Enviromental Health nd factors effecting it .pptx

Environmental health factors effecting

1. ENVIRONMENTAL HEALTH Maj Rushda Kausar

2. Environment “All the external factors living and non living, Material and non material surrounding and affecting a given organism ”

3. Environmental health Clean air, stable climate, adequate water, sanitation and hygiene, safe use of chemicals, protection from radiation, healthy and safe workplaces, sound agricultural practices, health-supportive cities, and built environments, and a preserved nature are all prerequisites for good health who

4. Components of environment

5. Biological Environment Animals Plants and eukaryotic organisms Arthropods Viruses Bacteria Cholera Typhoid TB Fungal Infection, poisoning Zoonoses Rabies Yellow fever Plague Malaria (parasite) Dengue (Viruses) Chicken pox Polio myelitis Measles Influenza

6. SOCIAL ENVIRONMENT Values/ Culture/ Socio-Economic conditions/ Employment/ Poverty/ Education/ Politics/ Religion/ Technology/ Urbanization HEALTH EFFECTS Inequitable Health care Malnutrition Depression/ Anxiety Mental stress Accidents Poor dental hygiene Reduced life expectancy Hygiene-related diseases like Scabies/ Fungal infections Poor environmental sanitation diseases SOCIAL PROBLEMS Poverty Unemployment Corruption Hunger Drug Addiction Alcoholism Bullying Gambling Prostitution Underage marriages Inequality of wealth Gender inequality

7. Safe and whole some water Free from pathogenic agents free from harmful chemicals Pleasant to taste (free from color and odour Usable for domestic purpose Water is said to be polluted or contaminated if doesn't fulfill above criteria

8. Sources of water Rain - Is the prime source of water - Is the purest form of the water in nature - Chemically it is very soft water contains traces (0.0005%) of solids Surface water - Impounding reservoirs Artificial lakes for storing large quantities Next to rainwater in purity - Rivers and streams Grossly polluted unfit for drinking without treatment - tanks ponds and lakes

9. Sources of water Ground water - shallow wells moderately hard hard , grossly contaminated water Taps water from above 1 st impervious layer - deep wells much hard, pure water, constant supply taps water from below 1 st impervious layer - Springs

10. Criteria for identification of problem habitation Not covered (NC) / No Safe Source (NSS) Habitations: - drinking water source is not within 1. 6 km in plain 100 m elevation in hilly areas - water sources affected with quality problems like excess salinity, iron, fluoride, arsenic, or other toxic material or biologically contaminated - Quantum of availability of safe water is not enough to meet drinking and cooking needs Partially covered (PC) habitations: - drinking water source is within 1. 6 km in plain 100 m elevation in hilly areas - Capacity of system is 10 – 40 lpcd Fully covered (FC) habitations: include all the remaining habitations

11. Purification of water Purification of water in a large scale Storage of water - physical - Chemical - Biological Filtration of water - slow sand (biological filters) - Rapid sand (Mechanical filters) Disinfection of water - chlorination - Ozonation - Ultraviolet irradiation

12. Cont … Purification of water on a small scale Household purification of water - Boiling - Chemical disinfection: bleaching powder, Chlorine solution, high test hypochlorite (HTH), Chlorine ( Halozone ) tablets, Iodine, Potassium permanganate - Filtration: Ceramic filters ( pasteur chamberland filter, berkefeld filter, katadyn filter) Disinfection of wells - Chemical: bleaching powder (double pot method )

13. • There are two cylindrical pots • One pot is placed inside the other • Outer pot: - Inside height is 30 cm - Inside diameter is 25 cm - A hole (1 cm diameter) is made at 4 cm above the bottom • Inside pot: - Fits into the outer pot - Has a hole (1 cm diameter) near the upper end • A mixture of 1 Kg bleaching powder and 2 Kg sand is prepared and moistened with some water • The inner pot is filled with this mixture up to 3 cm below the hole • The inner pot is placed into the outer one • The mouth of the latter is closed with polyethylene foil The pot should be immersed at least 1 m below the water level to prevent damage by the buckets used for drawing water This device works satisfactorily for 2 – 3 weeks in small household wells containing 4500 L of water and a draw off rate of 360 to 450 L per day

14. Comparison of rapid and slow sand filters RAPID SAND FILTER SLOW SAND FILTER Space Occupies very little space Occupies large area Rate of filtration 200 m.g.a.d 2-3 m.g.a.d Effective size of sand 0.4-0.7 mm 0.2-0.3 mm Preliminary treatment Coagulation, sedimentation Plain sedimentation Washing By black- washing By scraping sand bed Frequent washing Required Not required Mechanism of action Physically essential Both physically and mechanically Operation Highly skilled Less skilled Loss of head allowed 6-8 feet 4 feet Removal of turbidity Good Good Removal of colour Good Fair Removal of bacteria 68-69 percent 99.9-99.9 percent Suitability For big cities For small towns

15. WHO recommendations for drinking water quality Color < 15 true color units (TCU) Turbidity < 1nephlometric turbidity units (NTU) Hardiness < 100 – 300 mg / ltr calcium ion PH 6.5 – 8.5 Total dissolved solids (TDS) < 1000 mg / ltr Pathogenic microorganisms Zero Infectious viruses Zero Pathogenic protozoa & infective stages of helminths Zero Fluoride < 1.5 ppm(0.5 – 0.8: optimum level) Nitrates < 50 mg / ltr Nitrites < 3 mg / ltr Gross alpha radiological activity < 0.5 Bq / ltr Gross beta radiological activity < 1.0 Bq / ltr

16. Chlorination of water Disinfecting action of chlorine in water is due to: Hypochlorous Acid (HOCL)– main role in disinfection Hypochlorite ions (OCL) – minor role in disinfection Chlorine has germicidal effect (not Ozone or UV rays): provides a margin of safety against subsequent microbial contamination, as occurs during storage and distribution Phases of chlorination - phase I: formation of chloramines - phase II: destruction of chloramines - phase III: appearance of breakpoint - phase IV : accumulation of free residual chlorine Recommended contact period of free residual chlorine in water:1hr

17. (1 mg per ltr = 1ppm)

18. Level of free residual chlorine ( frc ) Water type Recommended Residual chlorine level Contact period Drinking water > 0.5 mg per ltr (PPM) 1 hr Water bodies, post disaster > 0.7 mg per ltr (PPM) 1 hr Swimming pool sanitation > 1.0 mg per ltr (PPM) 1 hr

19. Instrument used in chlorination of water Instrument Utility Horrock’s Apparatus Chlorine demand estimation Chlorinator / chloronome Mixing or regulating dose of chlorine Chloroscope Measuring residual level of chlorine

20. Test for chlorination of water Ortho-toluidine (OT) test : measure the level of Free (residual) chlorine Free and combined chlorine Ortho-toluidine Arsenite (OTA) test : a measure of the level of Free chlorine Combined chlorine The OTA test is better than the OT test as : Detects both free and combined chlorine separately Not affected by interfering substances (nitrites, iron, manganese )

21. Horrock’s apparatus Use: to find out the dose of bleaching powder required for disinfection of water, i.e. ‘ chlorine demand estimation of water ’ Contents: - 6 white cups (200 ml capacity each) - 1 black cup (with a circular mark inside) - 2 metal spoons - 7 glass stirring rods Indicator: starch inside (producing blue color) - Dose of bleaching powder required (chlorine demand): n x2 gms to disinfect 445 liters of water (where n= no. of the first cup which shows a distinct blue color) - Development of blue color indicator: presence of free residual chlorine

22. Hardness of water Hardness of water is defined as the ‘soap destroying power of water Hardness of water is of two types: type of hardness Underlying causes Temporary hardness(carbonate hardness) Calcium and magnesium salts of bicarbonates Permanent hardness (non-carbonate hardness) Calcium and magnesium salts of sulfates Calcium and magnesium salts of chlorides Calcium and magnesium salts of nirates

23. Hardness of water Hardness of water is expressed in terms of milliequivalents per liters ( meq / litre ) of CALCIUM CARBONATE (CaCO 3 ) - 1meq/liter hardness= 50 CaCO3 (50 ppm) per liter of water Classification of hardness in water: Classification Level of hardness ( mq /liter) Soft water < 1(< 50 mg/l) Moderately hard water 1-3 (50-150 mg/l) Hard water 3-6 (150-300 mg/l) Very hard rock >6 (> 300mg/l)

24. Hardness of water Softening of water is recommended at least of hardness > 3 meq /liter (> 150 mg/liter of calcium carbonate) Methods of removal of hardness of water Type of hardness Methods of removal Temporary hardness Boiling Addition of lime Addition of sodium carbonate Permutit process Permanent hardness Addition of sodium carbonate Base exchange process

25. Bacteriological indicators of water quality Coliform organism - Primary and reliable bacterial indicator for water quality - E. coli is the most important coliform indicator - Reasons for choosing coliform as an indicator of fecal pollution rather than water-borne pathogen : - A constant presence in great abundance in the human intestine; foreign to potable waters. - Easily detected by culture methods. - Longer survival period. - Greater resistance of natural purification. Fecal streptococci: - Indicate ‘recent contamination of water’ Clostridium perfringens: - Indicate ‘remote contamination of water

26. Presumptive coliform test MPN Multiple Tube tests: based on estimating the most probable number (MPN) of coliform organisms in 100 ml of water - Culture medium: McConkey’s Lactose Bile Salt broth - Indicator: Bromocresol purple - Presumption: Tube showing fermentation (acid and gas) contains coliforms - Method: 4 tubes inoculated with 0.1,1.0,50 ml of water and incubated for 48 hrs - Confirmatory tests ( EIKJMAN’S tests) : Subculture each presumptive positive tube in 2 tubes of brilliant green bile broth - Incubate one tube 37 C x 48 hrs : confirmation of the presence of coliforms - Incubate second tube at 44 C x 6-24 hrs : confirmation of presence of E.coli - True MPN Index: calculate revised MPN from McCrady’s tables Membrane Filtration Technique: - Membrane: cellulose ester - Method: pass a known volume of water through membrane, inoculate membrane on suitable media, and count colonies In 20 hrs.

27. Public health classification of water-borne diseases Waterborne disease: occurs due to drinking contaminated water, transmitted by faeco-oral route - Example: typhoid, cholera, dysentery, viral hepatitis A Water-washed diseases: include infections of the outer body surface which occur due to inadequate use of water or improper hygiene - Example: scabies, trachoma, typhus, bacillary dysentery, amoebic dysentery Water-based disease: refers to infections transmitted through aquatic invertebrate animal - Example: schistosomiasis, dracunculiasis (guinea worm disease) Water-related disease (water breeding disease): are infections spread by insects that depend on water - Examples: malaria, filariasis, dengue, yellow fever, onchocerciasis