Question

Why are construction sites considered major sources of water pollution?

They introduce high levels of salt into local water sources.


Soil erosion rates accelerate dramatically, impacting water quality in streams and rivers.


Sawdust leaches into the soil, causing the water that runs into rivers and streams to be cloudy and full of particles.


They cause sinkholes to form, which pollute local water sources.

Answer 1

The correct choice is:
"Soil erosion rates accelerate dramatically, impacting water quality in streams and rivers."

Why: construction often leaves large areas of bare, disturbed soil. Rain and runoff carry that soil as sediment into storm drains and waterbodies. Sediment (the most common pollutant from construction) increases turbidity, smothers fish eggs and benthic habitat, transports attached nutrients and metals, and can clog streams and storm systems.

Notes on the other options:
- High salt levels: possible in cold regions where de‑icing salts are used, but not a primary, universal cause of construction‑site pollution.
- Sawdust: may contribute organic material or turbidity locally, but it’s not a major widespread source compared with sediment and construction chemicals.
- Sinkholes: not a typical mechanism by which construction sites pollute water.