What does LC50 mean?

What does LC50 mean?

• A. The lethal dose for 50% of test animals
• B. The concentration of pesticide in the air that must be present to kill 50% of test animals
• C. The dose required to kill 50% via dermal exposure
• D. The amount needed to cause 50% of tests to show any effect

Answer: (B)

LC50 is the concentration of a pesticide in the exposure environment that will kill 50% of the test animals under defined conditions. It’s used for inhalation (air) or aquatic exposures, so it’s expressed as a concentration (like parts per million in air or mg/L in water), not as a dose per animal. This distinguishes it from LD50, which is the lethal dose per animal. The statement describing the concentration in air needed to kill 50% of the test animals matches this definition, making it the correct interpretation. The other ideas refer to dose per animal, dermal exposure, or nonlethal effects, which are not what LC50 measures.

LC50 is the concentration of a pesticide in the exposure environment that will kill 50% of the test animals under defined conditions. It’s used for inhalation (air) or aquatic exposures, so it’s expressed as a concentration (like parts per million in air or mg/L in water), not as a dose per animal. This distinguishes it from LD50, which is the lethal dose per animal. The statement describing the concentration in air needed to kill 50% of the test animals matches this definition, making it the correct interpretation. The other ideas refer to dose per animal, dermal exposure, or nonlethal effects, which are not what LC50 measures.