September 7, 2018 Water Pollution Written by Greentumble Editorial Team
Water pollution
Long, long ago our planet was just a rock,

a shell that had cooled over its molten hot interior, devoid of life.  Hot gases poured out of its fissures, forming dense clouds in the atmosphere.  And then it rained.  It rained for thousands and thousands of years, filling the craters and grooves, percolating down through the fissures to fill underground caverns. 

With water and then sunlight, came life.  Vegetation took hold, decayed, creating topsoil and more life.  Single-celled life formed and from these simple cells, more complex life forms evolved. 

Genetically, we homo sapiens claim our origins from the ocean [1]. A tiny human fetus passes through these evolutionary stages, dropping its tail and gills before birth.  Human bodies are 60 percent water.

 
We need water.  Our planet needs water to maintain life.

Of the water that covers 70 percent of our planet, only 2.5 percent of that is fresh water and less than 1 percent is available to our exploding population. 

We are 6.8 billion now, growing at an unstoppable rate of 83 million a year.  Still, the United Nations suggests that we would have enough water for our population if it were evenly distributed and if it were clean.  Too much of it is wasted, polluted and unsustainably managed [2].

A prime example of our wastefulness:  an average hamburger takes 630 gallons, that is 2,400 liters of water to produce [3].

 

 

What is water pollution?

Water pollution is degraded water, toxic to humans or the environment [4]. It occurs when harmful chemicals or microorganisms or sometimes simply garbage or too much sediment contaminates a stream, river, lake, wetland, groundwater aquifer, ocean, in short, any body of water. 

Anthropogenic thermal differences caused by the discharge of hot water from power plants and factories directly into an open water source is also considered water pollution as it decreases oxygen levels and alters the species that can survive there, often inviting non-native species invasion, altering the food chain and typically reducing species biodiversity [5].
 

Alarming facts about water pollution worldwide

Globally, 70 percent of industrial waste is dumped directly into water. 

Even greater than the dumping of toxic industrial chemicals is the contribution of domestic garbage and sewage, accounting for 80 percent of water pollution globally.  Asia has the highest number of polluted rivers in the world, mostly due to its dumping of raw sewage and the resulting bacteria.

The sacred Ganges River in India

The sacred Ganges River in India

The sacred Ganges River takes the prize for the world’s most polluted river, carrying sewage, trash, animal carcasses and wasted food. 

It is estimated that globally 80 percent of wastewater is dumped back into the water supply untreated. 

 

    • Waterborne diseases are on the rise

Globally, 1.1 billion people do not have access to clean water and 2.4 billion people do not have proper sanitation.

The World Health Organization estimates waterborne diseases cause two million deaths annually, mostly of young children [6]

These deaths were attributed to drinking water contaminated with fatal micro-organisms and inadequate handwashing facilities and sanitation services.  The latter facilitates transfer of fatal micro-organisms through hand contact and food preparation. 

Deaths from the effects of toxic chemicals are less simple to pinpoint.

Not surprisingly, water pollution is the major medium for typhoid and cholera.
 

    • Is the situation better in the United States? Not really…

Even in the United States, which unlike developing countries regulates industrial discharges and the human and solid waste flows, 40 percent of the rivers and 46 percent of the lakes are polluted to the extent that they are too unhealthy for swimming, fishing or aquatic life [7]

Discharge from abandoned mines containing copper, cadmium, arsenic and zinc is responsible for the pollution of 40 percent of western US rivers [8]

And many of the wastewater management systems that are in place are old and lack the capacity to serve its population base, often overtaxed during storms when storm water runoff surges and allows sewage and runoff to discharge directly into nearby streams, rivers and other water bodies.  

Each year 860 billion gallons [9] overflows from sewer systems across America and ends up in our waterways.

Annually, a total of 1.2 trillion gallons of untreated sewage, storm water, and industrial waste are dumped into U.S. waters [10].

 

    • Garbage and untreated sewage in the ocean: a global-scale disaster

Fourteen billion pounds of garbage mostly plastic, is dumped into the ocean every year. 

Plastic bottles on the beach

Plastic bottles on the beach

Over 30 billion tons of urban sewage discharged into lakes, rivers and oceans each year [11].   

Cruise ships, ubiquitous now in the ocean, the largest of which can carry over 7,000 passengers and crew and on just a one-week voyage is estimated to generate 210,000 gallons of human sewage and 1 million gallons of graywater, as well as large volumes of oily bilge water, sewage sludge, garbage and other hazardous wastes. 

Some is treated before discharging directly into the ocean; some is not [12].
 

    • Dead zones are the biggest danger

But the most prevalent problem in open waterways is eutrophication, the dumping of high nutrient loads mostly from fertilizers into open waterways [13].

The excess nitrogen creates algal blooms and consequent dead zones in the water where nothing can live.
 

    • Are we polluting our drinking water? Yes, we are

And then there is groundwater pollution. 

Almost half of Americans get their drinking water from groundwater. 

Groundwater is vulnerable to leakage from petroleum storage tanks, of which there are an estimated ten million buried underground, septic systems, landfills, road salt and other road runoff as well as hazardous waste sites. 

It is believed that there are over 20,000 abandoned and uncontrolled hazardous waste sites [15]

Groundwater is also vulnerable to pesticide and fertilizer runoff that percolates into the ground and all of the pollution the rain brings down.

And the situation is not improving.  The United Nations Educational, Scientific and Cultural Organization (UNESCO) reports that water pollution is on the rise globally [16].
 
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What are the causes of water pollution?

Unfortunately, there are many causes of water pollution, both point source and non-point source

Point source means simply that the source of the pollution can be easily identified such as direct discharge into a body of water from a factory, household or a sewage treatment plant. 

Non-point source means that the source is more difficult to identify. 

For example, agricultural runoff from many farms pollute the Mississippi River. It is not an easy matter to see from where or when the runoff happens as it may simply be in the eroded soil after a storm or it may rise from groundwater it previously trickled into.  Rain can carry air pollutants down into water bodies from hundreds, if not thousands of miles away. 

Obviously, point sources are easier to regulate than non-point sources.  Still, with enough investigation, the non-point sources might be identified. 

Polluted floodwater

Polluted floodwater

This is one of the goals of the US National Oceanic and Atmospheric Administration (NOAA) in order to more effectively curb coastal water pollution.  Non-point source pollution is the greatest threat to coastal waters.  Tributaries carry pollutants that wash into the sea.  But where exactly are these pollutants from? 

In partnership with the US Environmental Protection Agency through the Coastal Nonpoint Pollution Control Program, the NOAA is attempting to identify and control runoff from agriculture, forestry, urban areas, marinas, and shoreline and stream channel modification [17].

While it is important to recognize the different ways pollutants can enter the water, whether the source is point or non-point is more relevant to determining how to curb the pollution.  

Let’s look now at the primary contributors to water pollution.

 

#1 Household wastewater and sewage

Let’s start with domestic wastewater and sewage since it makes up 80 percent of water pollution

As the world population burgeons, the proper treatment of sewage and wastewater is increasing in importance not only to stop the spread of diseases [18], loss of biodiversity through nutrient pollution and consequent eutrophication [19], but also because water is a scarce and necessary resource in much of the world and must be properly treated and recycled if we are to survive.
 

#2 Agriculture

As the world population explodes, agribusiness is rising to the task of feeding the billions by deforesting the land and using the fastest, simplest techniques to grow vast quantities of grains and fatten thousands of cattle, pigs and chicken as quickly and cheaply as possible. 

Sustainable techniques are decidedly not practiced, but instead of nourishing the land through crop rotation and cover crops and using time-honored soil erosion techniques such as contour plowing, copious amounts of synthetic fertilizers and toxic herbicides, insecticides and pesticides are sprayed. 

Beef consumption is on the rise globally and thousands upon thousands of acres are devoted to quickly growing corn to feed the penned animals destined for an early demise in the slaughterhouse. 

A typical farm pollutes groundwater via soil absorption, the air through methane gas from the cows who do not easily digest the corn, and the volatilization of nitrogen from excess fertilizers and the other toxic chemicals sprayed, and via open water sources if not directly, then when rainwater washes the animal manure, fertilizers and toxic chemicals from the eroded soil into the nearest waterway and through atmospheric deposition of the volatile compounds.
 

#3 Industry and mining

Manufacturing activities generate a wide variety of waste products, including many toxic chemicals that are ultimately discharged into waterways. 

Most developed countries regulate industrial discharges, requiring filtration treatment prior to discharge, but developing countries do not.  As indicated above, 70 percent of industrial waste is discharged directly into our waters. 

Industrial discharges can be dumped into a landfill and then leach into the groundwater as well. 

Mining and oil drilling also cause substantial industrial pollution to both surface and groundwater, rendering it too toxic for any purpose.  The wastes typically change the acid level of surrounding water substantially as well [20].
 

#4 Oil spills

Of the one million tons of oil discharged into the ocean every year, around five percent comes from natural sources in the ocean floor, 35 percent comes from regular shipping operations including illegal tank cleaning and 45 percent comes from municipal and industrial effluents, that is wastewater, much of it from storm water washing oil from roadways. 

Oil spill in the water

Oil spill in the water

Oil tank and rig disasters account for around 10 percent of marine pollution [21]

Of course, a major oil spill could easily double that amount. 

The Persian Gulf oil spill of 1991 is so far the biggest oil spill in the world. As Iraqi troops retreated from Kuwait during the first Gulf War, they opened the valves of oil wells and pipelines, pouring up to 8 million barrels into the Gulf.

But the point here is that almost half of the million tons of oil discharged into the oceans annually is land-based and could be controlled with more responsible practices.
 

#5 Hazardous waste

As with industrial waste discharges, hazardous waste is largely uncontrolled in developing countries and can easily enter the waterways directly. 

In the United States, hazardous waste has been recognized as such for years and companies conceal their hazardous waste by storing it in barrels and burying it. 

It is estimated that there are over 20,000 abandoned and uncontrolled hazardous waste sites with a potential to leak hazardous waste into the groundwater [22].
 

#6 Landfills

Likewise, improperly constructed landfills or those whose liners have leaked pose a serious threat to groundwater contamination [23].
 

#7 Radioactive waste

Safe disposal of radioactive waste is a problem the world is still reckoning with. 

Thirteen countries routinely disposed of its radioactive waste by dumping it into the ocean from 1946 through 1993 [24]. Since then, international treaties have banned the practice.  

Container with nuclear waste

Container with nuclear waste

Still, problems arise like the tsunami that crippled a Tokyo nuclear power plant in 2011, causing a massive spill that contaminated Tokyo Bay. 

Tokyo Electric Power Company is still trying to decide what to do with 777,000 tons of water laced with tritium, asserting that it is harmless and could be dumped into the nearby sea without environmental consequences.  Others are not so sure. 

Any containment of nuclear waste risks ultimately failing and entering groundwater of nearby open waters. Even the United States does not have a good program for long term storage of nuclear waste. 

Its Department of Energy is grappling with cleaning up a legacy of five decades of government-sponsored nuclear weapons development and nuclear energy research at 107 sites [25].
 

#8 River and marine pollution

This is deliberate and direct dumping of garbage into rivers and oceans. Of increasing concern is the amount of plastic that makes its way into our waterways.
 

#9 Thermal pollution

As mentioned in the introduction, many power plants discharge very hot water into nearby waters, which reduces its oxygen and modifies the natural marine environment.

#10 Dredged silt

Rivers, canals and harbors are dredged to remove silt buildup or sometimes to establish new waterways.  About 20 percent of this dredged material, estimated at several million tons annually is dumped into the ocean. 

A sewage outlet

A sewage outlet

It is estimated that 10 percent contains heavy metal such as cadmium and mercury, heavy oils, pesticide toxins and fertilizer nutrients [26].
 

#11 Drugs

And finally, an emerging water quality concern is from the impact of pharmaceuticals like birth control pills, painkillers, antibiotics and other drugs that make their way into waste water, but are not filtered before re-entering the water supply or being discharged into open waters [27].
 
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What are the effects of water pollution?

#1 Eutrophication

Let’s start with eutrophication. A big word for a big problem. 

The dictionary definition is excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen. 

Statistically, in the United States and Europe, this equates to too much nitrogen from commercial fertilizer and animal manure from agribusiness.  It is not simply runoff when it rains, or even just contamination through groundwater entry into waterways, but the excess nitrogen can also enter the water via rain. 

Eutrophication of a lake

Eutrophication of a lake

Nitrogen is volatile and up to 60 percent can be lost to the atmosphere as it is being applied, though volatilization losses are more commonly 40 percent or less [28]. Still, that can be quite a bit considering that the application of fertilizers globally is over 200 million tons [29]

In the coastal waterways of Asia, South America and Africa, the primary source of nutrient pollution is urban wastewater, that is municipal wastewater treatment plants, industrial wastewater discharges and storm water runoff. 

Another growing source of nutrient pollution is aquaculture or fish farming, which has grown 600 percent as an industry in the past twenty years [30]

The burning of fossil fuel too, both in industry and in transportation contributes significant amounts of nitrogen into water bodies via nitrogen oxides pouring down in acid rain.

The nutrient pollution causes algal blooms which depletes the marine environment of oxygen and causes a dead zone. There are dead zones in oceans all over the world now.  Some of these are very large. 

The dead zone in the Gulf of Mexico at the mouth of the Mississippi River from fertilizer runoff along its banks covers 7700 square miles of 20,000 square kilometers [31].

 

#2 Human death and disease

Common waterborne diseases, largely from parasites and bacteria include legionnaire’s disease, severe acute respiratory syndrome, swimmer’s ear, dysentery, typhoid fever, cholera and Hepatitis A, blood flukes, and E.coli.

In humans, an accumulation of toxic chemicals can damage:

  • the liver
  • kidneys
  • reproductive and endocrine system
  • nervous system
  • thyroid gland and cause various cancers [32].

 
 
This accumulation can happen by drinking polluted water or eating seafood that has accumulated these toxins in its tissues. 

In marine life, reproductive damage has been observed from the accumulation of toxic chemicals. 

Radioactive waste that has been dumped into or leached into the water supply or which has come down in atmospheric deposition after nuclear testing or explosion has been shown to be highly toxic to humans, Strontium 90 has proven to cause bone cancer.  Seafood can also become contaminated.
 

#3 Oil spills kill wildlife

A study by the US National Institute of Health cautions that oil spills may involve health risks to clean-up personnel as well as those living along the coast affected by the spill [33].

A lake polluted by oil

A lake polluted by oil

And unfortunately, we are all familiar with the photographs of fish and birds who have washed up on the shores, dead or suffocating, drenched in oil after major oil spills.

#4 Impaired aquatic habitat

Dredged silt covers the ocean floor and can block the sunlight and alter the marine environment, displacing the species naturally living there. 

The effect of unsuccessful spawning in herring and lobster populations where the ocean floor has been covered with silt has been documented [34].
 

#5 Alteration of hormonal levels and reproduction cycles

The effects of small doses of pharmaceuticals over the long term on humans and marine life has not been studied.  It is simply a big question mark and one that is not going to be easily answered given the variety of pharmaceuticals a water supply can contain. 

One concern is that some of these products may mimic natural hormones and alter the reproductive system both in marine animals and humans.
 
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The summary

The following table shows many of the causes of water pollution and their effects:
 

Cause of Water PollutionEffects
Sewage and Wastewater

*Untreated sewage water is problematic in developing countries with insufficient sanitation.

*In developed countries, pharmaceuticals and other chemicals are flushed down the toilet and sink.



*Raw sewage in water causes environmental contamination and human illnesses like diarrhea.

*Chemicals and pharmaceuticals are harmful to the environment, wildlife, and humans.

Industrial Waste

*Many industrial plants worldwide use fresh water to dispose of their waste, polluting rivers, lakes, and oceans.



*Industrial chemicals can travel for many miles and result in biomagnification at progressively higher levels within the food chain. This effect especially impacts top-level predators and humans, causing illness and death.

Marine Dumping
*Litter is disposed of in the ocean and on beaches.



*Some litter items such as plastic six-pack rings do not readily degrade and may injure or kill animals.

*Litter may contain toxic chemicals that pollute the marine environment.

*Litter can persist for many years and accumulate in large patches and wash up on coastal areas.

Radioactive Waste

*Produced during industrial, medical, and scientific processes, and through the mining and refining of nuclear fuels like uranium and thorium.

*Nuclear processing plants give off wastes that can pollute the marine environment.



*Harmful to marine life and human health.
Oil Pollution

*Large oil spill events account for only 12% of total ocean oil pollution. The remaining oil pollution is through routine shipping, land run-off, and intentional oil dumping.



*Devastating to local marine life like birds, fish, and marine mammals.

*Does not dissolve in water but gathers together as a thick sludge.

*Can cause fish to suffocate.

*Marine birds’ feathers can get coated with oil, preventing their ability to fly.

*Marine mammals can also get coated with oil.

*Oil can block sunlight and prevent aquatic plants from undergoing photosynthesis.

Atmospheric Deposition

*Acid rain is created when water molecules in the atmosphere combine with particles of carbon dioxide, nitrogen oxides, and sulfur dioxide from the burning of fossil fuels to form a mildly acidic pollutant that can be present in rain.



*Stresses and harms fish and other aquatic life at low levels. Can kill aquatic life at higher concentrations

Eutrophication

*Occurs when ocean waters and other aquatic habitats are enriched with excess nutrients, such as phosphates and nitrogenous compounds caused by agricultural runoff.

*Excess nutrients feed algae and can cause algal blooms in the ocean and in lakes and other freshwater bodies.



*The excessive algae use up all of the dissolved oxygen in the water, leaving little left for other organisms like fish. This process can lead to the creation of “dead zones,” where fish cannot survive.

*Algal blooms may block sunlight from aquatic plants.

*Algae may produce toxins that are poisonous to aquatic life and humans, and can potentially lead to death.

Run-off from many different sources (non-point source pollution)

*Rainfall and snowmelt can wash natural and human-made pollutants from human development into rivers, lakes, wetlands, and coastal waters.



*Harmful to aquatic life and ecosystems, and human health.
Agricultural Runoff

*Agricultural pollutants include: excessive nutrients, ammonia and nitrates, pathogens, antibiotics and hormones, and heavy metals and salts.

*Manure, animal bedding, wasted feed, soil, dust, hair and feathers can be mixed together and can end up in waterways.



*Water pollutants can harm or poison both aquatic life and humans.

*Excessive organic matter in water bodies can lead to eutrophication issues.

*Private wells can become polluted from toxins from factory farm operations.

Greenhouse Gases

*Carbon dioxide gas is produced through the burning of fossil fuels.

*These gases are absorbed by the ocean.

*As increased carbon dioxide is released around the globe, the increased levels that are being absorbed by the ocean are making the ocean waters more acidic.

*These acidic waters are inhospitable to many types of marine life, particularly organisms with a calcium-based shell or skeleton, such as coral reefs.

 
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Practical solutions for water pollution

Because fresh and clean water is necessary for the health of everyone and for the environment, it is crucial that we create and maintain solutions to prevent and mitigate water pollution.

Children playing in a river

Children playing in a river


 

What can you do to help prevent water pollution?

Tackling such a large problem can seem overwhelming at first. 

Start by considering your own actions.  Each individual makes an impact.

 
Here is what you can do:

  • Reduce using products in your life that are going to quickly end up in the landfill.
  • Use a reusable cloth tote rather than plastic bags.
  • Make sure that your waste is properly disposed of.  This means not only making sure that it gets to the landfill rather than blowing out of the back of your truck, but that oils and household chemicals are disposed of in accordance with the rues of your municipality.
  • Make sure your vehicle does not leak oil or any other fluids on the roadways.
  • Consume less.  Less manufacturing and mining means less pollution.  Consumer demand dictates the market and if there is not a demand for a good, it will no longer be profitable to manufacture it.  Use the money you save for a massage.
  • Don’t flush pharmaceuticals down the toilet.
  • Use a renewable energy source when you can.
  • Drive less.
  • Reduce your power consumption.  Power plants burn fossil fuels that pollute the air and subsequently water.  Often they also contribute thermal pollution.  Turn off the light when you leave the room.  Turn your hot water heater off when you don’t need it.  Be moderate in heating and cooling your home and business.
  • Concerning the actions of the rest of the world, become involved in your own community and push for effective water treatment facilities that filter toxic chemicals and can handle storm water surges without discharging sewage.  Encourage the use of symbols like the painted blue storm water grates and bright yellow fish used in the UK to create an awareness that storm water drains into the sea and affects marine life.  The fact is that a lot of people simply don’t think about where water comes from or where it goes.  Educate those around you when you have an opportunity.
  • Adopt a highway or a stream or a beach.  Have friends join you and clean it up.  Propose the same to local organizations.
  • Advocate for strict regulations for industrial discharge of pollutants and for strong enforcement.  Encourage your government to set goals for reducing pollution and to enter into international treaties agreeing to meet worldwide goals.
  • Do not contribute to agribusiness nutrient pollution.  Buy locally from farmers and ranchers who utilize sustainable practices.  Advocate for banning toxic chemicals used in pesticides, herbicides and insecticides.
  • If you become involved in helping a community in a developing nation, follow the steps that a developed country has followed.  Create an awareness of the consequences of the adverse action, for example allowing animals to defecate in the creek where drinking water is gathered.  Teach the community about trash and disease and how it is spread.  Teach them about the toxicity of chemicals.  Teach them about water filtration.  Advocate for water treatment facilities.  Advocate for pollution regulation.  Dissuade them from being seduced by advertising into becoming a consumer nation by showing them the consequence.
  • When you go hiking, take a good water filter like the LifeStraw and enjoy a deep gulp of clean water!

 


 

How to enforce water protection worldwide?

The issue of water pollution requires the cooperation of us all and while you as an individual should help to make the impact, authorities also need to step in and apply necessary measures to make sure global water resources are protected.

There are a number of solutions available that could go a long way in helping to reduce water pollution around the world.

Examples of some are:
 

    • Creation and enforcement of water quality regulations

This involves creation of public policies that protect water resources, especially focused on the pollution from industrial and agricultural sources, and encourages collaboration among stakeholders in these industries to innovate and create sustainable ways of doing business that do not negatively impact the environment.
 

    • Education and awareness raising

Public education and awareness about the causes and impacts of water pollution needs to be improved and provided even in developing countries.
 

    • Switch to renewable energy

Reduction of the burning of fossil fuels comes with positive impacts, one of them is the decrease of acidification of the world’s oceans and of other associated pollution such as oil spills and groundwater pollution from fracking liquid.

By embracing and investing in sustainable energy technologies that are non-polluting our energy demand can be satisfied without endangering our water resources.
 

    • Employment of the best practices for watershed management, wastewater management, vessel sewage discharge, and stormwater source pollution

Where appropriate, such as in smaller communities, low-tech wastewater treatment through the use of wetlands should be considered, and will provide valuable wildlife habitat.
 

    • Smart and sustainable water management in cities

All new developments should be “green” to help prevent stormwater runoff in urban areas and capture rainwater through the use of trees, bioswales, and natural areas, and the use of structures such as permeable pavements, green roofs and rain gardens.

Natural areas should be conserved to help capture stormwater, especially near lakes, rivers, and streams.
 

    • Sustainable agriculture

Agricultural policies should encourage the use of ecological and organic farming methods that use few to no toxic chemicals and protect water bodies from pollution.

Policies should include the proper management of livestock and organic land policies through practices such as conservation tillage and buffer strips near waterways.

 


References

[1] http://www.pbs.org/your-inner-fish/home/
[2] http://www.unwater.org/water-facts/quality-and-wastewater/
[3] https://www.nationalgeographic.com/environment/freshwater/freshwater-crisis/
[4] https://www.nrdc.org/stories/water-pollution-everything-you-need-know
[5] https://en.wikipedia.org/wiki/Water_pollution
[6] http://www.who.int/sustainable-development/housing/health-risks/waterborne-disease/en/
[7] https://www.conserve-energy-future.com/variosus -water-pollution-facts.php
[8] https://www.denverpost.com/2011/05/29/thousands-of-old-mines-pollute-colorado-waters-with-no-help-in-sight/
[9] https://www.americanrivers.org
[10] https://www.seametrics.com/blog/water-pollution-facts/
[11] https://www.conserve-energy-future.com/various-water-pollution-facts.php
[12] https://foe.org/projects/cruise-ships/
[13] http://www.unesco.org/new/en/natural-sciences/environment/water/wwap/facts-and-figures/all-facts-wwdr3/fact-15-water-pollution/
[14] https://greentumble.com/the-main-causes-of-land-pollution/
[15] http://www.groundwater.org/get-informed/groundwater/contamination.html
[16] http://www.unesco.org/new/en/natural-sciences/environment/water/wwap/facts-and-figures/all-facts-wwdr3/fact-15-water-pollution/
[17] https://coast.noaa.gov/czm/pollutioncontrol/
[18] https://greentumble.com/diseases-caused-by-water-pollution/
[19] https://greentumble.com/the-main-causes-of-land-pollution/
[20] https://helpsavenature.com/industrial-water-pollution
[21] https://worldoceanreview.com/en/wor-3/oil-and-gas/oiling-the-oceans/?ivt=1#ivt-101
[22] http://www.groundwater.org/get-informed/groundwater/contmination.html
[23] https://greentumble.com/the-main-causes-of-land-pollution/
[24] https://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_waste
[25] https://www.energy.gov/national-security-safety/environmental-cleanup
[26] https://www.safewater.org/fact-sheets-1/2017/1/23/marine-dumping
[27] http://www.un.org/waterforlifedecade/quality.shtml
[28] https://www.wri.org/our-work/project/eutrophication-and-hypoxia/sources-eutrophication
[29] http://www.fao.org/news/story/en/item/277488/icode/
[30] https://www.wri.org/our-work/project/eutrophication-and-hypoxia/sources-eutrophication
[31] https://greentumble.com/the-main-causes-of-land-pollution/
[32] https://greentumble.com/diseases-caused-by-water-pollution/
[33] https://www.ncbi.nlm.nih.gov/pubmed/27221976
[34] https://www.safewater.org/fact-sheets-1/2017/1/23/marine-dumping