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Water pollution
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- 2. Overview o Types ofWater Pollution • Sewage • Disease-causing agents • Sediment pollution • Inorganic plant and algal nutrients • Organic compounds • Inorganic chemicals • Thermal pollution o Water Quality Today o Improving Water Quality o Laws related to Water Pollution
- 3. Water Pollution o Waterpollution • Any physical or chemical contamination of water that adversely affects the health of humans and other organisms • Varies in magnitude by location o It is a major issue globally due to lack of clean & disease-free water o Eight categories • Sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution
- 4. Sewage o The releaseof wastewater from drains or sewers • Includes human waste, soaps and detergents o Causes two serious environmental problems: • Enrichment • Fertilization of a water body by high levels of plant and algal nutrients (nitrogen and phosphorus) • Increase in Biological Oxygen Demand (BOD) • Amount of oxygen needed by microorganisms to decompose biological wastes • As BOD increases Dissolved Oxygen (DO) decreases
- 5. Disease-causing Agents o Infectiousorganisms that cause diseases • Originate in the wastes of infected individuals o Common bacterial or viral diseases: • Typhoid, cholera, polio and infectious hepatitis
- 6. Disease-causing Agents o Monitoredby testing for presence of E.coli in the water via Coliform Test o Indicates the presence of pathogenic organisms
- 7. Sediment Pollution o Excessiveamounts of suspended soil particles • Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines and construction o Problems • Limits light penetration • Covers aquatic animals and plants • Brings insoluble toxins into waterways
- 9. Inorganic Plant andAlgal Nutrients o Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae • Harmful in large concentrations o Sources: • Human and animal wastes, plant residues, atmospheric deposition and fertilizer runoff o Causes: • Enrichment, bad odors and high BOD
- 10. Organic Compounds o Chemicalsthat contain carbon atoms • Natural examples: sugars, amino acids, and oils • Manmade examples: pesticides, solvents, industrial chemicals and plastics
- 11. Inorganic Chemicals o Contaminantsthat contain elements other than carbon • Examples: acids, salts and heavy metals o Do not degrade easily o Lead • Found in old paint, industrial pollutants, leaded gasoline o Mercury • Mercury bio - accumulates in the muscles of top predators of the open ocean
- 12. Radioactive Substances o Containatoms of unstable isotopes that spontaneously emit radiation o Sources - • Mining • Processing of radioactive materials • Nuclear power plants • Natural sources
- 13. Thermal Pollution o Occurswhen heated water produced during industrial processes is released into waterways o Organisms affected • Temperature affects reproductive cycles, digestion rates, and respiration rates • Warm water holds less DO than cold water
- 14. Quality of WaterToday o Two types of Water Pollution o Point Source Pollution • water pollution that can be traced to a specific origin • Discharge via pipes, sewage and ditches o Non-Point Source Pollution • Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry • Runoff from agricultural fields or parking lots
- 15. Industrial Wastes inWater o Different industries generate different pollutants • Food Processing Plants - high BOD • Paper Mills - high BOD as well as toxic compounds • Textile Industry - Nitrogen , heavy metals and dyestuffs o Many industries recover toxins before they go into the waste stream
- 16. Water Pollution from Agriculture oAgriculture is also a source of water pollution worldwide • Animal wastes and plants residues have high BOD • Chemical pesticides can leach into groundwater o Almost all streams and rivers are polluted with agricultural pesticides
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- 18. Indian Scenario o Pollutionin Ganges • Used for bathing and washing clothes • Sewage and hazardous industrial waste discharged directly into river • Ganga Action Plan initiated by government in 1985 • Namami Gange mission is carried out since 2015
- 19. Water Pollution inOther Countries o Po River, Italy • Similar to Mississippi River of US • Pollutants: Sewage, Industrial waste, Sediment • More than 16 million Italians depend on the river for drinking water • Pollution is too high • Swimming and fishing prohibited • Cleanup will require a national management plan and may take decades
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- 21. Improving Water Quality- Treatment of Sewage Primary Treatment • Removing suspended and floating particles by mechanical processing Secondary Treatment • Treating wastewater biologically to decompose suspended organic matter thereby reducing BOD • Sewage Sludge is eliminated after these treatments Tertiary Treatment • Advanced wastewater treatment methods that aresometimes employed after above treatments • Reduces Nitrogen as well as phosphorus from water
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- 23. Laws related toWater Pollution The Water(Prevention and Control of Pollution)Act, 1974 • To provide for prevention control and abatement of water pollution • To maintain or restore the wholesomeness of water in country • To prevent the pollution of water by agricultural industrial and household sources • To assess the pollution levels and punish polluters
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