CIH Toxicology & Health Risk Assessment 3

Question 1

The International Agency for Research on Cancer (IARC) classifies Group 1 carcinogens as:

Accepted Answer

Carcinogenic to humans (sufficient evidence)

Answer

Possibly carcinogenic to humans

Answer

Probably carcinogenic to humans

Answer

Not classifiable as to carcinogenicity

Question 2

The Short-Term Exposure Limit (STEL) specifies the maximum concentration permitted for a period of:

Accepted Answer

15 minutes, no more than four times per shift

Answer

5 minutes, no more than twice per shift

Answer

30 minutes, no more than twice per shift

Answer

60 minutes, once per shift only

Question 3

A reproductive toxin is best defined as a substance that:

Accepted Answer

Adversely affects fertility, pregnancy, or development of offspring

Answer

Only affects the liver and kidneys

Answer

Causes cancer of the reproductive organs exclusively

Answer

Increases mutation rates in somatic cells only

Question 4

What is the fundamental difference between 'hazard' and 'risk' in health risk assessment?

Accepted Answer

Hazard is the potential to cause harm; risk is the probability of harm occurring under specific conditions

Answer

Hazard is quantitative; risk is qualitative

Answer

Hazard applies to chemicals only; risk applies to all agents

Answer

They are interchangeable terms in industrial hygiene

Question 5

In toxicokinetics, the term 'half-life' of a chemical in the body refers to:

Accepted Answer

The time required for the body to eliminate half of the absorbed chemical

Answer

The time for 50% of exposed workers to develop symptoms

Answer

The duration of toxic effects after exposure ceases

Answer

The time needed to reach steady-state blood concentration

Question 6

Which type of toxic effect is classified as 'local' rather than 'systemic'?

Accepted Answer

Acid burns on the skin at the site of contact

Answer

Lead causing neurological damage after absorption

Answer

Carbon monoxide reducing oxygen delivery to the brain

Answer

Mercury accumulating in the kidneys after inhalation

Question 7

When conducting a quantitative cancer risk assessment for an inhaled carcinogen, the inhalation unit risk (IUR) is used to estimate:

Accepted Answer

The excess lifetime cancer risk per unit concentration inhaled

Answer

The IDLH concentration for emergency planning

Answer

The safe exposure level with a 1000-fold safety factor applied

Answer

The acute toxicity reference concentration for short-term exposures