“Destabilization of the balance of the atmospheric composition.
“It is an unstable change in the composition of the environment due to its physical, chemical and biological changes, which is harmful for human life and other animals living on the earth.”
Types Of Pollution:
i) Air pollution
ii) Water pollution
iii) Land pollution
iv) Noise pollution
v) Industrial pollution
vi) Commercial or domestic sector pollution
vii) Chemical pollution
viii) Radioactive pollution (contamination)
Causes of Pollution
The ultimate cause of pollution is human activity itself. Pollution is a human contribution to nature. Science has evolved technologies and technologies have helped the human welfare. In the process, the pollution has been a part of technology and therefore a part of human miseries.
Human activities mainly include:
Industries for various human needs – directly and indirectly
Agriculture for food production and industrial needs
Health care for health of human beings and animals
Transport for mobility of human beings
Dwelling for settlement in city or villages
Energy for various direct human needs and industrial needs.
Pollutants are those substances which alter the natural composition of the atmosphere or destroy it to harmful level.
Types Of Pollutants:
1. Primary Pollutants
Primary pollutants are those substances which are directly produced by a process. These are:
ix) Sulphur oxides
x) Nitrogen oxides
xi) Carbon monoxide (CO)
xii) Carbon dioxide
xiii) Volatile organic compounds (VOC), such as hydrocarbon fuel vapours and solvents
xiv) Particulate matter (PM), such as smoke and dust.
xv) Metal oxides, especially those of lead.
xvi) Chlorofluorocarbons (CFCs)
xvii) Ammonia (NH3)
xviii) Garbage, sewage and industrial wastes.
2. Secondary Pollutants
Secondary pollutants are those pollutants which are not emitted. Rather, they form in the air when primary pollutants react or interact.
i) Ground level ozone (O3)
ii) Nitrogen dioxide
iii) Peroxyacetyl nitrate (PAN)
Effects Of Pollution:
1) Air Pollution: Irritation of eyes, nose, mouth and throat, Increased respiratory disease, Cancer, Reduced lung functioning, Premature death. Acid rain, Ozone,
2) Water Pollution: Waterborne diseases such as; Typhoid, Hepatitis, diarrhoea, vomiting, and stomach aches, death of aquatic animals, May disrupt photosynthesis in aquatic plants
3) Soil Pollution: Causes cancers including leukaemia, developmental damage to the brain, kidney damage; depression of the central nervous system, Also causes headaches, nausea, fatigue, eye irritation and skin rash, Contamination of crops, reduce crop yields.
“The presence of undesirable substances into fresh and natural water which cause harmful diseases in human beings as well as aquatic life is called water pollution.”
Types Of Water Pollution:
Following are the major types of water pollution.
i) Sea-water Pollution
ii) River water Pollution
iii) Land Water Pollution
Causes Of Water Pollution:
1) Pollution Through Domestic Activities:
Domestic activities pollute the water when following kinds of wastes are added.
i) Soap and detergents
ii) Chemicals used in the houses
iii) Waste from slaughter house
iv) Waste from hospitals
v) Waste from bakeries
vi) Human and animal faeces
vii) Waste food
2) Pollution Through Industrial Activities:
Industrial sector is a great source of pollution of water and air. Many industrial units produce waste materials in the shape of solids, liquids and gases. The industrial wastes are.
i) Poisonous gases
ii) Acids, bases and harmful salts
iii) Pesticides and plastics
iv) Radioactive wastes
v) Toxic wastes from fertilizer factories
vi) Wastes from chemical factories
Water Pollution In Pakistan:
In Pakistan people do not take pain to dispose the waste materials in a proper way. Instead of dumping wastes in the drums and places meant for them they freely throw these into the water drains.
Water pollution is very prominent and widespread as a result of urban and industrial activity. Sewage waste from cities and industrial waste are the main factors of water pollution. Many other kinds of wastes which pollute water are from agricultural lands which contain pesticides, waste foods, fertilizers and animal excreta. Wastes from power plants contain radioactive materials, hot water and minerals which also pollute the water. Soaps, detergents, human excreta, animal faeces, wastes from slaughter houses, disease causing micro-organisms from patients and chemicals etc. are drained into water which causes massive water pollution.
Two Important Industries Of Pakistan Causing Water Pollution:
1) One of the biggest sources of water pollution is the tanning and leather industry. The industry uses toxic chromium metal and many other toxic substances/chemicals. These toxins are released in natural waters. Effluent of this industry has polluted ground water and water of nearby rivers. This industry is frequent in Kasur and Sialkot area.
2) Pesticide industry in Kala Shah Kaku near Lahore releases huge quantity of acids, pesticides and other dangerous wastes. These wastes are getting entry into a stream flowing nearby. The water of the stream is dangerously polluted. This water ultimately goes to the rivers.
i) Bacteria, viruses, protozoa and worms are carried in polluted water. The diseases caused by them are as under:
a) Bacteria: Typhoid, cholera, Dysentery, enteritis.
b) Viruses: Hepatitis, Polio, Viral enteritis.
c) Protozoa: Amoebic dysentery, diarrhoea.
d) Parasitic worms: Schistostomiasis
ii) It causes death of aquatic animals.
iii) It decreases the fertility of the soil and results in low production.
Methods To Control Water Pollution:
Different methods can be used to control water pollution.
i) The whole sewage waste should be dumped after any treatment.
ii) Sewage treatment plants should be installed in cities.
iii) The sewage waste must not be drained in river to save water from pollution.
iv) Industrial waste should be treated before reaching natural water.
v) Industries should be established away from cities and rivers.
vi) Nuclear dumping in oceans should be banned.
vii) Modern scientific methods should be used in agriculture.
It is the process of destruction of the forests.
Causes Of Deforestation:
A number of agents are responsible for removal of forests. These are fires. Droughts or animals. The principle agent of deforestation is man himself. Humans are cutting forests to colonize the forest areas or to prepare more agricultural lands or for getting food.
Effects Of Deforestation:
i) Deforestation has many bad effects on human life. With destruction of the forest the process of cleaning of air and production of oxygen is badly affected.
ii) Forests are major agents of evaporation and rainfall. With deforestation rainfall is decreased.
iii) With cutting of forests, pollution is increasing as the hazardous gases are not completely absorbed by plants.
iv) With deforestation carbon dioxide is increasing which is causing global warming.
v) With reduction in area of forest, soil erosion is taking place resulting in floods which destroy crops and human life.
vi) Deforestation has badly damaged wild life and reduced recreation sites.