NEHA Hazardous Materials and Toxicology

Question 1

What is the fundamental principle of toxicology attributed to Paracelsus?

Accepted Answer

The dose makes the poison — all substances can be toxic at a sufficient dose

Answer

Paracelsus established the foundational toxicology principle that the dose determines whether a substance is toxic — virtually any substance can cause harm at a sufficient dose, and many toxic substances are harmless at low exposures.

Question 2

What is a 'dose-response relationship' in toxicology?

Accepted Answer

The relationship between the amount of a substance a person is exposed to and the magnitude of the resulting biological effect

Answer

A dose-response relationship describes how the severity of a biological effect increases (or changes) as the amount (dose) of a chemical substance to which an organism is exposed increases.

Question 3

What are the four primary routes of exposure by which toxic substances can enter the human body?

Accepted Answer

Inhalation, ingestion, dermal absorption, and injection

Answer

Toxic substances can enter the human body through inhalation (breathing), ingestion (swallowing), dermal absorption (skin contact), and injection (puncture), with inhalation often being the most rapid route.

Question 4

What is the difference between an 'acute' and 'chronic' toxic exposure?

Accepted Answer

Acute exposure occurs over a short period with high dose; chronic exposure occurs repeatedly over a long period at lower doses

Answer

Acute exposure refers to a single or short-term high-dose exposure, often causing immediate effects, while chronic exposure involves repeated or prolonged lower-dose exposures over months or years that may cause cumulative effects.

Question 5

What does 'bioaccumulation' mean in the context of environmental toxicology?

Accepted Answer

The progressive increase in concentration of a substance in an organism because it is absorbed faster than it is eliminated

Answer

Bioaccumulation is the process by which a substance builds up in an organism's tissues over time because the rate of uptake exceeds the rate of metabolism and elimination.

NEHA - National Environmental Health Association Practice Test

NEHA - National Environmental Health Association Practice Test

NEHA Hazardous Materials and Toxicology