What does leachate refer to?

Leachate refers to the contaminated liquid produced when rainwater or other liquids percolate through solid waste in landfills and dissolve various substances. This process can occur as waste decomposes and can lead to the contamination of surrounding soil and groundwater if not properly managed.

In contrast, the other choices do not accurately describe leachate. Solid waste in landfills is the source of leachate, but it does not capture the essence of what leachate is. Purified water after waste treatment refers to treated effluent that is safe for discharge or reuse, which is directly opposite to the nature of leachate. Lastly, inert materials remaining after recycling are those that cannot be reused or recycled further, lacking the contaminating properties associated with leachate. Thus, the definition of leachate as contaminated liquid from waste disposal sites is accurate and aligns with its environmental implications.