Environmental Pollution Concepts PDF

## 5. (b) Environmental pollution ### Concept of pollution (What is pollution?) Environment denotes the sum total of physical and biological factors that directly influences the survival, growth, development and reproduction of organism. Environment means biosphere which includes atmosphere, hyd...

## 5. (b) Environmental pollution ### Concept of pollution (What is pollution?) Environment denotes the sum total of physical and biological factors that directly influences the survival, growth, development and reproduction of organism. Environment means biosphere which includes atmosphere, hydrosphere and lithosphere. The whole of the earth including all its living organisms and nonliving substances are together called as biosphere. ## LIFE SCIENCE & ENVIRONMENT Any unfavourable change in physical, chemical and biological characteristics of surroundings (consisting of air, water and soil) due to several human activities which cause harmful effects on our life or other desirable species and cultural assets is known as environmental pollution. Pollution is an undesirable change in the physicochemical and biological characteristics of the biosphere that have adverse effects over living organisms and the environment. For reference only: - **Pollutants** - The materials which cause pollution of the environment are called pollutants. Pollutants may be gaseous pollutant (CO2, CO etc), metallic pollutant (Nickel), pesticides (DDT etc), toxic organic and inorganic compounds, radioactive substances etc. - Major causes of pollution are increasing human population, poverty, unscientific construction of buildings, misuse and wastage of natural resource etc. - Effects of pollution are different diseases, cancer, economic loss, increasing problem in life resulting into human sufferings directly or indirectly. ### Types of pollution (How does pollution affect our daily life?) ### AIR POLLUTION: Many pollutants (either natural or man made) may cause disruption of normal composition of atmosphere known as air pollution. There are many causes and effects of air pollution. Some common points are as follows: | Cause of air pollution | Effect of air pollution | |---|---| | 1. Greenhouse gases - A greenhouse gas is a gas that absorbs infrared radiation (IR) and radiates heat in all directions. Major greenhouse gases are CO2, CH4 (Methane), CFC (Chlorofluorocarbon) and N2O (nitrous oxide). Minor greenhouse gases are water vapour and ozone. | 1. The approximate warming effect of CO2, CH4 CFC and N2O are 60%, 20%, 14% and 6% respectively. <br> 2. Excess CO2 causes headache, nausea. <br> 3. Acid rain - The effect of air pollution by SOX (Sulphur oxides) and NOX (Nitrogen oxides) that react with water in the atmosphere during thunder producing sulphuric acid and nitric acid and come down to earth along with rain is called acid rain. | | | **Effects (consequences) of acid rain:** <br> On plants: <br> (i) Acid rain causes chlorosis, necrosis and damages the leaves of plant to yellow, brown which reduces the productivity of plants, forest, grasslands and crops. <br> (ii) Many natural forests have been destroyed by acid rain in different industrialized countries of the world. <br> (iii) It affects quality of soil and decreases soil fertility | ### ENVIRONMENT, ITS RESOURCES AND THEIR CONSERVATION | Cause of air pollution | Effect of air pollution | |---|---| | (a) CO2 s produced from burning of fuel, smoke from the chimneys of industry, forest fire, deforestation etc. | On Animals: <br> (i) Acid rain has killed and destroved many aquatic flora and fauna in different industrialised countries off world. <br> (ii) It may cause respiratory, skin disease in man. <br> Cultural effect: <br> (i) Acid rain can cause corrosion on metals, marble etc. CaCO, of marble is converted into CaSO, or Ca (NO₂), after reacting with H₂SO₄ and HNO, respectively. The reported threat to Tajmahal of Agra is because of SOX or NOX from Mathura Refinery. <br> 4. Lung disease - SPM may pass deep into lungs causing breathing and respiratory problems, irritation of lungs, allergic reactions, bronchial asthma, chronic bronchitis, emphysaema and other pulmonary problems. | | (b) CH4 (Marsh gas) is produced naturally by decomposition of organic matter, cowdung, incomplete combustion of fossil fuel (Petroleum). | | Cause of air pollution | Effect of air pollution | |---|---| | (c) CFC is released from refrigerators, aircrafts flying at high altitude, air conditioners etc. | | (d) N₂O is produced from nitrates, nitrites, high energy radiations, combustion process in industries, automobiles, nitrogen fertilizers etc. | | (e) Excessive greenhouse gases cause enhanced greenhouse effect - (i) Global warming, (ii) expansion of desert, (iii) decrease of rainfall, (iv) melting of iceberg. | | 2. SPM (Suspended Particulate Matter) - (i) SPM are finely divided solids or liquids, less than 10µ size, that may be dispersed through the air from combustion processes, industrial activities or natural sources. <br> (ii) SPM may be aerosol (less than 1µ), dust (more than 1µ) mist (liquid more than 1µ); Smoke, soot, flyash are also fine particulate matter considered as SPM that are dispersed from cotton dust, iron mill, flour mill, cement industry, asbestos industry, coal mine etc. | For reference only: Green House Gases (GHG) are essential for keeping the earth warm and hospitable. They radiate long wave radiations back to earth (called greenhouse flux) - so the mean annual temperature of earth is 15°C; otherwise earth temperature would fall to -18°C. Do you know the Bhopal gas tragedy? MIC GAS (Methyl isocyanate) ## WATER POLLUTION: Water pollution means the adverse changes in the composition and condition of water such that it becomes unsuitable for use. There are various causes and effects of water pollution of which few common points are discussed below: | Cause of water pollution | Effect of water pollution | |---|---| | 1. Agricultural run off: <br> (i) Various chemicals, used in agricultural fields like fertilizers, pesticides etc., are applied at one place and may be carried to a distant place by stormy wind, rainwater. This is called agricultural "run off". This is mostly man made pollution (anthropogenic). <br> (ii) Drainage from animal husbandry (poultry, dairy etc.) also cause water pollution. | 1. Disease - Various diseases like cholera, typhoid may develop in man by drinking contaminated water. Cholera is caused by _Vibrio cholerae_ bacteria; typhoid by _Salmonella typhi_. <br> 2. Many aquatic flora and fauna suffer from different diseases specially the fishes. Poisonous pollutants are absorbed by fishes from water. When we consume those fishes, we may suffer from diseases also. <br> 3. Eutrophication - The process by which a body of water acquires a high concentration of nutrients specially phosphates and nitrates, that promotes excessive growth of algae (algal bloom) and other aquatic plants is called as eutrophication. Agricultural "run off" encourages growth of unwanted aquatic organisms. Organic debris and silt are gradually deposited at the bottom of the water body (pond, lake, river etc.). Water becomes shallow and warmer where various plants and microbes grow.| | 2. Pathogenic organism: <br> (i) Varieties of pathogenic organisms like bacteria, fungus, etc. grow well in polluted water. They come from domestic sewage. Raw sewage contains a number of pathogens of typhoid, cholera, dysentery, diarrhoea etc. | ## SOIL POLLUTION: Soil pollution (land pollution) is the deterioration of the earth's land surface, naturally or man made, which decreases the quality and productivity of plants and ground water. There are various causes and effects of soil pollution of which few significant points are discussed below. | Cause of soil pollution | Effect of soil pollution | |---|---| |1. Pathogenic organisms: Various pathogenic organisms may cause soil pollution like bacteria, fungi, protozoa, helminthes, mollusca, arthropods - who can decrease soil fertility and can attack roots of plants. | 1. Effect on human - Human beings may be badly affected by soil pollution either through direct contact with polluted soil or by inhalation of soil contaminants. Contaminated soil with toxic chemicals and pesticides may lead to the problem of skin cancer and human respiratory disorder, reproductive disorder etc. <br> 2. Biological magnification (Biomagnification) - The process by which highly stable (persistent) toxic substance enters the food chain and its concentration gradually increases through successive higher trophic level is known as biological magnification. Let us suppose DDT is sprayed in a grassland. It has strong residual toxicity. Suppose, amount of DDT in grass (producer) is x. Each insect (primary consumer) eats 4 grass leaves - so the amount of DDT in insect will be 4x. Now frog (secondary consumer) eats three insects then amount of DDT will be 4x x 3 = 12x. Snake (tertiary consumer) eats 2 frogs when the amount of DDT will be 2 x 12x = 24x and so on. DDT (organochlorine) is an example where biomagnification causes problem in calcium metabolism in birds causing thinning of egg shell and other serious metabolic disorders in various organisms of any ecosystem including man. |- | 2. Chemicals : <br>(i) Fertilizers - Excessive use of fertiliser may decrease quality of soil, capillary water. Excess fertilizer may be harmful to plants. Agricultural "run off" may contaminate soil and soil water. <br>(ii) Pesticides and herbicide - These chemicals are used to kill the "pests" (target organism) but it may harm the nontarget organism. Example - in a paddy field, paddy pest may be target organism but earthworm, rhizobium etc. are nontarget organism. Indiscriminate use of pesticide may kill 'target' as well as 'nontarget' organisms. Moreover, remnants of these pesticides may be absorbed by soil particles which contaminate roots of plant. | ## ENVIRONMENT, ITS RESOURCES AND THEIR CONSERVATION ### NOISE POLLUTION Unwanted, irregular, unpleasant and annoying sound which is caused by the vibration of matters is known as noise and the pollution caused by them is called noise pollution. Some common causes and effect of noise pollution are discussed below: | Cause of noise pollution | Effect of noise pollution | |---|---| | 1. Vehicular noise: The engines of lorry, bus, car, motorcycle, train, tram, aeroplane etc. produce noise while running. Horn of vehicles, friction of wheels on train track also produce noise. | 1. Effect of noise on human - Noise pollution may occur above 80dB sound. <br> (i) Ear may develop deafness, hearing loss (temporary or permanent); difficult to hear and speak. <br> (ii) Heart also suffers lot of problems such as dilatation of blood vessels, high blood pressure, high cholesterol level, anxiety and increase in heart beat, constriction of blood vessels, etc. <br> (iii) Other physiological problems may be Insomnia (sleeplessness) damage to brain, liver etc. | | 2. Industrial noise: Factory, industry, workshop etc. emit high intensity sound due to friction, vibration or collision between the materials. | | For reference only: <br> 3. Miscellaneous: Musical noise (from TV, radio, musical instruments etc.), domestic appliances (washing machine, vacuum cleaner, water pump, mixer, grinder, air conditioner, exhaust fans, pressure cooker etc.), festival noise (loudspeakers, puja festival, marriage ceremony, amplifier, fireworks, crackers etc.) also cause terrible noise. | 2. Effect of noise on animals - <br> (i) Endocrine system may be disturbed. <br> (ii) Reproductive cycle of insects may be also disturbed. <br> (iii) Laying of eggs and hatching are also disturbed. <br> (iv) Development of embryo be also affected. <br> (v) Congenital defects appear in embryo. |