What Are The Major Sources Of Groundwater Contamination?

Oil spills and other contaminant leaks are a source of groundwater pollution.
Oil spills and other contaminant leaks are a source of groundwater pollution.

Groundwater, as the name suggests, is water found underneath the surface of the earth. The water from rainfall, lakes, rivers, and streams seeps through the porous ground to reach the water table; a level where the ground beneath is saturated with water. Groundwater is usually contained in an aquifer. An aquifer can be described as a geological structure made of permeable components able to store large quantities of water. Groundwater is found in almost all places but the depth of the water table varies depending on the region, meteorological factors, and rate of exploitation. The amount of groundwater also changes with the season. In the rainy season, the water levels increase while in the dry season, the level of groundwater decrease.

Importance of Groundwater

Groundwater is an essential natural resource in most places. It makes up about 30% of the world’s freshwater reserve. It is often clean and easily accessible. In the United States, more than half of the population depends on groundwater as the primary source for their drinking water. In most farming areas where irrigation is practiced, groundwater is often used to irrigate the crops. In dry regions like Australia, groundwater provides a cheap water source because it is the most cost-effective to extract. In times of no rain, the groundwater plays a vital role in the environment by releasing water into rivers, lakes, and streams. As a result, groundwater prevents them from drying up. It also sustains the ecosystem by providing water for the vegetation when rainwater has dried up.

Major Sources of Groundwater Contamination

For a long time, groundwater was known to be clean and free from contamination. However, due to rapid industrialization and increased use of chemicals, numerous contaminants often find their way into the groundwater. The significant sources of contamination in groundwater are farming chemicals, septic waste, landfills, uncontrolled hazardous waste, storage tanks, and atmospheric pollutants.

Agricultural Chemicals

Agricultural production has been scaled up in most developed nations. This large-scale production of farm goods means increased use of farm chemicals such as pesticides, herbicides, and fertilizers. These chemicals used on farms settle on the ground, and when it rains, they mix with the rainwater and seep through the porous ground to reach the underground water. That way, the chemicals pollute the groundwater.

Septic Waste

It is essential that septic waste is treated before it is disposed into the ground. Treatment prevents harmful substances from getting into the ground and spreading to the water. Additionally, the septic systems are structured to release the waste into the ground at an extremely slow rate which is harmless to the environment. However, poorly designed septic systems release viruses, bacteria, and household chemicals into the groundwater and make it unfit for human consumption. Poorly maintained septic tanks also result in leaks which cause groundwater contamination.


As the human population grows, so does the garbage produced daily. This garbage is collected and taken to particular locations known as landfills where it is buried. Landfills are required to have a protective layer at the bottom to stop the waste from seeping into the ground. Nonetheless, some landfills lack that protective layer, and in some cases, it is cracked. Such landfills result in leaks of contaminants such as household chemicals, car battery acid, oil, and medical products into the groundwater.

Hazardous Waste Sites

There are numerous sites around the world where hazardous products such as radioactive components, war chemicals, electronic waste, and similar products are disposed. The number of these waste sites keep growing by the day. In many cases, hazardous products’ disposal sites are not adequately monitored. The lack of proper monitoring and maintenance of such sites leads to leakage of dangerous substances into the groundwater.

Storage Tanks

Chemicals, oil, minerals, and other products are often kept in storage tanks above or below ground. In the United States alone, it is estimated that more than 10 million storage barrels containing different substances are stored underground. Over time, the storage containers erode, and this may result in harmful substances leaking into the ground. Subsequently, the contaminants move through the soil and reach the groundwater making it unfit for human use.

Atmospheric Pollutants

Groundwater is maintained through the hydrological cycle which is the movement of water above, below, and on the surface of the earth. As the water moves, it comes into contact with pollutants in the atmosphere such as harmful gases. When it rains, the water carries these contaminants into the ground and pollutes the groundwater.

Underground Pipes

As nations develop, they invent new methods of transporting different products using the underground pipes. Products such as oil, farm chemicals, cooking gas, and drinking water are mainly transported through underground pipes. In many instances, the underground pipes burst and release their content into the ground. These incidents often lead to groundwater contamination.

Road Salts

Road salts are mainly used in places that have snowfall during winter. Road salts are chemical products used to melt ice on the road. Once the ice melts it flows with the chemicals through the ground and into the groundwater hence contaminating the water.

Effects of Contaminated Groundwater

Contaminated groundwater can lead to severe effects on the environment, animals, and human beings. Firstly, groundwater is the primary source of drinking water for most people and animals around the globe. Once the groundwater is contaminated with harmful chemicals and bacteria, the humans and animals consume the harmful substances through drinking water and subsequently suffer health problems such as amoeba, typhoid, diarrhea, and even cancer. Secondly, the trees and vegetation that rely on groundwater are likely to dry up after absorbing contaminated water. As a result, the loss of vegetation leads to an imbalance in the ecosystem. Thirdly, contaminated groundwater may seep into rivers and streams and lead to the loss of marine life which is detrimental to the environment. Lastly, when groundwater is contaminated with reactive substances, it may result in harmful chemical reactions that destroy the soil around the area. The consequences of destroyed soil include poor plant development and bad soil quality.


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