AP BIOLOGY

Detailed explanation-1: -Nonpoint source pollution comes from oil, pet waste, pesticide, herbicide, fertilizer, road salt, bacteria, sediment, and any other contaminant that ends up on the ground naturally or from human activity.

Detailed explanation-2: -The main point source of pollution to water is from sewage and waste water treatment, while for diffuse pollution, main sources are from farming and fossil fuel power plants (via the air).

Detailed explanation-3: -Nonpoint source pollution is caused when precipitation (1) carries pollutants from the ground such as nitrogen (N) and phosphorus (P) pollutants which come from fertilizers used on farm lands (2) or urban areas (3).

Detailed explanation-4: -Therefore, nonpoint source pollution does not meet the legal definition of “point source” in the Clean Water Act. There are four main forms of nonpoint source pollution: sediments, nutrients, toxic substances and pathogens. Sediments are soil particles carried by rainwater into streams, lakes, rivers and bays.