Minnesota Pesticide Applicator Practice Test

What is the meaning of the acronym LC50 in relation to pesticide toxicity?

1. Lethal concentration for 50% of the population by respiratory exposure

2. Lethal concentration for 50% of the population by dermal exposure

3. Less concentrated formulation for 50% efficacy

4. Low concentration limit for pesticide effectiveness

The correct answer is: Lethal concentration for 50% of the population by respiratory exposure

LC50 stands for "Lethal Concentration 50," which refers to the concentration of a substance, such as a pesticide, that is expected to cause death in 50% of a defined population, typically measured in milligrams of substance per liter of air or water. The context of respiratory exposure is vital because LC50 values are primarily assessed through inhalation studies, which measure how lethal a chemical can be when organisms are exposed to it through breathing. For instance, LC50 values help safety assessors and regulators understand the potential risk of a chemical to non-target organisms, including humans, by gauging how effective a pesticide might be in causing harm through respiratory pathways. This definition highlights the importance of understanding how toxins are absorbed and act on living organisms, emphasizing the need for careful usage and proper protective measures during the application of pesticides.