Which terms denote lethal dose measures used in toxicity testing?

Which terms denote lethal dose measures used in toxicity testing?

• A. LD50 and LC50
• B. NOAEL and LOAEL
• C. NOAEL and LD50
• D. LOAEL and LC50

Answer: (A)

In toxicity testing, lethal dose measures describe the amount of substance needed to cause death in a population. The standard metrics are LD50 and LC50. LD50, or median lethal dose, is the dose that would kill 50% of the test animals, usually expressed as milligrams of substance per kilogram of body weight. LC50, or median lethal concentration, is the concentration in a given medium (air, water, or another exposure environment) that kills 50% of the organisms exposed, typically shown in units like mg per liter or parts per million. These metrics come from acute toxicity studies that focus on immediate, lethal outcomes after exposure. NOAEL (no observed adverse effect level) and LOAEL (lowest observed adverse effect level) describe levels where adverse effects are first observed or not observed, but they are not measures of lethality. They indicate non-lethal effects rather than death, which is why they’re not the lethal-dose metrics.

In toxicity testing, lethal dose measures describe the amount of substance needed to cause death in a population. The standard metrics are LD50 and LC50. LD50, or median lethal dose, is the dose that would kill 50% of the test animals, usually expressed as milligrams of substance per kilogram of body weight. LC50, or median lethal concentration, is the concentration in a given medium (air, water, or another exposure environment) that kills 50% of the organisms exposed, typically shown in units like mg per liter or parts per million. These metrics come from acute toxicity studies that focus on immediate, lethal outcomes after exposure.

NOAEL (no observed adverse effect level) and LOAEL (lowest observed adverse effect level) describe levels where adverse effects are first observed or not observed, but they are not measures of lethality. They indicate non-lethal effects rather than death, which is why they’re not the lethal-dose metrics.