Dieldrin is a banned pesticide that persists in soil and enters water through runoff. It accumulates in the body and is toxic to humans and wildlife, causing nervous system damage.

Dieldrin, a chlorinated hydrocarbon pesticide, was widely used from the 1950s to 1970s before being banned due to its toxicity and environmental persistence. It can remain in soil for decades, entering water through agricultural runoff and erosion. Dieldrin bioaccumulates in the food chain, posing risks to wildlife and humans. It's typically measured in water using gas chromatography. Despite its ban, dieldrin's legacy contamination continues to be a concern, leading to strict regulations on its presence in drinking water supplies.