Which statement best describes LD50 meaning?

Which statement best describes LD50 meaning?

• A. Lower LD50 = more toxic substance
• B. Higher LD50 = more toxic substance
• C. LD50 measures environmental persistence
• D. LD50 measures flammability

Answer: (A)

LD50 is the lethal dose for 50% of a test population, usually expressed as milligrams of substance per kilogram of body weight. It serves as a measure of acute toxicity. The smaller the dose needed to kill half the subjects, the more toxic the substance is, because a tiny amount causes death in a large fraction of the population. A larger LD50 means the substance is less toxic since it takes more to reach that 50% mortality point. LD50 does not tell you about environmental persistence or flammability—those properties are evaluated with different tests and metrics. So, the idea that a lower LD50 indicates greater toxicity is the best description of what LD50 means.

LD50 is the lethal dose for 50% of a test population, usually expressed as milligrams of substance per kilogram of body weight. It serves as a measure of acute toxicity. The smaller the dose needed to kill half the subjects, the more toxic the substance is, because a tiny amount causes death in a large fraction of the population. A larger LD50 means the substance is less toxic since it takes more to reach that 50% mortality point. LD50 does not tell you about environmental persistence or flammability—those properties are evaluated with different tests and metrics. So, the idea that a lower LD50 indicates greater toxicity is the best description of what LD50 means.