Fecal organisms in supplied and domestically treated waters in Dhaka: insights from Mohakhali, Niketon and Uttara

Abstract

Dhaka, the capital city of Bangladesh, is the most densely populated city of the world. So, it is always a challenge to meet the ever increasing demand for pure drinking water of this huge population. This study aims to detect the presence of fecal coliform (FC) and Salmonella spp. in the supplied and domestically treated waters in Mohakhali, Niketon and Uttara zones. A total of 108 samples were collected from October 2018 to April 2019. The supplied water samples collected from these three zones produced variable FC counts (cfu/100mL); zero, 1-5, 6-30, 31-100, and >100 were detected in 50%, 6%, 13%, 11%, and 20% samples respectively. While 67% of the boiled water samples yielded no FC, others showed variable degrees of FC counts (cfu/100mL); 1-5 in 7%, 6-30 in 13% and >100 count was detected in 13% samples. In case of the filtered waters 57% samples had zero FC counts. However, FC counts (cfu/100mL) of 1-5, 6-30, 31-100, and >100 were detected in 9%, 4%, 26% and 4% samples respectively. PCR-based detection of Salmonella spp. suggests occasional contamination in water samples from both Mohakhali and Uttara (five and four samples respectively). Results from this study reveals possibility of transmission of fecal pathogens via drinking water and generates evidence that contaminated drinking water is an overlooked health hazard in Mohakhali, Niketon, Uttara.