What do LD50 and LC50 measure?

What do LD50 and LC50 measure?

• A. They measure only the lethal effect which is death and do not indicate what smaller doses might cause.
• B. They measure the overall toxicity including all effects.
• C. They measure only the non-lethal health effects.
• D. They measure environmental persistence.

Answer: (A)

LD50 and LC50 quantify acute lethality—the dose (LD50) or concentration (LC50) that will kill 50% of a defined test population under specific conditions. They focus on death as the endpoint, not on non-lethal effects or sublethal outcomes that may occur at lower doses. Because of that, they don’t tell you what smaller doses might cause in terms of irritation, behavioral changes, or chronic health effects. They also don’t address environmental persistence or the broader spectrum of toxicity. So the best description is that these measures reflect only lethal effects and do not indicate what smaller doses might cause.

LD50 and LC50 quantify acute lethality—the dose (LD50) or concentration (LC50) that will kill 50% of a defined test population under specific conditions. They focus on death as the endpoint, not on non-lethal effects or sublethal outcomes that may occur at lower doses. Because of that, they don’t tell you what smaller doses might cause in terms of irritation, behavioral changes, or chronic health effects. They also don’t address environmental persistence or the broader spectrum of toxicity. So the best description is that these measures reflect only lethal effects and do not indicate what smaller doses might cause.