Water pollution is any incident, where a water reservoir is infiltrated by a contaminant to lead to a loss of quality for the stored water. As one of the most crucial substances for all biological life on Earth, water needs to be protected at all costs against contaminants that might come in natural or artificial forms. Whether it be drinking water in natural reservoirs or water for everyday use that has been integrated into modern water systems, water needs to retain certain qualities to be utile for human beings and human activities. The causes of water pollution can be described as an undesired substance infiltrating into a water source to reduce or eliminate its utility for different purposes.
What Is Water Pollution?
Water pollution is a term used to describe the incidents where contaminants such as chemicals or microorganisms enter a water source, like a lake, river, stream, underground aquifer, or ocean to dissolve in such water sources, get suspended in them, or deposited on the bed, and decrease the quality of the water in the source, making it undrinkable or unusable for human beings and harmful for the environment. Polluted water can infiltrate the soil and reach underground water sources to contaminate them, which is used by human beings in their daily activities, as well. (Denchak, 2018)
What Are the Causes of Water Pollution?
There are a variety of different causes of water pollution based on their origin and development methodology, meaning how and where they originate and how they create water pollution. The causes of water pollution are listed below:
- Industrial Waste
- Oil leaks
- Toxic Chemical spills and leaks from large scale transporters and containers
- Fuel spills from vehicles into the soil
- Fertilizers and pesticides from agricultural sites
- Excessive removal of surface and groundwater
- Salty run-off water during winter months
- Human and waste products
- Silt and soil spillage from construction sites and agricultural bank erosion
- Chemicals from wash waters
- Dumping (NetRegs, n.d.)
Categories of Water Contamination
Water contamination is categorized in accordance with the nature of the contaminants that infiltrate into water sources and the type of damage such infiltration causes for the water source. The categories of water contamination are as follows:
- Surface water pollution
- Groundwater pollution
- Ocean water pollution
- Transboundary water pollution
- Nonpoint source water pollution
- Point source water pollution
These categories of water contamination have been selected on the basis of them being the most observable and threatening types of water pollution in the world today that affect seas, oceans, rivers, lakes, aquifers, groundwater, and reservoirs.
1. Surface Water Pollution
Surface water pollution is a type of pollution caused by contaminants like fertilizers, flooding, and human waste. These contaminants pollute surface water with fertilizers leaking into rivers and groundwater from farmlands. Floods carry both regular and polluted items to surface water and spread around the land that is not normally exposed to water or any other interference from any surrounding areas. Human waste can also leak into surface water sources due to faulty and/or poorly maintained infrastructure, especially in developing countries, as most water and sewage systems run close to each other in underground facilities where it is not possible to monitor them. Industrial waste is also a common polluter of surface water sources since industrial facilities often dump their waste and byproducts to nearby water sources like lakes and rivers.
The problem with surface water pollution is that although water seems to be clear and clean, it might be possessing contaminants in its deeper levels, which is why local authorities have to implement testing and treatment programs on their water sources periodically to check for and remove potential contamination. Due to surface water pollution, several pathogens linked to waterborne diseases are passed onto human beings if contaminated surface water is drunk or used to prepare food, while fish from contaminated surface waters also carry toxic materials to humans who consume such fish. (AOS Treatment Solutions, 2018)
2. Groundwater Pollution
Groundwater pollution is a type of contamination that occurs when contaminants pass through the soil to infiltrate into underground water reservoirs where groundwater is stored. Although it is possible for groundwater contamination to occur naturally, commonly referred to as ‘geogenic’, most of such materials are man-made, like gasoline, chemicals, road salts, fertilizers, pesticides, motor oil, arsenic, fluoride, nitrate, heavy metals, pharmaceuticals, septic waste, and organic matter, and upon infiltrating into groundwater sources, these materials reduce the quality of stored water or make it completely toxic for humans and the environment.
Some of the most common reasons for groundwater pollution are leakage from on-site sanitation systems, sewage and sewage sludge, agricultural practices that produce fertilizer and pesticide residue, commercial and industrial leaks, hydraulic fracturing, leachate from landfills, over-pumping of land-water, and unregulated mining operations. If humans consume polluted groundwater for long periods of time, illnesses/complications like hepatitis, cholera, giardiasis, methemoglobinemia, learning disabilities in children, nerve, kidney, and liver problems, as well as pregnancy risks can be observed. For the community and the environment, contaminated groundwater results in loss of drinking water quality and water supply, degradation of surface water systems, as well as high clean-up and switching costs. (EPA New England, 1999, p. 2-7)
3. Ocean Water Pollution
Ocean water pollution is a type of pollution caused by excessive human activity either in a direct or indirect manner. Ocean water or marine pollution directly disaffects marine life in the oceans, largely due to the spreading of materials like oil, industrial and agricultural waste, numerous types of plastic, and chemicals from residential and commercial use and disposal. Marine pollution is a problem because oceans house a large scale of animals and plants that play a critical role in the well-being and functionality of the global ecosystem, within which humans are not only contributors but also recipients of several benefits.
The causes of ocean water pollution are the flow of sewage and toxic chemicals from industrial production, land runoffs, oil spills over vast bodies of oceanic water, mining activities within the ocean, and littering. Sewage and other polluting substances can directly enter oceans through sewage systems, rivers, and drainage systems, while mining operations also contribute to marine pollution by sending minerals and chemicals used in mining operations to the oceans and as a result the oxygen levels in the marine ecosystems are reduced, resulting in loss of plant life and reduced seawater quality. Both industrial production facilities and farms have been known to discharge toxic chemicals and liquids into the oceans through either sewage systems or directly through rivers, which are considered to be highly dangerous for marine life and also increase the oceanic heat to create thermal pollution that reduces the chances of survival for marine animals and plants. Excessive water from rainfall, the flooding it creates, or the melted water flows from snow and ice have been known to create land runoffs into the ocean to create marine pollution because such runoffs carry along contaminants with themselves, like oil, pesticides, human and animal waste, as well as fertilizers as they reach the ocean to create dead zones. Oil spills are a huge contributor to ocean water pollution as numerous incidents have taken place at oil rigs in the sea or in the ocean throughout the years due to mechanical or technical failures, natural disasters, or simple human errors, resulting in crude oil being spilled over long distances on marine surfaces to stay for several years, stopping sunshine from entering the water and the marine life that depends on it and suffocating marine animals that have become entrapped in floating crude oil layers that are almost impossible to clean up. Similarly, ships and tankers also experience accidents and externalities to lose cargo into the sea and the ocean, which becomes ocean water pollution eventually, and the noise pollution they create also can disrupt the delicate balance of marine life.
Mining companies have underwater operations in the ocean where they drill for valuable metals, elements, and minerals such as silver, copper, gold, zinc, and cobalt, and create sulfide deposits on the ocean floor to increase the toxicity in the areas, corrode the physical and chemical makeup of the soil, lead to leakages and spills of stored materials within the soil, and damage the ecosystems present in such regions. Littering refers to the act of depositing trash, debris, or any other man-made objects into the oceans either systematically or by accident, and numerous countries, like Vietnam, the Philippines, and Thailand, have been known to directly deposit their garbage into the Pacific ocean, in turn creating large masses of floating debris. Additionally, strong winds have the potential and capability to carry inland objects to the ocean over long distances, like dust, sand, debris, trash, and given the long-lasting nature of certain types of objects like plastic debris and litter, the ocean is polluted for long periods of time as the given objects remain in the ocean without degrading for long periods of time. Plastic waste and debris is bad news for marine animals, like dolphins, several types of fish, crabs, birds, turtles, sharks, and crocodiles, because they can either become trapped in such objects or consume them mistakenly to experience severe and sometimes fatal health issues. The addition of extra CO2 to the oceans through natural or artificial littering also increases both the temperature of the water that directly impacts the ecosystems and fish communities and also the acidity of the oceans and contribute to the formation of acid rain, which is a substantially harmful phenomenon for the oceans.
Ocean water pollution has catastrophic effects on marine life and natural marine cycles, with oil spills being one of the worst-case scenarios within the given context as the initial impact of crude oil on marine animals is the substantial limitation of the capability to move, fly, or feed their offsprings, while in the long run, marine life forms can experience far worse consequences like cancer, reproductive system related problems due to hazardous chemicals found in industrial and agricultural wastes that accumulate in animals’ fatty tissues, changes in behavior, and unexpected deaths in large numbers. Coral reefs are a very delicate and equally important part of marine life as they house several types of plants and animals alike and they require constant exposure to sunshine to photosynthesize and continue living and the blockage created by oil spills is a huge threat to their existence. The debris that enters the ocean takes a long time and significant amounts of oxygen to decompose and degrade and in turn, the oxygen levels in the ocean are reduced, which becomes a life-threatening issue for marine animals. When the industrial and agricultural chemicals are washed into the oceans through rivers, they immediately sink to the bottom without getting dissolved, where smaller marine animals consume them before being consumed by larger marine animals and the entire marine food chain is disrupted. Naturally, when human beings consume marine animals that have consumed contaminants directly or other smaller marine animals that have previously consumed contaminants, health issues such as birth defects and cancer are observed, which have devastating long-term impacts on human life and wellbeing. (Conserve Energy Future, 2017) (National Geographic Society, 2019a)
4. Transboundary Water Pollution
Transboundary water pollution is a type of water-based pollution that cannot be limited to a single country or nation but moves through national borders to affect other countries or nations, such as the flow of contaminated water or the seeping of industrial waste or discharge into neighboring countries. The causes of transboundary pollution are incidents like oil spills and leakage either during oil drilling operations or transportation of oil are great examples of how contaminants and pollutants can be transported between boundaries through the sea. In such cases, the original contaminants cannot be contained at the origin of the incident and the resultant scenario leads to total natural destruction over large surfaces of water. Similarly, rivers and oceans also carry such contaminants especially in regions like the Arctic where the water mass has been physically constrained by land and mountains to create a massive sized enclosed local lake-like geography, enabling the Arctic ocean and numerous rivers to carry contaminants between the countries of Russia, the United States, and Scandinavian states. Transboundary water pollution also takes place in smaller sized seas and large scale lakes as well such as the Black Sea and Lake Michigan where transboundary water pollution takes place between countries of Russia, Ukraine, Romania, Bulgaria, Turkey within the Black Sea basin and between the United States and Canada within the Lake Michigan area. As a result of transboundary water pollution, water sources in the form of seas, oceans, lakes, and rivers get contaminated by pollutants and in cases where such contamination reaches the land, the given contamination also infects the soil as well as the plant and animal life forms that reside on such lands. In cases where the contamination on sea and land remains on-site for prolonged periods of time, it also infiltrates into the air, decreasing air quality and allowing pollutants to be transported by air to other regions both on the sea surface and on land. (Fridgen, 2019) (Water Hell!, 2019) (Safe Drinking Water Organization, 2017)
5. Nonpoint Source Water Pollution
Nonpoint source water pollution is a case of pollution, where different types of pollution like land runoffs, atmospheric deposition, drainage, precipitation, seepage, and hydromodification carry contaminants and pollutants that reach water sources to contaminate the bodies of water stored in such locations. Land runoffs have the potential to carry fertilizers, herbicides, and insecticides from farms and residential areas, while oil, grease, and toxic chemicals can be carried to water sources through urban runoffs, mainly due to industrial and large scale sewage and industrial material disposals and energy production at such locations. Rainfall and snowmelt also carry both artificial and natural pollutants to lakes, rivers, coastal areas to seas and oceans, groundwaters, and wetlands, contributing to nonpoint source water pollution, mainly in the form of sediment. Such sediment can also originate from construction sites, abandoned agricultural and forest areas, as well as eroded streambanks, to be also carried by rainfall and snowmelt. Mining operations contribute acids and chemicals to this sediment transportation while excessive irrigation practices have been known to leave behind large quantities of natural salts that join the mentioned masses of transported materials. Bacteria and organic matter from livestock waste and dysfunctional septic systems also contribute to nonpoint source water pollution, while atmospheric deposition can either bring down ozone, nitrogen, and sulfur particles into the soil to be carried into water sources or directly send such particles to marine and freshwater bodies. Hydromodification, referring to the act of altering the natural flow of water through the land in the form of channelization, brings large quantities of sediment and contaminants into water sources like lakes, aquifers, streams, rivers, and bays. Nonpoint source water pollution has direct and devastating adverse effects on drinking water supplies, recreational activities within and around water sources, as well as fisheries and wildlife that live either in such sources or close by. (Ballotpedia, 2019) (United States Environmental Protection Agency, 2015)
6. Point Source Water Pollution
Point source water pollution (PSWP) is a type of pollution caused by the transportation of sediment, pollutants, and contaminants to water sources from distant origins. Unlike nonpoint source water pollution, the origin of point source water pollution is known and can be traced back to a single source. Both factories and power plants have long been identified as serious contributors to point source water pollution as the toxic gases and chemicals they emit like carbon monoxide, sulfur dioxide, chromium, arsenic, hydrocarbons, and heavy metals like mercury and lead directly enter water streams such as rivers and wastewater disposal systems that reach larger bodies of water like groundwater reservoirs, lakes, seas, and oceans. Oil refineries are equally important contributors to point source water pollution as pollutants like drilling fluid, petroleum wastewater, plant, and bottom tank sludge have been reported to infiltrate both into soil and water sources before being transported over both short and long distances into larger bodies of water. Similarly, municipal wastewater treatment and disposal plants and systems are also direct contributors to point source water pollution as they introduce nutrients into soil and water which harmful microorganisms thrive upon, while most of the previously mentioned harmful substances can also be found in waste and sewage water, which both get transported to larger bodies of water on a frequent and periodic basis. Consequently, the transportation of the bacteria and harmful substances creates significant health hazards to both human and animal life in the destinations they reach as well as along the river and channel banks where portions of these materials might get deposited and infiltrate into soil and water in such vicinities. Harmful wastewater and chemicals also deal substantial damage to non-human and animal life, degrading soil quality and destroying habitats within which plants, insects, and beneficial microorganisms live. (National Geographic Society, 2019)
What are the Common Types of Water Pollution?
Water pollution occurs in different types based on the source of pollution or contamination and the effects it has on water reservoirs. Not every type of water pollution is the same and the varying effects of different types of water pollution should be comprehended properly to understand the extent and scope of damage that water pollution might deal with water reservoirs, the environment, and human health.
The most common types of water pollution are:
- Surface water pollution: Contaminants and pollutants dissolve into or mix with surface water sources like rivers, lakes, lagoons, seas, and oceans either accidentally or intentionally.
- Groundwater pollution: Contaminants and pollutants like hazardous chemicals and toxic particles seep into the lower levels of the earth through rainwater to pollute underground water sources.
- Chemical pollution: Industrial solvents, metals, pesticides, insecticides, and fertilizers pollute rivers and lakes.
- Nutrients pollution: Wastewater in high nutrient content promotes vegetation and algae in water sources.
- Oxygen depletion pollution: Aquatic microorganisms begin to grow in water and consume excessive levels of oxygen to deplete the present oxygen in the water source and kill aerobic microorganisms, promoting the growth of anaerobic organisms that produce toxic substances like sulfides and ammonia that are harmful to humans and aquatic life.
- Microbiological pollution: Microbiological pollution refers to natural water contamination due to the existence of bacteria, viruses, and protozoa that help create and spread diseases like cholera and bilharzia in areas where untreated water is used for drinking water by people.
- Suspended matter: Contaminants that do not dissolve in water or are simply too large to mix with water accumulate in water sources like lakes, lagoons, and ponds, to form a covering layer over the body of water, prevent oxygen from penetrating into the water, and cause oxygen depletion. (International Environmental Technology, 2020)
Effects of Water Pollution
Water pollution has various different effects on both human and aquatic life as well as lifeforms around water reservoirs that might lead to catastrophic health and environmental consequences, necessitating awareness regarding such effects and motivation to take the necessary precautions.
Some of the most common effects of water pollution are:
- Effects of Water Pollution on Human Life: For humans, access to safe drinking water is critical for survival, with 2.1 billion people not having access to safe water and 785 million people lacking critical access to drinking water as of 2019 due to either lack of infrastructure or high levels of water pollution/contamination. Effects of water pollution on human life include water-related diseases such as cholera, leading to more than 120,000 deaths annually, while accidents like the Fukushima nuclear plant meltdown also contaminate water to create health-related complications, such as thyroid cancer in children, which has increased by 70% in Japan since the tragedy in 2011.
- Effects of Water Pollution on Environment: Water pollution directly impacts animal and plant life in areas affected by polluted water as they depend on water as a habitat, food, and water source, with even the slightest pollution leading to severe disruptions in their modes of living and severe pollution leading directly to the death of such lifeforms. A good example is the Gulf of Mexico oil spill in 2010 when more than 82,000 birds, 25,900 marine animals, 6165 sea turtles, and an unspecified number of fish and invertebrates have been directly harmed, with a large portion of lifeforms dying in short periods of time following the disaster.
- Effects of Water Pollution on Food Chains: Water pollution disrupts food chains present in aquatic environments as toxic contaminants move from one level to the next within the chain, while severe cases of contamination can also result in the total destruction of such food chains, leading to certain organisms growing excessively due to the death of their predators.
- Effects of Water Pollution on Ecosystems: Ecosystems are also directly threatened by water pollution as the introduction of certain microorganisms and nutrients lead to the destruction of certain other microorganisms that are not capable of co-existing with such new entrants or substantial increment of algae that depletes oxygen to kill fish and other aquatic life living in the given body of water.
- Effects of Water Pollution on the Economy: The economic effects of water pollution are also undeniable as it is highly expensive to manage and restore polluted water, with the Fukushima disaster being a great example of such a situation. Research shows that the costs of cleaning the water contaminated during the accident reached $660 billion. In addition, purifying drinking water is also expensive, while the economic costs of treating diseases related to contaminated water also add to healthcare expenses on a daily basis. (Suner, 2019)
What are the Ways to Measure Water Pollution?
Water pollution measurement is a technical business and it requires several analyses. There are numerous parameters and variables involved in the process of measuring water pollution as assessing the health and well-being of a water source is a multi-dimensional task that requires careful analysis of a number of different variables that reflect numerous aspects of water health.
Some of the most commonly used and utile ways to measure water pollution are:
- CDOM/FDOM Monitoring: This technique measures the amount of Chromophoric Dissolved Organic Matter (CDOM) and Fluorescent Dissolved Organic Matter (FDOM) in water to observe the tannin levels in the water, as well as its transparency.
- Chlorophyll Fluorescence Analysis: The amount of algae on the surface of water that results from high concentrations of phosphorus and nitrogen is assessed by measuring the percentage of wet-chemical chlorophyll and active chlorophyll in the given water sample.
- Conductivity, Salinity, and TDS Monitoring: Conductivity in water, which is directly correlated with water salinity, which is directly related to the amount of total dissolved solids (TDS) in water are measured and the specific electrical conductivity of electrolytes that have dissolved in the given body of water is analyzed to reveal the true concentration of oxygen in the given water sample.
- Recording of the Water Temperature: The temperature of the water is measured to assess several different water quality indicators such as the rate of photosynthesis and metabolism, the concentrations of dissolved gas, water conductivity and salinity, the pH level, and water density as the water temperature is directly related to all such indicators.
- Measurement of Dissolved Oxygen Levels: This method measures dissolved oxygen in the water to calculate the available oxygen for flora and fauna growth as a percentage of total saturation, with a dissolved oxygen level lower than 6 mg/L considered to be harmful to ecosystems living in the given body of water.
- pH and KH Testing: The acidity/alkalinity (pH) and the carbonate hardness (KH) of the water are measured checking to see if the pH level falls between the acceptable range of 6.0 and 8.0 or not and if the water contains desirable levels of carbonates and bicarbonates, as KH is a directly correlated parameter to pH, which is one of the most important indicators of water quality.
- Assessment of Water Turbidity, TSS, and Clarity: The turbidity, Total Suspended Solids (TSS), and clarity of water are measured to understand whether sufficient amounts of solar radiation enters the body of water to initiate photosynthetic processes and whether the water has been subjected to soil erosion and point-source pollution as indicators of water quality. (Neal, 2017)
How to Prevent Water Pollution?
Prevention of water pollution refers to all the policies, strategies, and actions taken to stop contaminants from entering water reservoirs and decreasing water quality or simply making it impossible for human or environmental use. Most of the types of water pollution discussed in previous sections are manmade and therefore they can be prevented when the proper precautions are taken. Even in some natural cases of pollution and contamination, proper observation and analysis allow early action that results in constructive results. The most proper way to understand the importance of the prevention of water pollution is to consider it as an integral part of general environmental awareness and protection, with various precautions to be taken in the pursuit. The most important ways to prevent water pollution are:
- Using less plastic
- Reusing items
- Preferring recyclable products and recycling such products
- Not disposing of oils or hazardous chemicals in residential sinks or in common garbage areas, handling toxic substances individually and properly
- Preferring non-toxic cleaners and pesticides
- Not throwing away medicines or regular household items in the toilet
- Installing garbage disposal systems at home
- Limiting the use of detergents and bleaches and using phosphate-free and environmentally friendly products
- Avoiding pesticides
- Conserving soil
- Carrying out regular vehicle maintenance operations to detect and stop oil and other chemical spills and leaks
- Monitoring cellar drains and septic tanks periodically
- Not littering in public or in natural habitats
- Using less water while doing regular household work or personal cleaning
- Planting fauna near lakes and rivers
- Cleaning the visible litter around natural habitats
- Immediately informing the authorities regarding visible forms of chemical pollution
- Consuming more organic food and preferring sustainable types of meat and overall reducing the consumption of meat
- Joining water conservation organizations
- Volunteering in cleaning programs for beaches, rivers, and local areas
These are possible and recommended precautions on the consumer side of the equation and to prevent water pollution on the governmental/institutional side:
- Political awareness should be created to inform the general public
- Special agencies and departments should be formed to address the observable and demanding issues
- Adequate funding should be granted to such agencies and departments to properly carry out campaigns (Conserve Energy Future, 2016)
For those more concerned about their own health regarding the possible health risks of drinking polluted water, this is the right time to ask the question: What is water purification? because purifying water is a great strategy against such risks. The most popular and utile ways to purify water are boiling, filtration, distillation, and chlorination with the first two methods being easily doable at one’s home, while the last two methods require the purchasing of specific equipment. Everything considered it should be understood by all that drinking clean water is not only a great option for one’s health but also a certain responsibility towards the society and the planet, given the costs of water pollution for all.
Water Pollution Rates by Country
Although numerous statistics exist regarding water quality and water pollution, the most reliable statistic has to be drinking water quality, which reveals that the top 10 countries with the worst quality of drinking water are Mexico, Congo, Pakistan, Bhutan, Ghana, Nepal, Cambodia, Nigeria, Ethiopia, and Uganda, in ascending order. However, it should be noted that most of the given countries lack technical infrastructure to extract and/or distribute water, or are in geographically unfavorable locations, and therefore a second perspective on the overall pollution statistics is required. In the top 10 annual deaths related to premature toxic air, water, soil, and chemical pollution-related deaths list, the worst scoring countries are India, China, Nigeria, Indonesia, Pakistan, Bangladesh, United States, Russia, Ethiopia, and Brazil, in descending order. (McPhillips, 2015) (Alliance Disposal, 2021)
The following is a table of 10 countries that pollute freshwater reservoirs the most by the year 2001:
Amount of Pollution (in tons/cubic km)
(Nation Master, 2019)
Is It Possible to Increase the Amount of Drinkable Water by Reducing Pollution?
It is possible to increase the amount of drinkable water by reducing pollution because a substantial portion of overall pollution reaches water sources eventually, meaning that whether it be soil, air, or chemical pollution, the consequences always disaffect water sources, with groundwater, river, lake, and rainwater constituting a large portion of the total amount of drinkable water on Earth. As previously stated, the issue of water pollution should always and only be considered as a part of a larger scale and integrated environmental crisis as water is the most important element for all lifeforms on Earth and therefore it is disaffected by all types of pollution and environmental damage. If air, soil, and chemical pollution levels are reduced substantially, drinkable water quality and availability will both significantly increase because water runs through both of the mentioned mediums, and in terms of chemical pollution, it is highly possible that chemically polluted substances or wastewater will also reach clean water sources to contaminate it. (World Health Organization, 2019)
As one investigates the correlation between drinkable water and pollution reduction, one immediately begins to wonder about types of drinkable water as the commercial water market is highly saturated and high competition pushes companies into silence regarding important details. Leaving the obvious tap water option aside, it is seen that numerous other options like mineral water, spring or glacier water, sparkling water, distilled water, purified water, flavored water, alkaline water, and well water are available for interested individuals but it is crucial to learn about their pros and cons before consuming them.