Which pollutants are commonly elevated due to stormwater runoff from impervious surfaces?

Which pollutants are commonly elevated due to stormwater runoff from impervious surfaces?

• A. Mercury
• B. Nitrates
• C. Sediment and phosphorus
• D. Oxygen

Answer: (C)

Stormwater from impervious surfaces carries more material into waterways because rain doesn’t soak in; it runs off quickly and erodes soil while picking up nutrients from fertilizers and other sources. The most common pollutants that ride along with that runoff are sediment and phosphorus. Sediment comes from eroded soil, and phosphorus often sticks to those soil particles or comes from lawn fertilizers, detergents, and waste—and travels with the sediment into streams and lakes. These two together are routinely elevated in urban runoff and are major drivers of degraded water quality. Mercury or nitrates can be present in some cases, but they’re not as consistently elevated in typical impervious-surface stormwater, and oxygen isn’t a pollutant itself, though it can be affected downstream by those pollutants.

Stormwater from impervious surfaces carries more material into waterways because rain doesn’t soak in; it runs off quickly and erodes soil while picking up nutrients from fertilizers and other sources. The most common pollutants that ride along with that runoff are sediment and phosphorus. Sediment comes from eroded soil, and phosphorus often sticks to those soil particles or comes from lawn fertilizers, detergents, and waste—and travels with the sediment into streams and lakes. These two together are routinely elevated in urban runoff and are major drivers of degraded water quality. Mercury or nitrates can be present in some cases, but they’re not as consistently elevated in typical impervious-surface stormwater, and oxygen isn’t a pollutant itself, though it can be affected downstream by those pollutants.