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H2S paper strip method - A bacteriological test for faecal coliforms in drinking water at various temperatures
Conference paper   Open access

H2S paper strip method - A bacteriological test for faecal coliforms in drinking water at various temperatures

J. Pillai, K. Mathew, R.A. Gibbs and G. Ho
First International Specialized Conference on Water Quality and Its Management - Proceedings, pp.277-283
CRC Press
Water Quality and Its Management: Proceedings of the First International Specialized Conference (New Delhi, India, 02/03/1998–06/03/1998)
1998
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1998 pillai delhi868.75 kBDownloadView
Open Access

Abstract

Waterborne diseases are a major health problem in many countries. Faecal contamination of drinking water is one of the main cause of these disease outbreaks as many pathogens are carried through human faeces. At present, the quality of drinking water is ensured by testing the water sample for total coli forms and thermotolerant coliforms or E. coli. However when applied in remote areas the standard methods have various limitations. The distance to laboratory facilities and the high cost of analysis restrict water quality assessment in remote areas and in developing countries. Under such circumstances an on-site bacteriological test is considered to be highly essential for routine water quality testing. The H2S paper Strip Method has been developed as a quick, inexpensive and easy to use method to test drinking water for remote and rural areas. With this method H2S producing bacteria cause water sample to tum black when faecal contamination is present. The present work analyses the reliability of the H2S method for detecting faecal contamination of water samples. A faecal sample of a healthy person was used for the study in order to get a well-balanced microbial population. The minimum concentration of faecal coliforms in a 100 ml sample that could be detected by this method as well as the incubation period required at various levels of faecal contamination were studied. The range of temperatures at which the method was effective and the incubation period required at various temperatures were also determined. The bacterial count in serial dilutions of the water sample was estimated by m-FC agar plates. The H2S method was found to be able to detect the contamination level down to I CFU of faecal coliform in a 100 ml sample. Although the H2S method could be used at a temperature range of 14 to 44°C, temperatures between 28 to 37°C gave faster results. An incubation period of only 24 hours was required at 37°C which was found to be the most suitable incubation temperature. The incubation period increased with a decrease or increase in temperature. It was concluded that a temperature ranging from 28 to 37°C could be recommended for the H2S method. Over this temperature range the concentration of faecal coliforms also had no influence on the incubation period.

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