What best describes non-point source pollution?

Non-point source pollution is characterized by its diffuse nature, meaning that it originates from multiple sources rather than a single, identifiable point. This type of pollution occurs when rainfall or snowmelt moves over and through the ground, picking up various pollutants such as fertilizers, pesticides, and sediment as it travels. Because it does not come from a specific discharge point, such as a pipe or a sewer, it can be more challenging to manage and regulate.

In contrast to non-point source pollution, concentrated chemical spills or direct discharge from industrial facilities are examples of point source pollution, which have a clear and defined origin. Contamination from municipal waste can also fall under point sources depending on how it is disposed of. The diffuse nature of non-point source pollution makes it particularly difficult to trace back to a specific source for mitigation efforts, reinforcing why the correct description is that it involves runoff contamination.