Which of the following are examples of nonpoint source pollution?

• A. Agricultural runoff
• B. Heavy metals discharge
• C. Pharmaceuticals
• D. Oils

Answer: (A)

Nonpoint source pollution comes from many diffuse origins rather than a single identifiable outlet. It happens when rain or irrigation water flows over land and picks up pollutants—nutrients, sediments, pesticides, and other substances—and washes them into streams and lakes.

Agricultural runoff is a classic example because water moving across farm fields during rainfall carries fertilizer nutrients, pesticides, and soil into water bodies without a single discharge point. That widespread, diffuse movement is exactly what defines nonpoint pollution.

Heavy metals discharge, by contrast, is typically traced to a specific facility or pipe, a point source. Pharmaceuticals usually enter waterways mainly through effluent from wastewater treatment plants, another point source. Oils can enter water from leaks, spills, or diffuse runoff, but they aren’t as clear-cut as agricultural runoff in illustrating diffuse, land-derived pollution.