Nutrient pollution is considered one of the dire issues in the present context throughout the globe. In general, we understand that nutrient pollution results from such a phase where there is an excessive amount of nutrients in the water bodies. 

Bernard Marcus, an American billionaire businessman, stressed, ‘If overfishing continues if pollution continues, many of these species will disappear off the face of the earth.’ This quote makes us think about the anthropogenic nutrient pollution that impacts aquatic organisms. 

The nitrogen and phosphorus are added up in the water, acting as fertilizer. Since there is a heavy presence of the nutrients, there is excessive growth in algae that ruins the water quality of the aquatic ecosystem.

Nutrient pollution results from the term Eutrophication, where there is the presence of massive algae. It is regarded as a challenging issue these recent days since it causes water pollution on a large scale.

When there is an excessive presence of nutrients in the water, it can decrease the oxygen content. The massive growth of the algae in the water can block the sunlight from penetrating the water bodies, which results in a lack of proper growth and development of the vegetation within the water body.

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The level of the nutrients may either increase or decrease with time. Several factors that influence nutrient pollution entail the nutrients input from wastewater treatment plants, numerous agricultural practices, and runoff from the land in urban regions during precipitation in the form of rain.

All these factors have a crucial role in increasing the nutrient pollution in various water bodies such as lakes, reservoirs, bays, coastal, rivers, and streams.


sources - nutrient pollution
Golf of Mexico nutrient supply sources (source)

Sources of nutrient pollution can be either natural or anthropogenic-induced activities. The natural sources entail weathering the rocks and soil in the watershed and mixing the water currents from the oceans on a large scale.

The other various sources of nutrient pollution led by human activities have been identified so far as listed below:

1. Municipal sewage

The rapid increment in industrialization and urbanization has led to an increase in municipal sewage in recent days.

It has been recorded that human sewage is the primary source of nutrient pollution in continents such as Asia, Africa, and South America. It boosts the nutrient levels in the water bodies.

2. Livestock waste

The manure is obtained from livestock farming. The use of waste as fertilizer in agricultural fields increases the amount of nitrogen and phosphorus in the soil and the water.

The livestock wastes comprise various nutrients which enhance the algal blooms in the water bodies, basically in the rivers, streams, and lakes.

3. Fossil fuels

The industry and the electric power generations used for household purposes add nitrogen. Likewise, transportation plays a vital role in increasing the nitrogen in the air.

Basically, from the indoor air pollution, there is high emission of carbon-related gases and nitrogen.

4. Around the residential areas

Various soaps, detergents, the wastes of the pets from the residential areas increase the nitrogen and phosphorus once it is discharged without proper treatment; it runoffs through the soil or the ground level through a recharging system, thereby piling the nitrogen and phosphorus levels in the various water resources.

5. Aquaculture

Direct discharge of the untreated waste products, food products, excrement, and organic materials piles up the amount of nitrogen and phosphorus.

It can have detrimental impacts on the surrounding fish, thereby deleting the aquatic organisms’ oxygen levels in the water.

The algal blooms once get up in the river and the lakes. It makes the water green and makes even the water unfit for human purposes.

6. Agricultural fertilizers

Using chemical fertilizers, pesticides, or agriculture to boost agricultural production increases nitrogen and phosphorus.

Upon seeped into the groundwater or washed as the runoff, it can create detrimental effects when reaching the aquatic water bodies. Since chemical fertilizers introduce various chemical compounds, it impacts the life of marine organisms.

7. Stormwater drainage

The stormwater runoff washes the nutrients from the residential areas and impervious surfaces in the rivers and streams. It, too, can lead the nutrition pollution seriously.


Several causes of nutrient pollution have been identified so far, which entails discharge of the wastewater treatment plants without pre-treatment, agricultural runoff, stormwater runoff, unmanaged septic systems, emission of the vehicles and the power plants.

Apart from these, the other causes of nutrient pollution include animal manures, unmanaged discharge of the detergents, and soaps. The causes of nutrient pollution vary following residential and industrial areas.


effect - nutrient pollution
Effect of nutrient pollution on fish (source)

There are multiple effects of nutrient pollution, basically nitrogen and phosphorus. The results are categorized under several headings and discussed as mentioned below:

1. Ecological effects

It has been revealed that Eutrophication has led to the dead zone formation in the aquatic bodies, limiting the organisms’ growths, thereby depleting the oxygen level.

For instance: In Mobile Bay of Alabama, the bottom-dwelling fish and the crabs move towards the shore.

This event results from the increased nitrogen and phosphorus concentration in the water. The dead zones are not limited to Alabama; instead, they have covered parts of the other countries.

2. Economic effects

There is substantial economic loss once the algal bloom in the aquatic bodies occurs. For instance, fish farming is highly affected when the algal colors degrade the water quality, depleting the fish’s oxygen level and resulting in the fish’s death.

Along with this, a high cost is demanded and required for cleaning the algal blooms once it invades the water resources.

The tourism sector will be hugely affected by nutrient pollution since it ruins the natural beauty of aquatic resources.

Once the tourism sector is devastated, it can directly or indirectly impact national revenue. People may lose their tourism job opportunities.

3. Human health effects

In most countries, drinking water is reserved for future use. While securing the water, algal blooming has become a serious threat to drinking water since it increases nitrogen and phosphorus.

Waterborne diseases have been reported from the drinking water reservoir and the consumption of sea fish.

It is estimated that roughly 21,000 waterborne infections have been detected due to the algal blooming along the Black sea coast between 1970 and 1990. Such a phenomenon may lead to the long-term persistence of waterborne diseases in the human body.

The excessive amount of nitrogen as a cause of nutrient pollution can negatively affect human lives and other living organisms, such as alteration of plant growth. 

Since nitrogen and phosphorus play a vital role in developing the algae with other plants, it provides food and shelter to the fishes and the smaller organisms in the aquatic ecosystem.

The algal blooms (increase in the number of algae in the water) can lead to many fishes in death and are very harmful to our health.

They can produce toxins when people or other living organisms close contact by drinking the contaminated water and consuming the fish.

It is to be noted that once nutrient pollution occurs in the reserved drinking water, infants are very vulnerable to the nitrogen-based compound called nitrates.

It can create an alteration in the face of infants when they drink water that contains an excessive amount of the nutrients such as nitrogen and phosphate.

When there is excessive nitrogen in the atmosphere, reaching the earth’s surface once again harms the soil and the forest ecosystem. The biogeochemical and the hydrological cycle are affected by the nitrogen level alteration.

Affected Location

Since the nutrient pollution is not limited to a specific area, it is spread throughout the globe in the Gulf of Mexico, the United States, and the Chesapeake Bay.

The research revealed roughly 100,000 miles of the rivers, around 2.5 million acres of lakes and ponds, and 800 sq. miles of estuaries and bays in poor water quality of the United States. It is the primary cause of the excessive presence of nitrogen and phosphorus in the water bodies.

The massive dead zones are detected in the Gulf of Mexico and the Chesapeake Bay, indicating the degraded water quality in the organism’s habitat, recreation, and irrigation purposes. 

Montana’s lower piper creek, upper and lower goat creek, was heavily affected by nutrient pollution. It had affected so that no aquatic organisms could survive there.

Due to the massive timber harvesting and construction of the forest road, they deteriorated the water quality.

The massive nutrients from agricultural and urban runoff degraded the lake quality when the algal blooms covered New York’s Oneida Lake. After the launch and strict implementation of the Clean Water Act, 1998, the lake turned in its original state. 

The phosphorus and nitrogen loads to the lake were significantly decreased through activities such as runoff management system, manure control system, and the sediments control system.

Solutions to the nutrient pollution

solution - nutrient pollution
Recycling water (source)

To provide solutions to nutrient pollution, we need to carry various activities. The exercises should be targeted to such water bodies which are highly impaired by nutrient pollution through detailed research on sediment and nutrient pollution, providing technical guidance and support to improve the quality of the water bodies.

Additionally, there should be a strict ban from discharging the nutrients into the water resources to the industries and the factories.

The grants can be awarded to the watershed working group and organizations working in nutrient and sediment pollution to address the nutrients-driven water quality issues.

Let us consider one perfect example: In Denmark’s case in 1986, it implemented the wastewater tax system where the discharge of the nutrients into the Baltic sea was strictly prohibited. 

The tax system aimed to reduce the nitrogen level by 50 % and the phosphorus level by 80%. Later, by 1990, the phosphorus concentration was significantly decreased by 22 %.

It could be set as the best example that the strict implementation of the laws and the regulations undoubtedly succeeds.


It’s not surprising to depict that nutrient pollution has a massive coverage throughout the world and deep-rooted the water quality, thereby increasing the level of nitrogen and phosphorus in the water.

The primary cause of nutrient pollution is a discharge of industrial effluents from the factories and the industries without adequate treatment.

Therefore, it becomes of an utmost imperative to reduce nutrient pollution to a minimum through the involvement of the stakeholders.

Funding must be invested to ensure that the water quality of the rivers, coastal, bay, lakes, and streams is good in terms of the shelter to the aquatic organisms, irrigation, recreation, and electricity generation from the hydropower plants.

Nutrient pollution can be minimized by effective monitoring and auditing of the water quality of the aquatic resources, and proper-plan-oriented action is always the foremost to carry the practical activities regarding the control of nutrient pollution at the local, regional, and national level.

(Last Updated on December 13, 2021 by Sadrish Dabadi)

Kalpana Ghimire holds a post-graduate degree in Environmental Science from Nepal. She possesses numerous research experiences working in water pollution, community forestry, environment conservation status, and wildlife ecology. She was an internee in the Department of Environment (EIA monitoring and auditing section) under the Government of Nepal. Kalpana Ghimire is an avid traveler, an enthusiastic wildlife researcher, and has a huge passion for working in the environment sector. She loves far traveling to the natural areas, conducting field wildlife research and reading the novels.