CIH Toxicology and Chemical Hazards 2 — Questions and Answers
Question 1: Which toxicokinetic process describes the movement of a chemical from the bloodstream into tissues and organs?
- Absorption
- Distribution (Correct answer)
- Metabolism
- Excretion
Correct answer: Distribution
Distribution is the process by which a chemical moves from systemic circulation into tissues and organs throughout the body.
Question 2: A worker is exposed to a chemical with a high octanol-water partition coefficient (Kow). This suggests the chemical is likely to:
- Be rapidly excreted by the kidneys
- Bioaccumulate in adipose tissue (Correct answer)
- Dissolve readily in blood plasma
- Cause acute irritation to mucous membranes
Correct answer: Bioaccumulate in adipose tissue
A high Kow indicates strong lipophilicity, meaning the chemical will preferentially partition into fat tissue and bioaccumulate.
Question 3: The Haber's Rule states that toxic effect is proportional to:
- The molecular weight of the toxicant
- The concentration multiplied by duration of exposure (Correct answer)
- The number of exposed workers
- The route of entry into the body
Correct answer: The concentration multiplied by duration of exposure
Haber's Rule (C × t = k) states that the toxic effect is the product of concentration and time of exposure.
Question 4: Which phase of biotransformation typically involves conjugation reactions that increase water solubility for excretion?
- Phase I
- Phase II (Correct answer)
- Phase III
- Phase IV
Correct answer: Phase II
Phase II biotransformation involves conjugation reactions (glucuronidation, sulfation, etc.) that add polar groups to increase water solubility.
Question 5: A chemical that causes damage specifically to the proximal convoluted tubule of the kidney is classified as a:
- Hepatotoxin
- Nephrotoxin (Correct answer)
- Neurotoxin
- Pneumotoxin
Correct answer: Nephrotoxin
Nephrotoxins cause damage to kidney structures, including specific regions like the proximal convoluted tubule.
Question 6: In risk assessment, the term 'bioavailability' refers to:
- The lethal dose for 50% of a test population
- The fraction of an administered dose that reaches systemic circulation (Correct answer)
- The total body burden of a chemical
- The rate at which a chemical is metabolized
Correct answer: The fraction of an administered dose that reaches systemic circulation
Bioavailability is the fraction of an administered dose that reaches the systemic circulation in an unchanged, active form.
Question 7: Which of the following is an example of a local toxic effect?
- Lead causing anemia
- Carbon monoxide binding to hemoglobin
- Hydrofluoric acid burns at the skin contact site (Correct answer)
- Mercury accumulating in the brain
Correct answer: Hydrofluoric acid burns at the skin contact site
A local toxic effect occurs at the site of first contact, such as hydrofluoric acid causing burns at the skin contact point.
CIH Toxicology and Chemical Hazards 2
Which toxicokinetic process describes the movement of a chemical from the bloodstream into tissues and organs?