Prognosticating the Impact of Seasonal Variability on Microbial Load in Water Bodies Around Dhaka City, Bangladesh

Background and Objective: Surface water of different reservoirs in Bangladesh is often contaminated with biological, chemical and physical wastes. Increasing population, urbanization and industrialization are contributing to the situation. The study aimed to assess seasonal variations in microbial load in water bodies surrounding Dhaka City, Bangladesh. Materials and Methods: Two rivers (Turag and Burigonga) and lakes (Banani and Dhanmondi) in and around Dhaka City were selected for the current study. Spread plate techniques were conducted to obtain bacterial load in water samples. Total Viable Count (TVC), Total Coliform Count (TCC), Total Fecal Coliform Count (TFCC) and Total Salmonella Shigella Count (TSSC) were conducted as well and data were represented as CFU/mL in a log scale. Results: The majority of the water reservoir exhibited a declining bacterial load during winter whereas it is significantly high during spring. Major bacterial genera in the water bodies included in this study were  Staphylococcus aureus, Micrococcus sp., E. coli, Salmonella sp., Shigella sp., Enterobacter sp., Pseudomonas sp., Acinetobacter sp., Proteus sp. and both river water and lake water harbored almost similar genera of bacteria. In general, there is a declining trend of microbial load (TVC CFU/mL; TCC CFU/mL; TFC CFU/mL and TSSC CFU/mL) in both types of water bodies around Dhaka City, Bangladesh. Conclusion: The current study implies that pathogenic isolates such as Escherichia coli, Salmonella sp., Enterobacter S. aureus, Klebsiella sp., Citrobacter sp., Shigella sp., Pseudomonas sp. can cause serious health issues if unsafe water from these reservoirs is used for day to day activity without treatment.