Simazine is a widely used herbicide that enters drinking water through agricultural runoff. It persists in the environment and may disrupt hormones in humans.

Simazine is a synthetic herbicide primarily used to control broadleaf and grassy weeds in corn fields. It can enter drinking water sources through agricultural runoff and soil leaching. Due to its slow degradation, simazine persists in the environment for months or even years. The EPA measures simazine levels in parts per billion (ppb) and has established a maximum contaminant level to protect public health. While its full health impacts are still being studied, simazine is suspected to be an endocrine disruptor in humans.