This work is licensed under the Creative commons Attribution 4.0 License. Published by Pacifc Group of e-Journals (PaGe) Original Article Physicochemical and Bacteriological Analysis of Bagmati River in Kathmandu Valley DOI: 10.21276/AABS.2213 Introduction Water is the most vital resource for the existence of all life and ecosystems in Earth. Certain standards in terms of its physical, chemical and biological parameters determine its suitability for intended purposes. Water is considered polluted when these parameters shift from the acceptable range of quality standards [1]. The Bagmati is a perennial river that originates at Shivapurilekh, north of Kathmandu and drains into the Ganges. It forms a catchment area of 3710sq. km in Nepal which includes area in 8 districts and constitutes about 15% of the total area in Kathmandu valley [2,3]. Most of its water is contributed by run-of and the river exhibits wide seasonal variation in fow and water quality [4]. Various religious and economic activities like cremation, irrigation, hydropower generation, sand quarrying and industrial manufacturing occur in the river vicinity. The most severe problem at present is the mismanagement of sewers into the river [5]. These activities have led to water quality deterioration resulting serious public health and environmental challenges [6,7]. The study aims to assess the quality of river water in terms of certain physicochemical and bacteriological parameters. The fndings of the study might be suggestive of the appropriateness of water for intended use and generate awareness about the probable chances of infection and other health problems associated with the use of river water. MATERIALS AND METHODS Sampling Sites and Sample Size: This study was conducted in the Microbiology laboratory of St. Xavier’s College from January to June 2017. Six diferent sites along the river (B 1 -B 6 ) were allocated. Bagmati River from Baghdwar to Sundarijal, Gokarna to Jorpati, Guheshwori to Pashupati, Tilganga to Tinkune, Thapathali to Teku and Balkhu to Chobhar were specifed as sites B 1 , B 2, B 3 , B 4 , B 5 and B 6 respectively. Four samples were collected from each site. Sample Collection and Transportation: Samples were collected in sterilized bottles with their mouth directed against the water current. Physicochemical parameters were determined at the site itself. Dilutions were made to those samples that were highly polluted and turbid. Samples for bacteriological analysis were taken to laboratory within 4 hours in an ice box and processed immediately. For less feasible sites, samples were processed within 24 hours [1]. Shraddha K C*, Apil Gurung, Laxmi Chaulagain, Shobha Amagain, Smrity Ghimire and JeenaAmatya Department of Microbiology, St. Xavier’s College, Maitighar, Kathmandu, Nepal ABSTRACT Background: The Bagmati River, fowing through the heart of Kathmandu valley, has undergone considerable degradation in water quality that possesses a threat to the river ecosystem and public health. The study had been envisioned to assess certain physicochemical parameters i.e. pH, temperature, Total Dissolved Solids (TDS), chloride, Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD), bacteriological analysis i.e. Total Plate Count (TPC), Total Coliform Count (TCC), isolation and identifcation of Salmonella spp., Vibrio cholerae and their Antibiotic Susceptibility Test (AST). Methods: Six sites (B1-B6) were allocated along the Bagmati River from Baghdwar to Chobhar. Four samples were collected from each site and analyzed by standard procedures. Result: Maximum average of pH, temperature, TDS, Chloride, DO, BOD was recorded to be 7.6, 29°C, 386ppm, 201mg/l, 9.68mg/l, 229.25mg/l respectively. Maximum and minimum average of TPC was 5.39×10 6 cfu/ml and 7.09×10 3 cfu/ml while that of TCC was 1.91×106cfu/ml and 5.38×102cfu/ml respectively. 45.83% (N= 11) samples exhibited growth of Salmonella spp.of which 12.5% (n=3) isolates were found to be S. Typhi, 8.33% (n=2) to be S. Paratyphi and rest 25% (n=6) to be other S. enterica serovar. All Salmonella spp. isolates were sensitive to Ofoxacin. 41.67% (N=10) samples showed growth for Vibrio cholerae. All isolates were sensitive to Chloramphenicol and resistant to Erythromycin. Conclusion: This study refected the current physicochemical and bacteriological status of Bagmati river and emphasizes the need to reduce pollution so as to prevent the transmission of bacterial pathogens. Keywords: Bagmati River, Physicochemical Parameters, Bacteriological Analysis, Salmonella spp.; Vibrio cholerae, AST