Water pollution

Addition of harmful substances like chemicals, or waste material in water sources causes water pollution.

Main reason behind water pollution is addition of unwanted substance to water resources. Removal of important substances from water resources and change in temperature of water resources.

Sources of water pollution

Rain water running from ground carries chemicals like weedicides, pesticides and minerals into river causing water pollution. If such water mixes with ground water it pollutes groundwater. Moreover, water weeds, algae, dead animals in water, animal waste, ashes from forest fires, sulphur compounds released from earthquake also causes water pollution. When such minerals enter into river water, it gets rich in minerals which further allows the growth of water bodies like algae. Algae appears as green layer on top of the river water. More the mineral greater will be the growth. However, growth utilise oxygen dissolved in water, thereby, reducing the quantity of oxygen in water. This process is known as Eutrophication. This causes severe effect on aquatic plants and animal thereby leading to death.



Other than these sources of water pollution, there are few manmade sources.

• Domestic sewage: It is the waste water from kitchen, bathrooms and toilets, etc. This water contains suspended impurities, organic waste like food and vegetable waste, phosphate mix into water sources, thereby, causing water pollution.
• Industrial waste: Industrial waste if let into sources of water, it causes water pollution. This is because industrial waste contains acids, alkalis, toxic metals like arsenic, oil grease, dyes, pesticides, radioactive materials and waste released from construction industries like gypsum, cement, metals and poisonous solutions.
• Radioactive waste: It contains waste from industries, medical, atomic power plants and waste from scientific processes
• Agricultural runoff: Use of chemicals during cultivation in large quantity pollutes ground water as well as surface water.
• Oil spills: Oil do not mix with water, however, accidental release of oil breaks the contact of air or oxygen with water. This causes threat to aquatic life.
• Thermal pollution: Thermal power plants and other industries use river water for cooling purpose and, then it release hot water into the river causing thermal pollution. Change in temperature of water increases and creates threat to aquatic life.

Till now we have talked about water and sources of water pollution. If such polluted water is used for drinking purposes then it can cause disease in human body. Hence, there is need of purification of water. Let’s now speak about methods to purify water.

• Household filters are most popular method of water purification. It is consist of candle type filter or assembly filters, which restrict impurities and allow passage of water. Hence, we get pure water.
• Boiling also an effective method. Boiling kills the germs present in water.
• Chlorination: Addition of chlorine containing liquids, tablets or bleaching powder in water. However, these chemicals must be used in very appropriate quantity, else it will cause problems in human body.
• Sewage treatment plants: These are used to treat industrial waste water before releasing it into water.
• Treatment by municipal corporation before supplying it to households is also important.

Keywords: Eutrophication, Thermal pollution