When groundwater becomes contaminated with organic matters especially with animal dung it may contain coliform bacteria. How can we detect the presence of coliform bacteria in water?
Basicaly Sudip Saha Coliform Bacteria is an indicator of contaminations. It is important to know the background for interpreting the observations. Hence I just mention the background first and then the method.
There are three categories commonly discussed.
a. Total Coliform: Environmental contaminations
b. Fecal Coliform: Fecal contaminations
c. E. coli: Sub group of Fecal coliform (E. coli O157:H7 is human pathogenic).
Hence you may have to select which of these to analyze.
Then there are several methods, Standard methods like APHA, USEPA and WHO are available. According to my experience, filtration method is easier compared to multiple tube method for your case.
https://www.who.int/water_sanitation_health/resourcesquality/wqmchap10.pdf
https://www.epa.gov/sites/production/files/2015-08/documents/method_1604_2002.pdf
There are some manufacturers who provide test kits (easy to operate for those who are not experts in the culture based analytical methods).
http://www.lamotte.com/en/microbiological/coliform
https://www.thomassci.com/scientific-supplies/Coliform-Test-Kit
Reference figures from: https://www.doh.wa.gov/Portals/1/Documents/Pubs/331-181.pdf
and USEPA.
Basicaly Sudip Saha Coliform Bacteria is an indicator of contaminations. It is important to know the background for interpreting the observations. Hence I just mention the background first and then the method.
There are three categories commonly discussed.
a. Total Coliform: Environmental contaminations
b. Fecal Coliform: Fecal contaminations
c. E. coli: Sub group of Fecal coliform (E. coli O157:H7 is human pathogenic).
Hence you may have to select which of these to analyze.
Then there are several methods, Standard methods like APHA, USEPA and WHO are available. According to my experience, filtration method is easier compared to multiple tube method for your case.
https://www.who.int/water_sanitation_health/resourcesquality/wqmchap10.pdf
https://www.epa.gov/sites/production/files/2015-08/documents/method_1604_2002.pdf
There are some manufacturers who provide test kits (easy to operate for those who are not experts in the culture based analytical methods).
http://www.lamotte.com/en/microbiological/coliform
https://www.thomassci.com/scientific-supplies/Coliform-Test-Kit
Reference figures from: https://www.doh.wa.gov/Portals/1/Documents/Pubs/331-181.pdf
and USEPA.
Dear Saha,
There are two main techniques to determine Coliform in the water samples,
1. MPN method
2. Membrane filtration method
MPN method will take long process and long time - 24 hrs for coliform bacteria and 48 hrs for feacal coliform bacteria. Results can take as MPN value.
Membrane filtration technique use for several possible mediums like MLGA.
MLGA will indicate different colors for Coliforms (yellow) and E.coli (green) therefore, identification and counting cell numbers easy than other methods. Results can take as CFU/100ml within 24hrs.
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