In the last few posts, we have been looking into the different types of pollution that are present in our waters. Let us now look into the sources of water pollution so that we can have a better understanding of how and where our problems begin.
Most of the pollution that ends up in the marine environment usually comes from 4 very different sources. As seen in the figure below, most of the pollution comes from land-based sources (both blue sections), either as runoff and discharges (44%) or released into the atmosphere (33%). Maritime activity and shipping incidents (12%), ocean dumping (10%) and offshore drilling and mining (1%) makes up the rest. (Potters, 2013)
There are 2 main sources of land-based water pollution (Nature Society, 2020):
1.) Point Sources
Point source pollution are sources of pollution which originate from a single place. Factories, septic systems and wastewater treatment facilities that clearly releases pollutants into water sources, intentionally or unintentionally, are a few examples of point sources.
2.) Diffuse Sources
Diffuse source pollution are sources of pollution that originates from many places, all at the same time. This type of pollution source is much, much harder to identify and solve as the pollutants cannot be traced easily back to a single, main location. Runoff containing sediments, fertilizers and chemicals from farms, mines and construction sites are but a few of the common examples of diffuse sources. Another common example would be landfills as substances from the accumulation of trash would eventually leach out into water bodies nearby.
Reference:
Nature Society, 2020. Point Source And Nonpoint Sources Of Pollution. [online] National Geographic Society. Available at: <https://www.nationalgeographic.org/encyclopedia/point-source-and-nonpoint-sources-pollution/> [Accessed 2 July 2020].
Potters, G., 2013. Marine Pollution. 5th ed. Oxford University Press.
