The lecture Water as factor of health its

The lecture Water as factor of health, its hygienic, endemic and epidemiologic value. Organization of drinkable water-supply. Methods of improvement of quality of drinking-water. Ecological problems and sanitary protection of objects of waters. Author: Lototska O. V.

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). • Water covers 71% of the Earth's surface; the oceans contain 97. 2% of the Earth's water.

Every organism consists mostly of water. The human body is usually made up of 50 to 75 percent water. All living things need a lot of water to carry out their life processes.

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.

Body Water Lost And Symptoms % 2% 3% 4% 5% 6 -7 % 8 -9 % 10 % 20 % Few symptoms or signs of any thirst present Beginning to feel thirsty loss of endurance capacity and appetite. Dry mouth performance impaired. Increased effort for exercise, impatience, apathy, vague discomfort, loss of appetite. Difficulty concentrating, increased pulse and breathing, slowing of pace. Further impairment of temperature regulation, higher pulse and breathing, flushed skin, sleepiness, tingling, stumbling, headache. Dizziness, labored breathing, mental confusion, further weakness. Muscle spasms, loss of balance, swelling of tongue. Heat Exhaustion, delirium, stroke, difficulty swallowing; death can occur.

Uses of water 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.

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.

Epidemiological and toxicological role of water A child dies every 20 seconds from water-related diseases.

Water can participate in spread of infections in the following ways: -as transfer factor of pathogens with the faecal-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);

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 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.

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. Mild fluorosis looks like this:

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;

- 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; - watering of the green areas within settlements; 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.

Sources of water

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: 1. It is usually free from pathogenic agents. 2. It usually requires no treatment. 3. Its supply is continuous. The disadvantages of ground water are: 1. It is high in mineral contents 2. It requires pumping or some arrangement to lift the water.

Springs: 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.

WELLS These 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

• • The pollution of water sources represents the import ecological problem. Depending on type of pollution th are: chemical, physical (radioactive substances, hot water), bacterial, virus and biological. Industrial wastewater is characterized by considera 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

Effects of water pollution on health and the economy • quality of drinking tap water, largely depends on the water quality of surface pond that is real or may be potential source of centralized water-supply • contaminated water reservoirs can not be used for irrigation of agricultural lands • loss of water due to pollution is a challenge for the national economy

Direct effects: water on public health Effects of a) during the ingress of water into the body orally, when a person knowingly drinking water from contaminated water or accidentally ingested it while swimming; b) contact of water with the skin and mucous membranes while swimming, bathing, etc. Indirect effects : a) polluted water – contaminated food ("seafood") – human; b) polluted pond – watering of farmland – plant – human; c) polluted pond – cattle – meat (milk) - human.

Sanitary protection of water reservoirs is a set of measures (legislative, organizational, economic, planning, scientific, technological, sanitary) to ensure protection of water from sources of pollution

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. Waters, used for drink and everyday needs, must correspond to the demands: Øgood organoleptic properties: refreshing temperature, transparence, colorless, no smell and no taste. Øharmlessness of its chemical composition Øthe absence of pathogenic microorganisms Øsafety in the radiological attitude

Impure water may be purified by either of the following methods: • • 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 • • Purification of water is of great importance in community medicine. It may be considered under two headings. Purification of water on large scale Purification of water on small scale Three main steps in purification of water on large scale: Storage, Filtration, Chlorination

1. Storage: Water is drawn out from source and impounded in natural or artificial reservoirs. Storage provides a reserve of water from which further pollution is excluded. Advantages • Physical — About 90% of suspended impurities settle down in 24 hours by gravity. • Chemical — The aerobic bacteria oxidize the organic matter present in water with the aid of dissolved oxygen. As a result the content of free ammonia is reduced and a rise in nitrates occur. • Biological — 90 % of total bacterial count drops in first 5 - 7 days.

2. Filtration is important because 98 – 99 % of bacteria are removed by filtration, a part from other impurities. Two types of filters are in use, they are: • a. Slow sand filters (biological filters) • b. Rapid sand filters (Mechanical filters)

Slow sand filter Ø Supernatant (raw) water: Ø Sand bed Ø Vital Layer Ø Under drainage system

Filter control valves: The filter is equipped with certain valves and devices which are incorporated in the outlet pipe system maintaining a steady rate of filtration. When the vital layer becomes dense and resistance to the passage of water is increased the supernatant water is drained off Sand bed is cleaned by scrapping of the top portion of the sand layer to a depth of 1 - 2 cms. Scrapping is done 20 - 30 times. The process is known as Filter Cleaning.

b. Rapid Sand Filter Rapid sand filters are of two types, the gravity type and the pressure type. Both the types are in use.

Filter Beds: Back - Washing: Rapid sand filters need frequent washing daily or weekly. Washing is accomplished by reversing the flow of water through the sand bed, which is called "back-washing". Back - washing dislodges the impurities and cleans up the sand bed.

Comparison of Rapid & Slow Sand Filters. Slow Sand Filter Rapid Sand Filter Space Occupies large space Occupies very little area Rate of filtration 0. 1 -0. 4 m 3/m 2/h 5 - 15 m 3/m 2/h Effective size of sand 0. 15 -0. 35 mm 0. 6 - 2. 0 mm Preliminary treatment Plain sedimentation Chemical coagulation Washing By Scraping the sand By back-washing bed Operations Less skilled Highly skilled Removal of turbidity Good Removal of colour fair Good Removal of bacteria 99. 9 -99. 99 per cent 98 - 99 per cent

Advantages of Slow Sand Advantages of Rapid Sand Filter filter 1. Simple to construct and 1. It deals with raw operate water directly. No. preliminary storage is needed 2. Cost of construction is 2. Occupies less space. cheaper 3. Physical, Biological and 3. Filtration rate is high. Chemical quality ' of filtered water is very high 4. Washing of filter is easy 5. More flexibility operation. in

Water treatment transforms raw surface and groundwater into safe drinking water. Water treatment involves two types of processes: physical removal of solids (mainly mineral and organic particulate matter) and chemical disinfection (killing/inactivating microorganisms).

Treatment practices vary from system to system, but there are four generally accepted basic techniques. The following steps are involved in the purification of water by rapid sand filters. i. Coagulation and Rapid mixing: ii. Flocculation: iii. Sedimentation: iv. Filtration:

How is water treated? Coagulation: Alum and other chemicals are added to water to form tiny sticky particles called "floc" which attract the dirt particles.

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.

CHLORINATION Chlorination is the process in which chlorine is added to water for purification. Chlorination-is more effective when p. H of water is around 7. 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 HOCI ► ► HCI- + HOCI H+ + OCI- The disinfecting action ofchlorine is mainly due to hypochlorous acid and to a small extent due to hypochloriteon.

Principles of Chlorination 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 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 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 p. H 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 The ozone disinfection Ozone contains three oxygen atoms. It is destroyed in water, forming atomic oxygen: O 3 → O 2 → O. Ozone disinfection • (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

Advanced Water Purification System

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. The effectiveness of UV irradiation depends on • the intensity of the light, • depth of exposure and • 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 UVirradiation 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.

PURIFICATION OF WATER ON SMALL SCALE • House hold purification of water • Disinfection 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 (Ca. OCI 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

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. v. Potassium Permanganate. It is a powerful oxidizing agent but not recommended as it alters colours, smell and taste of water.

DISINFECTION OF WELL Wells are main source of water in rural area. The most effective and cheapest method of disinfecting wells is by bleaching powder. Disinfection of well is required in normal days and during epidemics.

Steps: 1. Find volume of water in well. Measure depth of water column — (h) metres Measure the diameter of well— (d) metres Substitute (h) & (d) in: Volume (litres) = π x d 2 x h x 1000 π = 3. 14 4 One cubic metre - 1, 000 litres of water 2. Find amount of bleaching powder required Measures by Horrock's apparatus. Roughly 2. 5 gm of good quality bleaching powder would be required to disinfect 1, 000 litres of water.

3. Dissolve bleaching powder in water The calculated amount of bleaching powder is placed in a bucket (not more than 100 g in one bucket) and made into a thin paste. More water added till bucket is 3/4 full. The contents are stirred and allowed to stand for 5 - 10 minutes. When lime settles down, the supernatant solution which is chlorine solution is transferred to another bucket. 4. Delivery of Chlorine solution into the well. The bucket containing the supernatant chlorine solution is lowered some distance below surface water. The well water is agitated by moving the bucket violently both vertically and laterally. Note: The precipitate or lime is never entered in well because it increases the hardness of water. 5. Contact period - 1 hour contact period is required. 6. Ortho-Tolidine test: It is done to list for residual chlorine at the end of one hour. If "free" residual chlorine level is less than 0. 5 mg/ litre, then procedure should be repeated, before water is drawn.

EXPRESS METHODS OF WATER QUALITY IMPROVING • Deodorization - elimination of smack and odour of water by aeration, usage of oxidants (ozonization, dioxide of chlorine, large doses of chlorine, potassium permanganate), filtrating through a layer of absorbent coal, by introduction in water to sedimentation of absorbent coal. • Deironation is carried out by spraying water with the purpose of aeration in graduation towers. Thus, bivalent iron is oxydated in iron hydroxide, which sediments in settling tank, or delays on the filter.

Softening or Removal of hardness a. b. c. d. a. b. I. Temporary Hardness Boiling Addition of lime Addition of sodium carbonate Permutit process II. Permanent Hardness Addition of sodium carbonate Permutit process/ Base exchange process. Boiling: It removes temporary hardness by expelling carbon dioxide and precipitating the insoluble calcium carbonate. Ca (HCO 3)2→ Ca. CO 3 + CO 2 + H 2 O Addition of Lime: It removes temporary hardness. Lime absorbs carbondioxide and precipitates the insoluble calcium carbonate. Ca (OH)2 + Ca (HCO 3)2 → 2 Ca. CO 3 + 2 H 2 O

Householdwater softenerstypically use a different process, known as ion exchange. Ion-exchangedevices consist of a bed of plastic (polymer) beads covalently bound to anion groups, such as -COO-. The negative charge of these anions is balanced by Na+ cations attached to them. When water containing Ca 2+ and Mg 2+ is passed through the ion exchanger, the Ca 2+ and Mg 2+ ions are more attractedto the anion groups than the Na+ ions. Hence, theyreplacethe Na+ ions on the beads, and so the Na+ ions (which do not form scale) go into the water in their place.

Addition of Sodium Carbonate, It removes both temporary and permanent hardness. Na 2 CO 3 + Ca (HCO 3)2 → 2 Na. HCO 3 + Ca. COs (HCO 3)2 Na 2 CO 3 + Ca. SO 4 → Na 2 SO 4 + Ca. CO 3 Base Exchange Method In this method sodium permutit is used, which is a combination complex of Na, Al and Si (Na 2 Al 2 Si 2 OH 2 O) Sodium permutit has property of exchanging the sodium cation for Ca++ and Mg++ ions in water. Na 2 Al Si 2 O + H 2 O = Mg++/Ca++ When hard water passed, sodium permutit exchanges Mg/ Ca and is converted into calcium and magnesium permutit. With time permutit loses effectiveness, it is regenerated by adding conc. sol of Na. CI. * By this process hardness of water is removed to zero. As zero hardness is corrosive, therefore a part of raw water is mixed with softened water.

Desalting About 97 percent of the water on earth is in the salty oceans. People have found many ways to desalinate, the process for removing salt from seawater and brackish water. The desalination processes used most commonly today are distillation, reverse osmosis, and electrodialysis. These processes produce fresh water from salt water. This is a water purification plant Distillation is the oldest method of turning salt water into fresh water. Seawater can be distilled by simply boiling it in a teapot, and piping the steam into a cool bottle. The salt water turns to vapour under the sun's heat. The vapour rises until it hits the underside of the dome or glass, where it condenses.

Most modern distillation plants use a process called multistage flash distillation. This is a type of the age-old method of boiling and condensation.

In flash distillation, preheated seawater flows into a large chamber in which the pressure is low. The low pressure causes some of the water to instantly turn into steam The steam is condensed into salt-free water. The seawater passes through several distillation chambers. Each of the chambers has a lower pressure than the previous chamber. Often, the final water is so pure that it is tasteless, and some salt must be tossed back in to give it flavour

Reverse osmosis is a widely used method for desalting seawater and brackish water. In normal osmosis, a less concentrated liquid flows through a membrane into a more concentrated liquid. Thus, if salt water and fresh water are separated in a chamber by a special semi-permeable membrane, the fresh water will flow through the membrane into the salt water.

Electrodialysis is used chiefly to desalt brackish ground water and water from estuaries, or river mouths. Electrodialysis is based on the fact that when salt is dissolved in water, it breaks up into ions, or electrically charged particles, of sodium and chloride. Sodium ions carry a positive charge, and chloride ions carry a negative charge.

• Other desalting processes are also being studied. During the 1970's, several plants experimented with freezing as a method of desalination. When seawater freezes, the ice crystals produced are pure water in solid form. The salt is separated and trapped between the ice crystals.

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 1930 s. The maximum protection by fluoridation against tooth decay occurs when children consume fluoridated water from birth through age 13.

For hygienic purposes the examination of water is generally done under the following heads: 1. Physical Examination. 2. Chemical Examination. 3. Microscopical Examination. EXAMINATION OF 4. Bacteriological WATER Examination. Before water from any source is declared fit for human consumption, it is essential to carry out the following examination.

Water Quality Inspection Division conducts inspections of water quality from water sources to household taps and carries out surveys and research in order to ensure safe drinking water. Monitoring and control of water quality To monitor water resources, raw water taken from rivers and lakes is periodically inspected. Moreover, detailed inspections, surveys and research are also conducted with respect to tap water. Sampling in water sources

Water quality inspections Physical and chemical examination Measuring pesticides by GC/MS(gas chromatograph mass spectrometer) Physical, chemical and biological examination Measuring some metals and planktons by the electron microscope.

Response to emergencies Water quality inspection car Microbiological examination Tests for coli form group and standard plate count. Inside of water quality inspection car