2 ENVIRONMENTAL STUDIES UNIT V AIR POLLUTIONWATER POLLUTIONSOIL POLLUTION
3 IntroductionPOLLUTANT : Any physical, chemical or biological agent that in its sheer presence has impact on environment that makes a particular resource useless for its designated use.POLLUTION is a situation where pollutants bring undesirable changes in the environment.SOURCES of pollutant :Natural sourcesAnthropogenic/ Man made sourcesEFFECTSCONTROL MEASURES
4 AIR POLLUTIONAIR POLLUTION : Air Pollution may be broadly be defined as the presence of one or more contaminants like dust, smoke, mist, odor in the atmosphere which are injurious to human beings, plants and animals or which unreasonably obstruct life and property.Air Pollution may be described as “ The imbalance in quality of air so as to cause adverse effects on the living organisms on earth”.COMPOSITION OF AIR : Atmosphere is gaseous envelope surrounding the earth which constitutes Major gases (N2, O2, CO2), Minor gases (He, ) and Trace gases (SO2, CO, CH4).Based on Temperature changes Air environment is divided into 4 segmentsTroposphere (Altitude range is 0 to 11Kms)Stratosphere (11 to 50kms)Mesosphere (50 to 85kms)Ionosphere (85 to 100kms)
5 Types of Air pollutants Air Pollutants are of two types, Primary and Secondary pollutants based on the source.Primary pollutants are directly emitted from the source. e.g., SO2, CO2 etc.,Secondary pollutants are resulted from environmental reactions. e.g NO3, H2SO4 etc.,Particulates include Aerosols, Mist. Dust, Smoke, fumes, fog and smog.
6 Sources of Air Pollution Air pollutants are substances causing damage to animals, plants, building material which is adversely affected by pollutants.Major Sources of Air PollutionNatural Sources :Volcanic eruptions – poisonous gases such as SO2, H2S, CO etc.Forest fires - H2S, CH4 etc.Evapo transpiration process – CO2Oxidation process – natural photochemical reactionsMan made sources/Anthropogenic Sources includePopulation explosion – emission of GHG’s result in global warmingDeforestation – imbalance of CO2 and O2 in the natureBurning of fossil fuels – combustion processEmission from transportation sector – Automobile exhausts result in PCSRapid Industrialization – Power plants, Smelters, refineries etc.Agricultural activities – pesticides, insecticides, herbicides etc.
7 Effects of Air Pollution Pollutants are generally classified as Gaseous pollutants, Particulate pollutants, Aerosols, Radioactive pollutants.Gaseous pollutants – CO2, CO, SOx, NOx, Hydro carbonsCarbon dioxideTraps heat in the atmosphere result in Global warmingCarbon monoxideHarmful to humans, affects respiration, cardiac and pulmonary functionsSOx :Oxides of SulphurAcid rains wash away nutrients, necrosis on leavesbronchitis, emphysema and psychological disorders in humansEffects on materials,Stone leprosy: H2SO4 corrodes on marble monumentsNOx :Oxides of NitrogenToxic produces irritating effect, affects lungs – bronchitis, emphysema.chlorosis effects and decreased photosynthetic activity in plants.Hydro carbonsReact with NO to form secondary pollutants, Photo Chemical SmogParticulate pollutants (fumes, dust, smoke etc)Toxic mist, chronic non specific diseases, soil corrosion.AerosolsAir pollutants remain suspended in airRadioactive PollutantsCellular damage in man and animals
8 Control StrategiesControl of NOx pollution : Removal of NOx by catalytic decomposition and Scrubbing processDischarge of gaseous pollutants by building higher smoke stacks (vent)Control of SOx pollution : Removal of Sulphur from fuel before burning, and using sorption methods.Control of CO pollution : Exhaust gas analyzers to check emissionsVehicular pollution can be controlled by upgrading fuel quality, using catalytic convertors.Control of Hydro carbons : Incineration, adsorption, absorption and condensationControl of particulate matter : Cyclones, electrostatic precipitators, filters etc.Reforestation programs
9 WATER POLLUTION Water is elixir of life. Water pollution is defined as the alteration of physical, chemical and biological characteristics of water resulting in harmful effects on life systems.Characteristics of waterTypes of water pollution :Ground water pollutionSurface water pollutionLake, River and Sea water pollution.
10 Sources of Water Pollution Major sources are divided into Natural and Man madeNatural Sources:Eutrophication processFloodsMan made sources:Sewage and domestic wastesToxic metalsIndustrial effluentsAgricultural dischargesDetergents, pesticidesSiltation process
11 Effects of Water Pollution Sewage and domestic wastes effect human health resulting diseases such as cholera, typhoid, dysenteryIndustrial discharges contain Lead, arsenic, Mercury, Cadmium etc., which pose deleterious impacts in life systemsLead – damages liver and kidneyArsenic – lung cancer, ulcers in gastro intestinal tractCadmium – diarrhea, kidney cysts, bone deformation etcMercury – Neurological disordersAgricultural discharges include fertilizers, pesticides which are toxic to both aquatic and human life..
12 Control Strategies Sewage treatment plants Integrated approach and organic farmingIdeal maintenance of plant upkeep in IndustriesManagement and legislation – CPCBWater treatmentPrimary treatment involves coagulation and flocculationSecondary treatment involves disinfection processInformation dissemination through sensitization programs.
13 SOIL POLLUTIONSoil is the uppermost weathered layer of earth’s crust and is a significant ecological factor in sustenance of biosphere.SOURCES OF SOIL POLLUTION:NaturalErosion – wind, waterMan madeIndustrial WastesUrban wastesAgricultural wastesRadioactive wastesMining
14 Effects and control of Soil Pollution These pollutants affect and alter the chemical and biological properties of the soil, as a result these toxic elements enter into human food chain from soil or water and finally pose deleterious effects on living organisms – biomagnification process.Control Strategies :Check dams/ Rock filled damsTrenchesOrganic farming