CES CES Environmental Health & Toxicology

Question 1

Which principle in toxicology, attributed to Paracelsus, states that 'the dose makes the poison'?

Accepted Answer

Dose-response relationship

Answer

Hormesis

Answer

Threshold concept

Answer

Bioaccumulation

Question 2

What does the term 'bioaccumulation' mean in environmental toxicology?

Accepted Answer

The buildup of a contaminant in an organism's tissues over time at a higher concentration than in the environment

Answer

The breakdown of pollutants by microorganisms in soil

Answer

The transfer of toxins from parent to offspring

Answer

The accumulation of multiple pollutants in a single environmental medium

Question 3

Which of the following best defines 'biomagnification'?

Accepted Answer

The increase in a contaminant's concentration as it moves up successive trophic levels in a food chain

Answer

The process by which microbes enlarge contaminant molecules in soil

Answer

The amplification of toxicity when two chemicals are combined

Answer

The increase in bioavailability of a contaminant due to pH changes

Question 4

The Reference Dose (RfD) established by EPA for non-carcinogens represents:

Accepted Answer

An estimate of daily exposure that is unlikely to cause adverse effects in humans over a lifetime

Answer

The dose at which 50% of test animals show a toxic effect

Answer

The regulatory cleanup level for contaminated soil

Answer

The minimum concentration detectable by standard analytical methods

Question 5

Which route of exposure typically results in the fastest absorption of a toxic chemical into the bloodstream?

Accepted Answer

Inhalation (breathing)

Answer

Dermal (skin contact)

Answer

Ingestion (oral)

Answer

Ocular (eye contact)

Question 6

What is the difference between 'acute' and 'chronic' toxicity?

Accepted Answer

Acute toxicity involves a single high-dose exposure with rapid effects; chronic toxicity involves repeated low-dose exposure over a long period

Answer

Acute toxicity affects only the liver; chronic toxicity affects the nervous system

Answer

Acute toxicity is reversible; chronic toxicity always causes permanent damage

Answer

Acute toxicity requires dermal exposure; chronic toxicity requires ingestion