What are nonpoint sources of nutrients?

• A. Nutrients that cannot be attributed to industrial point sources and contribute to water pollution as water moves through the watershed.
• B. Direct discharges from factories.
• C. Nutrients from wastewater treatment plants.
• D. Nutrients released from atmospheric deposition.

Answer: (A)

Nonpoint sources are nutrients that enter water from many places rather than a single, identifiable discharge point. They move with runoff and other water movement through the watershed, so you can’t pin them to one pipe or facility. That broad, diffuse origin is what makes them nonpoint. Direct discharges from factories and nutrients released from wastewater plants are classic point sources because they come from specific, identifiable sources. Atmospheric deposition can contribute nutrients too, but the defining idea for nonpoint sources is the diffuse, watershed-wide input rather than a single emission point, which is why the statement describing nutrients that can’t be traced to industrial point sources and that reach water bodies as water moves through the watershed is the best fit.