LC50

LC50

The LC50 or Lethal Concentration 50% is a measure of the lethal dose of a toxin, radiation, or pathogen. The value of LC50 represents the concentration of a substance in air or water that kills half of a population of test organisms in a certain amount of time.

Definition

The LC50 value is commonly used as a general indicator of a substance's acute toxicity. A lower LC50 is indicative of increased toxicity. The test is usually conducted on fish, rats, mice, or rabbits with the results extrapolated for humans.

Calculation

The LC50 is calculated using a probit analysis or logit analysis. The LC50 value is expressed in terms of mass per volume, typically as milligrams of substance per liter of water (mg/L) for aquatic organisms, or milligrams of substance per kilogram of body weight (mg/kg) for terrestrial organisms.

Applications

LC50 values are used in regulatory and research contexts to assess and compare acute toxicity. They are also used in the classification and labeling of chemicals for regulatory purposes.

Limitations

While LC50 values are useful for comparing the toxicity of different substances, they do not provide a complete picture of a substance's toxicity under all conditions. Factors such as exposure time, the health and age of the organisms, and environmental conditions can all affect toxicity.

See also

• LD50
• Toxicity
• Acute toxicity
• Chronic toxicity
• Toxicology

LC50 Resources
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