Monitoring of fecal coliform bacteria and plant growth promoting

Abstract

The focus of this study was to determine the level of fecal pollution in Chilika waters especially using fecal indicator bacteria as an indicator. A total of 99 surface water samples were collected from 33 sampling points across four different sectors having different salinity gradients inside the Chilika Lagoon. Sampling was conducted on monthly basis over a period 3 month study period i.e., from January − March 2021. The mos probable number (MPN) method is used to determine the number of fecal coliform bacteria. In the present study, fecal coliforms were measured using multiple tube fermentation technique with presumptive medium being lactose broth and confirmatory medium being eosin-methylene-blue agar and results were expressed as MPN/100 ml. The results indicated that the mean concentrations of fecal coliform bacteria in water samples collected during January, February, and March were 1.0, 0.1, 0.7 MPN/100 ml, respectively. MPN index of all of the stations showed below 100 (threshold value according to the guidelines of Central Pollution Control Board (CPCB), New Delhi for class II surface water used for Bathing, Contact Water Sports and Commercial Fishing) in presumptive test during the study period. Positive presumptive result was found at station no. 4, 9, 19, 24, and 33 during January, station no. 33 during February and station no. 5, 6, 12, 16, 20, 25 and 33 during March 2021. The mean MPN index of 100 ml of samples in stations of Nalabana Island were 1.3, 0.5, and 0.5 during January, February, and March, respectively. None of the samples of the 33 stations of the Chilika Lagoon during the 3 month showed fecal contamination (negative confirmatory result). Thus, the MPN index of the Lagoon was within the threshold prescribed by CPCB. The study has direct relevance with respect to monitoring and management of lagoon. This study is necessary for ongoing monitoring of coliforms and human pathogens in Chilika Lake to evaluate water quality. A robust Fecal Indicator Bacteria Index would be developed to assess the risks associated with potential human pathogens.