Focusing on Water Pollution as we celebrate Pollution Prevention Week

Updated: Nov 27, 2020

Water is essential for life. A person could survive for up to three weeks without food, but they would only last three days without water. With that said, access to clean drinking water is of utmost importance. However, the finite nature of drinking water makes it quite difficult for people to have access to water. To make matters worse, human activities paved the way for water pollution and made some of the available freshwaters unfit for consumption. About 80 per cent of global wastewaters are dumped into bodies of water without treatment. Currently, we are facing a water crisis and because of this more people died from drinking unsafe water than from violence and conflict.1

What is water pollution?

Water pollution is pretty self-explanatory. It is the pollution of water. This occurs when the water is adulterated with dangerous substances or microorganisms that would turn the water hazardous for drinking and use. The harmful substances may dissolve in the water or sink to the bottom. Whatever the case may be, these pollutants would negatively affect aquatic ecosystems and the humans who would use these polluted waters.1,3

What are the main causes of water pollution?

Water is known as the universal solvent, and for good reason. This liquid is capable of dissolving a lot of substances. This property of water seems to act as a double-edged sword. The property that makes it a very useful substance makes it very susceptible to adulteration. Harmful substances that come from various sources such as farms and factories would dissolve and mix easily in water.1

There are several human activities that contribute to water pollution. Discharges from factories, winds and storms, spills and leaks from oil pipelines, and littering; all of these are human activities that damage water quality. Regulations placed upon by the government has lessened the occurrence of pollution due to factory discharges and pipeline spills. These days, the most common source of pollution are ‘nonpoint sources’. Nonpoint sources are pollutant sources that originate from a different place and are carried towards the body of water. The pollutants are carried from the source towards the body of water through the rain and snow. These run-offs would oftentimes carry fertilizers, pesticides, herbicides, bacteria, oils and chemicals that may come from automobiles, and sediments that may contain toxic substances.2

For drinking water, pollution may come from pipeline leakage which would allow the entry of natural toxins present in the soil, or chemicals that seep through the soils and enter the opening.2

Sources of water pollution

It is estimated that 75% to 80% of water pollution cases are caused by domestic sewage. Besides this, industrialization also contributed to the problem for 25% of water pollution cases are caused by large scale industries. Sugar production factories, pesticides, textile, electroplating, and pulp and paper, have all contributed to the problem.4

In developing countries, the ever-increasing population size has spawned problems with regards to sanitation and waste management. These lapses in sanitation and waste management resulted in the spillage of human excreta unto the bodies of water which led to microbial contamination.4

Urbanization and overcrowding lead to waste disposal problems, especially when the authorities are very lax. It may come to a point where the majority of the populace would litter indiscriminately. Polythene bags and plastic waste are some of the most common waste that is thrown into bodies of water. These plastic wastes are very hazardous to aquatic life. They are hazardous to humans as well, for plastics that remain in the water for a long time would become microplastics. Aquatic animals which we consume as seafood may consume these microplastics and concentrate them within their bodies. When we consume this seafood we also consume the microplastics concentrated within them.4

Types of water pollution

Water pollution cases may come in various forms and may exhibit similarities or huge differences from each other. Due to this, water pollution is best understood if they are categorized.

Take note that a water pollution case may not be exclusive to one type but may also be categorized into two or more types. For example, an oil spill caused by an oil tanker ship may be categorized as ocean water pollution, point-source water pollution, and transboundary water pollution because the pollution occurs in the ocean, there is only one specific source of the pollution, the ship, and the oil spill may spread far and wide and cross into a neighbouring country’s borders. A detailed explanation of each type are presented below:

Groundwater pollution

A large number of people are reliant on groundwater for drinking and other use. There are a lot of ways that groundwater can become contaminated. Rain may dissolve chemicals and seep towards the bottom and mix with the groundwater. Usually, it is pesticides and fertilizers that are carried by the rain into the groundwater. However, oil, gasoline, and other chemicals may seep into the groundwater as well.1

Surface water pollution

Besides groundwater, tap water may also come from surface water sources. These surface waters are what fills oceans, lakes, and rivers but they are often used to denote lakes and rivers. Waters found within dams and reservoirs are considered surface waters. These bodies of water are just as vulnerable to pollution as groundwater. Run-off from either agricultural lands, mining operations, factories, and natural deposits may end up in the water reservoir or end up in a river that flows to the dam.1

Ocean water pollution

We don’t use ocean or marine water as drinking water. However, this does not mean that we shouldn’t be concerned about ocean water pollution. We still obtain some of our food, seafood, from the ocean. When our oceans would become polluted, this seafood would harbour some harmful pathogens and chemicals that would make consuming them a health risk. One of the worst forms of ocean water pollution is an oil spill. However, this is not a usual occurrence. Most of the time, ocean water pollution originates from land. This means that oil companies are not the only ones who are accountable, we are equally accountable as well.1

Point-source water pollution

Point-source pollution is a kind of pollution that originates from a single specific place. This is not exclusive to water pollution, for any other type of pollution may fall under point source pollution. Point-source pollution is often caused by large scale operations like mining and factories. Due to the nature of their operations, they would produce waste that may or may not undergo treatment and are dumped into bodies of water. The distance of their damaging effects is far-reaching. Waste dumped into rivers and other moving bodies of water may carry the hazardous wastes for miles.1

Nonpoint-source water pollution

In developed countries like the United States, where the government has implemented strict rules about pollution control; nonpoint-source pollution is the most common type of water pollution and pollution in general. Nonpoint-source pollution is somewhat the opposite of point-source pollution. Where in point-source pollution there is only a single source of the pollutants. In nonpoint-source pollution, contamination may come from several sources. For example, run-offs are nonpoint-source water pollution. It may be that the run-off passed through several agricultural fields and carried the pesticides and fertilizers present in their soils and deposit it in a body of water. This type of pollution is quite challenging to tackle especially when it comes to finding the source. Applying regulations to prevent nonpoint source pollution is also challenging because sometimes there are no culprits.1

Transboundary water pollution

Transboundary water pollution is a kind of water pollution that crosses a country’s borders and into the neighbouring country’s jurisdiction. This may occur abruptly such as in an oil spill or may take months or years such as in industrial, agricultural, or municipal discharge. Transboundary water pollution shows the ubiquitous nature of water and how it acts as a medium of transport for water pollutants, allowing these pollutants to cross boundaries.1

The Most Common Types of Water Contamination

Agricultural Contamination

Farming and livestock production consumes about 70 per cent of the Earth’s freshwater. It is the biggest consumer of fresh water. To make things worse, agriculture is one of the biggest contributors to water contamination. A significant number of nonpoint-source water pollution cases have been attributed to livestock operations. Huge patches of empty land are often used for grazing which results in the continuous deposition of the grazing animal’s waste. When the rainy season comes, the topmost soil layers, which are rich in animal waste, are eroded away by run-offs. These run-offs would often end up in bodies of waters like lakes, rivers, and streams. Once this happens, the bodies of water are contaminated with the nitrogen, phosphorus, and potassium-rich manure which are carried by the run-offs. Aside from this, whatever enteric pathogen was present in the grazing animal would also pollute the bodies of water. Nutrient pollution may also occur as a consequence to farmland run-off, for crop-growing lands are often rich in fertilizers and pesticides. Nutrient pollution is the leading cause of algal blooms. Therefore, we could say that agricultural run-off leading to agricultural contamination is the leading cause of algal blooms.1

Sewage and Wastewater Contamination

Not all water is drunk, some of them are used for cleaning and other purposes. It is unsanitary to have stagnant used water laying around. This is the main reason why we have drainages and sewer systems. Flushing, showering, washing dishes, all of the water used in these activities would all wind up in our sewage system. Commercial, industrial, and agricultural activities may require special sewage systems and pre-treatment facilities to handle their wastewater. Despite this, not all sewage systems and pre-treatment facilities are adequate or even existent. Due to this, pathogens, phosphorus, nitrogen, heavy metals, toxic chemicals and other domestic, agricultural, and industrial waste may end up in bodies of water which could negatively affect public health and or the environment.1

Sewage and Wastewater Contamination is more prevalent in the least developed countries as their infrastructures are still underdeveloped. The ever increasing population and the stagnation of our infrastructures exacerbate these problems. There may come a time that even the developed countries may end up worse than the developing countries.1

Oil contamination

There is a huge misconception regarding the largest contributor of marine oil pollution. Although it doesn’t feature in news headlines, oil pollution due to man’s activity inland, especially the usage of automobiles, actually contributes more to the problem than oil tanker spills. But how do automobiles contribute more to the oil pollution problem than oil tanker spills? For one, oil tanker spills, although releases a lot of oil, does not happen often. Secondly, there are a lot of cars all over the globe and a significant number of them are leaking oil to the ground. These oils may seep into the water table or get carried towards the sea through the rain and rivers. To put this into a better perspective, about 500,000 tons of oil are transported from factories, farms, and cities into the sea through natural means each year. While oil tanker spills contribute only 10,000 tons of oil on average per year.1

Radioactive contamination

Some materials, in an effort to achieve stability, would release energized particles which we call radiation. Substances that release radiation are referred to as ‘Radioactive’. In this day and age, mankind has dealt with a significant amount of radioactive materials for the purpose of developing an energy source and or a weapon. These activities have placed several communities at risk of exposure. In fact, there are documented cases of radioactive materials contaminating bodies of water.1

Nuclear power plants and nuclear weapon production facilities are not the only sources of radioactive materials, research laboratories and hospitals may release radioactive wastes as well.1

Effects of water pollution

Common sense dictates that if we drink contaminated water we would experience negative effects on our health. However, there are other things to worry about besides the negative effects of drinking contaminated water. The consequences of water pollution have greater repercussions which go beyond than just making drinking water hazardous.

Effects of water pollution on human health

The most evident effect of water pollution is its negative effects on human health. Assessing the effects of water pollution on the environment is not always easy as it can be quite subtle. However, when several people would suddenly fall ill it is only then that an investigation would uncover a case of water pollution.4

Waterborne diseases are a huge issue worldwide. Polluted waters may carry dangerous pathogens that cause diseases when ingested. Besides this, using polluted waters in growing crops may contaminate the crops as well.4

Bacterial diseases

There are a lot of bacterial diseases that you could acquire if you drink untreated water frequently; according to the World Health Organization, cholera, dysentery, and typhoid are the most common. These bacterial diseases are caused by Vibrio cholerae, Shigella, and Salmonella bacteria respectively.5

When someone consumes food or drinks water that contains the bacterium Vibrio cholerae, that bacterium is introduced to the person’s colon. Once this happens, the bacteria would release toxins that affect the cells that line the colon. Once the cells are exposed to the toxins, they would release a lot of fluid which leads to watery diarrhoea.8 Similarly, the bacteria Shigella enters the body through ingestion. However, Shigella does not produce a toxin, this bacteria infiltrate the cells in the colon which leads to inflammation, bloody diarrhoea, stomach cramps, vomiting, and nausea.6 Salmonella operates the same way as Shigella does. However, it infiltrates a specific cell, the Payer’s Patches, the lymphoid cell in the colon, from there the bacteria may travel the entire body through the lymphatic system. Once the Salmonella bacteria establishes itself in the human body, symptoms like diarrhoea, stomach pain, weakness and fever would appear.7

Viral diseases

Some viral diseases are transmitted through contaminated water. Viral hepatitis A and E can be acquired by drinking contaminated water. Once the virus infects the liver, the individual affected will experience symptoms such as jaundice, fatigue, discomfort, high fever, and, of course, inflammation of the liver or hepatitis.4

Gastroenteritis is another disease that is acquired through the consumption of contaminated water. Technically, it is not a viral disease for gastroenteritis is a general term. Viruses that can cause gastroenteritis include Norwalk virus, caliciviruses, adenoviruses, and rotaviruses. Symptoms include fever, headache, vomiting, and diarrhoea.4

Viral diseases, which are acquired through the consumption of polluted water, is not the only problem that comes with water pollution. Mosquitos, especially the Culex genus, like to lay their eggs in polluted waters. So if there are a lot of polluted bodies of water, there are a lot of breeding grounds for the Culex mosquitoes ultimately increasing their population. Since Culex mosquitoes are vectors of viral Encephalitis, their large population would lead to an increase in viral Encephalitis cases. Therefore we could say that the more we pollute our waters, the more we increase the cases of viral Encephalitis.4

Parasitic disease

Cryptosporidiosis, Galloping amoeba, and Giardiasis are the most common parasitic diseases that are acquired through the consumption of polluted drinking water. The causative agents for these parasitic diseases are the Cryptosporidium parvum, Entamoeba histolytica, and Giardia lamblia respectively. Cryptosporidiosis causes stomach cramps and diarrhoea. Symptoms of Galloping amoeba include fever, chills and watery diarrhoea. Some cases of Entamoeba histolytica are so severe that it leads to death. Giardiasis may present with the following symptoms bloating, excess gas, watery diarrhoea and weight loss. The worst part about parasitic diseases is that they may persist even after the drinking water has been treated.4

Effects of water pollution on the Environment

The ecosystem is a complex interconnected web of organisms relying on each other for survival. When one species in this web is taken out, disastrous consequences are to be expected. Water pollution, in the worst-case scenario such as in fish-kills, can eliminate an entire species in an ecosystem. In the fish-kill scenario, whatever creature that relies on the fishes as a food source may starve to death. Aside from this, animals that the fishes would usually prey on may experience a sharp increase in population. It is difficult to determine the magnitude of the damage that water pollution may bring to an ecosystem.1

Aquatic animals are always the first ones affected when it comes to water pollution. This is especially true when it comes to algal blooms. When excess nutrients, like phosphorus and nitrogen, that come from pollution are introduced into bodies of water; the algae present in the body of water would take up the nutrients and grow exponentially. This exponential growth would also be their downfall for soon enough the algae would run out of nutrients. Once they begin to die in large numbers, the decomposition process would take away all of the dissolved oxygen present in the body of water. Any creature reliant on oxygen, like fish, will essentially suffocate and die. Terrestrial creatures that rely on the aquatic animals that were present in the body of water would experience a huge shortage of food and may die in huge numbers. If these creatures are apex predators which are responsible for controlling the population of other animals to some degree, then their deaths may lead to an increase in the population of their other prey. If the creatures are the prey of other larger predators then their decreased numbers would also lead to starvation and death of the larger predators.1

Harmful substances, chemicals, and heavy metals that are produced and dumped into rivers, lakes, and oceans as a result of human activities would lead to a phenomenon called bioaccumulation. This phenomenon occurs when organisms at the bottom of the food chain absorb hazardous substances present in their environment. Although these creatures would absorb only a tiny amount, predators that would consume these creatures would amplify that amount by consuming several prey animals. This process of amplification increases as we go up the food chain. Once it reaches the apex predator, the concentration of the hazardous substance present in their prey may become high enough to cause significant health concerns.1,9

Harmful substances don't need to be dissolved in water to do harm to animals. Plastics and other similar garbage may suffocate, starve, and strangle aquatic animals. It is estimated that around 200 species of aquatic animals are harmed by discarded fish gear and other similar garbage.1

There is a connection between water pollution and air pollution. As we burn more fossil fuels, the carbon dioxide that we emit would subsequently make the rain more acidic. This acid rain may find themselves in rivers and oceans which would acidify the bodies of water. In the case of ocean acidification, corals and shellfish would have a harder time creating tough protective layers. Creatures that rely on corals and shellfish would also be negatively affected. Fishes that live on corals may lose shelter while predators that rely on shellfish may drop in numbers as there would be fewer shellfish.1


Water pollution is a serious problem which has negative effects of untold magnitudes. It comes in many types and forms but ultimately it is man’s activities that contribute most to the problem. What’s ironic is that water is severely limited and we are highly reliant on water for survival. Efficient solutions to this problem must be developed quickly before all of the global freshwater supply either runs out or becomes too polluted that it is no longer fit for consumption.











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