Which scenario is an example of non-point source pollution?

The scenario involving pesticides dissolving and moving through soil after rainfall is an example of non-point source pollution because it originates from widespread, diffuse sources rather than a single, identifiable source. Non-point source pollution occurs when contaminants are carried by rainfall or snowmelt across broad areas, making it challenging to pinpoint exactly where the pollution is coming from. In this case, the pesticides are not released from a specific location but rather wash off land surfaces and integrate into the soil and waterways over a larger area.

In contrast, other scenarios illustrate point source pollution, where pollutants can be traced back to a specific source. For example, a chemical spill in a factory is a clear point source because it originates from a single identifiable location. Similarly, runoff from a sewage treatment plant and vehicle exhaust can both be traced back to specific sources of pollution, reinforcing the distinction between point and non-point source pollution. This understanding is vital for developing effective strategies to manage and reduce pollution in the environment.