ABT Environmental Toxicology 3

Question 1

Which environmental fate parameter describes the tendency of a chemical to partition between octanol and water?

Accepted Answer

Octanol-water partition coefficient (Kow)

Answer

The octanol-water partition coefficient (Kow or P) is used as a surrogate for lipophilicity and predicts a chemical's tendency to bioaccumulate in fatty tissues.

Question 2

Endocrine-disrupting chemicals (EDCs) can mimic or block hormones. Which effect describes a chemical that binds estrogen receptors without activating them?

Accepted Answer

Estrogen receptor antagonism

Answer

An estrogen receptor antagonist binds to estrogen receptors but does not activate transcription, effectively blocking endogenous estrogen from exerting its effects.

Question 3

Under CERCLA, which term describes the party legally responsible for cleanup costs at a Superfund site?

Accepted Answer

Potentially Responsible Party (PRP)

Answer

CERCLA defines Potentially Responsible Parties (PRPs) as current or former owners/operators, transporters, and generators who may be liable for cleanup costs at hazardous waste sites.

Question 4

Which route of exposure is most significant for volatile organic compounds (VOCs) at contaminated sites?

Accepted Answer

Inhalation of vapors (vapor intrusion)

Answer

Vapor intrusion — the migration of VOC vapors from contaminated soil and groundwater into overlying buildings — is often the dominant exposure pathway for volatile contaminants.

Question 5

The concept of 'hormesis' in environmental toxicology describes:

Accepted Answer

A biphasic dose-response with low-dose stimulation and high-dose inhibition

Answer

Hormesis is a biphasic dose-response phenomenon where low doses produce a stimulatory or beneficial effect and higher doses produce an inhibitory or toxic effect.

ABT - American Board of Toxicology Practice Test

ABT - American Board of Toxicology Practice Test

ABT Environmental Toxicology 3