Pollution An undesirable and unfavorable change in physical, chemical and biological characteristics of land air and water that harmfully affect both plant and animal life including that of man. Caused mainly by population growth, urbanization and technological advances. Things that cause pollution are called pollutants
Two Types of Pollutants Biodegradable pollutants : Those which are rapidly decomposed by natural processes. Eg. Domestic sewage Non-degradable pollutants: That degrade very slowly into natural environment. Eg. Plastic, aluminum cans, glass, DDT, mercuric salts etc.
Classification based on environment : 1. Atmospheric pollution 2. Water pollution 3. Soil pollution Classification based on nature of pollutants 1. Chemical pollution 2. Noise pollution 3. Pollution by radio activity.
Atmospheric pollution Contamination of atmospheric air due to accumulation of harmful or toxic materials Natural sources . 1. Volcanic eruption 2. Forest fire 3. Decaying organic matter 4. Sand storms Man made pollutants Only 0.05% of total atmospheric pollutants. Caused by the outputs of industries and automobiles
Gaseous pollutants: 1. Carbon monoxide. 2. nitrogen oxide, 3. sulphur dioxide etc. Particulate substances Solid and liquid particles 1.Large particles that easily settle down in air. (sand and water drops) 2.Fine paricles that float in air for long time (dust and mist). 3.Finer particles that never settle (smoke, aerosol and fumes)
Primary pollutants Those emanating from a source Eg. Carbon monoxide, nitrous oxides etc. Secondary pollutants Produced by combustions of primary pollutants in atmosphere Eg. Atmospheric reactions of hydro-carbons and nitrous oxide, peroxy acetyl nitrate
Sources of Air Pollution Stationary combustion sources: Combustion of coal and petroleum produces CO,SO 2 ,various Nitrogen compounds and fly ash containing trace metals like arsenic, lead and Mercury. Incomplete burning of petroleum produces soot and other toxic gases. Oxides of sulphur react with atmosphere producing sulphuric acid which forms acid rain or acid precipitation.
Mobile combustion sources Automobile is a major source of pollution Their exhaust contain carbon monoxide(77.2%), Oxides of nitrogen(7.7%) and hydrocarbons(13.7%) Photochemical reactions on Oxides of nitrogen and hydrocarbons produce photochemical smog which contains Peroxy acetyl nitrate and Ozone. Tetra ethyl lead in petroleum produces various lead compounds.
Industrial processing and other sources Smoke from factories Compounds contain Chorine and Fluorine used in propellants, refrigerants and in aerosol can produce toxic outputs Solvents in spray painting. Dyeing, printing etc. Blasting, drilling, crushing, mixing etc.
Effects of air pollution Human health Allergic reaction and bronchial asthma Co is respiratory poison NO impairs functioning of lungs SO 2 penetrates tissues and causes mouth drying Hydrocarbons and soot are carcinogenic
Damage to vegetation Injury to animals Deterioration of materials Aesthetic insults Change in climate Other effects
Control Measures Removal of pollutants Conversion of pollutants into harmful materials Reduce sulphur content before burning Use of energy sources other than fossil fuels Legal measures from authorities Increased planting of vegetation
Water Pollution Contamination of water by addition of undesirable organic, inorganic or biological substances to water sources Natural sources: soil erosion, leaching of minerals from of rocks and decay matter. Industrial effluents Destroys ecosystem and effects human health
Sources of water pollution Community waste waters Industrial wastes Agricultural sources Thermal pollution Under ground water pollution Marine pollution
Effects of water pollution Mercury poisoning causes Mina Mata disease in man. Inorganic nitrates promote excessive plant growth in lakes and reservoirs Pesticides are harmful to aquatic life Organocholrines pass through food chain to animals and is harmful Dyes and inorganic compounds induce colour change in animals .
Increased turbidity due to suspended particles. Unpleasant odours and bad taste Soaps and alkalies cause foam formation Eutrophication provides rich growth of micro organisms that consume dissolved oxygen Thermal pollution cause damage to aquatic life
Control of water pollution Treatment of garbage and sewage. Extraction of useful substances. Chemical treatment. Reduction of temperature of waste water. Minimize the use of non - degradable pesticides. Proper enactment of laws by government.
Soil pollution Undesirable change in the physical, chemical or biological property which adversely affects its productivity Caused by dumping of wastes, agrochemicals and as indirect result of air pollution
Control of soil pollution Proper disposal of industrial and agricultural wastes Recycling and recovery of materials Minimize the manufacture and use of chemical fertilizers Reduce the use of pesticides
Land degradation The productivity of soil is going down. The main reasons are Soil erosion Shifting cultivation Desertification Developmental activities
Control measures Control soil erosion and floods by restoring forest and grass cover to the soil Crop rotation and mixed crops Improved drainage facilities to prevent salinity Mulching to prevent sand shifting. Belt of trees as wind breakers
Radio active pollution Physical pollution that affects air, water and soil. Caused by ionizing radiations of harmful nature emitted from disintegrating atomic nuclei. The natural sources include cosmic rays that reaches the earth surface and radiations from radium 224, uranium 235 thorium 232 etc
Man made sources Nuclear weapons Reactors and Nuclear fuel Radioactive isotopes used for scientific research( carbon 14 iodine 125 etc.) Waste waters containing these wastes X-rays used in medical practices Ultra violet rays present in solar radiations
Effects Depolymerization of DNA Denaturation of proteins Induce mutations and cancer Radioactive substances in food chain cause retarded growth, leukemia and bone cancer. Causes sterility Increases infant mortality rate
Control measures Prevention of leakage of radioactive elements from nuclear reactors. Proper storage and disposal of nuclear wastes Regular monitoring and high risk analysis Increasing the use of non harmful energy sources Global understanding about nuclear explotions
Noise pollution Unwanted high pitch sound that pollutes the environment. Maximum tolerable intensity of sound is 85 decibels The main sources are automobiles, aero planes, loudspeakers, industries and other electro-mechanical devices.
Effects of noise pollution Damage to ear drum and impairment to hearing. Damages heart, liver and brain Emotional disturbances and behavioral changes Leads to anxiety and stress
Control measures Design machines with minimum sound Proper lubrication maintenance of machines and installation of silencers. Use of sound absorbing materials Use of noise protective devices Acoustic Zoning. Keep plenty of vegetation proper enforcement of legal measures.