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water.born disease and environmental health
- 1. Prepared by Ms.Saeeda Tariq Environmental Health 1
- 2. Environmental health addresses all the physical, chemical, and biologicalfactors external to a person, and all the related factors impacting behaviors. It encompasses the assessment and control of those environmental factors that can potentiallyaffect health. It is targeted towards preventing disease and creating health-supportiveenvironments. This definition excludes behavior not related to environment, as well as behaviourrelated to the social and cultural environment, and genetics.(WHO) 2 Definition
- 3. Necessity of human life, without which, terrestrial animals and vegetablelife must cease to exist. Helps man in many ways: Domestic:cooking, washing, personal cleanliness, cleaning etc. Public purpose: publiccleansing, fire-fighting, gardening, swimming poolsetc. Agriculturepurpose: cultivationsof food. 3 Waterandenvironmenthealth
- 4. The consumption of water depends upon climatic conditions, standards of living and habits of life. Followingare the sources of water: Rain water Surface water Ground water 4 Source
- 5. Rain is main source of all water. Purest in nature Physicallyclear, bright and sparkling. Tends to become impure when passes through the atmosphere, pick up suspended particles of dust micro-organism, and gases like CO2, N2 and ammonia. 5 Rainwater
- 6. Surface water is the water on surface of planet such as in river, lakes, stream and ocean. It consist of following: Reservoirs: artificial lakes usually, constructed by earthwork or masonry in which large quantity of surface water is stored . It should be kept clean and free from human and animal habitation. 6 Surfacewater
- 7. Tanks: tanks, lakes and ponds are important source of water, use for washing clothes, cattle, human cooking pots and swimming purpose. Easily polluted by animals, plants and discharge from drains. Highly dangerous as a source of drinking water and leads to many water borne diseases. Rivers: another source of surface water, grossly polluted and quiet unfit for drinking. 7 Cont
- 8. Superior to surface water, usually require no filtering medium, Likely to be free from pathogens, High in mineral contents, Require pumping and some arrangement to lift water. Includes wells. Technically there are two types of wells: Deep well: penetrates the first layer of ground Shallow well: penetrates from above the impervious layer in the ground. 8 Ground water
- 9. Tube wells: bacteriologicallysafe and cheap in comparison to other sources of water supply. Springs: impermeablestratum of the ground approaches the surface. The sub soil water gushes out and forms springs. 9 Cont.
- 10. According to study conducted in UN states that more than 3.5 Million children are at high risk of death because of constantly use of contaminated water. 20- 40% of beds occupied in hospitals are because of those people who are effected with the use of polluted water more than 100 Million cases of diarrhea is registered with in the country. Polluted water is the main reason of more than 40% death annually within the country. More than 1.6 Million disability cases are recorded within the country because of water pollution. 10 Waterpollution
- 11. Major water borne diseases in Pakistan are as follow: Acute Respiratory Infection Cholera Malaria Typhoid fever Hepatitis A & E Polio Bacterial diarrhea Dysentery Tuberculosis. 11 Cont..
- 12. In terms of financial loss Pakistani government spending 112 billion RS per year on sanitation and hygiene related diseases, but becauseof increasing population, lack of planning, uneducated peopleand due to less valueswater pollution in Pakistan is increasing day byday. 12 Cont..
- 13. Disease and Transmissi on Microbial Agent Sources of Agent in Water Supply General Symptoms Amoebiasis (hand-to-mouth) Protozoan (Entamoeba histolytica) (Cyst-like appearance) Sewage, non-treated drinking water, flies in water supply Abdominal discomfort, fatigue, weight loss, diarrhea, bloating, fever Cryptosporidiosis (oral) Protozoan (Cryptosporidium parvum) Collects on water filters and membranes that cannot be disinfected, animal manure, seasonal runoff of water. Flu-like symptoms, watery diarrhea, loss of appetite, substantial loss of weight, bloating, nausea Cyclosporiasis Protozoan parasite (Cyclospora cayetanensis) Sewage, non-treated drinking water cramps, nausea, vomiting, muscle aches, fever, and fatigue Giardiasis (fecal- oral) (hand-to- mouth) Protozoan (Giardia lamblia) Most common intestinal parasite Untreated water, poor disinfection, pipe breaks, leaks, groundwater contamination, campgrounds where humans and wildlife use same source of Diarrhea, abdominal discomfort, bloating, and flatulence 13
- 14. Disease & Transmi ssion Microbial Agent Sources of Agent in Water Supply General Symptoms Ascariasis Ascaris lumbricoides Drinking water contaminated with feces Mostly, disease is asymptomatic or accompanied by inflammation fever, and diarrhea. nausea, vomiting, Enterobiasis Enterobius vermicularis Drinking water contaminated with eggs Peri-anal itch, nervous irritability, hyperactivity and insomnia Taeniasis Taenia Drinking water contaminated with eggs Intestinal disturbances, neurologic manifestations, loss of weight, 14 Parasiticinfection
- 15. Disease & Transmission Microbial Agent Sources of Agent in Water Supply General Symptoms Cholera Spread by the bacterium Vibrio cholerae Drinking water contaminated with the bacterium Symptoms include very watery diarrhea, nausea, cramps, nosebleed, rapid pulse, vomiting. E. coli Infection Certain strains of Escherichia coli (commonly E. coli) Water contaminated with the bacteria Mostly diarrhea. Can cause death in immunocompromised Dysentery Caused by a number of species in the genera Shigella and Salmonella with the most common being Shigella dysenteriae Water contaminated with the bacterium Frequent passage of feces with blood and/or mucus and in some cases vomiting of blood. 15
- 16. Disease & Transmissi on Microbial Agent Sources of Agent in Water Supply General Symptoms SARS Coronavirus Manifests itself in improperly treated water Symptoms includefever, myalgia, lethargy, GI symptoms, cough, and sore throat HepatitisA HepatitisA virus (HAV) Can manifest itself in water (and food) Symptoms are only acute (no chronicstage to the virus) and includeFatigue, fever, abdominal pain, nausea, diarrhea, weight loss, itching, jaundice and depression. Enters water 90-95%of patientsshow no symptoms, 4-8% have minor 16 Viral infection
- 17. Is the process of removing undesirablechemicals, biologicalcontaminants, suspended solids and gases from contaminated water. The goal of this process is to produce water fit for a specificuse. In general the methods used include physical processes such as filtration, sedimentation, and distillation, biologicalprocesses such as slow sand filters or biologicallyactive carbon, chemical processes such as flocculationand chlorination and the use of electromagnetic radiation such as ultraviolet light. 17 Waterpurification
- 18. The removal of dissolved and suspended particles of water can be dealt under two headings. Purification on large scale: Storage Filtration Chlorination Purification on small scale: Boiling Using chemicals Domestic filters 18 Cont.
- 19. By storage in reservoirs or lakesgross turbidity is removed and color is improved. Water is stored as a preliminary to filtration. Process involved in storage is sedimentation. Over 90% impurities settle bygravitation in 4 hours during storage. 19 Storage
- 20. Filtration removes all suspended impurities from the water 98-99 % of bacteria, ova, cyst etc. Filtration may be carried out by: Slow sand Rapid sand 20 Filtration
- 21. Slow sand filters are used in water purification for treating raw water to produce a potableproduct. They are typically1 to 2 meters deep, can be rectangular or cylindrical in cross section and are used primarily to treat surface water. The length and breadth of the tanks are determined by the flow rate desired by the filters. 21 Slow Sand Filter
- 22. It consist of supernatant water, bed of graded sand, an under drainage system over a system of filter control valves. Supernatant wateror raw water above the sand bed, serves two important purposes i.e. it provides constant head of water, promotes the downward flow of water through the sand bed and provides wasting period of some hours for the raw water to undergo partial purification by sedimentation, oxidation and particle agglomeration. 22 Cont.
- 23. Sand bed is important part of filter, supported by layer of graded gravel which prevents the fine grains being carried into drainage. Water percolates through the sand bed slowly. Formation of vital layer is known as ripening of filter it may take several days. It removes organic matter, holds back bacteria, and oxidizeammonical nitrogen into nitrates and helps in yielding a bacteria free water. 23 Cont.
- 24. At the bottom of filter bed is under drainage system, consists of porous and perforated pipeswhich serve the dual purposeof providing an outlet for filtered water and supporting the filter medium. Filter is equippedwith certain valvesand devices which are incorporated in the outlet pipesystem to maintain the steady rate of filtration. 24 Cont
- 25. In slow sand filtration, purification is the biological process. A zoological film, which grows on the surface of sand filter arrest suspended solids and many of the bacteria in water. Advantage : simple to construct and operate, cheap in construction and 99% bacterial count is reduced. Disadvantage: takes time and labour, beds tend to freeze in cold slowing the rate of filtration. 25 Cont..
- 26. Rapid mixing: water treated with alum is subjected to violent agitation in a mixing chamber for 30 min. Flocculation:slow and gentle stirring of the treated water in flocculationchamber for about 30 min. Sedimentation: the coagulated water is now led into sedimentation tanks, where it is detained for periods verifying from 2-6 hrs when the flocculantprecipitates together with impurities and bacteria settle down in the tank. 26 Cont.
- 27. Filtration: partly clarified water is now subjected to rapid sand filtration, carried by filter beds. Below sand bed is gravel levels which permits the filtered water to move freely towards drain. As filtration proceeds, the suspended impurities and bacteria clog the filters then filtration is stopped and backwashingdone. It is done on dailyor weekly. 27 Cont.
- 28. Most widelyused disinfectant for killing pathogenic bacteria. It oxidizes iron and manganese in water and has proved a great advancement in water purification on small and large scale. The point at which chlorine demand of water is met is called Break point. If further chlorine is added, free chlorine begins to appearon water. Super chlorination is needed at times when water is colored and contains more organic matter i.e. a large dose of chlorine is used. In such cases, excess of chlorine is neutralized by addition of sodium thiosulphate in the ratio 0.5gm per gallons of water. 28 Chlorination
- 29. Boiling : boiling of water takes 5-10 and kills the cysts, spores of bacteria, expels carbon dioxide and removes temporary hardness. Chemical Disinfection: Bleaching powder: required to disinfect certain quantity of water. Chlorine solution : may be prepared from bleaching powder. High hypochlorite, chlorine tablets, Iodine and potassium permanganate. 29 Purificationon smallscale
- 30. The principle of these filters is that water is made to pass through porous candles which consist of coarse grained or fine grained according to material of which they are made. The domestic filters in use are: Berekefeld Filter : consist of candle made of porcelain. It does not require pressure. Candleshould be boiledgently at the interval of 3-4 days it use. 30 Domesticfiltration
- 31. Pasteurchamberlandfilter : porous tube made of unglazedporcelain. It keeps bacteria by mechanical action. It is quiet reliable in action. 31 Cont