Which pollutant category is associated with unlined landfills and discharges?

• A. Major Water Pollutants
• B. Sources of Heavy Metals
• C. Toxic Chemicals
• D. Thermal Pollution

Answer: (B)

Unlined landfills create leachate when rainwater percolates through waste, pulling dissolved substances into the groundwater and nearby streams. Heavy metals are common components of household and industrial waste (batteries, electronics, paints, and contaminated soil), and they remain toxic and persistent in water. When leachate reaches water bodies or migrates toward groundwater, these metals—such as lead, cadmium, mercury, and arsenic—pose serious health and ecological risks. That direct link between landfill leachate and metal contaminants makes heavy metals the most fitting pollutant category for this scenario. The other options are broader or unrelated: the category “major water pollutants” is too general, “toxic chemicals” is wide and doesn’t emphasize the metal-specific pathway from landfills, and “thermal pollution” relates to temperature changes, not leaching metals from waste.