CIH - Certified Industrial Hygienist Toxicology and Chemical Hazards Questions and Answers

Question 1

A worker is exposed to two chemicals simultaneously.
Chemical A has a toxic effect of 2 units, and Chemical B has a toxic effect of 3 units.
When combined, the total toxic effect is measured as 10 units.
Which type of chemical interaction does this scenario describe?

Accepted Answer

Synergistic

Answer

Additive

Answer

Antagonistic

Answer

Potentiation

Question 2

Which of the following is the primary target organ for toxic effects from both acute and chronic inhalation exposure to toluene?

Accepted Answer

Central Nervous System (CNS)

Answer

Liver

Answer

Kidneys

Answer

Lungs

Question 3

An industrial hygienist is evaluating a substance's acute toxicity. The data sheet reports an 'LC50 of 100 ppm (rat, 4 hr)'. What does this value represent?

Accepted Answer

The airborne concentration that is lethal to 50% of the rat population following a 4-hour exposure.

Answer

The oral dose that is lethal to 50% of the rat population within 4 hours.

Answer

The dermal concentration that is lethal to 50% of the rat population after 4 hours of exposure.

Answer

The lowest concentration that causes an observable adverse effect in 50% of the rat population.

Question 4

Organophosphate pesticides primarily exert their toxic effect through which mechanism of action?

Accepted Answer

Inhibiting the enzyme acetylcholinesterase

Answer

Binding to hemoglobin and preventing oxygen transport

Answer

Causing severe methemoglobinemia

Answer

Acting as a simple asphyxiant by displacing oxygen

Question 5

A worker in a poorly ventilated garage is exposed to carbon monoxide (CO) from a running engine. According to the ACGIH, what is the Threshold Limit Value - Time-Weighted Average (TLV-TWA) for CO?

Accepted Answer

25 ppm

Answer

50 ppm

Answer

100 ppm

Answer

35 ppm

Question 6

What toxicological principle describes a situation where a non-toxic substance enhances the toxicity of another substance when exposure occurs concurrently?

Accepted Answer

Potentiation

Answer

Antagonism

Answer

Synergism

Answer

Additive Effect