Water of Class 7
Water management is preventing wastage of water, using water carefully and recharging ground water.
Water management can be done by :-
- Repairing leaking pipes and taps.
- Not wasting water during brushing teeth, shaving, bathing, washing clothes and during other activities.
- Rainwater harvesting.
- By drip irrigation of plants.
An undesirable change in the physical, biological or chemical qualities of water that adversely affects the aquatic life, and makes water less fit or unfit for use, is called water pollution.
Sources of Water Pollution:
Pure water found in nature cannot retain its purity for a long period and sooner or later it becomes impure. Some of the major sources responsible for polluting water are as follows –
- Sewage: Sewage is a kind of fluid waste, which contains human excreta, waste water from bathrooms and kitchens, paper, pieces of clothes and other waste materials. In India sewage is generally allowed to flow towards nearby pond, lake or river and this causes heavy water pollution.
- Municipal waste: Municipal waste or city garbage includes waste from kitchen, papers, rags, old shoes, polythene bags, bottles, toothpaste tubes and many such things. Many times this waste is dumped in water bodies or the garbage is mixed to water sources along with rain water and this causes water pollution. Highly infected hospital waste also becomes the part of municipal waste in most of the cities and towns.
- Water pollution by animals, human beings and dead bodies: Animals found in villages, towns and cities like cows, buffaloes, dogs, pigs, etc., bathe in water sources and pollute them. Washing clothes in water sources, washing trucks, buses and other vehicles by human beings causes water pollution.
- Industrial effluents: Almost all industries use water in various processes. After its use water loaded with impurities is allowed to flow outside the industry's campus. This fluid is known as industrial effluent. This effluent reaches water sources and pollutes them. Industrial effluents contain many inorganic and organic pollutants, such as metals, oil, grease, plastic, phenol, toxins etc. Most of these are not easily degraded and thus cause heavy pollution in water bodies. Several metals like copper, chromium, zinc, cadmium, lead, mercury etc. are. toxic in nature and have fatal effects on animals and vegetation.
- Oil slick: Petroleum is one of the major pollutants which pollute sea water. Several countries of the world are producing petroleum and they send it to other countries through sea routes. Whenever an oil tanker meets with an accident, oil spreads over water surface and causes heavy water pollution.
Control of Water Pollution:
- Septic tanks should be used for each house.
- Rivers, lakes etc. should not be used for bathing and washing purposes.
- Too much use of pesticides which are not degradable should be avoided. These are highly toxic substances.
- Water reuse has a special significance in mining and similar industries where the wateravailability is less. These efforts will save the fresh water from being polluted.
- Waste water treatment techniques should be applied before the polluted water enters a river, lake or pool.
- Distribution of water on earth
- Necessity Of Water
- Occurrence Of Water
- Physical Properties Of Water
- Chemical Properties Of Water
- Action Of Water On Metals
- Action Of Water On Non- Metals
- Tests Of Water
- World water day
- Water Cycle
- Depletion of water table
- Water management
- Mind map
- Exercise - 1
- Exercise - 2
- Exercise - 3
- Exercise - 4