Injecting or placing waste beneath Earth's surface is known as what?

• A. Containment building
• B. Leachate
• C. Open dump
• D. Geologic disposal

Answer: (D)

Placing waste underground relies on using the stability of earth materials to isolate hazards for long periods. This approach, called geologic disposal, involves burying waste in deep geological repositories or boreholes within solid rock, often with engineered barriers to limit water movement and prevent contaminant release. The goal is to keep hazardous waste away from people and ecosystems for the timescales required by the waste’s hazard, leveraging the natural and engineered barriers provided by the rock and surrounding materials.

This differs from a containment building, which is a surface- or near-surface structure used to handle and store waste temporarily or for short durations. Leachate is the contaminated liquid that can form when water infiltrates waste, not a disposal method. An open dump is an unregulated, surface disposal site, not a controlled underground method.