Which of the following is an example of point source pollution?

• A. Agricultural runoff
• B. Discharge that contains heavy metals
• C. Salt from irrigation
• D. Bacteria from livestock operations

Answer: (B)

Point source pollution comes from a single, identifiable outlet where pollutants are discharged, such as a pipe or other conduit. Discharge that contains heavy metals fits this description because it implies a targeted release from a specific facility’s outlet. In contrast, agricultural runoff, salt from irrigation, and bacteria from livestock operations generally originate from many diffuse locations across a landscape and are driven by rainfall or irrigation, making them nonpoint sources. Therefore, the example of point source pollution is discharge that contains heavy metals.