Groundwater pollution can occur when which occurs?

• A. Metals or other compounds dissolve in the water
• B. The water remains completely pure
• C. The water is heated by sunlight
• D. The water is oxygen-saturated

Answer: (A)

Groundwater pollution happens when substances dissolve into the water and are carried by its flow. When metals or other compounds dissolve, they become dissolved contaminants that can move with groundwater through soil and rock and reach wells or springs. This solubility and transport of pollutants is what makes groundwater vulnerable.

If water were completely pure, there would be no pollution. Heating by sunlight isn’t a typical mechanism for groundwater pollution, and oxygen-saturated water isn’t pollution itself; dissolved oxygen is generally a normal, healthy part of water. The key idea is that pollutants must dissolve in water and then move with it.