What is the most common pollutant in runoff from construction sites?

• A. Sediment
• B. Nutrients
• C. Pathogens
• D. Oils

Answer: (A)

Sediment from soil erosion is the most common pollutant in runoff from construction sites. When soil is exposed during grading and earthwork, rainfall easily detaches and transports soil particles into storm drains and nearby waterways, increasing turbidity and depositing sediment downstream. Other pollutants like nutrients, pathogens, or oils can occur, but the sheer amount of erodible soil on typical sites makes sediment the dominant pollutant load. That’s why erosion control is the primary focus of construction-site stormwater management: stabilize soils quickly, use silt fences and sediment basins, stabilize exposed areas with vegetation or mulch, minimize the disturbed area, and phase grading to reduce erosion.