What is the lethal dose that will cause death in 50% of the population referred to as?

The term that refers to the lethal dose causing death in 50% of the population is known as LD50, or Lethal Dose 50. This measure is widely used in toxicology to assess the acute toxicity of substances. LD50 indicates the amount of a substance (in milligrams of substance per kilogram of body weight) that is sufficient to kill half of a defined population under controlled conditions.

Understanding LD50 is critical for evaluating the risk that a particular agent poses to humans and animals. It provides a standardized way to compare the toxicity of different substances, which is essential for safety assessments, regulatory decisions, and risk management strategies in hazardous materials handling.

Other terms mentioned serve different purposes: Lethal Concentration (LC50) refers to the concentration of a substance in air or water that results in the death of 50% of a test population, but it is not comparable directly to dosage. Infectious Dose pertains to the amount of a pathogen required to cause infection, and Permissible Exposure Limit (PEL) is a regulatory limit on the amount of a substance a worker can be exposed to over a specified period.