What is water pollution?
The contamination of water of rivers, lakes and ponds etc with unwanted and harmful substances is called water pollution.
What are water pollutants?
The unwanted and harmful substances which make the water contaminated are called water pollutants.
Major water pollutants:
The major pollutants which cause water pollution are sewage, fertilizers, pesticides and industrial wastes. Hot water from power plants and industries is also considered a pollutant.
Sources of water pollution:
There are several sources of water pollution. They are as follows.
1. Dumping of untreated sewage into rivers causes water pollution.
2. Use of fertilizers in agriculture causes water pollution.
3. Use of pesticides in agriculture causes water pollution.
4. Discharging of untreated industrial wastes into rivers and lakes causes water pollution.
Harmful effects of common pollutants
1. Untreated sewage from homes
The waste water containing human excreta and carried in sewers or underground pipes is called sewage. Sewage contains several harmful microorganisms such as bacteria, protozoa, fungi, viruses and parasites which cause serious diseases in humans. The drinking of river water contaminated with can cause water borne diseases such as typhoid diarrhoea dysentery and jaundice.
2. Fertilisers used in agriculture
The water pollution caused by fertilizers used in agriculture decreases the amount of dissolved oxygen in water bodies and leads to the death of fish and other aquatic animals.
3. Pesticides used in agriculture
The farmers use toxic chemicals called pesticides on standing crops in the fields to protect them from pests and diseases. Some of these pesticides dissolve in rain water and run into rivers, lakes and ponds and pollute their water. This poisonous pesticides kill the aquatic animals like fish. The non biodegradable pesticides in the polluted water are absorbed by aquatic plants. This aquatic plants are then eaten by aquatic animals like fish. During this pesticides are transferred from aquatic plants to fish and when a person eats the fish grown in this polluted water the pesticides present in the fish enter his body and damage his health.
4. Untreated industrial wastes
The toxic chemicals present in industrial wastes are the compounds of harmful metals such as Mercury, lead, arsenic, nickle and cadmium. The water of rivers and lakes polluted with toxic industrial waste can kill fish and other aquatic animals which live in this river or lake. The toxic metal compounds present in this polluted water can enter the human body through the food chain like eating fish grown in this polluted water. They can damage our nervous system and cause diseases such as blood poisoning and cancer.
Harmful effects of water pollution
The various harmful effects of water pollution are as follows.
1. Drinking of water polluted with untreated sewage can cause diseases such as Cholera, Typhoid, Diarrhoea, Dysentery and Jaundice.
2. Water of rivers and lakes polluted with fertilizers can cause the death of aquatic animals like fish.
3. Water of rivers and lakes polluted with pesticides can kill aquatic animals like fish and also damage our health through food chain.
4. Water of rivers and lakes polluted with toxic industrial waste kills the aquatic animals like fish damages our nervous system and causes diseases such as blood poisoning and cancer.
Controlling water pollution
The various ways of controlling our minimising water pollution are as follows.
1. Sewage should be treated properly at sewage treatment plants to make it harmless before discharging it into nearby rivers.
2. Farmers should use correct amounts of fertilizers and pesticides in the fields so that excessive amounts of these harmful agricultural chemicals are not washed into the rivers, lakes and ponds.
3. All the industries should treat the toxic wastes produced by them suitably to make them harmless before discharging them into rivers.
4. Water pollution prohibition laws which exist for the industries producing toxic chemical waste should be implemented strictly by the concerned authorities.
5. Garbage or household wastes should not be thrown into open drains, rivers, lakes or ponds. Dead bodies should not be thrown into rivers. Dead bodies should be cremated or buried properly to prevent pollution of water.
6. People should be made aware of the harmful effects of water pollution so that they may co-operate and help in preventing it.
Conservation of water
As there is scarcity of fresh water in our country, we should conserve water by using it carefully, economically and avoiding is wastage. The various ways to conserve water or save water at home are as follows.
1. Turn off the tap immediately after use. Get the leaking taps repaired immediately.
2. Brush your teeth by filling water in a mug. Leaving the tap running while brushing the teeth may waste several litres of water.
3. Wash the utensils by filling water in a basin and not under the running tap.
4. Use water from washing rice, pulses, vegetables and fruits after wearing the plants at home.
5. Do not use the full flash from the cistern in the toilet when a half flush is sufficient.
Potable Water
The water which is safe for drinking is called potable water.
Ways to make water potable
The various methods which can be used to make water potable are as follows.
1. Water can be filtered to make it potable by using porcelain candle filter or electric water filter.
2. Water can be made absolutely safe for drinking by boiling for sufficient time.
3. Chlorination is a commonly used chemical method for purifying water.
Pollution of river Ganga
The water of river Ganga has been highly polluted because the villagers, town, and cities which are situated on the banks of this very long river through large quantities of garbage, untreated sewage, toxic industrial vestige, dead bodies of infants and many other harmful things directly into the river.
GANGA ACTION PLAN
WWF has found that Ganga is one of the most polluted rivers in the world. At present, the pollution level in many stretches of river Ganga is so high that no aquatic animals like fish etc can survive in it. The river is said to be dead at those places. An ambitious plan to cleanse the highly polluted river Ganga and save it, was launched in 1985. It is called Ganga action plan. The aim of Ganga action plan is to reduce the pollution level in the water of river Ganga. However, the increasing population and industrialization has already damaged this mighty and sacred river beyond repair.
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