In ash basin operations, which pollutants are commonly involved?

• A. dissolved metals and fly ash
• B. nitrates and phosphates
• C. oil and grease
• D. bacteria and viruses

Answer: (A)

In ash basin operations, the water interacts with coal combustion residuals, so the main pollutants are dissolved metals released from the ash and the fine particulate fly ash itself. Metals can leach into solution as the ash contacts water under varying pH and redox conditions, creating dissolved contaminants that can move with the basin water. At the same time, the fine fly ash particles can remain suspended or settle within the basin, contributing solid-phase pollutants. The other pollutants listed—nutrients like nitrates and phosphates, oil and grease, or bacteria and viruses—are more typical of other wastewater or environmental contexts and are not the defining issue for ash basins. Therefore, dissolved metals and fly ash are the pollutants commonly involved.