Water Quality

Question 1

PSMSID #SRS (Sidharth Revision Series)

Ten one liners/ day

Bacteriological Indicators of Water Quality (Faecal Pollution)

A. Organisms:
1) PRIMARY, MOST RELIABLE :
2) indicating recent contamination
3 indicating remote contamination

B. Tests:

1. Presumptive:
2. Confirmatory:

Biological Water Quality Standards
In 100 ml water

Answer 1

Bacteriological Indicators of Water Quality (Faecal Pollution)

A. Organisms:

1. Coli forms: Primary & most reliable bacterial indicator (E. coli is most important indicator)
2. Faecal streptococci: recent contamination
3. Clostridium: remote contamination

B. Tests:

1. Presumptive: MPN test
   a. Indicator is bromocresol purple
   b. True MPN Index: Mc Crady’s tables
2. Confirmatory: EIKJMAN TESTS

Biological Water Quality Standards
In 100 ml water
1. No sample should have E.coli
2. No sample should have > 3 coliforms
3. Not > 5% samples throughout year should have coliforms
4. No 2 consecutive samples should have coliform organism
A.