to separate the soluble components from (e.g. soil or other mixed material) by the action of a liquid, esp water, passing through it

to remove (something soluble) in this way

to pass out or through by or as if by percolation

Harmful chemicals leached into the river

a perforated vessel used in leaching, esp one used to hold wood ashes through which water is passed to extract the lye (alkaline liquid used in making soap)

a solution or product obtained by leaching

the act or process of leaching