CIH Toxicology & Health Risk Assessment 2

Question 1

A Threshold Limit Value-Ceiling (TLV-C) is a concentration that should:

Accepted Answer

Never be exceeded at any time during the work shift

Answer

Not be exceeded for more than 15 minutes

Answer

Not be exceeded on average over 8 hours

Answer

Only apply to skin contact situations

Question 2

Which organization publishes Threshold Limit Values (TLVs) for occupational chemical exposures?

Accepted Answer

ACGIH

Answer

OSHA

Answer

NIOSH

Answer

EPA

Question 3

Carbon monoxide causes toxicity primarily by:

Accepted Answer

Binding to hemoglobin with greater affinity than oxygen

Answer

Directly destroying lung tissue

Answer

Inhibiting the enzyme acetylcholinesterase

Answer

Causing lipid peroxidation in cell membranes

Question 4

In toxicology, a 'sensitizer' is a substance that:

Accepted Answer

Can induce an allergic response upon repeated exposure

Answer

Causes immediate irritation on first contact

Answer

Destroys nerve tissue on contact

Answer

Requires very high doses to cause any effect

Question 5

The No-Observed-Adverse-Effect Level (NOAEL) is defined as:

Accepted Answer

The highest tested dose producing no detectable adverse health effect

Answer

The lowest dose causing a statistically significant adverse effect

Answer

The dose resulting in 50% response in the population

Answer

The regulatory exposure limit divided by a safety factor

Question 6

Which organ is primarily responsible for biotransformation (metabolism) of toxic chemicals in the body?

Accepted Answer

Liver

Answer

Kidney

Answer

Lung

Answer

Spleen

Question 7

When a worker is simultaneously exposed to multiple chemicals, the combined exposure is evaluated using the mixture formula. If the sum of (C1/L1 + C2/L2 + ... Cn/Ln) exceeds 1, this indicates:

Accepted Answer

The combined exposure has exceeded the acceptable limit

Answer

The exposure is within acceptable limits

Answer

The TLV of the most toxic chemical is exceeded

Answer

Individual chemicals are below their limits so no action is needed