What is the primary storm water pollutant at a construction site?

What is the primary storm water pollutant at a construction site?

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

Answer: (A)

Sediment is the primary storm water pollutant at a construction site. When soils are disturbed and vegetation is removed, rain easily washes particles off the exposed ground into runoff. That suspended soil—sediment—is carried into storm drains and nearby waterways, causing turbidity, sediment deposition, and habitat smothering. Construction sites typically expose large areas of bare soil, so the volume of sediment that can be washed away tends to exceed other potential pollutants, making it the main concern to control. Effective erosion and sediment control measures—such as silt fences, sediment basins, inlet protection, stabilization of exposed areas, and phased grading—are essential to reduce this pollutant. While nutrients, metals, and oils can appear on-site (from fertilizers, vehicle fluids, or debris), they are generally present in smaller amounts and are often attached to or transported by the sediment, which is why sediment is addressed first.

Sediment is the primary storm water pollutant at a construction site. When soils are disturbed and vegetation is removed, rain easily washes particles off the exposed ground into runoff. That suspended soil—sediment—is carried into storm drains and nearby waterways, causing turbidity, sediment deposition, and habitat smothering. Construction sites typically expose large areas of bare soil, so the volume of sediment that can be washed away tends to exceed other potential pollutants, making it the main concern to control. Effective erosion and sediment control measures—such as silt fences, sediment basins, inlet protection, stabilization of exposed areas, and phased grading—are essential to reduce this pollutant. While nutrients, metals, and oils can appear on-site (from fertilizers, vehicle fluids, or debris), they are generally present in smaller amounts and are often attached to or transported by the sediment, which is why sediment is addressed first.