Quality Analysis of Dhaka WASA Drinking Water: Detection and
Keywords:Drinking Water, Microbial Contamination, Indicator microorganisms, Coliform, E. coli
KR Mahbub added as the First author on 08/08/2012 and corrected PDF loaded on 08/08/2012.
The aim of the study was to assess the microbiological quality of Dhaka WASA drinking water. A total of 45 samples were collected from different outlets of WASA water supply chain. Among the these samples 29 samples were collected from house tap, 5 samples from street pipe line tap and 11 samples from WASA source pump. The results of the Total Viable Count (TVC) showed that 62 % samples of house tap water, 60 % pipeline water and 45.45 % WASA pump water were exceeded the BDS standard (1240:2001) and WHO Guideline for drinking. The highest count was 2 × 106 cfu/ml in the house tap water of Gandaria. Total coliform and E. coli count ranged from <1.8 (MPN) /100 ml to >1600 (MPN)/100 ml. Among all the tested samples, 57.78 % water samples were positive for coliform and 51.11 % samples were positive for E. coli bacteria. Out of twenty three E. coli isolates, 8 isolates were subjected to biochemical and microscopic examination for confirmation. All 8 isolates were detected as E. coli based on biochemical parameters. The antibiotic sensitivity pattern of those isolates was determined. Most of them were found resistant to Ampicillin, Amoxicillin, kanamycin, Penicillin, Sulphomethoxazole antibiotics. Nearly all of them were found sensitive to Gentamycin and Nalidixic acid. The samples collected from different house tap water and road side tap water were more contaminated than WASA source pump water. It may therefore be concluded that distribution lines of Dhaka WASA supply chain might be the main source of microbiological contamination of drinking water. In this regard further investigations with more representatively drawn samples are required.
J. Environ. Sci. & Natural Resources, 4(2): 41-49, 2011