2,4–D is primarily used as a selective herbicide which kills many terrestrial and aquatic broadleaf weeds, but not grasses

2,4-D is one of the oldest pesticides that’s still legally on the market today. It was one of the two active ingredients in Agent Orange (Vietnam War defoliant).

An exceedance for the pesticide 2,4-D was detected in Dublin city’s public drinking water supply in August 2020. Dublin water supply relies on raw water from the River Liffey, which is vulnerable to pesticide runoff from land.

Irish Water has asked users of any herbicide or pesticide products in the Liffey catchment to consider the vulnerability of the water supplies to contamination and the importance of this supply to the local homes and businesses in the community.

https://www.thejournal.ie/pesticides-detected-increase-irish-water-5383330-Mar2021/