What is a common cause of non-point source pollution?

Non-point source pollution refers to contaminants that do not originate from a single, identifiable source. Instead, it is characterized by diffuse sources that contribute pollutants to the environment, often carried by rainfall or snowmelt into water bodies. Urban runoff is a prime example of non-point source pollution. It occurs when precipitation flows over surfaces such as roads, parking lots, and buildings, picking up various pollutants like oils, heavy metals, trash, and chemicals found in urban areas. This contaminated water then enters streams, rivers, and lakes, contributing to water quality degradation.

In contrast, industrial discharge, wastewater treatment plants, and landfill leachate are all considered point sources of pollution because they originate from specific, identifiable locations. Industrial discharge comes directly from factories, wastewater treatment plants treat sewage before releasing it, and landfill leachate is the liquid that drains from the waste itself. These sources are easier to regulate and manage compared to the diffuse nature of non-point source pollution, which requires broader management strategies aimed at controlling runoff and improving urban planning to minimize environmental impact.