Water pollution is one of the leading environmental issues in the world.
Pollution includes both fresh water pollution (lakes, rivers and groundwater), and ocean/marine water pollution.
In this guide, we’ve outlined what water pollution is, as well the types, causes, sources, examples, effects & prevention/solutions of water pollution.
Summary – What To Know About Water Pollution
- Water pollution can involve pollution of ground water (freshwater), surface water (freshwater), or the ocean (saltwater)
- Water can become polluted from a number of sources and in a number of ways
- Agricultural run off (fertilizers, pesticides, agricultural chemicals, and animal waste) is the main cause of freshwater pollution
- Sewage and wastewater are the main causes of ocean water pollution (More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused)
- These causes differ between developed and developing countries – in developing countries, lack of sewage waste treatment and lack of sanitation can lead to water pollution
- Water pollution impacts humans who can experience a lack of drinking water or freshwater to use. It impacts animals who live in and drink the water. And there are environmental effects.
- Water pollution is tied to other environmental issues like eutrophication (oxygen dead spots in water where aquatic life can’t live), ocean acidification (carbon uptake by the ocean of the atmosphere’s carbon in the air), acid rain (rains down on water sources) and other environmental issues
- Potential solutions on the social level might be aimed at addressing agricultural pollution, and wastewater and sewage pollution
What Is Water Pollution?
- Water pollution occurs when harmful substances—often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment.
Types Of Water Pollution
- Surface water pollution (includes freshwater sources like rivers and lakes)
- Ground water pollution (underground freshwater sources. Over time, water from rain and rivers seeps into the ground and accumulates within cracks or pores in the rocks (aquifers), forming groundwater under the earth’s surface.)
- Salt water/ocean water (self explanatory)
Surface Water Pollution
- Surface water from freshwater sources accounts for more than 60 percent of the water delivered to American homes.
- According to the most recent surveys on national water quality from the U.S. Environmental Protection Agency, nearly half of the rivers and streams, and more than one-third of the lakes are polluted and unfit for swimming, fishing, and drinking.
- In specific numbers, a 2000 survey published in EPA’s National Water Quality Inventory found almost 40 percent of U.S. rivers and 45 percent of lakes are polluted
- A major cause of this pollution in surface freshwater sources is fertilizer, pesticides and animal waste from agriculture. A lot of this pollution simply runs off the land and is nonpoint (coming from not one point, but many points) source pollution
You can read more about surface water pollution and contamination here – http://www.pollutionissues.com/Ve-Z/Water-Pollution-Freshwater.html
- Nearly 40 percent of Americans rely on groundwater, pumped to the earth’s surface, for drinking water. For some people in rural areas, it’s their only freshwater source.
- Some figures say groundwater use for drinking use in the USA is as high as 50%
- Groundwater gets polluted when contaminants—from pesticides and fertilizers to waste leached from landfills and septic systems—make their way into an aquifer, rendering it unsafe for human use.
- Ridding groundwater of contaminants can be both difficult and costly.
- Once polluted, an aquifer/groundwater source may be unusable for decades, or even thousands of years.
- Groundwater can also spread contamination far from the original polluting source as it seeps into streams, lakes, and oceans.
You can read more about groundwater contamination and pollution here – http://www.groundwater.org/get-informed/groundwater/contamination.html
Marine/Ocean Water Pollution
- Eighty percent of ocean pollution originates on land—whether along the coast or far inland.
- 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.
- Meanwhile, marine debris—particularly plastic and other waste—is blown in by the wind or washed in via storm drains and sewers.
- Seas also suffer oil pollution (spills, and general oil pollution from cars and household) and are consistently soaking up carbon pollution from the air. The ocean absorbs as much as a quarter of man-made carbon emissions.
You can read more about ocean/marine water pollution facts here – https://www.nrdc.org/stories/ocean-pollution-dirty-facts
The Point At Which Water Is Polluted
Water isn’t always polluted at one single source or point. The points at which water is polluted are:
- Point Source (pollution from a single point/source)
- Non Point Source (pollution from multiple points/sources)
- Transboundary (pollution from over the border/another country)
Point Source Water Pollution
- Examples include wastewater (also called effluent) discharged legally or illegally by a manufacturer, oil refinery, or wastewater treatment facility, as well as contamination from leaking septic systems, chemical and oil spills, and illegal dumping.
Nonpoint Source Water Pollution
- Nonpoint source pollution is contamination derived from diffuse (spread out or scattered) sources. These may include agricultural or stormwater runoff or debris blown into waterways from land.
- 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.
Transboundary Water Pollution
- Transboundary pollution is the result of contaminated water from one country spilling into the waters of another.
- Contamination can result from a disaster—like an oil spill—or the slow, downriver creep of industrial, agricultural, or municipal discharge.
- Another way to say it is, sometimes pollution that enters the environment in one place has an effect hundreds or even thousands of miles away.
- One example is the way radioactive waste travels through the oceans from nuclear reprocessing plants in England and France to nearby countries such as Ireland and Norway.
Causes & Sources Of Water Pollution (Human, & Natural)
Causes of water pollution can be natural, or anthropogenic (caused by humans).
Read more about the causes of water pollution and contamination in this guide.
- Natural causes include things like naturally decaying plant matter, naturally occurring water bacteria and organisms, animal waste (from wild animals), and natural events like volcano eruptions, earthquakes, flooding and tsunamis that contaminate water sources.
- However, by far and away … human based sources … are the main contributors to water pollution.
Some of the most common and major causes and sources of human based water pollution are:
- Agricultural pollution (a major cause of pollution in freshwater lakes, rivers etc.)
- Sewage and wastewater pollution (a major cause of pollution in oceans)
- Oil pollution
- Radioactive pollution
- Chemical waste
- Plastic Waste
- Alien species pollution
- Heat/Thermal pollution
- Sediment pollution
- Air pollution
- + more
You can read more about each of these in the FAO, NRDC, EPA, UNESCO,
- Around the world, agriculture is the leading cause of water degradation.
- In the United States, agricultural pollution is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It’s also a major contributor of contamination to estuaries and groundwater.
- Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens—such bacteria and viruses—into our waterways.
- They often seep from the soil they absorb into, into these water sources.
- Nutrient pollution, caused by excess nitrogen (nitrates) and phosphorus (phosphates) in water or air, is the number-one threat to water quality worldwide and can cause algal blooms, a toxic soup of blue-green algae that can be harmful to people and wildlife.
- Nutrient pollution is the leading type of contamination for freshwater sources (rivers, lakes, streams etc.) in particular. While plants and animals need these nutrients to grow, they have become a major pollutant due to farm waste and fertilizer runoff.
Together, fertilizers AND sewage can cause a massive increase in the growth of algae or plankton that overwhelms huge areas of oceans, lakes, or rivers.
Eutrophication is when a body of water becomes overly enriched with minerals and nutrients that induce excessive growth of plants and algae. Eutrophication is almost always induced by the discharge of nitrate or phosphate – containing detergents, fertilizers, or sewage into an aquatic system.
Sewage and Wastewater Pollution
- Used water is wastewater. It comes from sinks, showers, and toilets (think sewage) and from commercial, industrial (factories), and agricultural activities (think metals, solvents, and toxic sludge).
- The term also includes stormwater runoff, which occurs when rainfall carries road salts, oil, grease, chemicals, and debris from impermeable surfaces into our waterways.
- More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused, according to the United Nations; in some least-developed countries, the figure tops 95 percent.
- Sewage contains all kinds of other chemicals, from the pharmaceutical drugs people take to the paper, plastic, and other wastes they flush down their toilets.
- When people are sick with viruses, the sewage they produce carries those viruses into the environment. It is possible to catch illnesses such as hepatitis, typhoid, and cholera from river and sea water.
- In the United States, wastewater treatment facilities process about 34 billion gallons of wastewater per day. These facilities reduce the amount of pollutants such as pathogens, phosphorus, and nitrogen in sewage, as well as heavy metals and toxic chemicals in industrial waste, before discharging the treated waters back into waterways.
- That’s when all goes well. But according to EPA estimates, the USA’s aging and easily overwhelmed sewage treatment systems also release more than 850 billion gallons of untreated wastewater each year.
- Another way to say the above is – around half of all ocean pollution is caused by sewage and waste water.
- Each year, the world generates perhaps 5–10 billion tons of industrial waste, much of which is pumped untreated into rivers, oceans, and other waterways. In the United States alone, around 400,000 factories take clean water from rivers, and many pump polluted waters back in their place.
- However, there have been major improvements in waste water treatment recently. Since 1970, in the United States, the Environmental Protection Agency (EPA) has invested about $70 billion in improving water treatment plants that, as of 2015, serve around 88 percent of the US population (compared to just 69 percent in 1972).
- However, another $271 billion is still needed to update and upgrade the system.
- Factories are point sources of water pollution, but quite a lot of water is polluted by ordinary people from nonpoint sources; this is how ordinary water becomes waste water in the first place.
- Consumers account for the vast majority of oil pollution in our seas, including oil and gasoline that drips from millions of cars and trucks every day.
- Nearly half of the estimated 1 million tons of oil that makes its way into marine environments each year comes not from tanker spills but from land-based sources such as factories, farms, and cities.
- At sea, tanker spills account for about 10 percent of the oil in waters around the world, while regular operations of the shipping industry—through both legal and illegal discharges—contribute about one-third.
- Oil is also naturally released from under the ocean floor through fractures known as seeps.
Radioactive Substance Pollution (Nuclear Pollution)
- Radioactive waste is any pollution that emits radiation beyond what is naturally released by the environment.
- It’s generated by uranium mining, nuclear power plants, and the production and testing of military weapons, as well as by universities and hospitals that use radioactive materials for research and medicine.
- Radioactive waste can persist in the environment for thousands of years, making disposal a major challenge.
- The decommissioned Hanford nuclear weapons production site in Washington cleanup of 56 million gallons of radioactive waste is expected to cost more than $100 billion and last through 2060.
- Accidentally released or improperly disposed of contaminants threaten groundwater, surface water, and marine resources.
- At high enough concentrations it can kill; in lower concentrations it can cause cancers and other illnesses.
- The biggest sources of radioactive pollution in Europe are two factories that reprocess waste fuel from nuclear power plants: Sellafield on the north-west coast of Britain and Cap La Hague on the north coast of France.
- Both discharge radioactive waste water into the sea, which ocean currents then carry around the world. Countries such as Norway, which lie downstream from Britain, receive significant doses of radioactive pollution from Sellafield.
- The Norwegian government has repeatedly complained that Sellafield has increased radiation levels along its coast by 6–10 times. Both the Irish and Norwegian governments continue to press for the plant’s closure.
Other Water Pollution Causes & Sources…
Some of these sources are related to the above sources, whilst some are their alone separate sources:
Chemical Waste Pollution
According to ExplainThatStuff.com:
- Chemical waste can come in varying forms and extremities.
- They can come from households – like detergents and cleaning products.
- But, they can come from commercial and industrial sources like factories, plants, and mines. We are talking about asbestos, lead, mercury, petrochemicals etc.
- Detergents are relatively mild substances, while at the opposite end of the spectrum are highly toxic chemicals such as polychlorinated biphenyls (PCBs).( They were once widely used to manufacture electronic circuit boards)
- Another kind of toxic pollution comes from heavy metals, such as lead, cadmium, and mercury. Lead was once commonly used in gasoline (petrol), though its use is now restricted in some countries.
- Mercury and cadmium are still used in batteries (though some brands now use other metals instead). Until recently, a highly toxic chemical called tributyltin (TBT) was used in paints to protect boats from the ravaging effects of the oceans.
- Ironically, however, TBT was gradually recognized as a pollutant: boats painted with it were doing as much damage to the oceans as the oceans were doing to the boats.
- Virtually everyone pours chemicals of one sort or another down their drains or toilets. Even detergents used in washing machines and dishwashers eventually end up in rivers and oceans. So do the pesticides people use on their gardens.
- A lot of toxic and chemical pollution also enters waste water from highway runoff. Highways are typically covered with toxic chemicals—everything from spilled fuel and brake fluids to bits of worn tires (themselves made from chemical additives) and exhaust emissions.
- When it rains, these chemicals wash into drains and rivers. It is not unusual for heavy summer rainstorms to wash toxic chemicals into rivers in such concentrations that they kill large numbers of fish overnight.
- It has been estimated that, in one year, the highway runoff from a single large city leaks as much oil into our water environment as a typical tanker spill. Some highway runoff runs away into drains; others can pollute groundwater or accumulate in the land next to a road, making it increasingly toxic as the years go by.
Plastic & Waste Pollution
Plastic is one of the most common things that washes up on a beach.
There are three reasons for this:
- plastic is one of the most common materials, used for making virtually every kind of manufactured object from clothing to automobile parts;
- plastic is light and floats easily so it can travel enormous distances across the oceans;
- most plastics are not biodegradable (they do not break down naturally in the environment), which means that things like plastic bottle tops can survive in the marine environment for a long time. (A plastic bottle can survive an estimated 450 years in the ocean and plastic fishing line can last up to 600 years.).
While plastics are not toxic in quite the same way as poisonous chemicals, they nevertheless present a major hazard to seabirds, fish, and other marine creatures.
When we look at waste in general, littering, improper waste disposal and dumping in landfills can cause waste to spill over into water sources.
In addition to plastic, glass, aluminum, styrofoam, cigarette butts and more can be found in water sources.
Alien Species Pollution (Biological Pollution)
- Most people’s idea of water pollution involves things like sewage, toxic metals, or oil slicks, but pollution can be biological as well as chemical.
- In some parts of the world, alien species are a major problem. Alien species (sometimes known as invasive species) are animals or plants from one region that have been introduced into a different ecosystem where they do not belong.
- Outside their normal environment, they have no natural predators, so they rapidly run wild, crowding out the usual animals or plants that thrive there. Examples are Zebra Mussels, algae, jellyfish, clams etc. In 1999, Cornell University’s David Pimentel estimated that alien invaders like this cost the US economy $123 billion a year.
Heat Or Thermal Pollution
- Heat or thermal pollution from factories and power plants also causes problems in rivers.
- By raising the temperature, it reduces the amount of oxygen dissolved in the water, thus also reducing the level of aquatic life that the river can support.
- Another type of pollution involves the disruption of sediments (fine-grained powders) that flow from rivers into the sea.
- Dams built for hydroelectric power or water reservoirs can reduce the sediment flow. This reduces the formation of beaches, increases coastal erosion (the natural destruction of cliffs by the sea), and reduces the flow of nutrients from rivers into seas (potentially reducing coastal fish stocks).
- Increased sediments can also present a problem. During construction work, soil, rock, and other fine powders sometimes enters nearby rivers in large quantities, causing it to become turbid (muddy or silted).
- The extra sediment can block the gills of fish, effectively suffocating them. Construction firms often now take precautions to prevent this kind of pollution from happening.
Air pollution can cause water pollution in some of the following ways:
- Ocean Acidification – is the ongoing decrease in the pH of the Earth’s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. – Wikipedia – https://en.wikipedia.org/wiki/Ocean_acidification
- Acid rain – SO2 and NOX emitted into the air from fossil fuel burning, vehicles and manufacturing react with water, oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground. It can get into water sources via the soil it has polluted and fallen onto – https://www.epa.gov/acidrain/what-acid-rain
- Global Warming – a result of greenhouse gases like carbon dioxide contributing to climate change and causing an increase in water temperature
- Underground storage leakages
- Damming of rivers – WaterWise.co.za
Summary Of Pollutants
- Microorganisms, toxins, pathogens – from waste water, sewage, animal waste (agriculture)
- Chemicals & Nutrients – fertilizer, pesticides/herbicides, detergents, cleaning products, oils (oil spills, household oils, and car oil), PTBs, phosphates, nitrates
- Heavy Metals – lead, mercury, cadmium etc,
- Hard Waste – plastic, aluminium, cigarette butts, glass etc.
- Air Pollution – carbon, other air pollutants that mix together
- Soil Pollution – seep and runoff from soil
- Natural Pollution – plant decay, natural waste and bacteria, natural events
This is not an extensive list – just some of the main contaminants.
Ocean/Marine Water Pollution
- As a summary to the above for saltwater – around half of all ocean pollution is caused by sewage and waste water
- As a summary to the above for freshwater – agricultural pollution (fertilisers, pesticides/herbicides and animal waste) is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It’s also a major contributor of contamination to estuaries and groundwater.
Effects Of Water Pollution
Some water pollution is inevitable as a result of human and economic activity – it can’t completely be eliminated.
However, water pollution also has human, environmental and economic costs – so it’s in everyone’s best interests to minimise it or find a way to address it.
Some of the effects are as follows:
Human Health Effects
- Water pollution can cause death. It caused 1.8 million deaths in 2015, according to a study published in The Lancet.
- Contaminated water can also make you ill. Every year, unsafe water sickens about 1 billion people. And low-income communities are disproportionately at risk because their homes are often closest to the most polluting industries.
Pathogens are found in polluted/contaminated water and diseases spread in the water include cholera, giardia, and typhoid.
- Thousands of people across the United States are sickened every year by Legionnaires’ disease (a severe form of pneumonia contracted from water sources like cooling towers and piped water), with cases cropping up from California’s Disneyland to Manhattan’s Upper East Side.
- Flint, Michigan was the result of cost-cutting measures and aging water infrastructure creating a lead contamination crisis
- The problem goes far beyond Flint and involves much more than lead, as a wide range of chemical pollutants—from heavy metals such as arsenic and mercury to pesticides and nitrate fertilizers—are getting into water supplies. Once they’re ingested, these toxins can cause a host of health issues, from cancer to hormone disruption to altered brain function. Children and pregnant women are particularly at risk.
- Even swimming can pose a risk. Every year, 3.5 million Americans contract health issues such as skin rashes, pinkeye, respiratory infections, and hepatitis from sewage-laden coastal waters, according to EPA estimates.
- Interruption with how animals, plants, bacteria, and fungi in an ecosystem interact with each other
- [algal blooms from excess nutrients like fertilizers can cause oxygen depleted dead spots in water – which aquatic animals can’t live in]
- Chemicals and heavy metals from industrial and municipal wastewater contaminate waterways as well. These contaminants are toxic to aquatic life [and can find their way up the food chain when big animals eat smaller ones]
- Marine ecosystems are also threatened by marine debris, which can strangle, suffocate, and starve animals. [plastic and fishing gear are two big examples of this]
- Meanwhile, ocean acidification is making it tougher for shellfish and coral to survive. Though they absorb about a quarter of the carbon pollution created each year by burning fossil fuels, oceans are becoming more acidic.
On top of the human health and environmental effects of water pollution, there are also economic effects such as:
- Cleaning up oil spills
- Killing fish which harms the fishing industry
- Treating humans who get sick from water pollution
- Costs to lost tourism
- Costs of lower supplies of freshwater – restriction or increased prices can restrict business growth and employment
Plus much more.
How To Measure Water Quality
It should be noted that water quality depends on the purpose for the water, or what you want to use it for.
For example, water that could be unfit for human consumption could be still usable in industrial or agriculture applications like irrigation.
Once you know the purpose of the water, there are two main ways of measuring the quality of water:
- One is to take samples of the water and measure the concentrations of different chemicals that it contains.
- Another way to measure water quality involves examining the fish, insects, and other invertebrates that the water will support.
- If many different types of creatures can live in a river, the quality is likely to be very good; if the river supports no fish life at all, the quality is obviously much poorer.
Water Pollution & Quality – Developing vs Developed Countries
Access to, and availability of safe drinking and usable water (and also sanitation) is certainly an issue in developing countries.
A lack of income certainly plays a role in this – not being able to purchase and set up drinkable and useable water infrastructure, and having the same financial restrictions with sanitation and waste water/sewage treatment facilities and infrastructure.
However, water pollution is more of a country by country issue which depends on a lot of factors.
Water quality in developing countries is often hampered by lack of or limited enforcement of:
- emission standards
- water quality standards
- chemical controls
- non-point source controls (e.g. agricultural runoff)
- market based incentives for pollution control/water treatment
- follow-up and legal enforcement
- integration with other related concerns (solid waste management)
- trans-boundary regulation on shared water bodies
- environmental agency capacity (due to resources or lack of political will)
- understanding/awareness of issues and laws
Having said this, developed countries also face significant issues of their own with an excess of resources at the consumer and household level producing contaminants and waste, and the various business, industries and agriculture sectors doing the same.
Countries That Pollute Water The Most
According to All-About-Water-Filters.com, the 7 biggest water polluting countries are:
- United States
- As an example in China, 54% of the Hai River basin surface water is so polluted that it is considered un-usable
- Another example is India, where 80% of the health issues come from waterborne diseases. Part of this challenge includes addressing the pollution of the Ganges (Ganga) river, which is home to about 400 million people.
- The river receives about over 1.3 billion litres of domestic waste, along with 260 million litres of industrial waste, run off from 6 million tons of fertilizers and 9,000 tons of pesticides used in agriculture, thousands of animal carcasses and several hundred human corpses released into the river every day for spiritual rebirth.
- Two-thirds of this waste is released into the river untreated.
Countries With Some Of The Worst Water Quality
According to IBTimes.co.uk, the 10 countries with the poorest water quality in 2017 are:
- Democratic Republic Of The Congo
- Papua New Guinea
Potential Water Pollution Solutions, & How To Prevent It
On an individual level – we can use environmentally friendly detergents and household products, not pour oil and harmful chemicals down drains, maintain our cars and make sure they don’t leak, reduce pesticides and fertilisers in our gardens, recycle as opposed to use plastic, and so on.
We can take community action too, by helping out on beach cleans. We can also take action as countries to support and pass laws and regulations (like the the Clean Water Rule, which clarifies the Clean Water Act’s scope and protects the drinking water of one in three Americans) that will make pollution harder and the world less polluted.