WATER QUALITY STANDARDS.ppt

water quality

1. WATER-QUALITY
STANDARDS
DR. ANCHU R NATH
1
ST
YEAR PG RESIDENT
DEPARTMENT OF COMMUNITY MEDICINE

2. Guidelines are related to
Acceptability
aspects
Microbiological
aspects
Chemical
aspects
Radiological
aspects
Physical
parameters
Inorganic
Constituents
Bacteriological
indicators
Virological
Aspects
Inorganic
Constituents
Biological
aspects
Organic
constituents

3. Acceptability aspects
Physical parameters :
(a) Turbidity: It is caused by particulate matter.
It interferes with disinfection and microbiological
determination.
Guideline value is 5 NTU(Nephelometric Turbidity Unit).

5. (b) Color: It may be due to presence of colored organic
matter, metals such as Fe and Mn or highly colored
industrial wastes.
Guideline value is 15 TCU (True Color Unit).
(c) Taste and odor :Originate from contamination by
chemicals, biological sources and as a by-product of
Water treatment.
No guideline value.
(d) Temperature :Cool water is more palatable.
Low water temperature decreases efficiency of
treatment process .
High water temperature increases growth of micro
organisms

6. Microbiological aspects
Bacteriological aspects
Coliform organisms
Fecal streptococci
Cl.perfringens
Virological aspects
Biological aspects
Protozoa
Helminths
Free-living organisms

7. Bacteriological aspects
Ideally drinking water should not contain any microorganism known to be
pathogenic
It should be free from bacteria indicative of fecal contamination
Failure to provide protected water supply will expose the community to
out breaks of intestinal & other infectious diseases
Those at great risk are infants, young children, sick & elderly.

8. Coliform organisms
Primary indicator recommended for this purpose
Include all aerobic & facultative anaerobic, gram-negative, non-sporing,
motile & non-motile rods
Typical eg., fecal-E. coli & non fecal-Klebsiella aerogens
Practically all coli forms should be assumed are of fecal origin unless a
non-fecal origin prove.

9. Why Coliform ?
Constantly present in great abundance in human intestine (average person
excretes 200-400 billion organisms/day)
These organisms are foreign to potable waters
They are easily detected by culture methods ( 1bacteria in 100ml. of water)
Survive longer than pathogens
Have greater resistance to the forces of natural purification

10. Fecal streptococci
Regularly occur in faeces, but in small no.
Confirmatory evidence of recent faecal pollution of
water
Highly resistant for drying, and valuable for routine
control testing after laying new mains or repairs in
distribution systems for detecting pollution by surface
run off to ground or surface waters.

11. Cl.perfringens
Also occur regularly in faeces
Spores survive for longer time than Coliform group and
usually resist chlorination at normal doses
The spores in natural water suggests faecal
contamination at remote time and presence in filtered
supplies indicate deficiency in filtration practice

12. Virological aspects
Drinking water should be free from any viruses
infectious to man
Disinfection with 0.5 mg/lit of free chlorine for 30min.
Contact time at pH 8 is sufficient to inactivate virus
(esp. if the area is endemic for hepatitis)
Ozone has been shown to be effective viral disinfectant,
if residuals of .2 -.4mg/L are maintained for 4min.

13. Biological aspects
Protozoa: E.histolytica, Giardia spp.,
B.colithese organisms can be
introduced into water supplies through
fecal contamination (filtration should
be effective in removing)
Helminths: Food is the major route of
entry
Free living org.: Fungi, Algae etc.,
impede filtration add unwanted colour,
taste, turbidity, & odourto finished
water

14. Chemical aspects
The chemicals selected for the development of guideline value include those
considered potentially hazardous to human & those detected in relatively high
concentrations
They cause adverse effects after prolonged exposure & some heavy metals
have cumulative toxic & carcinogenic properties

15. Chemical constituents-health related
Inorganic constituents
Arsenic, Cadmium, Chromium, Cyanide, Fluoride, Lead,
Mercury, Nitrate and Nitrite, Selenium
Organic constituents
Polynuclear aromatic hydrocarbons, Pesticides

16. Radiological aspects
Somatic effects: if the effects manifest in
the exposed individual (malignancy is the
most important delayed effect)
Hereditary: if they affect the descendants
The activity of a radioactive material is
the number of nuclear disintegration per
unit of time. The unit of activity is a
Becquerel, 1Bq = 1 disintegration per
second
Guideline values are
Gross alpha activity 0.1Bq/L
Gross beta activity 1.0Bq/L

17. Surveillance of drinking water
Sanitary survey
Sampling
Bacteriological surveillance
Presumptive coliform test (multiple tube method,
membrane filtration technique)
Detection of faecal streptococci & Clostridia
Colony count
Biological examination
Chemical surveillance

18. Swimming pool sanitation
Water is exposed to
Faecal contamination
Organisms from skin and nasopharynx

19. Health hazards of
swimming pool
Fungal and viral infections of the skin
Infections of the eye, ear, nose & throat
Infections of the upper respiratory tract
Intestinal infections, and
Accidents

20. Sanitation of swimming pool
Recommended area
Surveillance
Filtration of water
Chlorination
Bacteriological quality

21. Surveillance
Rules & regulations should be posted
Persons suffering from communicable diseases should not be allowed
All bathers should empty bladder & bowel if necessary
Spitting, spouting, blowing nose etc, prohibited
Should provide shower rooms, walk ways & pool decks should receive
proper disinfection

22. Distribution of water supply
Intermittent supply
Continuous supply
Dual supply (most dangerous)

23. Health education
The provision of mere good water supply does not in itself secure freedom
from water borne diseases.
People must recognize safe water as a felt health need and give up their old,
unhygienic habits of polluting water supplies.
In these circumstances health education emerges as an important weapon in
creating among people a desire for higher standards of life.

24. UNICEF
If you are planning for a year -sow rice
If you are planning for a decade -plant tree
If you are planning for a life time -educate the
people