Leaching from a garbage dump has been found to pollute wells located how far away?

Leaching from a garbage dump, also known as landfill leachate, can travel significant distances depending on various factors such as soil composition, groundwater flow, and the type of waste present. In many states, regulatory agencies often use a distance of 2000 feet as a standard benchmark for potential leaching effects from landfills to wells.

This distance is based on studies and guidelines which suggest that contaminants can migrate through the subsurface over long distances, especially if there is porous or permeable soil that allows for easier movement of water and associated pollutants. Given this context, the correct answer emphasizes the recognized impact of leachate on water quality, particularly in relation to well location and safety standards.

Furthermore, while the other distances may represent some potential leaching effects in certain scenarios, they do not align with the more widely accepted and conservative estimate of 2000 feet used for regulatory and protective measures in environmental health to ensure safe drinking water supplies.