The term for the amount of the substance absorbed in a unit volume of an organ or an individual dose that caused death in a given percentage of test animals is what?

• A. Lethal Concentration
• B. Additive Effects
• C. Lethal Dose
• D. Effective Dose

Answer: (C)

A key idea here is how toxic effects are quantified with a lethal dose metric. It describes the amount of substance, relative to body weight, that will cause death in a defined portion of a test population. For example, the LD50 is the dose that kills 50% of the animals, usually expressed as mg of substance per kg of body weight. This is different from a lethal concentration, which is per unit volume (such as mg per liter) and is used when exposure is by concentration in air, water, or tissue. An effective dose refers to the amount needed to produce a specific nonfatal effect, not death, and additive effects describe how multiple chemicals combine to change the overall effect. Given the description of an individual dose causing death in a percentage of animals, the correct term is lethal dose.