Létale

Létale is a term used in various contexts, primarily in biology and toxicology, to describe a dose of a substance that is lethal to a certain percentage of a population. The most common application is the LD50 value, which represents the lethal dose for 50% of a tested population. This value is a standard measure of the acute toxicity of a substance.

The determination of LD50 is typically performed on laboratory animals, with the substance administered through different routes such as oral ingestion, dermal application, or injection. The results are usually expressed in milligrams of substance per kilogram of body weight (mg/kg). A lower LD50 value indicates a higher toxicity, meaning less of the substance is required to cause death in half of the test subjects.

Beyond LD50, other related terms include LC50 (lethal concentration 50), used for substances that are inhaled or dissolved in water, and LT50 (lethal time 50), which measures the time it takes for a substance to kill 50% of a population. These metrics are crucial for risk assessment, setting safety guidelines, and understanding the potential hazards of chemicals and environmental agents. The concept of lethality is fundamental to pharmacology, toxicology, and environmental science, informing decisions about drug development, pesticide regulation, and industrial safety.