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What does LD50 mean in MSDS toxicity data？

Posted Date:2020/5/29

LD lethal dose

LD50 is the half-lethal measurement, which refers to the measurement of the poison used to cause half of the experimental animals to die within 14 days after being exposed to the experimental animals once.

LD50——oral or trans-dermal half lethal dose. A simpler definition refers to the dose required to cause 50% of individuals in a group of subjects to die.

The precise definition refers to a single dose statistically obtained, which is expected to cause half of the animal's death.

The unit of LD50 is mg / kg. The smaller the value of LD50, the stronger the toxicity of the poison. On the contrary, the bigger the value of LD50, the lower the toxicity of the poison.

LC Lethal Concentration

LC50 is the half lethal concentration, and the definition is similar to LD50, which can kill half of the test subjects. LC50——half the lethal concentration in the respiratory tract. LC50 refers to the concentration required to cause the death of 50% of a group of subjects. If the test substance is in liquid, the unit is mg / L. LC50 is also used to indicate the concentration of chemicals in the air, expressed in mg / m³.

According to the LD50 value of the substance's LD50, the American Academy of Sciences classifies the risk of toxic substances into five levels

① "0": No toxicity, LD50> 15000mg / kg;

② "1": Actually non-toxic, 5000mg / kg <LD50;

③ "2": Mild toxicity, 500mg / kg <LD50;

④ "3": Moderate toxicity, 50 mg / kg <LD50;

⑤ "4": highly toxic, LD50 <50 mg / kg

If LC50 is used to indicate the acute toxicity of air poisons to mammals, it generally refers to the test results of the animal inhalation of the poison 2 or 4 hours. The inhalation time may not be indicated, but sometimes the time parameter may also be indicated. For example, LCt50 refers to the product of the concentration that caused half of the animal's death and the inhalation time. Time (t) is generally expressed in minutes.