What are three sources of groundwater pollution and how do pollutants get into the water?

Hint: Groundwater serves as the largest source of freshwater in the world. Groundwater may be defined as the water that is found underground either in cracks or spaces of soil. Pollutants on the other hand are the substances or energy introduced in the environment that cause undesirable side effects like pollution and thus degrading the natural environment.

Complete answer:
The sources of groundwater contamination include:
1. Storage Tanks: These tanks contain gasoline, chemicals, or petroleum oils that are present below the ground, the leakage of contaminants of these tanks into the groundwater can cause groundwater pollution.
2. Landfills: Landfills are the areas where the waste products and garbage are dumped. The landfills are supposed to have a protective layer for the prevention of contamination into the water. But if the layer is cracked or no such layer is present then it can cause contamination.
3. Septic tanks and systems: These are tanks and systems specially designed for the removal of household wastes. These are designed mainly for the removal of human waste products underground. The leakage of these tanks or pipes can lead to contamination of the groundwater system.

Additional information:
In the case of surface water, the pollutants enter the water by either industrial wastes in which the industrial pipes release pollutants from the industry into the rivers or other water sources. Other pollutants include the agricultural wastes that are carried from the agricultural fields into the river through drainage or rain. Dumping waste products into the river, ponds can act as a source of water pollution. Cleaning of clothes into rivers mainly with the use of detergents can also cause water pollution. Some sources of groundwater pollution are mentioned above.

Note:
Water pollution not only damages water bodies but also destroys the aquatic habitat, may it be aquatic plants or aquatic animals. The wastewater that is obtained from domestic sewage contains \[0.1\% \] waste or impurities. The impurities may include suspended solids like sand, colloidal material (fecal material, cloth, paper fibers), dissolved materials (nitrate, ammonia).