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What is water pollution?
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Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater), very often by human activities.
Water pollution occurs when pollutants (particles, chemicals or substances that make water contaminated) are discharged directly or indirectly into water bodies without enough treatment to get rid of harmful compounds. Pollutants get into water mainly by human causes or factors. Water pollution can be a Point-source, Non Point-source, or Transboundary in nature (Click to learn more).
Water pollution is the second most imperative environmental concern along with air pollution.
Any change or modification in the physical, chemical and biological properties of water that will have a detrimental consequence on living things is water pollution.
The water pollution problem
Water covers over 70% of the Earth’s surface. It is a very important resource for people and the environment.
Water pollution affects drinking water, rivers, lakes and oceans all over the world. In many developing countries, it is usually a leading cause of death, by people drinking from polluted water sources.
More to this, water pollution affects not only individual living species, but also populations and entire functioning ecosystems that exists in the waters.
Humans have now realised the importance of clean water as a foundation for life. In recent time, more and more organisations and councils are working hard to educate, protect, restore waterways and encourage practices that help keep waters from contamination, and also to preserve water ecosystems from destruction.
In this lesson, we shall learn all about water pollution, the types of water pollution, causes of water pollution, effects and some preventive practices that we can all use to help deal with water pollution. Use the menus on your left to learn more. Enjoy.
Types of water pollution
There are many types of water pollution because water comes from many sources. Here are a few types of water pollution:
- Nutrients Pollution
Some wastewater, fertilizers and sewage contain high levels of nutrients. If they end up in water bodies, they encourage algae and weed growth in the water. This will make the water undrinkable, and even clog filters. Too much algae will also use up all the oxygen in the water, and other water organisms in the water will die out of oxygen starvation. - Surface water pollution
Surface water includes natural water found on the earth’s surface, like rivers, lakes, lagoons and oceans. Hazardous substances coming into contact with this surface water, dissolving or mixing physically with the water can be called surface water pollution. - Oxygen Depleting
Water bodies have micro-organisms. These include aerobic and anaerobic organisms. When to much biodegradable matter (things that easily decay) end up in water, it encourages more microorganism growth, and they use up more oxygen in the water. If oxygen is depleted, aerobic organisms die, and anaerobic organism grow more to produce harmful toxins such as ammonia and sulfides. - Ground water pollution When humans apply pesticides and chemicals to soils, they are washed deep into the ground by rain water. This gets to underground water, causing pollution underground.
This means when we dig wells and bore holes to get water from underground, it needs to be checked for ground water pollution. - Microbiological
In many communities in the world, people drink untreated water (straight from a river or stream). Sometimes there is natural pollution caused by micro-organisms like viruses, bacteria and protozoa. This natural pollution can cause fishes and other water life to die. They can also cause serious illness to humans who drink from such waters. - Suspended Matter
Some pollutants (substances, particles and chemicals) do not easily dissolve in water. This kind of material is called particulate matter. Some suspended pollutants later settle under the water body. This can harm and even kill aquatic life that live at the floor of water bodies. - Chemical Water Pollution
Many industries and farmers work with chemicals that end up in water. This is common with Point-source Pollution. These include chemicals that are used to control weeds, insects and pests. Metals and solvents from industries can pollute water bodies. These are poisonous to many forms of aquatic life and may slow their development, make them infertile and kill them. - Oil Spillage
Oil spills usually have only a localized effect on wildlife but can spread for miles. The oil can cause the death to many fish and get stuck to the feathers of seabirds causing them to lose their ability to fly.Do you remember the BP Oil spill in 2010? (Read about it here) Over 1,000 animals (birds, turtles, mammals) were reported dead, including many already on the endangered species list. Of the animals affected by the spill, only about 6% have been reported cleaned, but many biologists and other scientists predict they will die too from the stress caused by the pollution.
Industrial causes of water pollution.
Industrial waste
Industries cause huge water pollution with their activities. These come mainly from:
Sulphur – This is a non-metallic substance that is harmful for marine life.
Asbestos – This pollutant has cancer-causing properties. When inhaled, it can cause illnesses such as asbestosis and some types of cancer.
Lead and Mecury – These are metallic elements and can cause environmental and health problems for humans and animals. It is also poisonous. It is usually very hard to clean it up from the environment once it gets into it because it is non-biodegradable.
Nitrates & Phosphates– These are found in fertilizers, and are often washed from the soils to nearby water bodies. They can cause eutrophication, which can be very problematic to marine environments.
Oils – Oils form a thick layer on the water surface because they do not dissolve in water. This can stop marine plants receiving enough light for photosynthesis. It is also harmful for fish and marine birds. A classic example is the BP oil spill in 2012 with killed thousands of animal species. Read more on this HERE
Oil Pollution by Oil Industires
Routine shipping, run-offs and dumping of oils on the ocean surfaces happen everyday. Oil spills make up about 12% of the oil that enters the ocean. Oil spills cause major problems, and can be extremely harmful to local marine wildlife such as fish, birds and sea otters and other aquatic life. Because oil does not dissolve, it stays on the water surface and suffocates fish. Oil also gets caught in the feathers of sea birds, making it difficult for them to fly. Some animals die as a result.
Other causes of water pollution.
Apart from the industrial causes of water pollution, as we saw in the previous page, here are some more:
Sewage and waste water
Everyday, we cook, do laundry, flush the toilet, wash our cars, shower and do many things that use water. Think about how we use water in schools, hospitals and public places.
Where do you think all the water, liquid waste, toilet and urine ends up? In many developed communities, this waste water and soluble waste (called sewage) is treated, cleaned and dumped into the sea or river. Even though they are treated, they are never the same as fresh water.
In some not-so-developed countries, the sewage is not treated, but quickly dumped into the sea or water bodies. This is VERY dangerous because they contaminate the environment and water bodies and bring many deadly diseases to us.
Septic Tanks
Every domestic (home) toilet is connected to septic tank usually located outside the house. Each time poop is flushed down the toilet, it goes into this tank, where the solid part is separated from the liquid part. Biological processes are used to break down the solids and the liquid is usually drained out into a land drainage system. From this stage, it can escape into the soil and nearby water bodies.
Ocean and marine dumping
Again, think of the rubbish we all make each day. Paper waste, food waste, plastic, rubber, metallic and aluminum waste. In some countries, they are deposited into the sea. All these waste types take time to decompose. For example, it is know that paper takes about 6 weeks, aluminum takes about 200 years and glass takes even more years. When these end up in the sea, they harm sea animals and cause a lot of water animal deaths.
Underground storage and tube leakages
Many liquid products (petroleum products) are stored in metal and steel tubes underground. Other sewage systems run in underground tubes. Overtime, they rust and begin to leak. If that happens, they contaminate the soils, and the liquids in them end up in many nearby water bodies.
Atmospheric
Atmospheric deposition is the pollution of water bodies caused by air pollution. Each time the air is polluted with sulphur dioxide and nitrogen oxide, they mix with water particles in the air and form a toxic substance. This falls as acid rain to the ground, and gets washed into water bodies. The result is that, water bodies also get contaminated and this affects animals and water organisms.
Effects of water pollution.
You will notice in the previous pages that water pollution is very harmful to humans, animals and water life. The effects can be catastrophic, depending on the kind of chemicals, concentrations of the pollutants and where there are polluted. Below, we shall see a summary of the effects of water pollution. (Make sure you see the factsheet page for some very unfortunate incidents of water pollution in recent time)
The effects of water pollution are varied and depend on what chemicals are dumped and in which locations.
Many water bodies near urban areas (cities and towns) are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by manufacturing industries, health centers, schools and market places.
Death of aquatic (water) animals
The main problem caused by water pollution is that it kills life that depends on these water bodies. Dead fish, crabs, birds and sea gulls, dolphins, and many other animals often wind up on beaches, killed by pollutants in their habitat (living environment).
Disruption of food-chains
Pollution disrupts the natural food chain as well. Pollutants such as lead and cadmium are eaten by tiny animals. Later, these animals are consumed by fish and shellfish, and the food chain continues to be disrupted at all higher levels.
Diseases
Eventually, humans are affected by this process as well. People can get diseases such as hepatitis by eating seafood that has been poisoned. In many poor nations, there is always outbreak of cholera and diseases as a result of poor drinking water treatment from contaminated waters.
Destruction of ecosystems
Ecosystems (the interaction of living things in a place, depending on each other for life) can be severely changed or destroyed by water pollution. Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans in many ways.
Prevention of water pollution.
Dealing with water pollution is something that everyone (including governments and local councils) needs to get involved with. Here are a few things you can do to help. Learning about the issue (like you are doing) is the greatest and most important step to take. Here are a few more:
You can help
Never throw rubbish away anyhow. Always look for the correct waste bin. If there is none around, please take it home and put it in your trash can. This includes places like the beach, riverside and water bodies.
Use water wisely. Do not keep the tap running when not in use. Also, you can reduce the amount of water you use in washing and bathing. If we all do this, we can significantly prevent water shortages and reduce the amount of dirty water that needs treatment.
Do not throw chemicals, oils, paints and medicines down the sink drain, or the toilet. In many cities, your local environment office can help with the disposal of medicines and chemicals. Check with your local authorities if there is a chemical disposal plan for local residents.
Buy more environmentally safe cleaning liquids for use at home and other public places. They are less dangerous to the environment.
If you use chemicals and pesticides for your gardens and farms, be mindful not to overuse pesticides and fertilizers. This will reduce runoffs of the chemical into nearby water sources. Start looking at options of composting and using organic manure instead.
If you live close to a water body, try to plant lots of trees and flowers around your home, so that when it rains, chemicals from your home does not easily drain into the water.
Governments, local councils and laws
Many governments have very strict laws that help minimize water pollution. These laws are usually directed at industries, hospitals, schools and market areas on how to dispose, treat and manage sewage. Do you know the laws in your country? This is the time to find out.
In many developed cities, waste or sewage treatment is very efficient, and designed to minimise pollution of water bodies. (The next page explains that process)
There are also lots of organizations and groups that help educate people on the dangers of water pollution. It is always great to join these groups, because they regularly encourage other members of their communities to have a better attitude towards water.
Liquid Waste (Sewage/Wastewater) Treatment
Wastewater (liquid waste) from flushing the toilet, bathing, washing sinks and general cleaning goes down the drain and into a pipe, which joins a larger sewer pipe under the road. The larger pipe also joins a major pipe that leads to the treatment center.
- STAGE ONE: SCREENING
Screening is first stage of the wastewater treatment process. Screening removes large objects like, diapers, nappies, sanitary items, cotton buds, face wipes and even broken bottles, bottle tops, plastics and rags that may block or damage equipment.
Special equipment is also used to remove grit that gets washed into the sewer. - STAGE TWO: PRIMARY TREATMENT
This involve the separation of organic solid matter (or human waste) from the wastewater. This is done by putting the wastewater into large settlement tanks for the solids to sink to the bottom of the tank. The settled solids are called ‘sludge’. At the bottom of these circular tanks, large scrappers continuously scrape the floor of the tank and push the sludge towards the center where it is pumped away for further treatment. The rest of the water is then moved to the Secondary treatment.STAGE THREE: SECONDARY TREATMENT
The water, at this stage is put into large rectangular tanks. These are called aeration lanes. Air is pumped into the water to encourage bacteria to breakdown the tiny bits of sludge that escaped the sludge scrapping process.STAGE FOUR: FINAL TREATMENT
Next the ‘almost’ treated wastewater is passed through a settlement tank. Here, more sludge is formed at the bottom of the tank from the settling of the bacterial action. Again, the sludge is scrapped and collected for treatment. The water at this stage is almost free from harmless substances and chemicals. The water is allowed to flow over a wall where it is filtered through a bed of sand to remove any additional particles.The filtered water is then released into the river.
*This description is not a standard for all treatment plants, but the principle is similar.
Now let us see some stunning facts and disasters from water pollution in recent time.
Important facts of water pollution.
40% of America’s rivers and 46% of America’s lakes are too polluted for fishing, swimming, or aquatic life.
1.2 trillion gallons of untreated sewage, storm water, and industrial waste are discharged into US waters annually.
Source: Combined Sewer Overflow (CSO), http://www.epa.gov/nrmrl/wswrd/wq/
stormwater/cso.pdf
Polluted drinking waters are a problem for about half of the world’s population. Each year there are about 250 million cases of water-based diseases, resulting in roughly 5 to 10 million deaths.
Source: Top Facts about Pollution., http://theexpeditionproject.com/info/top-enviro-stuff/522-top-facts-about-pollution
In 2010, there was a huge oil spill in America by BP. Of the 400 miles of Louisiana coast, approximately 125 miles have been polluted by the oil spill. Over 1,000 animals (birds, turtles, mammals) have been reported dead, including many already on the endangered species list. Of the animals affected by the spill that are still alive only about 6% have been reported cleaned, but many biologists and other scientists predict they will die too. In November 2012, BP agreed a settlement with the US government worth $4.5bn, including a $1.26bn criminal fine.
Source: River Pollution., http://prezi.com/q1rbkwvv6xqi/river-pollution/
In April 2010, The Transocean Oil Rig exploded, killing 11 workers. The disaster also damaged the Gulf of Mexico coast causing one of the biggest environmental disasters in US history. In January 2013, the company paid $400m (£248m) in criminal penalties and a $1bn civil fine after pleading guilty to violating the Clean Water Act.
Source: http://www.bbc.co.uk/news/science-environment-13123036
In developing countries, 70% of industrial wastes are dumped untreated into waters where they pollute the usable water supply.
Source: WWAP
How the world uses freshwater:
• about 70 percent for irrigation
• about 22 percent for industry
• about 8 percent for domestic use
Source: World Water Assessment Programme (WWAP)
27% of the urban population in the developing world do not have piped water in their homes. Source: UNESCO
A lack of safe water and sanitation in cities leads to cholera, malaria and diarrhoea. Source: WHO
In March 2011, a very powerful earthquake in the sea (tsunami) hit the Japan coast. The sea level rose and water came into the land, damaging 4 of the 6 reactors in the Fukushima Daiichi Nuclear Power Plant.
World Health Organisation (WHO) experts confirm that there is slight increased risk of some cancer types for some people who were exposed to the radiation. These included people living in that area and some workers at the plant. Below is a peice of the information given on BBC website:
“The biggest lifetime risks were seen in those exposed as infants, compared with children or adults.
For girls exposed to radiation from the accident as infants, the report found a 4% increase above the lifetime expected risk of solid tumours and a 6% increase above that expected for breast cancer.
Boys exposed as infants are expected to have a 7% increased risk of leukaemia above that expected in the normal population.
The biggest risk was seen in thyroid cancer, which for infant girls could be up to 70% higher than expected over their lifetime.”
BBC Website: /news/health-21614722
More Water Pollution Facts Here
SOURCES (Some of our research on this lesson included the following)
1. Natural Resources Defense Council, Water. www.nrdc.org/water/
2.Watercare, Au. Water Pollution Fact, Sheet 1 PDF
3. Rio’s Olympic waters blighted by heavy pollution. By Julia Carneiro, BBC Brasil, Rio de Janeiro
4. UK Rivers Network, www.ukrivers.net/pollution.html
5. Accidental discharges of oil.www.oils.gpa.unep.org/facts/oilspills.htm
6. EPA, Collecting Used Oil for Recycling/Reuse. www.epa.gov/osw/wycd/downloads/recy-oil.pdf
7.Managing Water under Uncertainty and Risk. The UN World Water Development Report 4 VOL1
8. Lesson 4, Water Pollution www.water.me.vccs.edu/courses/env227/lesson4_print.htm
9. BBC News, www.bbc.co.uk/news/world-latin-america-25686805
10. Accidental discharges of oil; www.oils.gpa.unep.org/facts/oilspills.htm