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									Absolute Acaademy Of Advanced Studies
                               Expert Studies- Great Results

                        ENVIRONMENTAL ISSUES

An undesirable change in the physical, chemical or biological characteristics of air,
land, water or soil is called pollution. The agents responsible for this are called


Any undesirable change in the physical, chemical and biological characteristics of air
that exert adverse effects on human beings is included in air pollution.


   1.   Smoke from forest fire, volvano eruption
   2.   Decomposition of garbage producing unwanted gases
   3.   Burning of fossil fuels
   4.   Use of leaded petrol
   5.   Chemical industries like pesticides, fertilisers or fungicides.

Air pollutants can be Particulate pollutants like metal particles, dust, soot etc or can be
gaseous pollutants like CO, NO2, H2S etc.

Harmful effects:

CO: causes gidiness, headache, decrease in vision, asphyxia.

H2S: causes nausea, eye/ throat irritation

SO2: causes respiratory tract infections like asthma, bronchitis, cancer, emphysema

Methods to control air pollution:

   1. Electrostatic precipitator: it removes more than 99% particulate matter present
      in the exhaust from a thermal power plant. It is based on the colloidal nature of
      the unburnt carbon particles which can be coagulated by electric field.
   2. Scrubber: it is used to remove gases like SO2. Here the exhaust is passed
      through a spray of lime or water due to which gases like SO2 dissolve to form
      CaSO4 and sulphides.
   3. Catalytic converter: they are fitted into automobile for reducing emission of
      poisonous gases. As the gases like NO and CO passes through converter then
      Pt/Pd/Rh converts them to N2+O2 and CO2 respectively.

E-46, MAIN KHYALA ROAD, VISHNU GARDEN, NEW DELHI-18                   9891402133, 9953840650
Absolute Acaademy Of Advanced Studies
                              Expert Studies- Great Results
   4. Control of air pollution in Delhi: steps like coversion of entire fleet of public
      transport from diesel/ petrol to CNG for public transport. CNG is cheaper, burns
      more efficiently, can’t be adutrated and can not be siphoned off by thieves. Use
      of low sulphur diesel or petrol and phasing out the old vehicles as well as norms
      like Bharat II and EuroII helped at easing the pollution.


    it is the unwanted high level of the sound. It can cause sleeplessness, stress,
   increase in heart rate, damage to ear drum and breathing problems. It can be
   reduced by using acoustic material in the wall of the homes, silencers in the
   automobile and use of sound absorbing material.


   It is defined as the undesirable change in physical, chemical or biological properties
   of water that can affect human beings and domestic species.

   Water pollutants can be:

   1. Domestic sewage: it includes suspended solids like sand, slit or clay or colloidal
      materials like fecal matter, bacteria, paper or cloth fibres and dissolved
      materials like nitrates, ammonium phosphate, sodium or calcium salts.
   2. Agricultural run off: like fertiliser run off or pesticide run off.
   3. Industrial waste: includes chemical wastes like organic compounds
      (phenol/dyes) or inorganic ( heavy metals Pb, Cd, Hg) as well as physical
      pollutants like thermal waste water or oil spill.

   Domestic sewage:

   It includes everything that comes from a residential area to common public sewage
   system. It includes suspended solids, colloidal materials and dissolved materials. It
   also contain biodegradable organic wastes which are readily decomposed with
   decomposers which consumes a lot of oxygen hence rendering aquatic life to

   BOD: the amount of oxygen required for the complete microbial breakdown of
   biodegradable organic mater is called Biochemical Oxygen Demand. It is higher in
   more polluted water.

   Eutrophication: domestic sewage contains nutrients like nitrogen and phosphorus
   which favours the excessive growth of planktonic( free floating) algae called algal
   bloom. It causes deterioration of water quality and death of the fishes. Excessive
   growth of water hyacinth ( Eichhornia crassipes), which is the most problematic
   weed in the world is called terror of bengal, causes severe damage to water

E-46, MAIN KHYALA ROAD, VISHNU GARDEN, NEW DELHI-18                9891402133, 9953840650
Absolute Acaademy Of Advanced Studies
                             Expert Studies- Great Results
   Industrial waste: materials like DDT and Hg affect the living organisms following the
   pattern of biological magnification. Biological Magnification refers to increase in
   concentration of toxic materials at each trophic level of a food chain. E.g. Minamata
   disease is caused by consumption of mercury contaminated fish of Minamata bay
   which causes blurring of vision, mental disorders etc.

   High concentration of DDT disturbs calcium metabolism in birds which causes
   thinning of the egg shell and their premature breaking, ultimately causing decline in
   bird population.

   Case study of integrated waste water treatment:

   Done in the town of Arcata in California by biologists from Humboldt state university.
   They allowed water contaminated with heavy metals/ pollutants to flow through
   marshes over 60 hectares of marshland which was seeded with bacteria, algae,
   fungi etc which neutralised and assimilated the pollutants. The naturally purified
   water is then allowed to flow out.


   Solid wastes are the discarded solid materials produced due to activities of human
   which include municipal waste, hospital waste, agriculture waste etc. some wastes
   are biodegradable while others non-biodegradable. While electronic wastes also
   called e-waste, are generated in developed countries and exported to developing
   countries including India where metals like gold, nickel, silicon, copper and iron
   were recovered during recycling. During this process, the workers are exposed to
   toxic substances.

   Case study of plastic waste: In Bangalore, a plastic sack manufacturer, Ahmed Khan
   developed POLYBLEND which is a fine powder of recycled modified plastic.
   Polyblend when mixed with bitumen helps in increasing the road life by three times.

   Agrochemicals and their effects:

   Pesticides and fertilisers are two agrochemical pollutants which reduces soil
   productivity by decreasing its bacterial population. It reduces soil texture, increases
   salt concentration and fertilisers washed out to water bodies causes eutrophication.

   Case study of organic farming: Ramesh Chandra Dagar, from Sonipat, developed
   integrated organic farming which includes bee keeping, dairymanagement, water
   harvesting. Composting and agriculture which support each other.Dung is used in
   place of fertilisers and crop waste are used to create compost which can be used as
   natural ferilisers.

E-46, MAIN KHYALA ROAD, VISHNU GARDEN, NEW DELHI-18                9891402133, 9953840650
Absolute Acaademy Of Advanced Studies
                             Expert Studies- Great Results
   Radioactive waste: nuclear energy is highly productive but may cause serious
   problems. It may result into radiation leakage or radioactive waste production. This
   nuclear waste damage biological organism and cause mutation.


   The phenomenon of keeping earth warm due to the presence of certain gases in the
   atmosphere is called green house effect. Gases like CO2, CH4, N2O, CFC allow the
   solar radiations to enter but prevent escape of heat radiations of longer wavelength.
   So they are called green house gases. They are so used for growing tropical plants
   in temperate regions. Due to pollution, ever rising levels of CO2 has caused increase
   in the green house effect due to which average temperature of the earth is


   It refers to increase in level of green house gases in the atmosphere leading to
   trapping of greater heat radiations leading to global warming. The average
   temperature of earth has increased by 0.6*Cin last three decades. This will lead to
   increased melting of polar ice caps which may increase water sea level due to which
   many coastal areas have danger of getting submerged.

   Control of global warming:

   1.   By reducing deforestation
   2.   Planting trees
   3.   Slowing down the growth of human population
   4.   Reducing the emission of green house gases
   5.   Cutting down use of fossil fuels
   6.   Improving efficiency of the machines of energy usage.


   Ozone as a layer is present in the stratosphere. The thickness of the ozone layer is
   measured in a unit called Dobson Unit. This layer protects us from harmful
   ultraviolet radiations.

   Ozone layer is formed in the upper atmosphere by the action of UV rays on
   molecular oxygen. The CFC produce active chlorine in the presence of UV radiations
   which converts ozone into oxygen. The depletion of ozone occurs over the antartica
   region. This is referred to ozone hole. In 1987, an international treaty called
   Monotreal protocol was signed to control the emission of ozone depleting

E-46, MAIN KHYALA ROAD, VISHNU GARDEN, NEW DELHI-18               9891402133, 9953840650
Absolute Acaademy Of Advanced Studies
                              Expert Studies- Great Results
   Nascent oxygen combines with molecular oxygen to form ozone according to

   O2------[O] + [O]

   O2 + [O]------O3

   UV further cause photo dissociation of ozone into O2 and [O] but the two combines
   to produce O3 again

   O3-----O2 + [O]

   O2+ [O]-----O3


   Natural resources occur by pollutants and by improper utilisation and maintainance.
   Soil erosion and desertification is caused by human activities like over cultivation,
   over grazing, poor irrigation practices and deforestation.


   Removal of forest areas to fulfill the needs of growing human population is called
   deforestation. Almost 40% of the forests are lost in tropics and 1% are lost in
   temperate regions. According to National Forest Policy, 33% forest cover should be
   present in the plain and 67% for the hill.

   Major cause of deforestation:

   1. Human settlements
   2. Forest fires
   3. Jhum cultivation= shifting cultivation. It is a slash and burn agriculture of tribals
      for clearing an area for cultivation which is rich in minerals due to ash of burnt
   4. Hydroelectric projects
   5. Overgrazing by livestock
   6. Demand for wood

   The process of restoring a forest that once existed but was removed at some point
   of time in the past is called Reforestation.

   People participation has always stood in front in such programmes:

   1. In 1731, a Bishnoi woman showed exemplary courage by hugging a tree in order
      to prevent its cutting. Then rest of bishnois followed her and killed by the soldiers
      of king of Jodhpur. Government of India gives Amrita Devi Bishnoi award for
      those who help in conservation of wild life.

E-46, MAIN KHYALA ROAD, VISHNU GARDEN, NEW DELHI-18                  9891402133, 9953840650
Absolute Acaademy Of Advanced Studies
                            Expert Studies- Great Results
   2. Chipko movement was started in Garhwal by shri Sundar Lal Bahuguna to
      prevent cutting of trees.
   3. In 1980, the Government of India has introduced the concept of Joint Forest
      Management so as to work closely for local communities for protection and
      managing forest on mutual benefits.

E-46, MAIN KHYALA ROAD, VISHNU GARDEN, NEW DELHI-18             9891402133, 9953840650

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