Elderly• Respiratory Disease• Genetics

Dose Response Curve

Quantifying Health Effects

Table 2: Toxicity Classes: Gosselin, Smith and Hodge

Probable Oral Lethal Dose (Human)

Toxicity Rating or Class

Dose For 70-kg Person (150 lbs)

6 Super Toxic Less than 5 mg/kg

1 grain (a taste - less than 7

drops)

5 Extremely Toxic 5-50 mg/kg 4 ml (between 7 drops and 1

tsp)

4 Very Toxic 50-500 mg/kg 30 ml (between 1 tsp and 1 fl

ounce)

3 Moderately Toxic

0.5-5 g/kg 30-600 ml (between 1 fl oz and 1

pint)

2 Slightly Toxic 5-15 g/kg 600-1200 ml (between 1

pint to 1 quart)

1 Practically Non-Toxic

Above 15 g/kg More than 1200 ml (more

than 1 quart)

Four steps of Risk Assessment

• Hazard Identification– Laboratory vs Epidemiological Studies

• Dose-response• Exposure Assessment• Risk Characterization

versus

• The Precautionary Principle

The Delaney Clause

Ecological Risk Assessment

• Consequences of a shift to biomass energy• Water diversion in dry areas• Herbicide use in eutrophic aquatic systems

Factors in Understanding Environmental Toxicity

• Persistence• Bioaccumulation• Biological Magnification

Water Qualityin Southern FloridaFlorida, 1996–98