Which scenario is an example of point source pollution?

• A. Diffuse urban runoff from many sources
• B. A single pipe discharge into a river
• C. Air pollution from multiple factories
• D. Volcanic ash discharge

Answer: (B)

Point source pollution comes from a single, identifiable outlet. A single pipe discharging into a river fits this definition because the pollutants can be traced to one location—the pipe. In contrast, pollutants entering water from many streets and surfaces over a wide area form diffuse runoff, so it’s nonpoint pollution. Air pollution from multiple factories involves many distinct emitters rather than one outlet, and volcanic ash discharge is a natural process from a vent rather than a controllable single source. So the scenario with the single pipe is the clear example of point source pollution.