BACTERIOLOGICAL EXAMINATION OF DRINKING WATER IN RAWALPINDI AND ISLAMABAD AREA
Objective: The purpose of the study was to assess bacteriological quality of drinking water in Rawalpindi and Islamabad-Pakistan by determining the presence of coliforms and E.coli.
Material and Methods: This cross-sectional descriptive study was conducted at the Department of Microbiology, Armed Forces Institute of pathology, Rawalpindi from Sep 2018 to Dec 2018. All samples submitted to AFIP from Rawalpindi and Islamabad areas for bacteriological examination of water were collected in sterile bottles under aseptic condition and were inoculated on MacConkey agar after being filtered through Millipore water testing system using 0.22 µm filter as per manufacturer instructions. Coliforms were identified by lactose fermentation, colony morphology, gram stain, motility, catalase, oxidase and indole test. Indole positive colonies were tested by API-20E to confirm the presence of E.coli. Results were interpreted according to WHO criteria for drinking water.
Results: A total of 462 water samples were analyzed, out of which 164 (35.5%) were declared unsatisfactory based on fecal coliforms contamination and rest of the samples were found satisfactory after bacteriological examination of drinking water. Out of 462 samples 362 (78%) were treated (filtered/chlorinated) and 100 (22%) were untreated. Out of 362 treated samples 98(27%) were found unsuitable for drinking. While out of 100 untreated samples 67(67%) were found unsatisfactory.
Conclusion: A high frequency of unsatisfactory drinking water samples was found among the specimens tested. Regular monitoring of water treatment processes and proper maintenance of already established water filter plants can markedly improve this situation.
Key Words: Bacteriological examination, Drinking water, Membrane filtration.