Presentation on theme: "Hygiene localities, its bioethics’ aspects. Water hygiene and water supply. The impact of drinking water quality in General and dental health. The lecture."— Presentation transcript:
Hygiene localities, its bioethics’ aspects. Water hygiene and water supply. The impact of drinking water quality in General and dental health. The lecture Author: Lototska O.V.
Water covers 71% of the Earth's surface; the oceans contain 97.2% of the Earth's water. Water covers 71% of the Earth's surface; the oceans contain 97.2% of the Earth's water. Water is a chemical substance with the chemical formula H 2 O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often coexists on Earth with its solid state, ice, and gaseous state (water vapor or steam).chemical substance chemical formulaoxygenhydrogencovalent liquidambient conditionssolidicegaseouswater vaporsteam
Every organism consists mostly of water. The human body is usually made up of 50 to 75 % water. All living things need a lot of water to carry out their life processes.
Body Water Lost And Symptoms %..... Few symptoms or signs of any thirst present;. 2%..... Beginning to feel thirsty; loss of endurance capacity and appetite. 3%..... Dry mouth; performance impaired. 4%..... Increased effort for exercise, impatience, apathy, vague discomfort, loss of appetite. 5%..... Difficulty concentrating, increased pulse and breathing, slowing of pace. 6-7%..... Further impairment of temperature regulation, higher pulse and breathing, flushed skin, sleepiness, tingling, stumbling, headache. 8-9%..... Dizziness, labored breathing, mental confusion, further weakness. 10%..... Muscle spasms, loss of balance, swelling of tongue. 20%..... Heat Exhaustion, delirium, stroke, difficulty swallowing; death can occur.
Its main functions are that it: Replaces loss of fluids from tissues. Maintains the fluidity of blood and lymph. Helps elimination of waste material of the body. Acts as a vehicle for dissolved food. Helps in the secretion of digestive juices. Regulates body temperature and acts as a distributor of body heat.
Domestic Use: 7 % of water available is for domestic use i.e drinking, cooking, washing, bathing etc. Recommended need of water is 120 liters/day/person. It includes all aspects of life which a person has in his routine life i.e bathing, washing, drinking & for toilet use. Uses of water
Public purpose: Water is required for public cleansing, maintenance of gardens, and swimming pools and other civic activities. Industrial Use: 23 % of available water is used in industries. Agricultural Use: 70 % of available water is used for growth of food and raw materials required.
- as transfer factor of pathogens with the fecal-oral transfer mechanism: enteric infections of bacterial and viral origin (typhoid, paratyphoid А, В, cholera, dysentery, salmonellosis, coli-entheritis, tularaemia /deep-fly or rabbit fever/, viral and epidemic hepatitis А, or Botkin disease, viral hepatitis E, poliomyelitis and other enterovirus diseases, such as Coxsakie, EСНО etc.); geohelminthosis (ascaridiasis, trichocephaliasis, ankylostomiasis); biohelminthosis (echinococcosis, hymenolepiasis); of protozoal etiology (amebic dysentery (amebiasis), lambliasis); zooanthroponosis (tularemia, leptospirosis and brucellosis); Water can participate in spread of infections in the following ways:
as a transfer factor of pathogens of the skin and mucous membrane diseases (when swimming or having another contact with water): trachoma, leprosy, anthrax, contagious molluscum, fungous diseases (i.e., epidermophytosis); -as the habitat of disease carriers – anopheles mosquitoes, which transfer malarial haemamoeba malarial haemamoeba and others (open water reservoirs).
Toxicological role of water consists in it containing chemical agents that may negatively influence people health causing different diseases. They are divided into chemical agents of natural origin, those, which are added to water as reagents and chemical agents, which come into the water as the result of industrial, agricultural and domestic pollution of water supply sources. Insufficient or non-effective treatment of such waters at waterworks procures the continuous toxic effect of small concentrations of chemical agents, or, rarely, in cases of accidents and other emergency situations – acute poisonings.
Balneal role of water Water is used in medicinal purpose for rehabilitation of convalescents (drinking of mineral waters, medicinal baths), and also as tempering factor (bathing, swimming, rub-down).
Domestic and economic role of water Sanitary-hygienic and domestic functions of water include: - water usage for cooking and as a part of dietary intake; - usage of water as means of keeping body, clothes, utensil, residential and public premises and industrial areas, settlements clean;
- watering of the green areas within settlements; - sanitary-transport and disinfection functions of water – disposal of residential and industrial waste through sewer system, waste processing on plants, self-purification of water reservoirs; fire fighting, atmospheric pollution clearing (rain, snow).
Economical functions of water: -usage in agriculture (irrigation in crop and gardening, greenhouses, poultry and cattle breeding farms); -industry (food, chemical, metallurgy etc.); - as the route of passenger and cargo transportation.
RAIN Prime source of all water. Part of rain water sinks to form ground water, part of it evaporates and some runs in streams and rivers. These events are called "water - cycle".
Characteristics: Purest, bright & sparkling colour, soft water, only traces of dissolved solids, corrosive action on lead due to softness, in clean areas rain water is free of pathogens. Impurities: Picks up local impurities such as dust, soot, micro-organisms, CO 2, N 2, O 2, Ammonia & Sulphur. In areas where NO 2 and SO 2 are present in atmosphere, rain water becomes acidic and the rain is called acidic rain.
SURFACE WATER Surface water mostly originates from rain water. It has highest chance of being polluted particularly river water because people near banks throw wastes in it. Sources of surface water are. a.Impounding reservoirs b.Rivers and streams c.Tanks, ponds and lakes.
GROUND WATER It is in form of: a. Wells — Deep well, shallow well, Artesian well. b.Springs — Seasonal springs, thermal springs, mineral spring, shallow springs, and deep springs. The advantages of ground water are: a.It is usually free from pathogenic agents. b.It usually requires no treatment. c.Its supply is continuous. The disadvantages of ground water are: a.It is high in mineral contents b.It requires pumping or some arrangement to lift the water.
A spring is ground water which finds its way to the surface because of topographical features. Cracks present in earth, water enters and comes out from other opening at a low level. So source may be quite far away such as 100-200 miles. Springs:
WELLS These are artificial holes or pits dug into the earth to reach the underground water level. They constitute a very important source of water supply in villages. There are four varieties of wells: WELLS These are artificial holes or pits dug into the earth to reach the underground water level. They constitute a very important source of water supply in villages. There are four varieties of wells:
There are four varieties of wells: 1. Shallow Wells, 2. Deep Wells 3. Artesian Wells are a variety of deep wells in which water under great pressure comes out to the surface automatically 4. Norton's Abyssinian Tube Wells are really shallow wells which are bored by simply driving iron pipes 3.8 to 5 cm. in diameter and 6 to 7.62 metres deep to tap the ground water. A pump is attached to the pipe to draw the water.
Types of aquifers and wells. In a water table well, the water table is at atmospheric pressure. In an artesian well, the water pressure is greater than atmospheric. In a flowing artesian well, the water pressure is such that it can flow freely above the ground surface
Waters, used for drink and everyday needs, must correspond to the demands: good organoleptic properties: refreshing temperature, transparence, colorless, no smell and no taste. harmlessness of its chemical composition the absence of pathogenic microorganisms safety in the radiological attitude The population should be provided not only with enough of water, but also with qualitative water. Water should not cause any pathological change in the organism, should not cause of spread of infectious diseases, and also not to cause unpleasant sensations.
The pollution of water sources represents the important ecological problem. Depending on type of pollution there are: chemical, physical (radioactive substances, hot water), bacterial, virus and biological. Industrial wastewater is characterized by considerable quantity of components. Major categories of water pollutant 1. Infections agents - Bacteria, viruses 2. Organic chemical - Pesticides, plastics, detergents, oil, and gasoline 3. Inorganic chemicals - Acids, caustics, salts, metals 4. Radioactive materials - Uranium, thorium, cesium, iodine, radon
Fluoridation of drinking water as a hygienically problem.
Fluoridation of drinking water as a hygienic problem
Fluoride is a naturally occurring mineral that is found in all water sources. It is considered a beneficial nutrient and is present in trace amounts in the body. At low concentrations in drinking water, it helps strengthen teeth and bones. Fluoride
The amount of fluoride present naturally in drinking water is highly variable, depending on the specific geological environment from which the water is obtained.fluoride In non-fluoridated drinking water (i.e., drinking water to which fluoride has not been intentionally added for the prevention of dental caries) levels may reach up to about 2.0 mg/litre.dental caries However, some places can have fluoride levels in drinking water of up to 20 mg/litre. In areas in which drinking water is fluoridated, the concentration of fluoride in drinking water generally ranges from 0.7 to 1.2 mg/litre. concentration
An "optimum" level of fluoride in drinking water, associated with the maximum level of dental caries protection and minimum level of dental fluorosis, has been determinedfluoridedental cariesdental fluorosis 0,7-1,5 mg/dm 3 of fluoride is the optimal concentration of fluoride in water.
Fluoridation is addition of fluoride to public water supplies to reduce tooth decay. Fluoride is a compound consisting of the element fluorine and a metallic element such as sodium (forming sodium fluoride, used in water supplies) or tin (forming stannous fluoride, used in toothpaste). Water fluoridation has been recognized as a significant method in preventing tooth decay since the 1930s. The maximum protection by fluoridation against tooth decay occurs when children consume fluoridated water from birth through age 13.
Water fluoridation is the controlled addition of fluoride to a public water supply to reduce tooth decay. Fluoridated water has fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride. Fluoridated water operates on tooth surfaces: in the mouth it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities.fluoride public water supplytooth decaysaliva tooth enamel remineralizes
Chronic (long term) exposure to Fluoride in water above 1.5 - 2 mg/liter can result in coloration of the teeth (fluorosis). At higher levels, more severe impacts can result including alteration of bone density resulting in arthritis and tooth damage. The Maximum Contaminant Level (MCL) that has been established by the EPA for Fluoride is 1,5 mg/l. Boiling water with Fluoride will actually increase the concentration. Drinking water systems with source water containing Fluoride in excess of the MCL must treat the water to lower the concentration. Mild fluorosis looks like this:
Even more disturbing than the cosmetic impact that fluoride can have on teeth, research is also linking fluoride to increased risk of cancer (particularly bone cancer) gene mutations reproductive problems neurotoxicity (hyper or depressed activity) bone fluorosis (decreasing density) Dental fluorosis is a health condition caused by an overdose of fluoride. In its severe form it is characterized by black and brown stains, as well as cracking and pitting of the teeth.
Skeletal Fluorosis: Skeletal fluorosis is a bone disease exclusively caused by excessive consumption of fluoride. In advanced cases, skeletal fluorosis causes pain and damage to bones and joints. Common causes of fluorosis include consumption of fluoride from drinking water, and consumption of fluoride from the drinking of tea. In India, the most common cause of fluorosis is fluoride-laden water derived from deep bore wells.
Geographical areas associated with groundwater having over 1.5 mg/L of naturally occurring fluoride, which is above recommended levels. A 1994 World Health Organization expert committee suggested a level of fluoride from 0.5 to 1.0 mg/L groundwaterWorld Health OrganizationgroundwaterWorld Health Organization
Reverse Osmosis FiltrationReverse Osmosis Filtration - This is used to purify several types of bottled water (not all), so some bottled waters are unfluoridated. Reverse osmosis systems are generally unaffordable for personal use. Ways to Remove Fluoride from Water - Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits.
Ways to Remove Fluoride from Water Activated Alumina Defluoridation Filter - These filters are used in locales where fluorosis is prevalent. They are relatively expensive and require frequent replacement, but do offer an option for home water filtration. Distillation Filtration - There are commercially available distillation filters that can be purchased to remove fluoride from water.
Hazards of Polluted Water: 1.Biological Hazards These are due to some specific agent that causes ill- health. Bacterial Typhoid, Bacillary dysentery, Cholera etc. Viral Viral hepatitis A & E, Poliomyelitis. Protozoal Amoebiasis, Giardiasis. Helminthic Round worm, whip worm, hydatid disease Leptospiral Weil's disease Cyclops Guinea worm.
2. Other Hazards a. GIT disturbances due to Na ++, Mg ++ & Ca++ ions, e.g) increased MgSO4 lead to diarrhea. b. Lead poisoning c. Iodine deficiency d. Fluorine deficiency e. Hardness of water f. Infant methaemoglobinemia.
Impure water may be purified by either of the following methods: A. Natural A. Natural (a) Pounding or Storage. (b) Oxidation and Settlement. B. Artificial I. Physical Distillation. Boiling. II. Chemical Precipitation. Disinfection or Sterilization. III. Filtration "Biological" or "Slow Sand" Filtration. "Rapid Sand" or "Mechanical" Filtration. Domestic Filtration.
PURIFICATION OF WATER ON SMALL SCALE House hold purification of waterHouse hold purification of water Disinfection of wellsDisinfection of wells HOUSE HOLD PURIFICATION a.By Boiling: Water should be boiled for 5 -10 minutes. It kills all bacteria, spores, cysts & ova. It removes temporary hardness Taste is altered but is harmless
b.Chemical disinfection i) Bleaching Powder (CaOCI 2 ) Bleaching powder is a white amorphous powder. Produced by action of chlorine on slaked lime. When freshly made contains 33 % of available chlorine. It must be stored at dark, cool, dry place in a closed container that is resistant to corrosion. In practise one cup (250 g) of laundry bleach is mixed with three cups (750 ml) of water to make a litre. Three drops of this solution are added to 1 litre water for disinfection. Contact period is 30 minutes to 60 minutes.
ii Chlorine Solution Chlorine solution may be prepared from bleaching powder. * If 4 kg of bleaching powder with 25 % available chlorine is mixed with 20 litres of water, it will give a 5% solution of chlorine. * This solution should be kept in dark, cool and dry place in closed container
v.Potassium Permanganate. It is a powerful oxidizing agent but not recommended as it alters colours, smell and taste of water. iii. Chlorine tablets Available under different trade name e.g. Halazone One tablet of 0.5 g is sufficient to disinfect 20 litres of water. Used in camps and during travel. iv. Iodine: Two drops of 2 % ethanol solution of iodine is used. A contact period of 20 - 30 minute is sufficient for 1 litre water.
CHLORINATION Chlorination is the process in which chlorine is added to water for purification. Chlorination-is more effective when pH of water is around 7. Effects of Chlorine: Effects of Chlorine: a. Chlorine kills pathogenic bacteria, it has no effect on spores and certain viruses. b.It has germicidal effects. c. It oxidizes iron, manganese and Hydrogen sulphide d.If destroys some taste and odour producing constituents. e. It controls algae and slim organisms f. It aids coagulation
Action of Chlorine When Chlorine is added to water, there is formation of hypochlorous and hydrochloric acid. The hydrochloric acid is neutralised by alkalinity of the water. The hypochlorous acid ionizes to form hydrogen ions and hypochlorite ions as follows. H 2 O + CI 2 ► HCI - + HOCI HOCI ► H + + OCI - The disinfecting action ofchlorine is mainly due to hypochlorous acid and to a small extent due to hypochloriteon.
Principles of Chlorination First, water should be clear and free from turbidity. a.First, water should be clear and free from turbidity. b.Chlorine demand of water should be estimated. c.At least one hour is essential as a contact period of free residual chlorine for killing bacterial and viruses. d.Minimum recommended concentration of free chlorine is 0.5 mg/L for one hour. e.The sum of the chlorine demand of the specific water plus the free residual chlorine of 0.5 mg/l constitutes the correct dose of chlorine to be applied.
Methods of Chlorination a.By means of chlorine gas It is of first choice because it is cheap, quick in action, efficient and easy to apply. Chlorinating equipment is required to apply chlorine gas to water as chlorine gas is irritant to eyes. b.By means of Chloramine: Chloramines are loose compounds of chlorine and ammonia. They have slower action than chlorine. They give more persistent type of residual chlorine. They have a less tendency to produce chlorinous taste.
Chlorine Demand It is the difference between the amount of chlorine added to the water and the amount of residual chlorine remaining at the end of a specific period of contact (1 hour) at a given temperature and pH of water. Residual Chlorine: Amount of untreated chlorine, remaining in the water after some time as an effective disinfecting agent i.e. 0.3 – 0.5 mg/liter Break point chlorination: The point at which the chlorine demand of water is met and if further chlorine is added free chlorine begin to appear in water Super Chlorination: It is addition of large doses of chlorine to the water and removal of excess of chlorine after disinfection.
Agents alternative to Chlorination Agents alternative to Chlorination The ozonization of water Ozone contains three oxygen atoms. It is destroyed in water, forming atomic oxygen: O3 → O2 → O. ozonization is one of the best methods of disinfection: water is well disinfected, organic admixtures become destroyed, organoleptic features are improved. Water becomes blue and it is equated with spring water. Ozone dose is 0,5 - 6 mg/l. Sometimes, higher doses are necessary for the lighting of water and improving other organoleptic features. The time of disinfection is 3-5 min. The remaining ozone should make up 0,1 – 0,3 mg/l. The concentration of the remaining ozone 0.4 mg/l provides the reliable inactivation of 99 % viruses for 5 min.
Asaka Water Purification Plant Ozone has been used in water treatment since 1903. It is more effective against bacteria and viruses than chlorine and adds no chemicals to the water. Ozone cannot be stored and requires an on-site ozone generator. In general, ozonation equipment and operating costs are higher than other treatment procedures Ozone has been used in water treatment since 1903. It is more effective against bacteria and viruses than chlorine and adds no chemicals to the water. Ozone cannot be stored and requires an on-site ozone generator. In general, ozonation equipment and operating costs are higher than other treatment procedures
Ultraviolet Light Ultraviolet irradiation will kill bacteria by creating photochemical changes in its DNA. No chemicals are added to the water by this process. Most ultraviolet water treatment units consist of one or more ultraviolet lamps usually enclosed in a quartz sleeve, around which the water flows. The UV lamps are similar to fluorescent lamps and the quartz sleeve surrounding each lamp protects the lamp from the cooling action of water. The killing effect of the lamp is reduced when the lamp temperature is lowered. Ground water is usually a constant temperature year round and so it is possible to set a flow rate that will not lead to excess cooling. Ultraviolet irradiation will kill bacteria by creating photochemical changes in its DNA. No chemicals are added to the water by this process. Most ultraviolet water treatment units consist of one or more ultraviolet lamps usually enclosed in a quartz sleeve, around which the water flows. The UV lamps are similar to fluorescent lamps and the quartz sleeve surrounding each lamp protects the lamp from the cooling action of water. The killing effect of the lamp is reduced when the lamp temperature is lowered. Ground water is usually a constant temperature year round and so it is possible to set a flow rate that will not lead to excess cooling. The effectiveness of UV irradiation depends on the intensity of the light, the intensity of the light, depth of exposure and depth of exposure and contact time. contact time.
Water passes in a relatively thin layer around the lamp; therefore, water flow must be regulated to ensure that all organisms receive adequate exposure. If the water is at all turbid, or if it contains traces of iron, the effectiveness of UV is greatly reduced. In such cases, the water needs to be filtered before it reaches the UV system. The maximal bactericidal effect is achieved by the waves 250-260 nm, which pass even through the 25 cm layer of transparent and decolorized water. The disinfection proceeds very quickly: vegetative forms of microorganisms die in 1-2 min. The turbidity, colour and iron salts decelerate the disinfection, decreasing the transparence of water. Consequently, it is necessary to light and decolorize water before the disinfection.
There are some advantages of UV- irradiation over the chlorination: bactericidal rays don't denaturate the water and don't change its organoleptic features, they have wider biological action. Their bactericidal action is spread over the spores, viruses and worm eggs, resistant to chlorine. Many investigators consider this method the best for the disinfection.
The following steps are involved in the purification of water by rapid sand filters. i. Coagulation: ii. Rapid mixing: iii. Flocculation: iv. Sedimentation: v. Filtration:
Coagulation: Alum and other chemicals are added to water to form tiny sticky particles called "floc" which attract the dirt particles. How is water treated?
Sedimentation: The heavy particles (floc) settle to the bottom and clear water moves to filtration.
Filtration: The water passes through filters that help to remove smaller particles.
Disinfection: A small amount of chlorine is added to kill any bacteria or microorganisms that may be in the water.
Storage: Water is placed in a closed tank or reservoir where it flows through pipes to homes and businesses in the community.