Water pollution might be one of the leading environmental and social issues in the world, and is certainly one of the leading water issues.
Water pollution includes pollution of both fresh water sources (lakes, rivers and groundwater aquifers), and also ocean/marine water pollution.
In this guide, we’ve outlined what water pollution is, the different types of water pollution, along with causes, sources, examples, effects & potential solutions.
Summary – Water Pollution
It involves the pollution or contamination of a body of water, that leads to a degradation of that body of water, and can result in negative effects on human health, wild life and living organisms, the environment and it’s ecosystems, and the economy
There are many different types of water pollutants and contaminants, and each can come from either man made or natural sources, or both
Water pollutants are often found in different types of waste such as wastewater or sewage, just to name two examples
Man made pollutants come from all areas of society – households, industry and agriculture
There are many different ways that pollutants and contaminants can get from their origin source, into a clean water source
Pollutants may degrade the water directly, or there may be some type of secondary reaction first before water pollution and degradation happens
Two of the major causes for water pollution in the world are:
1. Agricultural pollution in the form of nutrient pollution, and;
2. Waste water and sewage pollution resulting from untreated sewage and waste water (some estimates indicate 80% of waste water is released into the environment globally without treatment).
But, there are others such as industrial waste pollution (especially in the ocean).
A new emerging cause of water pollution is from pharmaceuticals, personal care products, and so on – although, less is know about them at this stage
Nutrient pollution can result in eutrophication (as well as algal blooms and dead zones with little to no oxygen in the water), and there’s been studies done on the different foods we produce, and their different eutrifying effects (just as one source of nutrient pollution)
There are different types of water sources that get polluted – surface water sources (lakes, rivers, etc), ground water sources, and marine/ocean water
These water sources are polluted via a single point (point source), dispersed/multiple points (non point source), or, from an original point in another region or country (transboundary)
In the US, non point source is the main way water is polluted, but, it can be difficult to regulate, since there’s no single, identifiable culprit
It should be noted though that even developed and considerably wealthy nations are experiencing levels of water pollution in surface and ground water sources, and also water contamination in drinking water and tap water (the US is one example)
Additionally, some countries are responsible for causing more water pollution than others. Some lists show China, the US, India, Japan, Germany, Indonesia and Brazil among the top water polluting countries or regions
Solutions to water pollution will ultimately be custom solutions to a specific geographic location or city, because each location has different causes of water pollution, and different capabilities to address water pollution (developing and low income regions are likely more vulnerable to and less capable to address water pollution issues than developed and higher income regions)
Solutions may focus around reducing the main sources of water pollution, and cleaning up and treating (to make them safe and clean according to the relevant water quality test or standard) the water sources that are already polluted
There can be a significant cost to cleaning up water pollution, and the concentration of water pollution in the water source may not decrease significantly as a result of clean up/water treatment.
So, costs might need to be weighed up against how effective clean up is, and what the expected benefits are.
Water pollution might be very important to address now and in the future for water scarcity reasons – because water demand and populations are projected to grow, whilst usable water supplies are projected to decrease (demand is outpacing supply … leading to limited water availability)
Although water augmentation (such as desalination) technology exists to create more fresh water, it might still be important to address and manage water pollution as a preventative measure (and also because desalination and other technology can have it’s drawbacks, and be expensive).
What Is Water Pollution?
Water pollution happens when harmful substances, pollutants or contaminants (such as chemicals or microorganisms) contaminate a body of water, degrading water quality, and resulting in some type of negative impact for humans, animals and living organisms, the environment, or some other aspect of society such as the economy
Main Types Of Water Pollutants
Waste pollution and water pollution are closely linked, as waste material itself can pollute water, but waste can also carry certain types of pollutants and contaminants into water.
Pollutants and the waste that carries them, can come in many forms – liquid, solid, gas, micro organisms – just to name a few.
Some of the main types of pollutants and pollutant carrying wastes are:
Waste water (used water) and storm water run off (from sinks, showers, and toilets, and from commercial, industrial, and agricultural activities)
Sewage and septic system waste
Leachate from landfills
Heavy metals and solvents, and toxic sludge
Household chemicals, waste and products (for example, cleaning products, as well as personal care products and pharmaceuticals, such as birth control pills, painkillers and antibiotics)
Organic chemicals (chemicals produced in a lab)
Greenhouse gases (carbon emissions are absorbed by the ocean)
Solid Debris like Plastic (can be inadequately disposed of, or littered)
Oil, gasoline, break fluid, grease
Heat (via thermal water pollution – such as discharge of heated water from a power plant)
Mining Tailings and effluent
Pollution from bacteria and microorganisms like microbes, viruses, pathogens, parasites, and protozoa (high levels of pathogens are usually caused by a lack of proper sanitation systems, and/or untreated sewage getting into a water source)
Natural pollution from volcano eruptions, earthquakes, flooding and tsunamis
Suspended Particulate matter (and other sediments)
Biodegradable waste like animal manure (especially from livestock) or urine, and naturally decaying plant material
Other Types Of Waste Or Pollutants (medical, industrial, toxic, domestic, food wastes, carcinogens and so on)
[Whilst not technically a pollutant or contaminant, some water may be brackish or semi saline water. Brackish water may have a salt content somewhere in between salt water and fresh water, and may happen when fresh water mixes with salt water, or in brackish fossil aquifers]
Some types of waste carry a common pollutant.
For example, wastewater, fertilizers and sewage can all contain nutrients (nitrates and phosphates) – and nutrient pollution is a type of water pollution in itself.
Where Do Water Pollutants Come From?
Water pollutants can come from a range of both human and natural sources.
Some of the main places that water pollutants come from are:
Construction and Building Sites
Households & Personal/Consumer Products
Roads/Highways, Pavements & Impermeable Surfaces
Nature (air, soil, other water sources, animals, micro organisms)
Waste Management Sites (landfills)
Sewage and Water Treatment Plants
Water Infrastructure Like Pipes
Storm Drains & Sewers
Ships & Sea Vessels
Below Ground Storage Tanks
Metal Ore Mining Sites
Uranium Mining, Nuclear Power Plants, and the Production and Testing of Military Weapons (in the case of radioactive waste)
Human Source Vs Natural Source Water Pollutants
Human based sources … are the main contributors to water pollution (nrdc.org).
Causes Of Water Pollution (How Water Pollution Happens)
There are many causes and different ways that water pollution can occur.
Some of them are:
Direct dumping or discharging of treated or untreated pollutants or waste into a water source
Loss or spill of pollutants or waste directly into a water source
Run off of pollutants from a soil, pavement or road surface (or some other type of surface)
Leaching, percolating or seepage of pollutants from soil into water, or from other polluted water sources into a new water source
Absorption of pollutants from the air
Littered or inadequately disposed of waste or pollutants being washed or blown into a water source directly, or into a system that leads to the water source, by the wind/air, rain or ocean tide
Pollutants or contaminants developing naturally in the water source
*An indirect way water pollution can occur is also water politics or poor political management of water quality that leads to conflicts of interest, and poor management and pollution of water sources
Specific examples of the above are:
Untreated sewage or waste water being discharged directly into water sources, or industrial sludge and dredging being dumped directly into the ocean by businesses and industrial organisation.
Fishing gear being lost or dumped into the ocean from a fishing vessel. Another example is oil being spilt or lost into a water source from an oil tanker or an oil rig
Pollutants in contaminated soil being washed by rain through the crevices in the soil into ground water sources. For example, pesticides are sprayed onto crops, soak into the soil, and can be washed down into ground water sources
Waste like plastic being washed into storm drains and sewers, and flowing out to the ocean
Wind blowing solid debris like plastic, cigarette butts and paper bags into the ocean, and the tide washing beach litter into the ocean. The wind may also blow chemicals like pesticides into water sources (this is called pesticide ‘drift’)
Water sources absorbing carbon or air pollutants from the air
Acidic rain (from air pollution) mixing with water sources
Nuclear waste that isn’t properly contained, managed or buried can contaminate water sources
Discharged mine effluent and seepage from tailings and waste rock, and other waste
Chemicals found in public water pipes can leach into the public water supply
Rainwater harvesting from roofs with oil based lead paint can pollute water
Contamination of soil by landfill leachate, and then leaching from the soil into a water source. Pesticides can also leach or percolate from soil into water sources (read more about the 4 major routes pesticide reaches and pollutes water in the Wiki guide listed in the sources list)
Run off of chemicals from soil or road surfaces into water (e.g. runoff of pesticides from farms, or runoff of oil from roads)
One polluted water source converging with or washing into another clean water source, and polluting that new clean water source (e.g. from a river, to a bay, to the ocean)
Animals carrying waste or pollutants into water sources, or urinating, bathing and defecating in water sources
People carrying waste or discharging of waste into water sources (via bathing, urinating and defecating)
Other biodegradable waste like plant life may grow in and around water, leading to an imbalance or certain micro organisms. Also, too much biodegradable waste in the water can lead to more micro organism growth and increased oxygen being used in the water and eventually depleted … and, this leads to aerobic organisms dying, and anaerobic organisms growing. This could happen for example after a natural disaster or natural event like a flood or hurricane where biodegradable waste is upended and carried into water sources
Viruses, pathogens, bacteria and protozoa, or other types of micro organisms (aerobic and anaerobic) developing naturally in the environment due to some type of natural process. A lack of clean/safe water treatment, hygiene and sanitation infrastructure, facilities, and technology can be part of this problem
Secondary, & Reactionary Causes Of Water Pollution
Once in the water, some pollutants react in a certain way or settle in a certain way that causes a further loss in water quality.
A few examples are:
Nutrients – wastewater, fertilizers and sewage contain nutrients. Nutrients encourage algae and weed growth, and algae deplete the water of oxygen, along with weeds clogging up water which needs to be filtered or treated in some way (eschooltoday.com).
Anaerobic Organisms – in water, they can produce harmful toxins such as ammonia and sulfides (eschooltoday.com).
Suspended Particulate Matter – certain types of pollutants or even biodegradable material may not dissolve easily in water and wash away or dilute. If it doesn’t, it can either stay suspended on the surface of the water, or settle in sediments on the bottom of a water source (water-pollution.org.uk)
It’s also important to mention that some pollutants are a primary type of waste or pollutant that cause direct pollution.
But, other pollutants come from a secondary source where primary pollutants react or interact with each other, or other compounds, and cause a more indirect form of water pollution.
A few examples are:
Ocean acidification – an ongoing decrease of the ocean’s pH level, from absorption of CO2 in the air
Acid Rain – Acid rain has many ecological effects … such waters more acidic, which results in more aluminum absorption from soil, which is carried into lakes and streams. That combination makes waters toxic to … aquatic animals (nationalgeographic.com)
Depletion of groundwater and droughts can cause salinity issues in water sources as well – although this isn’t traditionally seen as water pollution – it is a water quality issue.
Most Common Causes/Sources Of Water Pollution Globally
In each country, and each region within a country, different water sources (ground water, surface water, or ocean water) may be polluted by different pollutants, and pollutants may come from different sources.
But, as a general guide …
The most significant sources of water pollution [globally] are:
… inadequate treatment of human wastes, and
… inadequately managed and treated industrial and agricultural wastes
The most common causes and sources of water pollution globally are:
Agricultural water pollution [via nutrient pollution] is the number one threat to water quality worldwide
Others are: Sewage and waste water pollution [especially when untreated], Oil pollution [from cars and trucks, and from factories, farms, and cities], and Radioactive substances
There is a graphic available about planetary boundaries (stockholmresilience.org)
This graphic illustrates how reactive nutrient supply levels of nitrogen and phosphate (from agricultural and industrial activities) in the biosphere (and water sources) are one of the planetary boundaries that have reached the point of high risk/beyond the zone of uncertainty.
Most Common Causes/Sources Of Water Pollution In The US
For surface water specifically in the United States:
Nutrient pollution, which includes nitrates and phosphates, is the leading type of contamination in … freshwater sources [and comes from farms and fertilizers]
Municipal and industrial waste discharge [into water sources like waterways also contributes]
… nearly half of … rivers and streams and more than one-third of … lakes are polluted and unfit for swimming, fishing, and drinking
And, for ground water specifically in the United States:
… [it is] polluted when contaminants—from pesticides and fertilizers to waste leached from landfills and septic systems [get into aquifer sources]
[ground water sources can be hard to clean, and can cross contaminate other water sources like lakes and rivers]
More common/major causes of water pollution can be seen here (explainthatstuff.org)
They note that the US has invested heavily in improving waste water treatment plants.
Although it is less clear what the trends are for improvement in nutrients and sewage water pollution are.
Causes Of Water Pollution Specifically In Developed Countries vs Developing Countries
The water pollution causes in developed countries can be different than developing countries.
Developed countries may face these causes as the most common for water pollution:
Agriculture is the biggest cause of local water pollution in developed countries [specifically, pesticides and other agricultural chemicals leading to high concentrations of nitrates, that can result in algal blooms]
Factories & Industrial Pollutants – [via toxic chemical dumping]
Transport & Vehicles [via fuel and oil run off from vehicles and roads, especially in cities]
Air Pollution [via air contaminant emissions from vehicles and power plants, which leads to acid rain and water mixing]
Developing countries may face these causes as the most common for water pollution:
Waste Management & Sewage Management – in small towns, villages and rural areas, there’s often no dedicated sewage or septic systems available … and this leads to the spread of bacteria, illness, and parasites
Agricultural – happens due to more primitive and simple (and not as advanced) agricultural systems and technology. Waste management is a problem here … since animal waste isn’t disposed of properly and dead animal bodies are usually not either
Causes Of Local Water Pollution In Specific Countries & Cities
You can read this guide for some of the causes of water pollution and contamination in some of the major water sources in China, the US, India, Japan, Germany, Indonesia and Brazil (all-about-water-filters.com)
You can read this guide for some of the causes of water pollution and contamination in the Ukraine and other countries (bestlifeonline.com)
You can read this guide for some of the causes of water pollution and contamination in places across Africa, Central & South America, the US, and Asia and The Middle East (all-about-water-filters.com)
Types Of Water Sources That Get Polluted
There’s three main types of water sources that can get polluted:
– Surface Water Pollution
Pollution of above ground water sources like rivers and lakes
– Groundwater Pollution
Pollution of underground water aquifers (these aquifers are formed when water from rain and rivers seeps into the ground and accumulates within cracks or pores in the rocks)
– Ocean Water Pollution
Pollution of the sea/marine environment
Surface and ground water pollution are mainly fresh water pollution issues.
Ocean water pollution is really an issue on it’s own, separate to fresh water or land based water pollution.
We already outlined above in the United States Water Pollution section how ground water gets polluted there.
Read more about groundwater pollution in these guides:
Water pollution of fresh water (pollutionissues.com)
Ground water contamination (groundwater.org)
Surface Water Pollution
We already outlined above in the United States Water Pollution section how surface water gets polluted there.
Read more about surface water pollution in this guide (pollutionissues.com)
Ocean Water Pollution
[About 80% of] ocean pollution … originates on land
Contaminants such as chemicals, nutrients, and heavy metals are carried from farms, factories, and cities by streams and rivers into … bays and estuaries; from there they travel out to sea
[Plastic and oils are some other common wastes]
[The ocean also absorbs as much as one quarter of man made carbon emissions from the atmosphere]
Read more about marine pollution in this guide (nrdc.org)
Number Of Points At Which Water Pollution Can Occur, & Boundaries Of Water Pollution
Water isn’t always polluted at one single point. It can can polluted or contaminated from multiple points.
Water pollution can also come from outside of the country or region where the pollution takes place.
How water pollution can occur can include:
– Point Source (pollution from a single point/source)
An example might be a single discharge pipe for waste water/effluent
– Non Point Source (pollution from multiple points/sources)
An example might be pesticide which can drift in the air and pollute water, and, sink into soil and pollute ground water from multiple points.
Another example can be one body of water being polluted from several different points with several different types of pollutants – we see this in the ocean when all different types of industrial waste can be dumped into it
Nonpoint source pollution is the leading cause of water pollution in U.S. waters, but it’s difficult to regulate, since there’s no single, identifiable culprit (nrdc.org)
– Transboundary (pollution that originates from over another country or region)
For example, pollution in a river in one country may cause fresh water or ocean pollution in another country if that river spans or connects into a water source in another country.
Similarly, an oil spill in the ocean of one country may drift to the ocean of another.
Effects/Impact Of Water Pollution
Each different water pollutant and/or contaminant can have a different set of effects.
But, the main effects of water pollution include:
– Impact On Human Health
Humans use, drink and bathe in water (amongst other uses).
Polluted water can cause health issues/diseases, and might contribute to premature death.
– Impact On Wild Life & Animals
Animals live in, drink and bathe in water.
Water pollution degrades the aquatic environment they live in, and can cause health issues/diseases, and contribute to premature death.
– Impact On The Natural Environment
Plant life and soil for example can depend on water in one way or another.
Polluted water can degrade the natural environment and degrade ecosystems in several ways.
– Impact On The Economy
Water is not only used in many of our daily activities, but for business for many of the products and services we offer and use.
In addition to that, there is the economic cost to clean up and treat polluted water.
The effects of water pollution are usually experienced when:
There is direct consumption of the polluted water (drinking, or inhaling/ingesting it)
There is exposure to the polluted water (such as an aquatic species that lives in the water, or there is direct or close contact with that polluted water source)
The water needs to be used for a certain purpose, and in different industries and sectors of society (business, cleaning/bathing, agriculture and food production, recreation, fishing, municipally, etc.)
Read more about the effects of water pollution in this guide (nrdc.org)
Impact Of Water Pollution On Humans & Human Health
Some stats to consider:
People Most At Risk
… low-income communities are disproportionately at risk [to water pollution] because their homes are often closest to the most polluting industries (nrdc.org)
Every year, unsafe water sickens about 1 billion people (nrdc.org)
Globally … 200 million days of work are lost each year as a result of water-related diseases (weforum.org)
[Water pollution] caused 1.8 million deaths in 2015 (nrdc.org)
Every year 3,575,000 people die from water related diseases (theworldcounts.com)
Globally, 1.5 million children under five die … as a result of water-related diseases (weforum.org)
Impact Of Water Pollution On Animals & Wild Life
Just some of the effects on wild life and animals can include:
Eutrophication can create ‘dead zones’ in the water where there is a lack of oxygen for aquatic species living in them
[Pathogens and bacteria, algal blooms that produce neurotoxins, chemicals and heavy metals, plastic and other hard waste, and other solid debris can be ingested by wild life or they can become entangled in plastic nets and other solid waste material, and ocean acidification, can all impact animals in the water]
Impact Of Water On The Environment
[Water pollution generally disrupts the] complex web of animals, plants, bacteria, and fungi … which interact, directly or indirectly, with each other
… this leads to a chain effect in the environment where plant life and living organisms can be affected, but also the soil, air and other water sources
Impact Of Water Pollution On The Economy
The overall impact of water pollution on the economy is hard to estimate because of the different sources of water pollution and the various industries they each impact.
But, nutrient pollution alone in the US has costs to remove nitrates and algal blooms from drinking water (can cost in the billions to clean up one water source), there are tourism losses (close to $1 billion a year), commercial fishing and shellfish losses (can be tens of millions of dollars a year), and real estate losses.
Read more about nutrient pollution in this guide (epa.gov)
[In some region in the world, such as India, water pollution can reduce GDP growth by a third or a half]
[Water pollution can also reduce agricultural revenues, as well as agricultural yields]
The health costs relating to water pollution [in India] are alone estimated at about INR 470-610 billion ($6.7-8.7 billion per year) – most associated with diarrheal mortality and morbidity of children under five and other population morbidities
Potential Solutions To Water Pollution
One example of a good solution could lie within water recycling via waste water treatment and reuse.
As a summary, there are general solutions to water pollution such as reducing or eliminating water pollutants and waste before they pollute a water source, and also treating and cleaning water that has already been polluted.
But, each local body of water that has been polluted also needs it’s own custom water pollution solution strategy with solutions being implemented.
Some of the key things to be aware of are:
Identify the water source that is being polluted or contaminated (usually a surface water, ground water, or marine water source)
Identify the main pollutants and contaminants (e.g. industrial chemicals and waste water)
Identify the source they are coming from (e.g. factories in the area)
Identify the point/s at which they are polluting or contaminating the area (single point, or multiple/dispersed points?)
Identify the IMPACT of the water pollution – how significant is the impact it’s having on humans, wild life, the environment and the economy?
Identify how you are going to reduce or eliminate pollutants and waste getting to the identified point/s from the identified sources – does it involve waste and pollutant treatment and management systems? Are new or better enforced waste and pollutant laws and regulations required? Etc.
Identify how you are going to remove waste and pollutants from the water, and make it clean and safe again
[It’s possible that other water sources are being cross contaminated by the first water source, and these water sources would need to be assessed too]
But, there’s also major challenges and problems associated with addressing and solving water pollution and contamination issues, which is why water pollution and contamination issues still exist.
How To Measure Water Quality
Some countries have different water quality guidelines and standards for different water uses.
For example, the standards and testing in place for drinking water are usually different to the testing that takes place for water used for irrigation and industry.
Water’s physical and characteristics are usually tested against these guidelines to get an assessment of water quality.
In the case of drinking water, water may be tested and monitored continually to make sure it meets certain standards to be clean and safe for drinking.
But, water can be tested for different end uses, and also for concentrations of specific minerals, chemicals, pollutants and contaminants.
Most Common Water Quality Problems
Most Common Water Quality Problems
Globally, the most prevalent water quality problem is eutrophication, a result of high-nutrient loads (mainly phosphorus and nitrogen)
Major nutrient sources include agricultural runoff, domestic sewage (also a source of microbial pollution), industrial effluents and atmospheric inputs from fossil fuel burning and bush fires.
Nitrogen concentrations exceeding 5 milligrams per litre of water often indicate pollution from human and animal waste or fertilizer runoff from agricultural areas.
Emerging Water Quality Problems
An emerging water quality concern is the impact of personal care products and pharmaceuticals, such as birth control pills, painkillers and antibiotics, on aquatic ecosystems.
Little is known about their long-term human or ecosystem impacts, although some are believed to mimic natural hormones in humans and other species.
There is a table available in this guide (wikipedia.org).
This table identifies the food type with the highest levels of eutrophying emissions per 100 grams of protein.
Beef, farmed fish, farmed crustaceans, cheese, lamb and mutton, pork, and poultry (in that order from highest emissions to lowest), are some of the foods with the highest emission levels.
Why Is Water Pollution & Degradation Of Water Quality A Problem?
Apart from the effects listed above in this guide, water pollution is a problem because:
Because we use water for almost everything we do in society – drinking, bathing, industry and business, food production and agriculture, and so on.
Poor water quality decreases or completely eliminates the amount of available useable (safe and clean) water in an area.
This is a potential issue when you consider projections for 2050 estimate that billions of people globally will be living with limited access to water, and in many cities around the world, demand will be outpacing supply.
By 2050, global demand for freshwater is expected to be one-third greater than it is now (nrdc.org)
Water Pollution vs Water Contamination: What’s The Difference?
What is important to note is that a developed country like the US may mostly have access to safe drinking water (by some standards), but harmful contaminants can still be found in tap water in different States in the US.
Some of the most common contaminants found in US tap water are listed in the nrdc.org resource in the resources list
Which Countries Have The Worst Water Pollution?
Which Countries Are The Biggest Water Polluters?
Miscellaneous Water Pollution Stats
Globally, 80% of wastewater flows back into the ecosystem without being treated or reused
Sewage & Effluents
Every day, 2 million tons of sewage and other effluents drain into the world’s waters.
Every year, more people die from unsafe water than from all forms of violence, including war
In the United States, pesticides were found to pollute every stream and over 90% of wells sampled in a study …
Pesticide residues have also been found in rain and groundwater