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Title: Physicochemical and Bacteriological Analysis of Five Selected ponds in Chittagong University Campus

Author: Ummey Shahina Khanom

Supervisor: Wahhida Shumi

Research Field: Environmental Microbiology

Batch: 10th

Session: 2009-2010


Water, an essential requirement for all forms of life, needs protection from pollution which otherwise pose a threat to human life. Environmental conditions such as salinity, oxygen, temperature and nutrients influence the composition, distribution and growth of its biota.
Physicochemical parameters and bacteriological analysis of five selected ponds of Chittagong University was studied and determine the quality of ponds for aquaculture and various other use purposes.
In these investigation physical parameters such as temperature, pH, electrical conductivity, BOD, total solid, turbidity; chemical parameter NO2, PO4, free CO2, carbonate, bi-carbonate, acidity, Cl-, COD and biological analysis total viable bacterial count, total coli form count, isolation and identification of E. coli, Salmonella of five selected ponds were examined. Antibiotic sensitivity of the E. coli and Salmonella were done against commercially available antibiotic. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against ciprofloxacin were also observed.
In this study, temperature of all the selected ponds did not exceed 20°c. Water temperature of the ponds ranged from 19°c to 20°c. The ponds water was slightly acidic to slightly alkaline and the pH of the water ranged from 6.72 to 7.40. BOD of the ponds water was ranged from 40.2 to 122.6 mg/L. Turbidity of the selected ponds was 0.050 to 0.203. During the investigation, electrical conductivity of the selected ponds was observed 653.33-7933.33 μS/L. The concentration of Nitrite in the study area ranged from 1.333 to 2.6784 mg/L. The Phosphate concentration in water at different sites varied from 0.6889 to 17.591 mg/L. The chloride concentration in water varied from 3.19 to 12meq/L. Carbonate was absent in these ponds and the concentration of HCO3- was ranged from 1464 to 5856 mg/L. In these five selected ponds free CO2 was ranged from 0.1936-0.5808 mg/L. COD was ranged from 119.68 to 401.28 mg/L. Total viable count of the selected ponds was 1.3×104 to 6.6×105 cfu/ml. The highest microbial load was observed in botanical garden pond in which fish was not cultivated and lowest was observed in science faculty pond. Total coliform of the ponds was found 0.0205 × 102/ml to >1.10 × 102/ml. Presence of total coli form was highest in botanical garden pond in which fish was not cultivated. Isolation of the E. coli and Salmonella was done by using various selective media that is MacConkey, Eosin Methylene Blue (EMB), Brilliant Green Agar (BGA) and Bismuth Sulfide Agar (BSA). By observed various morphological and biochemical characteristics identification was done. Then the isolated E. coli and Salmonella were selected for the antibiotic sensitivity test. Antibiotic sensitivity pattern were observed against commercially available disc of amoxicillin, erythromycin, tetracycline and cefixime. Most of them were sensitive but some also were show resistance against these antibiotics. Then the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against ciprofloxacin was determined. E. coli and Salmonella isolated from botanical garden pond in which fishes were commercially cultivated shows more resistance than other ponds isolates.
From this study, it can conclude that the ponds water was beyond the limit of aquaculture and various other use purposes, from bacteriological and physicochemical point of views. This shows that the ponds contain microorganisms and chemicals that can cause disease to the fish and eventually to man when consumed.