【Basic Knowledge of Occupational Health】: The Lethal Dose for 50% of the Population, LD50
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It’s quite similar to the LC50, right? This is LD50, which means the lethal dose for half of the population. Who knows? GBZ/T224-2010 \"Terminology for Occupational Health\" defines it as the dose of a chemical substance that, under certain experimental conditions, results in a 50% probability of death in the tested animals. In English, it is referred to as the median lethal dose. The unit for LD50 is mg/kg of body weight; the lower the LD50 value, the stronger the toxicity of the poison ； Conversely, the higher the LD50 value, the lower the toxicity of the poison.
Indicators that describe the toxicity of toxic substances or radiation. The median lethal dose (LD50) refers to the minimum amount of bacteria or toxin required to cause half of the animals of a certain weight or age to die within a specified time, via a particular route of exposure. In toxicology, the median lethal dose, abbreviated as LD50 (that is, Lethal Dose, 50%), is a commonly used indicator to describe the toxicity of toxic substances or radiation. According to the definition in the Medical Subject Headings (MeSH), LD50 refers to the “dose of a harmful substance, toxic substance, or ionizing radiation that can kill half of the subjects in a test group”. The lower the LD50 value, the greater the toxicity of the exogenous chemical ； Conversely, the higher the LD50 value, the lower the toxicity
If 100 mice are used in a 10L container for testing over a period of 4 hours, with 50mg of toxic gas introduced, and if 50mg is sufficient to kill half of the mice, that is, 50 out of them, then the LC50 value is 50mg/10L = 5mg/L; this represents the concentration. The LD50 value is more straightforward – it is 50mg, which is the absolute amount of the toxin. If the test is conducted in a 100L container, the LD50 value remains unchanged; however, when considering LC50, the absolute dose must be increased by a factor of 10.