Faecal contamination of drinking water sources of Dhaka city during the 2004 flood in Bangladesh and use of disinfectants for water treatment.

During 2004/2005 a total of 300 water samples were collected from 20 different drinking water sources in Kamalapur, Dhaka city. The unacceptable level of contamination of total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS) ranged from 23.8% to 95.2%, 28.6% to 9.2% and 33.3% to 90.0%, respectively. The isolation rates of V. cholerae O1 and O139 were both 0.33%, and non-O1/non-O139 was 7.0%. Although alum potash, bleaching powder, Halotab and Zeoline ® -200 were all effective general disinfectants, Halotab and Zeoline ® -200 were superior to bleaching powder and alum potash against FC. The study showed that during and after floods, point of use water treatment could reduce waterborne diseases among flood-affected people. Journal of Applied Microbiology 2007;103:80-7.