More on Pollution and Wastes...

What is pollution?

Not necessary a substance. Noise pollution and light pollution also exist.
When the presence of an agent goes over the tolerated amount, it can be considered pollution.
Pollution management has been a challenge for mankind since the Industrial Revolution but has been a significant issue since the late 1990s.

Types of pollution

Point source: Can be tracked to a particular source, such as an oil spill.

Non-point source: Can't be tracked, such as a red tide that can be everywhere and happen from several factors.

Sources of pollution: Air, water, soil.

Air
Point-source: Factory plumes releasing large levels of CO2.
Non-point source: The use of products that release fluorocarbons that deplete the ozone layer.

Water
Point-source: The Deepwater Horizon Oil Spill that has released an estimated 4.5 million barrels of crude oil to the Gulf of Mexico affecting marine life. Groundwater under or near agricultural fields that have been polluted by chemicals flowing from pesticides.
Non-point source: Rainfall flowing to rivers or lakes containing trash from the cities. Polluted runoff.

Soil
Point-source: A chemical plant that buries its toxic residues in the nearby soil.
Non-point source: Water runoff also affects soil as larger residues might filter.