Causes of water pollution

Water pollution is a critical environmental issue that affects humans, animals and all forms of life. This chapter explains the causes of water pollution in detail, giving a comprehensive understanding of the subject.

Understanding water pollution

Water pollution occurs when harmful substances are added to water bodies such as rivers, lakes and oceans, making the water unsuitable for drinking, swimming, cooking and other activities. Polluted water is not only harmful to humans but also to the entire ecosystem.

Major causes of water pollution

1. Industrial waste

Industries release pollutants directly into water bodies without proper treatment. This waste contains lead, mercury, sulfur, nitrates and other harmful chemicals that can cause serious damage to the environment.

For example, a factory located near a river that releases untreated waste will cause considerable pollution downstream.

2. Sewage and wastewater

Sewage and wastewater from households can also cause water pollution. It contains organic pollutants that get absorbed into water bodies.

For example, untreated sewage can cause waterborne diseases such as cholera and typhoid.

The chemistry behind the decomposition of sewage:

    (CH2O)n + O2 → CO2 + H2O + Energy
    (CH2O)n + O2 → CO2 + H2O + Energy

3. Agricultural runoff

Chemicals used in agriculture, such as pesticides and fertilizers, often run off into nearby water bodies, causing nutrient pollution. This can lead to increased algae growth, known as eutrophication.

Eutrophication can cause dead zones, where aquatic life cannot survive due to decreased oxygen levels.

4. Oil spill

An oil spill is the accidental release of liquid petroleum into large bodies of water. It can occur during the transportation of oil or as a result of accidents on oil rigs.

The oil forms a layer on the surface of water, affecting marine animals and birds that come in contact with it.

5. Marine dumping

Throwing waste materials directly into the sea is another important cause of water pollution. This includes garbage, plastic, and heavy metals.

For example, large amounts of plastic waste can cause the death of marine creatures that consume it.

6. Radioactive substances

Radioactive substances released from nuclear power plants, nuclear weapon tests, and disposal of nuclear waste can contaminate water bodies.

Such pollution poses long-term environmental and health hazards.

Chemical equation for radioactive decay:

    U-235 → Th-231 + 4/2 He (Alpha Decay)
    U-235 → Th-231 + 4/2 He (Alpha Decay)

7. Urban runoff

Urban runoff comes from urban structures including roads, bridges and buildings, carrying pollutants such as oil, heavy metals and debris into water bodies.

This type of runoff often occurs after a rain storm, when water carries pollutants off impervious surfaces.

8. Chemical contaminants

Chemicals such as mercury and lead can enter water bodies through industrial processes, mining, and even household products such as batteries and paint.

These toxins accumulate in biological tissues and can cause serious health problems.

Effects of water pollution

Water pollution affects both aquatic ecosystems and human health. It disrupts the food chain, harms water-dwelling animals and plants, and causes a number of health problems for humans such as diarrhea, respiratory infections, and even cancer.

Fish and other aquatic organisms can ingest pollutants, which then affect larger animals, including humans, who eat them.

Conclusion

Water pollution is a complex problem that has many causes, including industrial emissions, sewage, agricultural runoff, and more. Understanding these causes can help us take action to prevent it and protect this vital resource.

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