There are two major categories of water pollution.  There is point source pollution, which refers to pollution coming from a pipe or ditch or other discrete mechanism or formation.  Plants typically discharge wastewater from a pipe for which they require a permit.

In contrast is a diffuse or non-point source where the pollution enters the stream, river, lake or other water body through surface runoff, by flowing freely across land.   Diffuse pollution includes run-off from farmlands, forests, roads, and construction activities.  The pollutants include nutrients, pesticides, chemicals, manure and sediments.

Diffuse pollution presents particular problems in identifying and remediating the source.  A point source, such as a pipe, is visible, easily identified and discrete, whereas pollution in run-off can be from a number of sources, and often is commingled.  Separating the different pollutants and responsible parties is a challenge.

Some further ideas to explore on Diffuse Pollution:

Identify a point source of pollution near where you live, and in what waterbody that source is discharging.

Identify several potential diffuse sources of pollution that are or could be releasing pollutants into the same waterbody near the pipe.

How do you differentiate the damages from the point and diffuse sources of pollution?

Sources:

“Diffuse Pollution,” Scottish Environment Protection Agency  bit.ly/3b09WoQ

“Diffuse sources,” European Environment Agency. bit.ly/3bHqP72

OECD, Diffuse Pollution, Degraded Waters: Emerging Policy Solutions.  bit.ly/3sB3o6d