Causes Of Water Pollution

The causes of water pollution are numerous.

All these polluting factors change the physical, biological and chemical conditions of the water source, harmfully disturbing the ecological balance previously achieved in the water body.

Below, we discuss some of the main water pollution causes today.


Causes of water pollution 1:
Sewage and wastewater

With billions of people on the planet (and the number is increasing), disposing of sewage and waste water is a major problem. The treatment capabilities for sewage and waste water is still lacking in many parts of the world, especially in the poorer and undeveloped countries. As a result, large amounts of sewage-polluted untreated water are discharged into water bodies every day, contaminating water that is used for drinking and other uses. As such sewage and wastewater is still one of the major causes of water pollution in the world today.

According to the Natural Resources Defense Council, about a million people all over the world do not have access to clean water. And this situation is worsened by the effects of global warming – the droughts are drying up whatever little supplies of fresh water there are in some areas, while floods in other areas are causing untreated sewage to overflow into fresh water bodies, or even out onto streets and into homes in very severe cases.

In turn, water contaminated with untreated sewage and other waste is the cause of water-bourne diseases like Amoebiasis (protozoal infection), Tapeworm (or Taeniasis; parasite infection), E Coli infection (bacterial infection) and Hepatitis A (caused by viral infection), etc.

Diarrhea is also a common effect of consuming contaminated water. According to a report by the World Health Organization in 2008 titled “Safer Water, Better Health”, about 1.5 million people worldwide die of diarrhea (including cholera, dysentery and typhoid) caused by using or drinking contaminated water every year, with about 1.4 million of these deaths involving children.


Causes of water pollution 2:
Pollution from farms

Many causes of water pollution, such as manure and chemical fertilizers, as well as sewage and farm livestock waste, pollute the water bodies through Eutrophication. These water pollutants actually contain much nutrients that promote the growth of micro-organisms like algae and bacteria that break down decaying matter. The decay of the organic matter from the fertilizers and sewage uses up oxygen in the water.

At the same time, the excessive algae growth at the surface of the water blocks out sunlight to other water plants within the water. As a result, oxygen dissolved in the water does not get replenished. Fishes and other water life in that area suffocate to death, leading to areas known as dead zones.

Eutrophication can extent over large areas in the water bodies. For example, based on a publication by the International Lake Environment Committee, “Survey of the State of the World’s Lake (1988 – 1993), it was found that 54% of the lakes in Asia have been affected by Eutrophication, while 53 % of the lakes in Europe, 41% in South America, 48% in North America, and 28% in Africa have been similarly impacted.

In addition to pollution via eutrophication, chemicals in synthetic fertilizers and pesticides that leech from farms are also harmful to humans and other living organisms in the long-run. Read about the dangers of pesticides and fertilizer pollution.


Causes of water pollution 3:
Mining

Mining is another of the major causes of water pollution. Mining activities consumes large amounts of water in processing the ores from the mines. In addition, mining also results in large amounts of chemicals, heavy metals soil and other waste rock materials contaminating and polluting the water bodies. Let me elaborate a bit more.

During mining, large quantities of ore (rocks containing valued substances like metals or coal) are excavated from the mines. The ore comprises a large proportion of waste rock (rocks not containing the desired substance) and only a very small proportion of the desired substance.

For example, only 1% of copper ore contains copper; the rest of the ore is waste rock. To extract the desired substance from the ore, the ore is crushed finely (into what is known as tailings) and then processed with water and chemicals to extract the desired substance.

As a result of the mining activities, large amounts of waste rock and tailings are generated. According to the Safe Drinking Water Foundation, the Canadian mineral industry produces a million tones of waste rock and 950 thousand tones of tailing every day. That amount adds up to 650 million tones of mining waste every year.

These mining wastes are often left in piles above ground. Exposed to the elements, harmful materials from the mining waste are readily leeched out and these materials drain freely into water bodies nearby. Other than the excavated rocks, leeching could also take place from exposed underground mines.

The materials leeched from mining sites include heavy metals eg. arsenic, cadmium and lead. These heavy metals are extremely harmful to humans as well as other living things. Besides heavy metals, sulphide minerals that are present in the mining rocks also leech (through a process known as acid rock draininge) from the mining sites when exposed to water and oxygen. The sulphuric acid formed creates acidic conditions that accelerate the leeching of heavy metals from the rocks. Chemicals from the processing of ores (e.g. cyanide) used by miners may also be leeched from mining sites.

All these harmful materials, constituting causes of water pollution, are usually carried off by rainwater into nearby surface drainage systems, underground water supplies, streams or rivers. In the water bodies, these causes of water pollution degrade the quality of the water, and threaten the lives of living organisms, including humans, dependent on the water for survival.

Besides the leeching of harmful substances from mining activities into water bodies, mining activities also cause soil erosion. Mining or mining related activities (e.g. construction of roads, etc) often destabilize the ground structures in the area, causing soil erosion to take place more frequently, especially when the necessary prevention and control measures are lacking. Large amounts of soil are then washed off into the water bodies, clogging up the river-beds and burying some of the organisms in the water bodies.


Causes of water pollution 4:
Oil pollution

Water bodies are sometimes polluted by oil run-offs from land-based automobiles, oil discharge by vessels and other sea-based modes of transport, and accidents like oceanic oil spills from vessels or off-shore oil rigs. Such water pollution by oil usually occur on a larger scale in the seas and oceans. Read more about oil spills as one of the major types of pollution in the sea.


Causes of water pollution 5:
Chemical and industrial waste

One of the major causes of water pollution is the effluents discharged from industries (e.g. chemical plant, pharmaceutical factory, etc).

When factories and manufacturers pour their chemicals and industrial wastes into streams, rivers or the seas untreated, the water becomes contaminated and poisonous.

The contaminated water threatens the health of human beings, directly through contact with or consumption of the contaminated water, or indirectly through the use of contaminated water in irrigating farm lands or rearing of livestocks. The contaminated water also threatens the ecosystems in and around the water bodies, threatening the survival of fish and water plant populations dependent on the water bodies.

For example, according to the Institutional and Economic Instruments for Sustainable Water Management in the Meditteranean Region (INECO), the Seybouse River Basin (located in northern Algeria) receives about 4.5 million cubic metre of industrial discharge per year from its city’s industries located along the river banks. And yet, the Seybouse River is an important water source for agriculture in Algeria.


Read more about the causes of water pollution:

Read more about the ways to stop water pollution:

  • ways to stop pollution (in the sea)
  • how to stop water pollution
  • how to stop pollution in water
  • water pollution solutions for the household
  • solutions to water pollution globally


Most appalling water pollution scenes

If you have ever witnessed water pollution scenes that are either disturbing or heart-wrenching, share photos of these pollution scenes with our readers, so that the photos may open the eyes of those who are still unmoved about the environmental problems of the world today.


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