CET Health Risk Assessment 2

Question 1

In the classic four-step NRC (1983) risk assessment paradigm, which step comes immediately after hazard identification?

Accepted Answer

Dose-response assessment

Answer

The NRC Red Book sequence is hazard identification, dose-response assessment, exposure assessment, then risk characterization.

Question 2

A worker's chronic daily intake of a chemical is 0.006 mg/kg-day and the reference dose (RfD) is 0.003 mg/kg-day. What is the hazard quotient?

Accepted Answer

2.0

Answer

HQ = exposure ÷ RfD = 0.006 ÷ 0.003 = 2, indicating potential for non-cancer effects.

Question 3

Which term describes the highest tested dose at which no statistically or biologically significant adverse effect was observed?

Accepted Answer

NOAEL

Answer

The No Observed Adverse Effect Level (NOAEL) is the highest dose without observed adverse effects and is often the starting point for an RfD.

Question 4

When the combined effect of two chemicals is much greater than the sum of their individual effects, the interaction is called:

Accepted Answer

Synergistic

Answer

Synergism occurs when the combined effect exceeds the sum, such as asbestos exposure combined with smoking.

Question 5

A cancer slope factor of 0.05 (mg/kg-day)^-1 is applied to a lifetime average daily dose of 0.0002 mg/kg-day. What is the estimated excess lifetime cancer risk?

Accepted Answer

1 × 10^-5

Answer

Risk = slope factor × dose = 0.05 × 0.0002 = 0.00001, or 1 in 100,000.

CET - Certified Environmental, Safety & Health Trainer Practice Test

CET - Certified Environmental, Safety & Health Trainer Practice Test

CET Health Risk Assessment 2