Pollution means,any change in the properties of air ,water or land which have undesired effects on man or other living things or may have such effects in future.Human activities in the modern industrial world produce a large amount of wastes.Different gases (carbon dioxide,sulphur dioxide,carbon monoxide and oxides of nitrogen),smoke,useless particles and toxic water are released from factories and vehicles.Human excreta,left over food stuff and domestic trash is also included in wastes causing pollution.Fertilisers and pesticides are used to increase agriculture production.They are washed off by water or blown away with wind and cause environmental pollution.Any excess or waste substance that can cause pollution is called a pollutant.There are three types of pollution.
Air or Atmospheric Pollution:
Air is considered polluted when a change occurs in its composition or quality.This change in quality of the air is due to the addition of different gases,smoke and other particles.Some important resources of these materials are,Burning of fuels in factories,vehicles and fuel driven power stations.Materials released during the preparation of goods in the factories or coming out stacks of furnaces.Release of chlorofluorocarbons from spray cans and during the preparation of packing foam.Dust,chemical fertilizers and insecticides blown into the atmosphere by wind.Air pollution affects plant,animal and human life in many ways.Hydrocarbons,carbon monoxide,lead particles and asbestos fibres may cause cancer and respiratory and eye diseases.A brown coloured gas called nitrogen peroxide combines with some other gases in the presence of light and form a compound called smog.Smog causes lung diseases.Other than this,the things cannot be seen clearly.Excess of carbon dioxide in the atmosphere produces green house effects.Earth's temperature is said to be rising due to the green house effect.Sulphur dioxide and oxides of nitrogen in air cause acid rain,which damages plants,aquatic animals and buildings.
Water Pollution:
Water pollution is generally caused when industrial wastes,trash and sewage from cities is discharged into the water bodies like rivers,oceans,streams,lakes and ponds.Water pollution is a problem chiefly of industrialised countries but now a days many developing countries like Pakistan are also facing this problem.Heavy metals (lead,chromium and mercury)are produced as wastes in the leather,plastic,textile and other chemical factories.They get entry into the water bodies.When heavy metals and other toxic materials enter into bodies of living organisms,they may cause cancer and various other diseases.Sewage and domestic wastes contain left over food,detergents and human excreta.On entering into the water bodies they increase the concentration of salts and organic matter in water.This results in the decrease of amount of oxygen in water.Consequently,aquatic life(fish and other aquatic plants) is badly affected.Fishes have disappeared from Nallah Dek and river Ravi near Lahore(Pakistan) due to water pollution.In addition to the above effects,polluted water becomes unfit for drinking as well as for domestic and industrial use.Disease causing germs are another serious cause of water pollution.They cause cholera,typhoid and disease due to worms of digestive tract.Especially the children are affected by these diseases.Chemical fertilizers and pesticides sprayed on crops are washed off with rain water and enter into rivers,streams and underground water.Oil spills from oil tankers have dangerous effects on the life of marine plants and animals as they form thick layer of oil on the surface of sea water.In 17,July 2003 a Greek oil tanker Tasman Spirit met accident near Karachi (Pakistan) harbour and split up into two sections.About 20,000 tons of crude oil spilled into the sea,most of it reaching the Clifton beach Karachi.This oil spill badly affected coast line environment,marine life and recreational spots like Manora(Pakistan).Dumping of nuclear wastes into the sea or oceans may become another source of water pollution.
Land Pollution:
Municipal trash,sewage sludge,agriculture wastes and chemicals from industries are the major sources of land pollution in Pakistan and all over the world.Solid wastes are often disposed of either by burning in or dumping into the ground.From the environmental view point both these methods are not completely safe.Germs and toxic substances from heaps of trash enter into the environment or food by wind,water and flies.Waste polythene bags are not decomposed and are often seen flying in streets and open places.They also cause choking of drains.
Measures to Reduce Pollution:
Pollution and environmental degradation can only be prevented if individuals,society and government feel their responsibility.Everyone should be aware of and sensitive to the environmental problems.All should play an active role in the solution of these problems.Agriculture and industry are essential for economic development and better living but keeping pollution to the minimum level is also necessary,so that human beings,other organisms(plants and animals)and thus future generations live a healthy and happy life.We should:not throw waste articles here and there or into the water bodies,dispose of the things properly.Make minimum and only necessary use of resources,do not waste them.Prefer things that can be reused,materials can also be recycled.Throw domestic industrial and hospital wastes into air,land or water only after treating to make them harmless.The owners of industries and factories be bound to the measures that should minimize pollution.Implant more and more trees and should take care of them.Trees can make our environment clear and healthy every time.Because they produce oxygen every time,and oxygen is the basic need of human and animals.
No comments:
Post a Comment