Which statement is true about pesticide toxicity?

Which statement is true about pesticide toxicity?

• A. Pesticide toxicity is always immediate.
• B. Only organochlorine pesticides cause acute toxicity.
• C. Cholinesterase inhibition due to exposure to organophosphate or carbamate insecticides can cause acute or delayed effects.
• D. Toxicity is unaffected by exposure routes.

Answer: (C)

Pesticide toxicity can show up in different ways, but a key idea is how certain pesticides disrupt nerve signaling by blocking cholinesterase. Organophosphate and carbamate insecticides inhibit acetylcholinesterase, the enzyme that breaks down acetylcholine. When this enzyme is inhibited, acetylcholine accumulates at nerve endings, overstimulating cholinergic receptors. This can trigger a range of effects that appear soon after exposure (an acute cholinergic crisis) and, for some organophosphates, a delayed, longer-term effect like a distal neuropathy weeks later. Carbamates also inhibit cholinesterase, but often in a reversible and shorter-lived way, which is why the delay risk is typically lower with them. The broader point is that toxicity is not limited to immediate effects, not limited to one class like organochlorines, and the route of exposure influences how quickly and how severely toxicity develops. Hence, the statement about cholinesterase inhibition by organophosphates or carbamates causing acute or delayed effects is the correct concept.