Which of the following describes a measure of how poisonous a pesticide is after a single, one-time exposure?

• A. Acute toxicity
• B. Chronic toxicity
• C. Allergic effect
• D. Medical antidote

Answer: (A)

Acute toxicity describes how poisonous a pesticide is from a single, one-time exposure. It captures the immediate toxic effects that can occur right after that moment of contact or intake and is often expressed with metrics like LD50 or LC50, which indicate the dose needed to kill 50% of test animals. The lower the LD50, the more acutely toxic the chemical is, which is why labels warn about potential dangers of a one-time exposure. In contrast, chronic toxicity concerns harm from repeated or long-term exposure and uses different risk measures; allergic effects are immune responses rather than a general measure of a pesticide’s immediate poison strength; and a medical antidote is simply treatment after exposure, not a measurement of how poisonous the substance is.