The lecture

1. Hygiene of populated places its bioethical issues. Hygiene and water supply. Effect of water quality on the general and dental health. The lecture Author: Lototska O.V.

2. Water is a chemical substance with the chemical formula H2O. 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.

3. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. Epidemiological and toxicological role of water

10. Water can participate in spread of infections in the following ways: - 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);

11. 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).

12. 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.

13. 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).

14. 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;

15. - 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).

16. 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.

18. Sources of water

19. 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".

20. 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, CO2, N2, O2, Ammonia & Sulphur. In areas where NO2 and SO2 are present in atmosphere, rain water becomes acidic and the rain is called acidic rain.

21. 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.

22. GROUND WATER • It is in form of: • a. Wells — Deep well, shallow well, Artesian well. • 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. • It usually requires no treatment. • Its supply is continuous. • The disadvantages of ground water are: • a. It ishigh in mineral contents • It requires pumping or some arrangement to lift the water.

23. 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.

24. WELLSThese 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:

25. There are four varieties of wells:1. Shallow Wells,2. Deep Wells3. Artesian Wellsare a variety of deep wells in which water under great pressure comes out to the surface automatically4. Norton's Abyssinian Tube Wellsare 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 theground water. A pump is attached to the pipe to draw the water.

26. 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

27. 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: • 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

28. 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

29. Fluoridation of drinking water as a hygienically problem.

31. Fluoridation of drinking water as a hygienic problem

32. Fluoride 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.

33. The amount of fluoride present naturally in drinking water is highly variable, depending on the specific geological environment from which the water is obtained. 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. 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.

34. 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 determined 0,7-1,5 mg/dm3of fluoride is the optimal concentration of fluoride in water.

35. 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.

36. 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.

37. 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:

38. 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. • 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)

39. 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. Skeletal Fluorosis:

41. Geographical areas associated with groundwaterhaving 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

42. Ways to Remove Fluoride from Water - Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. Reverse 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.

43. 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.

44. Hazards of Polluted Water: • Biological Hazards • These are due to some specific agent that causes ill-health.

45. 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.

46. 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.

47. 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

48. Chemical disinfection • i) Bleaching Powder (CaOCI2) • 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.

49. 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

50. 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.