Risk assessment

Question 1

Risk equation

Answer 1

RISK = EXPOSURE × DANGER

In other words, for there to be a risk associated with a chemical compound, that compound must present a toxic potential, and exposure must be sufficient to cause adverse effects.

Question 2

Hazard identification

Answer 2

Approaches to assessing whether a substance presents a hazard:
- In vivo studies with laboratory animals
- In vitro studies with cell cultures
- Epidemiological studies (cases control, longitudinal, transversal, ecological)

Question 3

Dose-respose relation

Answer 3

Relations with threshold: For non-genotoxic effects, it is assumed that adverse effects occur above a certain dose (threshold).
Exceptions: PM2.5, lead, etc.
* benchmark dose modeling
* NOAEL: No observed adverse effect level
* LOAEL: Lowest observed adverse effect level

Relations without threshold

Question 4

Uncertainty factors

Answer 4

• Inter-individual factor (10x): Inter-individual variability in humans.
• Interspecies factor (10x): If toxicity data are derived from non-human animal studies.
• Subchronic-chronic factor (10x): If toxicity data are from a sub-chronic study.
• LOAEL-NOAEL factor (10x): If the study did not establish a NOAEL and only a LOAEL is available.
• Data factor (10x): If toxicological data are insufficient or of poor quality.

Question 5

Exposure evaluation

Answer 5

Acceptable daily dose (ADD)

• Measurement of contaminants in different media and rates of contact with different media
• Biological samples representing internal exposure

Question 6

Risk characterisation

Answer 6

Risk index

Always characterize risk in the light of available data used to establish a tolerable daily intake (TDI) or maximum acceptable concentration (MAC)