Environmental studies Pollution Notes in Pdf
Environmental studies Pollution Notes in Pdf :-
Q. 1. Define pollution and describe air pollution in detail.
Pollution may be defined as an undesirable change in the physical, chemical or biological aspects of environment which makes it harmful for human-beings. living organisms (plants, animals and microbes) and for cultural aspects. Any excessive addition of undesirable materials to the physical environment (air, land and water) making it unfit for living beings is pollution.
Man-made pollution is called as anthropogenic pollution. This is mainly caused by over use, misuse or mismanagement Of natural resources by men. e.g., agricultural pollution, Industrial pollution.
Natural pollution may result from volcanic eruption, UV radiation, soil erosion, forest fire, decomposition of dead organic matter etc.
It refers to the release into the atmosphere of materials in concentrations that are harmful to human beings, plants, animals and buildings cr other objects.
Composition of Air by Volume
|Rest (Ozone, Krypton. Argon, CO, Helium, Water vapour, NHS, CFI, , etc.)||0.97%|
Air pollution is caused either due to natural cause or anthropogenic (man-made) causes. Natural Causes
(i) Forest fire
(ii) Marsh gases
(iv) Cosmic dust
(v) Pollen. spores, etc. (vi) Extra terrestrial substances (vii) Volcanic eruption—releasing CO, H2S, SO 2 etc. (viii) Decay products of natural organic or inorganic substances.
(i) Domestic emissions
(ii) Industrial emissions (iii) Vehicular emissions (iv) War (chemical/biological/weapons)
(v) Agricultural activities
(vi) Burning of fossil fuels
Atmospheric pollution existed before the evolution of man. Man has only aggravated the pollution. It has been estimated that human activities contribute only a fraction 10.05%) 01 total emissions into the air. Out of total annual emissions of 1×1012 tonnes entering the only 5x 108 tonnes are due to human activities,
Photochemical Smog : It has secondary pollutants, grey or yellowish brown, opaque, produced over towns or cities due to still air at high temperature emissions of oxides of nitrogen, volatile hydrocarbons, solar energy.
Smog results in grey air if solar radiations are less intense and smog formation is incomplete. But in areas with intense solar radiations, photochemical smog results in formation of brown air.
(i) Cause toxic effects on living organisms, like plants and animals.
(ii) Reduces visibility and may cause accidents. Aldehydes cause irritation to GI and respiratory tracts.
(f) Fluorides : Compounds of fluorine.
Sources : Industries, coal combustion.
(i) Harmful to plants/animals, cause flurosis (spotting of’ teeth).
Particulate Pollutants : Industries automobiles and operations like blasting, drilling, crushing, grinding, etc. Pollens, spores, cysts of living organisms also act as pollutants. These pollutants may be solid or liquid. Larger particles like sand and water droplets, settle down in still air and are known as settleable particles. Particles like dust are small and remain in the air for a longer period and are called as suspended particles. Particles like tobacco, smoke are very fine and do not settle and are called as nonsettleable particles.
Liquid or solid particles under 1 pun in diameter are called as fumes, aerosols, smokes. Particles more than 1 gm in diameter are called dust (solid) and mist (liquid).
(a) Dust : Fly ash/soot from burning of coal, metal dust having nickle, arsenic, lead, cadmium etc. from metallurgical processes, stone particles, asbestos fibres, cotton dust are added to the air.
Effects(i) Lung fibrosis, stone particles cause silicosis, cotton fibres cause byssinosis, asbestos fibres casue asbestosis, lead affects nervous system.
(b) Mist : The pesticides which are sprayed on crop-plants remain in air as liquid particles.
(c) Aerosols : These are chemicals released in air with force as vapoure e.g., CFC, oxides of
Pollen, spores, bacteria, cysts occur in air and may cause allergies and respiratory diseases sulphur and nitrogen.
Radioactive Pollutants : These are released in air by nuclear explosions during war, these are harmful and may kill tissues of living organisms.
Control of Air Pollution
(i) Trees should be grown as they use CO2 and release O2. This helps in purification of air for human-beings and animals to breathe. Some plants like Phaseolus vulgarts. Ficus variegata can fix CO and plants like Pinus, Vites, Juniperus can metabolise nitrogen oxides.
(ii) Good quality fuel should be used in motor vehicles for reducing air pollution.
(iii) The industrial processes should be suitably modified so as to reduce air pollution. This can be done by using gravity settling tanks, porous filters, electrostatic precipitators, cyclonic separators, trajectory separators, catalytic converters.
(iv) Gaseous pollutants can be controlled by combustion, absorption, adsorption techniques.
(v) The use of tall chimneys can reduce air pollution at ground level.
(vi) To remove particulate matter, industrial smoke should be filtered before releasing it in the atmosphere.
(vii) Plants / trees should be grown around mining areas and road sides to reduce air pollution.
(viii) CNG should be used to reduce air pollution.
(ix) Population is one of the most important factor, of pollution. It should be brought under control.(x) Nuclear explosions should be stopped or minimized.
(xi) Electrification of rail track will greatly reduce air pollution.
(xii) Use of cycle for short distance movements.
(xiii) Use of public transport will reduce number of vehicles and air pollution.
(xiv) Use of ecofriendly fuel.
(xv) Use of alternate source of energy – solar, wind, etc.
(xvi) Use of battery in vehicles will reduce air pollution.
Q. 2. Write an essay on cyclones. Give its effects and disaster management.
A cyclonic storm or cyclone is an intense vortex or a whirl in the atmosphere with very strong winds circulating around it in anticlockwise direction in the northern hemisphere and in clockwise direction in southern hemisphere.
‘Cyclone’ word is derived from greek word cyclos which means coils of snake. The tropical storm in Bay of Bengal and Arabian sea appears like coiled repents Of the sea hence the name is ‘cyclone’ Cyclones are Intense low pressure areas from the centre of which pressure increases outwards. The intensity of cyclone and strength of winds depend upon the amount of pressure drop in the centre and the rate at which increase outwards.
Full grown cyclone is an isolent whirl in the atmosphere 150—1000 km across, 10—15 km high. Gale winds of 150 to 250 kmph or more spiral around the centre of very low pressure area below the normal sea level pressure (less than 17 knots or <31 kmph; I knot central calm region of the storm is known as eye ; the diameter of which varies between 30—50 km. It is region free of clouds and has light winds. Around the eye a “wall cloud region” of storm (50 km) is present where the gale winds, thick clouds with torrential rain, thunder and lighting prevail. The speed of wind gradually decreases away from wall cloud region. The gale give rise to a sea with waves as high as 20 meter, swells that travels thousands of’ miles. The cyclone may move 300—500 km in a day and hit along the coast, bringing with it storm surges as high as 3—12 meters, leaving behind death and destruction in the coastal region.
Destruction Caused by Cyclones
Three elements are associated with a cyclone causing destruction are as follows :
(a) Cyclones are associated with high pressure gradients and consequent strong winds. There is an abnormal rise of sea level near the coast caused by a severe tropical cyclone. The sea water intrudes with low lying areas of coastal region drowning human being and live stock, eroding beaches and embankments, destroying vegetation causing soil sterility.
(b) Very strong winds may damage installation, communication system, trees, dwellings etc causing loss of life and property.
(c) Heavy and prolonged rains due to cyclones cause floods submergence of low lying areas resulting in loss of life and property.
Cyclone Disaster Prevention and Nitigation Plans
These are :
(a) A cyclone forecast and warning service.
(b) Rapid dissemination of warning to the government agencies, marine interests like the ports, fisheries and shipping and to general public.
(c) Organisation to construct cyclone shelters in the cyclone-prone areas and ready machinery for evacuation of people to safer areas.
(d) Community prepared was at all levels meet the exigencies.
Disaster Prevention and Preparedness
(a) National : The government of India (1969) suggested, the states to set up “Cyclone Distress Mitigation Committee (CDMC)” in the respective sites. Prevention measures include construction of storm shelters, connecting roads for evacuation of people, construction of wind breaks, bunds, flood storage reservoirs afforestation along the coastal belts and improvement of drainage facilities. Public enlightenment is necessary without even advanced systems will work.
(b) International : The World Meterological Organisation (WMO) has established a Tropical Cyclone Project (TCP) in 1972 for assisting the member countries for increase their capabilities to detect and forecast the approach of land fall of the tropical cyclones, evaluate and forecast the storm surges. Guidelines are drawn up for disaster prevention and preparedness jointly by the WMO / ESCAP (Economic and Social Council for Asia and Pacific, League of Red Cross Societies (LRCS) and the United Nation’s Disaster Relief Organization (UNDRO) which are being implemented by the concerned countries.
In India the cyclone generally strike the east coast; some of the Arabian sea cyclones strike the west coast of India as well mainly the Gujrat and north Maharastra coast out of the storms that develop in the Bay of Bengal, over 58% approach or cross the east coast in october and november. India has a very long coast line of 8041 km, large parts of which are vulnerable to cyclone.
Post Disaster Assistance
The initial response by local authorities include points, which are given below :
(ii) Search and rescue
(iii) Emergency Shelter
(iv) Medical assistance
(v) Provision of short term food and water
(vi) Epidemiological surveillance
(vii) Provision of temporary lodging
(ix) Re-establishment of communications networks and contact with remote areas
(x) Debris clearance
(xi) Disaster assessment
(xii) Provision of seeds for replanting
Q.3. Describe water pollution and its control.
Ans. Water Pollution: Addition of foreign substances (chemical, biological or radiological) to water or any change in its physical properties Chat constitutes a health hazard or otherwise makes it less fit or unfit for use.
Causes of Pollution
1. Heat and oil spills, heated effluents synthetic detergents.
2. DDT, BHC, PCBS, organic wastes, synthetic detergents, chemicals like lead, mercury, cadmium, nitrates, nickel, arsenic, etc. Radioactive wastes, dyes, coal, acids, alkalies.
3. Pathogens, bacteria, viruses, helminthes, protozoa, algae, (ungi, ‘fungal spores, etc.
4. Decomposition products of animal/plant origin. Pollution takes place due to discharge of domestic waste water, sewage municipal wastes, industrial wastes was out of agricultural lands, oil slicks, vcaer soluble contaminants from air and land finally find their way is water and pollute it.
In India, all the major rivers like Ganga, Yamuna, Godavari, Gomati, Kosi, Cauvery, Ravi, Chenab, Narmada, Mahi, Tapti, Krishna are facing problem of water pollution. Rainfall exceeding the soil’s water holding capacity drains away into water-courses, carrying dissolved chemicals with it, this is called leiching. Leiching brings fertilizes, pesticides’ insecticides and soil fumigants.
Phosphorus / nitrates act as nutrients and cause an increase m the growth of algae, this is called as eutrophication containing toxic substances. Industrial wastes or pesticides pass through food chain and reach human body directly/indirectly. Concentration of the toxic material increases at each trophie level of food chain, this is called biomagnification.
The inland surface water has five classes which are given below :
Class A : Drinking water sources fit for consumption after only disinfection.
Class B : Water is safe for outdoor bathing.
Class C : Water not safe for drinking in crude form but it is made drinkable after treatment and disinfection.
Class D : Water not suitable for human beings but suitable for fish culture and wild lift propagation.
Class E : Water suitable for irrigation and cooling in industries. Lantic water bodies (water resources standing like pools, lakes, ponds etc. receiving large amounts Of nutrients organic matter which cause an increase in aquatic life forms on surface of water. This hinders the penetration of light, reduce O2 generation (photosynthesis) and finally way cause death of water bodies i.e., eutrophication.
Lotic water bodies (water in constant motion, e.g., rivers/streams etc.) are under stress duts human population, agriculture, industries (paper, textiles, fertilizer, detergents, drops, Oil refineries, etc.). Effluents discharged from industries have made the river of continuity polluted. It also affects the flora/fauna of the river adversly government of India has launched Ganga action plan, Yamuna action plane, Gomatie action plan, National River Action Plant (NRAP) for conservation of water resources. A good amount of money is being spent or these plans.
Most common pollutants of ocean are raw sewage, detergents, etc. Water pollution may cause typhoid, diarrhoea, cholera and other water borne diseases.
Oil pollution may cause :
(i) Reduction in dissolved O2
(ii) Reduce penetration of light.
(iii) Death of flora along sea coast and loss of marine biota.
(iv) Metabolic problems to marine animals.
(v) Water management is essential for overcoming hazards of water pollution.
(vi) Water treatment.
(viii) Waste recycle.
(ix) Use of reverse-osmosis for removal of salts.
(x) Use of iron-exchange resin for removal of metals.
(xi) Suitable steps should be taken to control water pollution in lakes, rivers, stream, etc.
(xii) Conservation of vegetation.
(xiii) Proper and efficient treatment of domestic water, industrial waste at source before discharging them in water bodies.
(xiv) Harvesting of rain water.
(xv) Recharging of ground water.
(xvi) Use of underground water reservoirs.
(xvii) Minimise the use of pesticides/insecticides.
(xviii) Conservation of drinking water resources.
(xix) Proper coastal management.
(xx) Use of modern techniques to remove oil spills.
Radioactive wastes are deadly. Their leakage may cause large scale human tragedy. Radioactive dust from mining processing of uranium finds its way into lakes / rivers may reach to Live stock and man via food chains.
Underground water is polluted by sewage/industrial effluents spilled over ground, fertiliser and pesticides used in fields, refuse dumps, septic tanks, seepage pits. The pollutants filter through soil and enter the underground water.
(i) Pollutants make water unfit for domestic and industrial use.
(ii) Pollutated water is harmful for plants/animals and may cause death of flora/fauna.
(iii) Mercury is changed to methyl mercury by bacteria. This undergoes biomagnification causes minimata disease to animals (minimata bay Japan).
(iv) Itai-itai disease is caused by cadmium pollution.
(v) Pollution due to arsenic causes blackfort disease.
(vi) Pollution may effect nervous system, respiratory system of animals.
Polluted Water Organisms
E. coli, Oscillatoria, Micro cysts, Senedesnzus, Potamogeton, Euglena Paramecium, Colpidium are found in water not excessively polluted blood worm, tubifex, culex larvae and leeches occur in highly polluted water.
Q. 4. Describe noise pollution.
Ans. Noise Pollution : It is an undesirable sound. High pitch sounds are produced by power plants, automobiles, jets, aeroplane, trains, rockets, DJ., TV, bomb explosions, rockets. public broadcasting system, crackers, generators, etc. The loudness of noise is measured in decibel (dB).
1 dB = 20 log 10(P/Pref)
P = Measured sound pressure in dynes/cm
Pref = Reference sound pressure which is equal to barely audible sound taken as 0.002 dynes/cm
According to WHO, 45 dB is considered safe noise level for city Noise level 80 dB or above causes noise pollution. 100 dB noise is uncomfortable and 120 dB is painful.
Different Sources of Noise Levels (dB)
|Jet aircraft (taking off)||12.5|
(i) Sudden loud noise may cause constriction of blood vessels, skin becomes pale, pupil dilates, eyes close muscle tense, B.P. increases.
(ii) Also effects on secretions of ductless glands.
(iii) Temporary loss of hearing. Explosions may cause deafness. Continuous exposure to high noise may cause permanent damage ear.
(iv) Disturb sleep and proper rest of animals / human beings.
(v) Sudden noise may cause accidents.
(vi) Irritation in behaviours of human / animals.
(vii) Stomach disorder.
(viii) Damage to heart, brain and liver has been reported in animals due to prolonged noise
(ix) Interferes in conversation, concentration and upsets mood.
Control Effects of Noise Pollution
1. Noise producing industries, railway stat non and aerodromes should be located at proper distance from human settlements,
2. A green vegetation belt of medium height around the airport, is a good idea Co reduce noise pollution.
3. Main roads should be away city.
4. Noisy machines settled in sound proof chamber.
5. Use of sound proof chambers for generators.
6. Use of insulating material to check noise production.
7. Ear malts and cotton plugs should be used by workers in noisy places.
8. Noise on roads may be reduced by planting many rows of trees on both Sides of roads.
9. Silence zones are essential near collages / schools, hospitals and residential areas.
Q. 5. Describe soil pollution.
Ans. Soil in very important resource. Now-a-days pollution of soil in rural, urban and industrial areas has become a serious problem.
In crop lands, weeds grow and compete with crop land for water and minuets from soil. Cusou is spread with bordany mix cure to kill these weeds. Some liner Sodium Chlorate, avseme compounds are also used. There chemicals cause soil pollution and are harmful to microbes. Many herbicides, postludes, fungicides are used which cause soil pollution. Compounds like DNOC (Dinitro compounds), weed killers like MCPA, Simazine, 24-D Moneron, organic herbicide, Dalapon, paraquat have long lasting effect on soil and remein for a very long time. There also show advance effect on soil microbes and create problem for humanbeings, animals. Fungicids are poisoned and get incorporated into soil. Some of them are washed in with rain, Later on enterers food chain and create serious problems to fish, birds, mammals. Insecticides like Bttc DDT, Aldrin polluts soil through rain. These chemicals slow biomagnification and also affect activities of Bacteria, earth worms adversely. Some chemicals influence the reproduction in earth worms. Compounds like Benoyl, Carboyl. Forrnofos, Carbonates are toxic to earth worms. Nematodes etc. Sodium methyl bromide, oxamyl are also toxic to earth worms. Pesticides also effect soil decomposition, enzyme activity of CO2 evolution,
Industries pollute soil through their effluents which have metals, plastics, chemicals. Threat of soil pollution also comer from human wastes, animal excretes, hospital waste etc. Soil adquires radio-active pollution from nuclear explosions. Major pollutant of soil are Industrial, Urban wastes and Agricultural activities.
Effects of Soil Pollution
(i) Pollutants alter natural composition of soil.
(ii) Pollutants may kill soil microbes which contribute to fertility of soil.
(iii) Chemicals, pesticides, insecticides weedcides, herbicides etc. make soil toxic for plant.
(iv) Use of chemical fertilizers may spoil the quality of soil in long run.
(v) Human wastes, animal wastes, hospital wastes, industrial wastes pollute soil and cause serious problems to crop yield which subsequently effect the human health, animal health adversely.
(vi) Radioactive dust may reach to human through food chain and cause damage to nervous system, chromosomes metabolism, skin etc.
(i) Recycling of wastes.
(ii) Burning of wastes without oxygen.
(iii) Use of cattle dung in production of cooking gas.
(iv) Use of domestic wastes, sludge for composting.
(v) Proper treatment of industrial wastes, agricultureal wastes, hospital wastes at source before final disposal.
Q. 6. What is nuclear hazards? What are its causes?
Ans. Nuclear Hazards: Nuclear pollution may be defined as ‘the physical pollution of air, water and soil caused by radioactive materials’ The radioactive wastes are mainly released from the thermo-nuclear explosions in which disintegration of atomic nuclei of certain elements emit electromagnetic waves of very short wavelength. The radioactive elements are uranium thorium, radium, etc. The nuclear pollution poses a serious threat to all living organisms.
The electromagnetic waves are (I-rays, and Y-rays. The (I-rays are normally a health hazard in the form of internal radiation through ingestion, inhalation or open wounds. These do not cause external hazard since they cannot penetrate other layers of skin. Fays can be a health hazard either as internal or external radiation due to ionization in the tissues. X-rays and Y-rays are very penetrating compared to and p. They constitute the chief health hazard of external radiation although y-rays and can be a hazard also as internal radiation.
Causes of Nuclear Hazards
Main sources of radioactive pollution are both : the natural and man-made. Their details are as follows .
Natural Sources : These are .
1. Cosmic rays which are fast moving highly energetic radiations. They reach the earth from outer space. The intensity of cosmic rays in the biosphere is low, therefore they are not a health hazard. But they are a major hazard in space.
2. The terrestrial radiation from nuclides of radioactive elements are present in the rocks, soil and water These elements could be Uranium 235, Uranium 238, Radon 222, Radium 224, Thorium 232 and Carbon 4, etc.
Man-made sources : These are .
1. Testing of nuclear weapons such as
(a) The use of Uranium 235 and Plutonium 239 for fission.
(b) Hydrogen of helium as fusion material.
Atomic explosions are uncontrolled chain reactions. They give rise to a very large neutron-flux conditions that cause other materials in the surrounding to become radioactive.
Huge clouds of fine radioactive particles and gases are thrown up in the environment and are carried away to distant areas by the winds. Gradually, they settle down on earth as fall out or are bought down by rain. Strontium-90, Iodine-131, Cesium-137, unused explosive and activation products are the radioactive substances present in the fallout. When raindrops containing these radioactive particles fall on earth, radioactivity is’ transferred to soil particles causing soil pollution. From the soil, these radioactive materials are washed into different water sources where the aquatic organisms absorb and accumulate them through the food chains and many pass them to human beings.
2. Atomic reactors and nuclear fuel
(a) In a nuclear power plant, processed nuclear fuel is inevitable.
(b) Both the fuel element and coolants are sources of radiation pollution.
(c) Besides these, the disposal of radioactive wastes from atomic reactors is a grave problem because the fission and activation products contained in them are hazardous to living organisms, Even if these are dumped in underground tanks for natural decay, they may become-free and escape into the surroundings. Inert gases and halogens escape as vapours and pollute the environment as they settle on land or are washed into surface water with rain.
3. Radioactive isotopes
(a) A large number of radioactive isotopes such as 1251, 14C, 32P and their compounds find wide usage in scientific research. The waste water from these research institutions contain varying amounts of radioactive materials. When this waste water reaches different water sources such as rivers, streams, lakes, etc. through the sewers, they cause water pollution.
(b) Radioactive iodine and phosphorus also enter the food chain through water and may finally reach man through fish, etc.
4. Other sourcee
(a) Varying concentrations ef radiations enter the human body during different medical treatment For instance, X-rays are common for detecting skeletal disorders, therapy for cancer patients often includes radium and other isotope radiations.
Q. 7. What is earthquake? What are its causes and effects?
Ans. Earthquake : An earthquake is a major demonstration of power of tectonic forces caused by endogenetic thermal conditions of the interior of the earth. It is a motion at the ground surface, ranging from a faint tremor to a wild motion capable of shaking buildings apart and causing gaping fissures to open in the ground. The earthquake is a form of energy of wave motion transmitted through the surface layer of the earth in widening circles from a point of sudden energy release The magnitude or intensity of energy released by an earthquake is measured by the RICHTER SCALE devised by Charles F. Richter in 1935. The number indicating intensity on Richter scale ranges between 0 to 9 but in fact the scale has no upper limit of number because it is a logarithmic scale. ‘It is estimated that the total annual energy released by all earthquakes is about 102 ergs and most of this is from a small number of earthquakes of magnitude over 7. The following description of Richter scale may help in assessing the devastation caused by the energy release during earthquakes of varying magnitudes. The world’s largest and most intensive record earthquake was of the magnitude of 90 and the number of recorded earthquke increases 10 times as magnitude decreases by one.
|0||Smallest earth tremor detected by seismograph only. Energy released by such
insignificant earthquake amounts to 3 x 1012 ergs.
|2.5 to 3.0||Such earthquakes may be felt and detected if they occur near the settlements. The annual frequency of such earthquakes is around 100,000. No damage is done.|
|4.5||Local damage .is done.|
|5.0||The quakes of this magnitude equal in energy to ordinary atomic bombe The atomic bomb hurled on Hiroshima (Japan) during Second Word War equalled to the magnitude of 5.7 on Richter Scale. The energy released from such earthquakes equals 8 x 1020 ergs.|
|6.0||Such earthquakes become destructive within a limited area provided that the geological structure is weak and the area is heavily populated.|
Causes of Earthquake : Earthquake are caused due to disequilibrium in any part of the earth crust. A number of causes may be assigned for it, such as given ahead:
Q. 8. Write a note on different types of floods.
Generally there are three types of floods.
1. Storm Surge : Floods in coastal areas and in river estuaries are due to storm surges, which result from the sea being driven on to the land by meteorological forces.
The physical forces act together. Storm with intense low pressure causes the level of sea sue because of barometric effects. Strong winds associated with this storm when directed to share, drive the sea on to the land. Storm surges one associated with tropical cyclones The storm then produces the, surge also give rise to heavy rainfall.
2. Snow Melt Flood : When the snow melt it infiltrates into soil. Water from the melting snow release catastrophically causing large runoff very rapidly warm rainwater a large cold spell may cause the snow pack to melt while the underlving ground is still frozen, which prevents any infiltration. Snow melt floods can be very large.
3. Flash Floods : Flash floods are floods of short duration into a relatively high peak discharge. They arise from local precipitation of extremely high intensity typical of thunderstorms. High concentration of rainfall on a small area can have devastating effect as the river flow can rise to several hundred times the normal flow in the space of a few hours. Such floods are common in •arid and semi arid areas. Mountainous areas are prone to thunderstorm and the steep terrain and thin soils in the mountains assume high runoff with a short delay time
Q. 9. What is a fault and what are its different types?
Fault is a fracture or zone of fractures between two blocks of rocks. It allows the block to move relative to each other This movement may occur rapidly, in the form of an earthquake or may occur slowly, in the form of a creep. Fault may range in length from a few millimeter and thousands of kilometers. The fault surface can be horizontal or vertical or may have an angle.
Earth scientists use the angle of fault with respect to the surface (dip) and the direction of slip along the fault to classify the faults. The faults are of following types .
1. Normal fault : Dip slip fault in which the block above the fault has moved downward relative to the block below.
2. Thrust fault : A dip slip fault in which upper block, above the fault plane, moves up and over the lower block.
3. Strike-slip fault: The two blocks slide past one another e.g., San andreas fault.
4. Left lateral strike-slip fault : Displacement of the far block is to the left when viewed either side.
5. Right lateral strike-slip fault : The displacement of the far block is to the right when viewed from either side.
Q. 10. Describe radioactive pollution.
Ans. Radioactive Pollution
It is a physical pollution of soil/air or water with radioactive materials.
Natural Sources of Radio Active Pollution
(i) Cosmic rays that reach the earth from outer space.
(ii) Emissions from isotopes of Uraniums (23811 arid 235U) and Thorium (232 TIO etc.
(iii) Nuclides of elements depicting radioactivity, e.g., 0K, 14C etc.
(iv) Radiation originating from our body from radioactive nucleides like Potassium.
Anthropogenic sources of radioactive pollution.
(i) X rays used in radiotherapy and diagnostic purpose. Treatment of cancer by gamma radiations.
(ii) Use of radioactive materials in the field of research, medicine, industry etc.
(iii) Operation of nuclear reactions and disposal or nuclear wastes may cause pollution of land.
(iv) Nuclear power plants.
(v) Use of nuclear installation for research etc. may cause wide range effects on flora/fauna. This causes imbalance in nature.
(vi) Atomic explosions performed by various countries. produce effect on local area as well as on board geographical region.
(vii) Various electrical implements, precipitators etc, generate electric fields causing radiation hazard.
It depends on
(i) strength of radiati013, (ii) rate of diffusion, (iii) duration of exposure, (iv) half life of pollutants, (v) Environmental factors like rainfall, wind, temperature etc.
(a) Non-ionising radiations (e.g., UV) have low penetrability and cause sunburn, blindness, adverse effect on metabolism and DNA, RNA.
(b) Ionising radiations (X-Ray) have very high penetrability and cause damage of cells by breaking macro-biomolecules may cause mutations, cancer, tumour, formation burns, loss of hairs, bleeding, change metabolism.
(c) Dividing cells show more prominent effect e.g., Skin cells, bone marrow cells, gamete forming cells, embryo cells.
(d) Radiation also show wide range of effect on plant as well as animal life, Dairy milk and products may get slighty contaminated.
(i) Control of occupational radiation exposure.
(ii) Nuclear detoxification.
(iii) Minimise nuclear power.
(iv) Minimise X-ray hazards.
(v) Disposal of radioactive wastes alongwith inert material after dilution.
(vi) Radioactive wastes should be concentrated ratio and locked up in a crystalline rock line structure synthesised for this purpose.
(vii) Radioactive wastes should be changed into harmless form.
(viii) Minimise atomic explosions and use of atomic weapons. ‘ vua/ifying Course)
Q. 11. Describe marine pollution.
Ans. Marine Pollution: sea is the sewer of the world now-a-days. Water pollutants (e.g.. pesticides. fertilizers. detergents. toxic metals infections agents, radioactive waste etc.),reach directly from coastal Cities and indirectly distant places through rivers. Discharges of Oil detergents, sewage, grease, garbage from also play an important role in polluting sea-water- Oil spilled In tanker accidents is a serious threat to ocean life Oil. In sea water affects adversly the flora and fauna of seawater. especially phytoplanktons, Zooplanktons, algae. Coral reefs. Birds, fishes, mamals, invertebrates, etc. In 1989, linkage from oil tanker near Alaska resulted in damage to sea water biota especially coral reefs and death of about 39000 aquatic birds. In 1991, during gulf war about 200 million gallons of oil spread in Persian gulf causing serious damage and marine ecosystem.
Oceans have limited to dispersal capacity through turbulance and lack decomposing capacity, Therefore. wastes discharged Ilito sea cause localised pollution. People using sea food often suffer from infections diseases such as cholera, hapatitis, G.I. disorders etc
Pollutants often reduce the oxygen concentration of coastal waters to levels the impair their capacity to support life.
(i) Direct discharge into sea from coastal areas should be discouraged.
(ii) Minimize developmented activitie”S near coastal areas.
(iii) Use biotechnological methods to remove oil spills.
(iv) Hot spots should be protected,
Q. 12. What is Tsunami tragedy? Explain disaster management in India.
Ans. Tsunami Tragedy: Tsunami is Japanese word related to large seismically generated sea wave capable of considerable destruction in certain coastal areas especially where underwater earthquake occurs.
It was December 26, 2004 and time was at 6.29 a.m. in the morning an undesired earthquake erupletin Sumatra, triggering off tidal wave called Tsunami after this at 7.49 am Tsunami hits car Nicobar, the island was most wiped out, Then tidal waves reached for south coast of India at 8.48 a.m., Tamil Nadu was hit. This ruined the lives. tribal communities of Andaman Island was lost due to this disaster severe impact of Tsunami was worsen by state of’ coastal environment. Over the year, natural protectors along the coast like sand dunes mangroove forests, have been continuouslv disturbed and in first 200m, from hotels with a sea view to an air force base almost on water to many settlements, homes to hundreds who drowned.
Disaster is not predictable, they follow no standard operating procedure, Disaster management is preparedness about unknown tragedv which will come suddenly.
Effective disaster management covers the following four factors :
(a) Forecasting (estimation that where and when disaster will hit).
(b) Mitigation (through measures like coastal zone regulation, building earthquake resistant buildings, before event)
(c) Relief (effective, quick action e.g., supplying relief quickly)
(d) Resettlement (buildinglives again)
There are two large disaster attacks in India these are Orissa 1999 and Bhuj 2001.
After Orissa and Bhuj, Union Govt. reviewed India’s disaster preparation. A high powered Committee was set up in 1999. By 2001, it had come up with ideas for a policy and supporting institutional mechanism. From Floods :
1. Flood plains the low lying areas which get I nundatcd (luring help to reduce floods.
2. Building up of flood control structures like flood walls or deepening, of river channels have only transferred the problems downstream. 13uiIding walls prevents spilling out the flood water over flood plains, but it increases the velocity of water to affect the areas downstream with greater force.
3. River net working in the country is also being proposed to deal with the flood problem.
Q. 13. What is marine pollution’? What are its effects’?
Ans. Marine Pollution: Marine pollution is a global problem. It affects the health of the oceans near both developed and developing countries. marine pollution problems are local, but many have international implications. It is a complex problem,
This form of marine pollution is quantitatively greater than oil on the sea. Consequently, it appears to be more harmful because ocean dumping takes place In and around a region which is vital for the marine ecosystem. Plankton, this microscopic forms of animal plant life, which is the basic food for other organisms, thrives in the very region. Thus, damage done to the marine ecosystem by the wastes disposed retards the sustenance of such marine creatures.
Effects of Marine Pollution
Main effects of marine pollution are the following :
1. It destroys the marine life and disturbs the marine ecosystem. 2. It harms the coastal amenities enjoyed byelocals and tourists. 3. It endangers the exploration of off-shore minerals. 4. It endangers the rarte species of the oceans. 5. It destroys the estuaries ecosystems. 6. Sea fishes, animals, birds and other living organisms are killed by oil seepage, etc 7, It poses threat to flora and fauna. 8. It destroys the ocean’s food sources. 9. Shell fishes are subjected to polio-virus, hepatitis, an other pathogens.
Q. 14. What is an earthquake and how it happens?
Ans. Earthquake is caused by a sudden slip on a fault. Stresses in the enrth’s outer layer
Push the sides of the fault together, stress builds up and the rocks slips suddenly, releasing energy in waves that travel through the earth’s crust and cause the shaking that we feel during earthquake. Earthquake occurs when plates grind of scrape against each other In California there are two plates the pacific plate and the north American plate. The primary boundary between these two plates is the San Andreas fault, which is more than 650 miles long extends to depth Of at least 10 miles. The pacific plate grinds northwestward part, the north American plate at a rate of about 2 inches per year. Parts of the San Andreas fault system adapt to this Movement by Constant ‘creep’ resulting in many tiny shocks and a moderate earth tremors. In other where creep is not constant, strain can build up for hundreds of years, producing great earthquakes when it finally releases.
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