logging in or signing up marine pollution mckashyap Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 2072 Category: Science & Tech.. License: All Rights Reserved Like it (4) Dislike it (0) Added: November 25, 2010 This Presentation is Public Favorites: 3 Presentation Description No description available. Comments Posting comment... By: vids87 (2 month(s) ago) Can I download this powerpoint ? I need it. Please. Saving..... Post Reply Close Saving..... Edit Comment Close By: zinmg (7 month(s) ago) Can I download that powerpoint ? I need it. Pleae. Saving..... Post Reply Close Saving..... Edit Comment Close By: afsalkollam (7 month(s) ago) like the presentation...........can i download it Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript SEMINAR ON MARINE POLLUTION : SEMINAR ON MARINE POLLUTION CONTENTS : CONTENTS INTRODUCTION MARINE POLLUTION POLLUTANTS: SOURCES AND ITS EFFECTS SEWAGE PESTICIDES PLASTIC WASTES DEEP SEA MINING METALLIC WASTES OIL HEAT RADIOACTIVE WASTE DREDGE SPOILS PREVENTION AND CONTROL OF MARINE POLLUTION CONCLUSION REFERENCES INTRODUCTION : INTRODUCTION Oceans cover about 71% of the Earth’s surface and they play an important role in the chemical and biological balance of the life on the earth. They are vital to our food security, commerce and transportation. But human activity has troubled the health of oceans. Many fish species have been harvested to a point that their populations are threatened. The coastal mangrove forests of Asia have been destroyed by shrimp farming. The habitats of marine mammals and fish have been degraded severely, with pollution responsible for the mass deaths of fish, mammals and corals. Organochloric pollutants, pesticides, polychlorinated biphenyls (PCBs) and a range of other toxic pollutants accumulate within fishes later moving up the food chain to cause reproductive disorders. MARINE POLLUTION : MARINE POLLUTION It is defined as the discharge of waste substances into the sea resulting in harm to living resources, hazards to human health, hindrance to fishery and impairment of quality for use of sea-water. Marine pollution is associated with the changes in physical, chemical and biological conditions of the sea water. The ocean water is also unfit for human consumption and industrial purposes because of high salt content. Chemically it is a solution of 0.5m NaCl and 0.005m MgSO4 containing traces of all conceivable matter in the universe. POLLUTANTS: SOURCES AND ITS EFFECTS : POLLUTANTS: SOURCES AND ITS EFFECTS Pollutants can simply define as the materials which cause pollution. The following are the important pollutants that cause the marine pollution. Sewage Pesticides Plastic wastes Deep sea mining Metallic wastes Oil Heat Radioactive waste Dredge spoil SEWAGE : SEWAGE Sewage may be entering the sea By direct drainage From inland towns and industries. Tipping at sea from ships, widely used for disposal of sewage and industrial wastes. Detrimental effects of sewage include foul deposits, reduced salinity, infection and toxic residues, deoxygenation, eutrophication, etc. PESTICIDES : PESTICIDES Pesticides are organically active chemicals which are used for killing the pests. Pesticides may enter the oceans from the atmosphere after aerial spraying, from overland runoff of sprayed areas, or from intentional dumping in the sea. Pesticides are more dangerous, since it affects food chain directly. These are more and more concentrated in fish, seagulls, seals, penguins and marine planktons. PCBs have pushed European otter to the brink of extinction. PCBs have been found to have a series effect on this aquatic animal’s reproductive cycle. PCBs have also been known to cause patches on the skin, immunotoxicity, kidney damage, weight loss and tumor formation in otters. PLASTIC WASTES : PLASTIC WASTES The mass of plastic in the oceans may be as high as one hundred million metric tons. Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey. Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection. Apart from the plastic bags and bottles, fishing nets, which are known as ghost nets, usually made of plastic, can be left or lost in the ocean by fishermen. These fishing nets entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, sea birds, crabs, and other creatures, restricting movement, causing starvation, laceration and infection, and, in those that need to return to the surface to breathe, suffocation. DEEP SEA MINING : DEEP SEA MINING Because of deep sea mining, the removing parts of the sea floor, disturbs the habitat of benthic organisms, possibly, depending on the type of mining and location, causing permanent disturbances Among the impacts of deep sea mining, sediment plumes could have the greatest impact. Plumes are caused when the tailings from mining (usually fine particles) are dumped back into the ocean, creating a cloud of particles floating in the water. There are two types of plumes: Near bottom plumes occur when the tailings are pumped back down to the mining site. The floating particles increase the turbidity, or cloudiness, of the water, clogging filter-feeding apparatuses used by benthic organisms. Surface plumes cause a more serious problem. Depending on the size of the particles and water currents the plumes could spread over vast areas. The plumes could impact zooplankton and light penetration, in turn affecting the food web of the area. METALLIC WASTES : METALLIC WASTES Metallic chemical elements have a relatively high density and toxic or poisonous at low concentrations. Examples are mercury, lead, nickel, arsenic, cadmium and so on. Metallic wastes can be enter the marine environment naturally through weathering of the earth’s crust. Significant quantities of heavy metals are present in domestic waste waters, sewage and in industrial waste waters. All of this waste water may reach the ocean from rivers or by direct discharges. Lead from automobile exhaust, mercury from the production of cement and zinc and other metals emitted during the combustion of fossil fuels may all reach the oceans through the atmosphere also. These can enter the sea through oil spill also. The use of antifouling paint on the bottoms of boats has been implicated as a major source of heavy metals in waters. These toxic metals can accumulate in the tissues of many species of aquatic life by a process called bioaccumulation, which results in more toxicity in fish. When we consume such fishes, it will affect our nervous system, kidneys, brains, respiratory system or even it will lead us to death. OIL : OIL Of all marine pollution, oil and petroleum hydrocarbons have received the greatest attention internationally, politically, and scientifically, because of oil’s unique property which forms a thin layer on the vast areas of water. Hundreds of small and big cases of oil spills occur every year causing significant ecological damage. Oil may enter the sea water by number of ways as follows; Cargo tanker washings at sea and international discharge of oily wastes from tank washings and accidental spillages pollute the sea water severely. Bilge pumping at sea Import oil losses: collisions in port Tanker accidents and maritime accidents due to collision, fire, explosion or grounding also result in oil release in water. Oil leakage from pipelines The blowout of wells, disposal of drilling mud, accidental damages to offshore drilling rigs add to oil pollution in water. Oily wastes from oil fields or refineries near the coast. Oil spills mixed with urban sewage, silt, plastics, pesticides and insidious toxic compounds are pervasive and complex the pollution problems in sea. OIL : OIL Oil pollution in water has been inevitable consequence of the dependence of rapidly growing population on oil based technology. The overall detrimental effects of oil pollution sea water are as follows; Reduction in dissolved oxygen. Reduction in light penetration. Oil spilling causes lethal toxicity to aquatic flora. Smothering coats of oil have killed lichens and algae along the shore lines. Sea otters will die when their fur become saturated with oil by losing insulation. Waste from oil refineries and discharged petroleum from ships cause heavy damage to fishery. Hydrocarbons in oil get incorporated in body tissues of marine animals. When the concentration of crude oil in the sea water reaches 0.02ppm, fish eggs begin to hatch irregularly or late, while the development of already-hatched young fish or larval crabs and lobsters becomes abnormal at oil concentrations between 1 and 100ppm. When men consume the fishes from oil polluted sea water, it may result in breathing problems, and can damage liver and kidneys. HEAT : HEAT It can be defined as an accumulation of unusable heat from human activities that disrupts ecosystems in the marine environment. The most important sources of thermal marine pollution are the nuclear power plants and Thermal power plants. These power plants use the sea water for cooling. This water is generally returned to the sea at temperatures 11 to 220C (20-400F), which is higher than it was initially. One nuclear power plant may use as much as one billion gallons of sea water per day. Marine life is extremely sensitive to changes in water temperature. Higher temperatures can lead to premature spawning, fish migration, lack of oxygen or death of marine life. RADIOACTIVE WASTE : RADIOACTIVE WASTE Radioactive materials enter to the oceans mainly from following ways:- From natural background source: From fallout of nuclear weapons testing. From operation of nuclear reactors through intentional and unintentional direct releases. Mining and processing of ores to produce radioisotopes. Emission from the industrial use of nuclear energy. Leakage from underground nuclear detonations. From shipboard reactors. The effect of radionuclide in marine water is high for living organisms. Radioactive contaminate sea water will consumed by plants during photosynthesis acts as a medium for radioactivity in them. By this, radionuclide enter into the food chain of marine water. Reports indicate that Zn-65 accumulates in oysters at high level; Fe-55 concentrates in fishes while Sr-90 accumulates in certain animals of marine environment and affects their metabolic activities seriously. When men consume these radionuclide fishes, it will cause cancers, leukemia, eye cataract, DNA breakage and carcinoma in humans. DREDGE SPOILS : DREDGE SPOILS Dredge spoils constitute the greatest pollutant input by volume to the oceans. Spoils from dredging or mining of offshore minerals are deposited within a few miles of shore, where the potential impact is the greatest. Often they also contain sewage or industrial waste solids and solids from street runoff. Consequently, they often contain objectionable amounts of hazardous chemicals, pathogens, or oil and may exert a high oxygen demand on the surrounding environment. The damage which can be caused by dredging is two fold: That occurring at the dredging site, and That occurring at the dredge spoils disposal area. The immediate effect of dredging is, of course, the destruction of benthic organisms at the dredge site. And there is much turbulence and resuspension of sediments, resulting in increased turbidity of the water. Turbidity reduces light penetration, there by interfering with photosynthetic process. Turbidity can also cause fish and crustaceans to suffocate. The same adverse impacts can also occur at the disposal site. In addition, bottom-dwelling animals at the disposal site may become obliterated by the solids falling onto the bottom PREVENTION AND CONTROL OF MARINE POLLUTION : PREVENTION AND CONTROL OF MARINE POLLUTION There are some ways and techniques to prevent or control the marine pollution. They are as follows:- Stabilization of the ecosystem Reutilization, recycling, renovation and recharge of the waste Removal of the pollutants To control the oil pollution, following methods are used Skimming By spreading a high density powder over the oil patch, it can be sunk to the bottom. Biodegradation Burning Using a suitable absorbing material. Heat can be removed from condenser cooling waters prior to their disposal into the marine water. PREVENTION AND CONTROL OF MARINE POLLUTION : PREVENTION AND CONTROL OF MARINE POLLUTION Removal of phosphorus by electrolysis. Adopting appropriate methods to remove heavy metals from the marine water. Radioactive wastes can be removed or reduced by the ion-exchange techniques, precipitation of radio-nuclides. The impacts of deep sea mining can be minimize or reduced by using proper mining techniques. Awareness on marine pollution. Local communities near sea must protect sea. Management by government Incentives must be offered for conservation. Industrial units should be equipped with pollution control instruments. CONCLUSION : CONCLUSION Since the oceans cover the earth’s surface, which is about 71% and plays an important role in the chemical and biological balance of the life on the earth, it is necessary to be aware about the marine pollution, and we have to prevent and control this pollution. REFERENCES : REFERENCES Water pollution: causes, effects and control by P K Goel, new age international (p) ltd, 2000. Advances in environmental sciences edited by A K Tripathi, A K Srivastava and S N Pandey. Ashish publishing house, 1993, pp93-109 Marine pollution and its control by Paul. L. Bishop, McGraw-Hill Book Company, 1983. Environmental chemistry by B K Sharma, Goel publishing house, Meerut, sixth edition 2001, pp 64-74 Oceanography, a brief introduction by K. Siddhartha, Kisalaya publishing pvt ltd 1999, pp 310-314 Environmental studies by Asha Rao S. N., Chethana book house, 2004, pp 128-130 Environmental studies by D K Kumarswamy, Mr. A. Alayappa modes, Dr. M Vasanthy, Bharathidasan University, Tiruchirapalli, I edition, October 2004, pp 142-145 www. wikipedia. org. www. geology.com www. ask.com www.oeceanimages.com www.earthobserver.org Google images THANK YOU : THANK YOU You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
marine pollution mckashyap Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 2072 Category: Science & Tech.. License: All Rights Reserved Like it (4) Dislike it (0) Added: November 25, 2010 This Presentation is Public Favorites: 3 Presentation Description No description available. Comments Posting comment... By: vids87 (2 month(s) ago) Can I download this powerpoint ? I need it. Please. Saving..... Post Reply Close Saving..... Edit Comment Close By: zinmg (7 month(s) ago) Can I download that powerpoint ? I need it. Pleae. Saving..... Post Reply Close Saving..... Edit Comment Close By: afsalkollam (7 month(s) ago) like the presentation...........can i download it Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript SEMINAR ON MARINE POLLUTION : SEMINAR ON MARINE POLLUTION CONTENTS : CONTENTS INTRODUCTION MARINE POLLUTION POLLUTANTS: SOURCES AND ITS EFFECTS SEWAGE PESTICIDES PLASTIC WASTES DEEP SEA MINING METALLIC WASTES OIL HEAT RADIOACTIVE WASTE DREDGE SPOILS PREVENTION AND CONTROL OF MARINE POLLUTION CONCLUSION REFERENCES INTRODUCTION : INTRODUCTION Oceans cover about 71% of the Earth’s surface and they play an important role in the chemical and biological balance of the life on the earth. They are vital to our food security, commerce and transportation. But human activity has troubled the health of oceans. Many fish species have been harvested to a point that their populations are threatened. The coastal mangrove forests of Asia have been destroyed by shrimp farming. The habitats of marine mammals and fish have been degraded severely, with pollution responsible for the mass deaths of fish, mammals and corals. Organochloric pollutants, pesticides, polychlorinated biphenyls (PCBs) and a range of other toxic pollutants accumulate within fishes later moving up the food chain to cause reproductive disorders. MARINE POLLUTION : MARINE POLLUTION It is defined as the discharge of waste substances into the sea resulting in harm to living resources, hazards to human health, hindrance to fishery and impairment of quality for use of sea-water. Marine pollution is associated with the changes in physical, chemical and biological conditions of the sea water. The ocean water is also unfit for human consumption and industrial purposes because of high salt content. Chemically it is a solution of 0.5m NaCl and 0.005m MgSO4 containing traces of all conceivable matter in the universe. POLLUTANTS: SOURCES AND ITS EFFECTS : POLLUTANTS: SOURCES AND ITS EFFECTS Pollutants can simply define as the materials which cause pollution. The following are the important pollutants that cause the marine pollution. Sewage Pesticides Plastic wastes Deep sea mining Metallic wastes Oil Heat Radioactive waste Dredge spoil SEWAGE : SEWAGE Sewage may be entering the sea By direct drainage From inland towns and industries. Tipping at sea from ships, widely used for disposal of sewage and industrial wastes. Detrimental effects of sewage include foul deposits, reduced salinity, infection and toxic residues, deoxygenation, eutrophication, etc. PESTICIDES : PESTICIDES Pesticides are organically active chemicals which are used for killing the pests. Pesticides may enter the oceans from the atmosphere after aerial spraying, from overland runoff of sprayed areas, or from intentional dumping in the sea. Pesticides are more dangerous, since it affects food chain directly. These are more and more concentrated in fish, seagulls, seals, penguins and marine planktons. PCBs have pushed European otter to the brink of extinction. PCBs have been found to have a series effect on this aquatic animal’s reproductive cycle. PCBs have also been known to cause patches on the skin, immunotoxicity, kidney damage, weight loss and tumor formation in otters. PLASTIC WASTES : PLASTIC WASTES The mass of plastic in the oceans may be as high as one hundred million metric tons. Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey. Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection. Apart from the plastic bags and bottles, fishing nets, which are known as ghost nets, usually made of plastic, can be left or lost in the ocean by fishermen. These fishing nets entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, sea birds, crabs, and other creatures, restricting movement, causing starvation, laceration and infection, and, in those that need to return to the surface to breathe, suffocation. DEEP SEA MINING : DEEP SEA MINING Because of deep sea mining, the removing parts of the sea floor, disturbs the habitat of benthic organisms, possibly, depending on the type of mining and location, causing permanent disturbances Among the impacts of deep sea mining, sediment plumes could have the greatest impact. Plumes are caused when the tailings from mining (usually fine particles) are dumped back into the ocean, creating a cloud of particles floating in the water. There are two types of plumes: Near bottom plumes occur when the tailings are pumped back down to the mining site. The floating particles increase the turbidity, or cloudiness, of the water, clogging filter-feeding apparatuses used by benthic organisms. Surface plumes cause a more serious problem. Depending on the size of the particles and water currents the plumes could spread over vast areas. The plumes could impact zooplankton and light penetration, in turn affecting the food web of the area. METALLIC WASTES : METALLIC WASTES Metallic chemical elements have a relatively high density and toxic or poisonous at low concentrations. Examples are mercury, lead, nickel, arsenic, cadmium and so on. Metallic wastes can be enter the marine environment naturally through weathering of the earth’s crust. Significant quantities of heavy metals are present in domestic waste waters, sewage and in industrial waste waters. All of this waste water may reach the ocean from rivers or by direct discharges. Lead from automobile exhaust, mercury from the production of cement and zinc and other metals emitted during the combustion of fossil fuels may all reach the oceans through the atmosphere also. These can enter the sea through oil spill also. The use of antifouling paint on the bottoms of boats has been implicated as a major source of heavy metals in waters. These toxic metals can accumulate in the tissues of many species of aquatic life by a process called bioaccumulation, which results in more toxicity in fish. When we consume such fishes, it will affect our nervous system, kidneys, brains, respiratory system or even it will lead us to death. OIL : OIL Of all marine pollution, oil and petroleum hydrocarbons have received the greatest attention internationally, politically, and scientifically, because of oil’s unique property which forms a thin layer on the vast areas of water. Hundreds of small and big cases of oil spills occur every year causing significant ecological damage. Oil may enter the sea water by number of ways as follows; Cargo tanker washings at sea and international discharge of oily wastes from tank washings and accidental spillages pollute the sea water severely. Bilge pumping at sea Import oil losses: collisions in port Tanker accidents and maritime accidents due to collision, fire, explosion or grounding also result in oil release in water. Oil leakage from pipelines The blowout of wells, disposal of drilling mud, accidental damages to offshore drilling rigs add to oil pollution in water. Oily wastes from oil fields or refineries near the coast. Oil spills mixed with urban sewage, silt, plastics, pesticides and insidious toxic compounds are pervasive and complex the pollution problems in sea. OIL : OIL Oil pollution in water has been inevitable consequence of the dependence of rapidly growing population on oil based technology. The overall detrimental effects of oil pollution sea water are as follows; Reduction in dissolved oxygen. Reduction in light penetration. Oil spilling causes lethal toxicity to aquatic flora. Smothering coats of oil have killed lichens and algae along the shore lines. Sea otters will die when their fur become saturated with oil by losing insulation. Waste from oil refineries and discharged petroleum from ships cause heavy damage to fishery. Hydrocarbons in oil get incorporated in body tissues of marine animals. When the concentration of crude oil in the sea water reaches 0.02ppm, fish eggs begin to hatch irregularly or late, while the development of already-hatched young fish or larval crabs and lobsters becomes abnormal at oil concentrations between 1 and 100ppm. When men consume the fishes from oil polluted sea water, it may result in breathing problems, and can damage liver and kidneys. HEAT : HEAT It can be defined as an accumulation of unusable heat from human activities that disrupts ecosystems in the marine environment. The most important sources of thermal marine pollution are the nuclear power plants and Thermal power plants. These power plants use the sea water for cooling. This water is generally returned to the sea at temperatures 11 to 220C (20-400F), which is higher than it was initially. One nuclear power plant may use as much as one billion gallons of sea water per day. Marine life is extremely sensitive to changes in water temperature. Higher temperatures can lead to premature spawning, fish migration, lack of oxygen or death of marine life. RADIOACTIVE WASTE : RADIOACTIVE WASTE Radioactive materials enter to the oceans mainly from following ways:- From natural background source: From fallout of nuclear weapons testing. From operation of nuclear reactors through intentional and unintentional direct releases. Mining and processing of ores to produce radioisotopes. Emission from the industrial use of nuclear energy. Leakage from underground nuclear detonations. From shipboard reactors. The effect of radionuclide in marine water is high for living organisms. Radioactive contaminate sea water will consumed by plants during photosynthesis acts as a medium for radioactivity in them. By this, radionuclide enter into the food chain of marine water. Reports indicate that Zn-65 accumulates in oysters at high level; Fe-55 concentrates in fishes while Sr-90 accumulates in certain animals of marine environment and affects their metabolic activities seriously. When men consume these radionuclide fishes, it will cause cancers, leukemia, eye cataract, DNA breakage and carcinoma in humans. DREDGE SPOILS : DREDGE SPOILS Dredge spoils constitute the greatest pollutant input by volume to the oceans. Spoils from dredging or mining of offshore minerals are deposited within a few miles of shore, where the potential impact is the greatest. Often they also contain sewage or industrial waste solids and solids from street runoff. Consequently, they often contain objectionable amounts of hazardous chemicals, pathogens, or oil and may exert a high oxygen demand on the surrounding environment. The damage which can be caused by dredging is two fold: That occurring at the dredging site, and That occurring at the dredge spoils disposal area. The immediate effect of dredging is, of course, the destruction of benthic organisms at the dredge site. And there is much turbulence and resuspension of sediments, resulting in increased turbidity of the water. Turbidity reduces light penetration, there by interfering with photosynthetic process. Turbidity can also cause fish and crustaceans to suffocate. The same adverse impacts can also occur at the disposal site. In addition, bottom-dwelling animals at the disposal site may become obliterated by the solids falling onto the bottom PREVENTION AND CONTROL OF MARINE POLLUTION : PREVENTION AND CONTROL OF MARINE POLLUTION There are some ways and techniques to prevent or control the marine pollution. They are as follows:- Stabilization of the ecosystem Reutilization, recycling, renovation and recharge of the waste Removal of the pollutants To control the oil pollution, following methods are used Skimming By spreading a high density powder over the oil patch, it can be sunk to the bottom. Biodegradation Burning Using a suitable absorbing material. Heat can be removed from condenser cooling waters prior to their disposal into the marine water. PREVENTION AND CONTROL OF MARINE POLLUTION : PREVENTION AND CONTROL OF MARINE POLLUTION Removal of phosphorus by electrolysis. Adopting appropriate methods to remove heavy metals from the marine water. Radioactive wastes can be removed or reduced by the ion-exchange techniques, precipitation of radio-nuclides. The impacts of deep sea mining can be minimize or reduced by using proper mining techniques. Awareness on marine pollution. Local communities near sea must protect sea. Management by government Incentives must be offered for conservation. Industrial units should be equipped with pollution control instruments. CONCLUSION : CONCLUSION Since the oceans cover the earth’s surface, which is about 71% and plays an important role in the chemical and biological balance of the life on the earth, it is necessary to be aware about the marine pollution, and we have to prevent and control this pollution. REFERENCES : REFERENCES Water pollution: causes, effects and control by P K Goel, new age international (p) ltd, 2000. Advances in environmental sciences edited by A K Tripathi, A K Srivastava and S N Pandey. Ashish publishing house, 1993, pp93-109 Marine pollution and its control by Paul. L. Bishop, McGraw-Hill Book Company, 1983. Environmental chemistry by B K Sharma, Goel publishing house, Meerut, sixth edition 2001, pp 64-74 Oceanography, a brief introduction by K. Siddhartha, Kisalaya publishing pvt ltd 1999, pp 310-314 Environmental studies by Asha Rao S. N., Chethana book house, 2004, pp 128-130 Environmental studies by D K Kumarswamy, Mr. A. Alayappa modes, Dr. M Vasanthy, Bharathidasan University, Tiruchirapalli, I edition, October 2004, pp 142-145 www. wikipedia. org. www. geology.com www. ask.com www.oeceanimages.com www.earthobserver.org Google images THANK YOU : THANK YOU