This document discusses environmental factors related to health, with a focus on water. It covers water requirements, sources of water supply like rain, surface water and ground water. It discusses water pollution, purification methods like filtration and disinfection, and standards for drinking water quality. The goals of national water programs in India to improve access are also mentioned.

1. Environment in health and
disease (Water)
Presented by,
Dr. Shivashankar.K
P.G., Dept of Public Health Dentistry

2. CONTENTS
 INTRODUCTION
 ENVIRONMENTAL FACTORS
 WATER REQUIREMENT
 USES OF WATER
 SOURCES OF WATER SUPPLY
 WATER POLLUTION
 PURIFICATION OF WATER
 WATER QUALITY-CRITERIA AND STANDARDS
 SURVEILLANCE OF DRINKING WATER QUALITY
 HARDNESS OF WATER
 CONCLUSION
 REFERENCES

3. Introduction
• The study of disease is really the study of man and his
environment.
• All external factors--- living+ non-living+ non-material
• Social and economic conditions

4. Components of environment
Physical
Social
Biological

5. Sanitation
Environmental sanitation: “the control of all
those factors in man’s physical environment
which exercise or may exercise a deleterious
effect on his physical development, health
and survival”.
(WHO)

6. Environmentalfactorsinfluencingthespreadof
communicablediseases

8. Water

9. Safe and wholesome water
Free of Pathogenic agents
Free of harmful Chemical substance
Pleasant to taste
Useable

10. Requirements
2 liters per head per day
The consumption of water – climatic conditions
A daily supply of 150-200l iters per capita
In rural India 40 liters per day is the target

11. USES OF WATER
a) Domestic
b) Public
c) Industrial
d) Agricultural
e) Power production
f) Carrying away

12. SOURCES OF WATER
3 main sources:
Rain
Surface water
Ground water

13. RAIN
 Physically- clear, bright and sparkling
 Chemically- soft
 Bacteriologically- free of pathogens

14. SURFACE WATER
IMPOUNDING RESERVOIRS
 Artificial lakes
 Dams built across rivers and mountain
streams.
RIVERS AND STREAMS
TANKS, LAKES AND PONDS
Large excavations in which surface water is
stored

15. • SEA WATER

16. GROUND WATER
• Rain water percolating into ground
• Cheapest & most practical way of
providing water to small communities
Advantages:
• Likely to be free from pathogenic agents
• Usually requires no treatment
• Supply likely to be certain even during
dry season
• Less subjected to contamination

17. Ground water
wells springs
Shallow and
Deep
Dug
and
Tube
Dug
Katcha well
(sanitary)
Pucca well

18. Characteristics SHALLOW WELLS DEEP WELLS
Definition Taps the water from above the
first impervious layer
Taps the water from below the
first impervious layer
Chemical quality Moderately hard Much hard
Bacteriological quality
Often grossly contaminated
Taps purer water
Yield Usually goes dry in summer Provides a source of constant
supply

20. SANITARY WELL
A sanitary well is one which is
properly located, well-constructed
and protected against
contamination with a view to yield
a supply of safe water.
Points to be taken into
consideration:
1. Location- 15m
2. Lining-6m
3. Parapet-70cms
4. Platform-1m
5. Drain
6. Covering
7. Hand pump
8. Consumer responsibility
9. Quality

21. SPRINGS
When ground water comes to the surface and flows freely under natural
pressure, it is called a ‘spring’.

22. WATER POLLUTION
Natural impurities
Dissolved gases
Microscopic organisms
Suspended
impurities
Dissolved
minerals

23. Man made impurities
Sewage Industrial and trade
wastes
Agricultural pollutants Physical polutants

24. Indicators of water pollution
• Amount of total suspended solids
• Biochemical oxygen demand (BOD) at 20 deg. C
• Concentration of chlorides
• Nitrogen and phosphorus
• Absence of dissolved oxygen.

25. Water related diseases

26. Water related diseases
b) CHEMICAL:
• Chemical pollutants of diverse nature
• may affect man’s health directly and indirectly
Other associated ...
Dental health
Cyanosis in infant
Cardiovascular diseases
inadequate use of water
Some diseases are related to the disease carrying insects

27. Water Pollution Law
• In India, water pollution is becoming a serious problem.
• Parliament in 1974-Water (Prevention and Control of
Pollution) Act.
• Seeks to provide legal deterrent against the spread of water
pollution.
• The Act is a comprehensive piece of legislation.
• It provides for the constitution of State and Central Water
Boards and Joint Water Boards endowed with wide powers for
controlling pollution.

29. Purification of water

30. Purification on large scale
Storage :
Water is drawn out from the source and impounded in
natural or artificial reservoirs.
Due to storage, purification occurs:
I. Physical
II. Chemical
III. Biological
Optimum period of storage 10-14 days.

31. Purification on large scale
Filtration
Second stage in water purification
 98-99% of bacteria are removed by filtration
Types of filters
 Slow sand filter/ biological
 Rapid sand filter/ mechanical

32. Slow sand filters
a) Supernatant (raw) water: Above sand bed; depth varies
from 1 to 1.5M (always kept constant).

33. b). Sand bed
• Most important part of the filter. Thickness of 1 Meter
• Sand grains are carefully chosen - round and have "effective
diameter" of 0.2-0.3 mm

34. VITAL LAYER: ‘Schmutzdecke’ layer, Zoogleal layer, Biological layer
• Slimmy gelatinous layer - Algae, planktons, diatoms & bacteria.
• Formation of vital layer – ‘Ripening’ of the filter.
• When fully formed -extends for 2-3 cm into the top portion of the sand
bed.
• Heart of slow sand filter.

35. c) UNDER DRAINAGE SYSTEM
• FILTER BOX
• Supernatant water- 1 to 1.5m
• Sand bed-1.2m
• Gravel support-0.30m
• Filter bottom-0.16m
d) FILTER CONTROL
• Venturi meter- measures loss of head
• Loss of head 1.3meter- uneconomical

37. Cleaning:
Scraping of the top portion by 1 or 2 cms
Advantages:
• Simple to construct and operate.
• The cost of construction is cheaper
• quality of water is very high.
• reduce bacterial counts by 99.9 to 99.99 per cent and E. coli
by 99 to 99.9 per cent.

38. Rapid sand filters
Gravity type Pressure type (Candy 's filter)
• Coagulation
• Rapid mixing
• Flocculation
• Sedimentation
• Filtration

40. 1.COAGULATION:
• Raw water+Alum (5-40mg/L) chemical coagulant
2.RAPID MIXING:
• Violent agitations in mixing chamber (few min)
3.FLOCCULATION:
• Slow & gentle stirring of treated water(30 min.)
• Mechanical type of flocculator
• Thick, copious, white floccules precipitate Of aluminum
hydroxide.

41. 4. SEDIMENTATION
• Detained here for 2-6 hrs
5. FILTRATION:
Filter bed
• Surface area: 80-90 sq.M
• Media: sand
• Particle size: 0.4-0.7mm
• Depth: 1M
• Depth of water on sand bed is 1-1.5mm
Slimmy layer: Absorbs bacteria - purification

42. Cleaning:
Advantages:
1.No preliminary storage is needed.
2.The filter beds occupy less space.
3.Filtration is rapid
1.washing is easy.
2.Flexibility in operation.

43. Properties Rapid sand filter Slow sand filter
Area Small Large
Rate of filtration
(L/m2/hr)
4000-7500 100-400
Sand size (diameter) 0.4-0.7 mm 0.2-0.3 mm
pretreatment Coagulation and
sedimentation
Sedimentation
Filter cleaning Back washing Scraping
Operation More skilled Less skilled
Removal of bacteria 98-99% 99.9-99.99%
Prior water storage Storage needed No need

44. DISINFECTION
CHLORINATION:
Mechanism of action:
H2O + CL2 -- HCL + HOCL
HCL is neutralized by alkalinity of water
HOCL (Hypochlorus acid) Ionises into H + OCL (Hydrogen & Hypochlorite
ion)

45. Methods of chlorination
1. Chlorine gas
2. Chloromine
3. Perchloron
Superchlorination
Orthotolidine (OT) test
Orthotolidine-arsenite (OAT) test

46. Other agents
a)Ozone oxidizing agent
b)U-V radiation

47. PURIFICATION OFWATER ONASMALL
SCALE
a. HOUSEHOLD PURIFICATION OF WATER:
• Boiling
• Chemical disinfection
• filtration
• Ultra violet irradiation
• Multistage reverse osmosis purification of water.

48. PURIFICATION OFWATER ONA
SMALLSCALE
b. Disinfection of wells

49. WATER QUALITY - CRITERIA &
STANDARDS
WHO guidelines for drinking water quality.
1. Acceptability aspects
2. Microbiological aspects
3. Chemical aspects
4. Radiological aspects

50. Microbiological aspects
Presence of fecal streptococci, sulfite reducing clostridia- primary
bacteriological indicator.
Acceptability aspects

51. Radiological aspects

52. Chemical aspects

53. NATIONALWATERSUPPLYAND SANITATION
PROGRAM
• The National Water Supply and Sanitation Program was launched
in 1954 by the Govt. of India …
• Provision has been made in the successive 5-year Plans to improve
the water supply.
• HEALTH EDUCATION…The provision of merely good water supply
does not in itself secure freedom from water-borne diseases.
…….important weapon in creating among people a desire for
higher standards of life.

57. CONCLUSION

58. REFERENCES
• Textbook of preventive and social medicine – K.Park 20TH Edition
• Environmental Health In Emergencies. WHO practical guide 2002
• The International Water and Sanitation Decade (1981-90) “Water for
All” by 1990
• WHO 1972.Health hazards of human environment, WHO, Geneva
• WHO 1995. The World health report 1995, Bridging the gaps, p-41
• WHO 2012, World health statistics 2012
• Water and sanitation interlinkages across the 2030 Agenda for
Sustainable Development. WHO