ABT Occupational Toxicology 2

Question 1

Silicosis results from occupational inhalation of which form of silica?

Accepted Answer

Crystalline silica (quartz)

Answer

Crystalline silica, particularly quartz, is fibrogenic and causes progressive pulmonary fibrosis (silicosis) upon inhalation.

Question 2

Which type of asbestos fiber is associated with the greatest risk of mesothelioma due to its biopersistent, thin, needle-like morphology?

Accepted Answer

Crocidolite (blue asbestos)

Answer

Crocidolite (blue asbestos), an amphibole fiber, carries the highest mesothelioma risk due to its biopersistance and fiber dimensions that allow deep lung penetration.

Question 3

Occupational asthma caused by toluene diisocyanate (TDI) primarily involves which immunological mechanism?

Accepted Answer

IgE-mediated (Type I) hypersensitivity

Answer

TDI-induced occupational asthma typically involves IgE-mediated sensitization, causing immediate hypersensitivity reactions with bronchospasm upon re-exposure.

Question 4

n-Hexane causes peripheral neuropathy through which specific mechanism?

Accepted Answer

Formation of 2,5-hexanedione which cross-links neurofilament proteins

Answer

n-Hexane is metabolized to 2,5-hexanedione, which pyrrylates lysine residues in neurofilament proteins, causing cross-linking and axonal swelling (giant axonal neuropathy).

Question 5

Minamata disease is caused by occupational and environmental exposure to which toxic substance?

Accepted Answer

Methylmercury

Answer

Minamata disease results from methylmercury poisoning documented in Minamata Bay, Japan, where industrial effluent contaminated the marine food chain.

ABT - American Board of Toxicology Practice Test

ABT - American Board of Toxicology Practice Test

ABT Occupational Toxicology 2