Risk Assessment/Communication and Toxicology

Question 1

What is the risk triplet?

Answer 1

Set of three questions used to define risk
What may go wrong?
What are the consequences?
How likely is it?

Question 2

What is the LD50?

Answer 2

Lethal Dose 50
The dose at which 50% of the population is killed

Question 3

What are the components of a risk assessment?

Answer 3

Hazard identification, exposure assessment, Dose-response assessment, risk characterization

Question 4

What questions does each component of risk assessment answer?

Answer 4

Hazard identification: Is a potential chemical a risk to humans or ecosystems?
Exposure Assessment: What is known about the frequency, timing and intensity of contact with a stressor?
Dose-response: What is the relationship between exposure and health effects?
Risk characterization: What is the additional risk due to the exposure to the stressor for a given population?

Question 5

LOAEL vs NOAEL

Answer 5

no observable adverse effect level: highest dose at which there was not an observed toxic or adverse effect
lowest observable adverse effect level: lowest dose at which there was an observed toxic or adverse effect (when the y value is 0.1)

Question 6

What uncertainty factors are used to translate a NOAEL into a reference dose?

Answer 6

Divide by around 100 to 10,000 (animal to human, human heterogeneity, subchronic to chronic)
Each uncertainty factor is usually 10x

Question 7

Identify LD50, LOAEL, and NOAEL on a dose-response curve

Answer 7

LD50: when y value is 0.5
LOAEL: when y value is 0.1
NOAEL: right when curve is about to be above 0