Which statement correctly distinguishes LC50 from LD50?

Which statement correctly distinguishes LC50 from LD50?

• A. LC50 refers to concentration in air or water; LD50 refers to dose via ingestion or injection
• B. LC50 refers to dose via ingestion; LD50 refers to concentration in air
• C. LC50 and LD50 both refer to concentrations in air
• D. LC50 is the dose to kill 50% of test population via ingestion; LD50 is the concentration for inhalation

Answer: (B)

LC50 and LD50 describe toxicity from two different perspectives. LC50 is the lethal concentration: the amount of a substance present per unit volume of air (for inhalation) or per unit volume of water (for aquatic exposure) that kills 50% of the exposed population under a defined exposure period. It reflects how toxic a substance is when people or animals encounter it as a contaminant in the environment. LD50, on the other hand, is the lethal dose: the amount of substance per unit body weight that kills 50% of the population when given by a specific route, such as ingestion or injection. Because it’s tied to body weight and the route of exposure, LD50 varies with species, route, and dose formulation. So the key distinction is: LC50 measures concentration in the environment that causes death, while LD50 measures the dose per body weight required to cause death via a chosen exposure route.

LC50 and LD50 describe toxicity from two different perspectives. LC50 is the lethal concentration: the amount of a substance present per unit volume of air (for inhalation) or per unit volume of water (for aquatic exposure) that kills 50% of the exposed population under a defined exposure period. It reflects how toxic a substance is when people or animals encounter it as a contaminant in the environment.

LD50, on the other hand, is the lethal dose: the amount of substance per unit body weight that kills 50% of the population when given by a specific route, such as ingestion or injection. Because it’s tied to body weight and the route of exposure, LD50 varies with species, route, and dose formulation.

So the key distinction is: LC50 measures concentration in the environment that causes death, while LD50 measures the dose per body weight required to cause death via a chosen exposure route.