What is the largest contributor to water pollution on job sites?

Sediment is indeed the largest contributor to water pollution on construction job sites. This is primarily due to the disturbances caused by land clearing, excavation, and other site preparation activities. When soil is disrupted, it can easily be washed away by rain or water runoff, leading to sedimentation in nearby bodies of water.

Sediment can have several detrimental effects on aquatic ecosystems. It clogs fish gills, damages aquatic habitats, and can transport nutrients and contaminants into water systems. Managing sediment through effective erosion and sediment control practices is critical for minimizing its impact on water quality.

The other options provided, such as oil spills, chemical runoff, and detergents, also pose serious environmental concerns but on construction sites, sediment typically represents a more pervasive and immediate threat due to the nature of construction activities that often disturb large areas of soil.