Which class of pollution is often a result of agricultural runoff and urban development?

Diffuse source pollution is a class of pollution that occurs when contaminants are released over a wide area, making it difficult to pinpoint a single source. This type of pollution is often associated with agricultural runoff, where fertilizers, pesticides, and sediments are carried by rainwater from fields into nearby waterways. Urban development contributes to diffuse source pollution as well, as impervious surfaces like roads and buildings result in increased surface runoff, carrying various pollutants (such as oils, metals, and nutrients) into water bodies.

The distinction of diffuse source pollution lies in its non-specific origin; unlike point source pollution, which can be traced back to a specific outlet or discharge point, diffuse pollution combines contributions from multiple sources, often across large geographic areas. This characteristic complicates management strategies because it requires comprehensive approaches to mitigate widespread pollution rather than targeting individual pollution sources. Additionally, background pollution generally refers to the baseline level of pollution that is always present in the environment, while hypoxic pollution refers specifically to low oxygen levels in water bodies usually resulting from excessive nutrient loading, making them less relevant to the context of agricultural runoff and urban development.