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Environment and Health
This document discusses various aspects of environmental health, with a focus on water sources and supply. It defines the environment as consisting of physical, biological, and social factors that surround humans. It emphasizes that sanitation must come from within communities as an obligation. Regarding water, it describes different sources like rain, surface water, and ground water. It provides details on rivers, tanks, dug wells, tube wells, artesian wells, and springs as sources. It discusses water quality criteria and requirements for drinking water.
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Environment and Health
- 1. Environment and health Dr.Rizwan S A, M.D., Assistant Professor, Department of Community Medicine, VMCH&RI, Madurai. 9.02.2015 1
- 2. Definition • Implies allthe external factors – living and non-living, material and non-material which surround man • Three components – Physical: water, air, soil, housing, wastes, radiation – Biologic: plant and animal life including bacteria, viruses, insects, rodents and animals – Social: customs, culture, habits, income, occupation, religion 2
- 3. Sanitation • Sanitation – away of life – expressed in clean home, clean farm, clean business, clean neighborhood and clean community – it must come from within the people – an obligation and an ideal in human relations • Environmental sanitation – the control of all those factors in man's physical environment which exercise deleterious effect on health 3
- 4. A way oflife, must come from within 4
- 5. Sections in thischapter Environmentandhealth Water Air Ventilation Noise Radiation Meteorological Housing Waste disposal Excreta disposal Medical entomology 5
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- 7. Water • Safe andwholesome water: defined as – free from pathogenic agents – free from harmful chemical substances pleasant to the taste – free from color and odor – usable for domestic purposes • Polluted or contaminated water - when it does not fulfill the above criteria 7
- 8. Water requirement • Physiologicalrequirements of drinking water just for survival – about 2 liters per capita per day • 150-200 liters per capita per day - urban areas • 40 liters per capita per day - rural areas • Close to the people 8
- 9. Uses of water •Domestic • Public • Industrial • Agricultural • Power production • Carrying away waste 9
- 10. Sources of watersupply • From any one of a number of points in its movement through the hydrological cycle • Sufficient to serve the population expected at the end of the design period, 10 to 50 years • Adequate 95 per cent of the year • Two criteria – quantity must be sufficient to meet present and future requirement – quality of water must be acceptable 10
- 11. Sources of watersupply • Rain • Surface water – Impounding reservoirs – Rivers and streams – Tanks, ponds and lakes • Ground water – Dug well - Shallow and deep – Tube well - Shallow and deep – Artesian well & Springs 11
- 12. Rain • Water cycle •Rain water is the purest water in nature – clear, bright and sparkling. – very soft water containing only traces of dissolved solids, corrosive action on lead pipes – free from pathogenic agents • Impurities – acid rain: dilute solution of sulphuric and nitric acid. – very few places - Gibraltar depend upon rain 12
- 13. Surface water • Surfacewater originates from rain water • Contamination from human and animal sources, high probability of organic, bacterial and viral contamination • Majority of Indian cities and towns depend • Types – Impounding Reservoirs – Rivers and Streams – Tanks, Ponds and Lakes 13
- 14. Impounding reservoirs • Artificiallakes constructed usually of earthwork or masonry • Catchment area • Fairly good quality, clear, palatable and ranks next to rain water in purity. • Keep the catchment area free from human or animal intrusion 14
- 15. Rivers • Delhi, Kolkataand Allahabad rely on river water • Always grossly polluted and is quite unfit for drinking without treatment – direct connection between the alimentary canal of the people living upstream and the mouths of those below – washings, sewage and sullage water, industrial and trade wastes, and drainage from agricultural areas – bathing, animal washing and disposal of the dead • Self-purification – natural forces, dilution, sedimentation, aeration, oxidation, sunlight, plant and animal life 15
- 16. Tanks • Large excavations •Important source of water supply in some Indian villages • Unlimited possibilities of contamination and are highly dangerous • Improvement of tanks – edges of the tank should be elevated, – fence, – no one should be permitted to get into the tank directly, – elevated platform, – cleaned at the end of the dry season – simplest solution: sand filtration 16
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- 18. Sea water • Manylimitations • 3.5% of salts in solution • Desalting and demineralization process involves heavy expenditure • It is adopted in places where sea water is the only source available 18
- 19. Ground water • Rainwater percolating into ground constitutes ground water – Limit to ground water in the world – Cheapest and most practical means – superior to surface water, • Advantages – free from pathogenic agents – requires no treatment – available even during dry season – less subject to contamination • Disadvantages – High in mineral content, pumping to lift the water • Types: wells and springs 19
- 20. Dug wells • Twotypes – Unlined katcha well – Masonry or pucca well • Improvement of dug wells – Deepening bottom – Installing a hand-pump with screen – Filling the well with coarse sand up to the water level, and clay above that level – Upper 10 feet water-tight lining 20
- 21. Difference between shallowand deep well Shallow well Deep well Definition Above the first impervious layer Below the first impervious layer Chemical quality Moderately hard Much hard Bacteriological quality Often grossly contaminated Taps purer water Yield Dry in summer Constant supply 21
- 22. Sanitary well 22 1. Location 2.Lining 3. Parapet wall 4. Platform 5. Drain 6. Covering 7. Hand-pump 8. Consumer responsibility 9. Quality
- 23. Tube wells • Bacteriologicallysafe, cheap – shallow tube wells – driven wells • Consists of a pipe into the water-bearing stratum and fitted with a strainer at the bottom, and a hand pump at the top • Lasts for a period of 5 to 10 years • Deep tube well - drilling through successive substrata until water is located • Chandigarh - entire water supply from tube wells 23
- 24. Artesian wells • Akind of deep wells, water rises above the ground, held under pressure • Artesian wells are not common in India 24
- 25. Springs • Ground watercomes to the surface and flows freely under natural pressure • Shallow springs and deep springs • Deep springs do not show seasonal fluctuations 25
- 26. THANK YOU Email yourdoubts to [email protected] Find this presentation at www.vmchcm2.blogspot.in 26