Endrin is a banned pesticide once used on crops and for rodent control. It can contaminate water through agricultural runoff and is highly toxic to humans and animals.

Endrin, a chlorinated hydrocarbon pesticide, was widely used from the 1950s to 1970s. Though banned in the US since 1986, it persists in the environment due to its chemical stability. Endrin can contaminate water sources through agricultural runoff and soil erosion. It bioaccumulates in aquatic organisms, posing risks to the food chain. Water utilities measure endrin in parts per billion, with the EPA setting a maximum contaminant level of 0.002 mg/L to protect public health.