What does an LD-50 of 50-500 mg/kg indicate about a chemical?

What does an LD-50 of 50-500 mg/kg indicate about a chemical?

• A. It is slightly toxic
• B. It is highly toxic
• C. It is moderately toxic
• D. It is safe for human exposure

Answer: (C)

An LD-50 (lethal dose, 50%) value indicates the amount of a substance required to kill 50% of a test population, usually expressed in milligrams per kilogram of body weight (mg/kg). An LD-50 value in the range of 50-500 mg/kg suggests that the chemical has moderate toxicity. A low LD-50 value (for example, below 50 mg/kg) typically signifies high toxicity, indicating that only small amounts of the chemical can cause harm. Conversely, a higher LD-50 value (above 500 mg/kg) would suggest lower toxicity and a greater safety margin for exposure. Given the specified range of 50-500 mg/kg, it falls into a category that indicates a moderate level of toxicity—meaning that while the chemical can be hazardous, it may not pose an immediate lethal threat with low-level exposure. Thus, characterizing it as moderately toxic reflects its potential to cause harm under certain levels of exposure, which is appropriate based on the LD-50 value.

An LD-50 (lethal dose, 50%) value indicates the amount of a substance required to kill 50% of a test population, usually expressed in milligrams per kilogram of body weight (mg/kg). An LD-50 value in the range of 50-500 mg/kg suggests that the chemical has moderate toxicity.

A low LD-50 value (for example, below 50 mg/kg) typically signifies high toxicity, indicating that only small amounts of the chemical can cause harm. Conversely, a higher LD-50 value (above 500 mg/kg) would suggest lower toxicity and a greater safety margin for exposure.

Given the specified range of 50-500 mg/kg, it falls into a category that indicates a moderate level of toxicity—meaning that while the chemical can be hazardous, it may not pose an immediate lethal threat with low-level exposure. Thus, characterizing it as moderately toxic reflects its potential to cause harm under certain levels of exposure, which is appropriate based on the LD-50 value.