An analysis of simultaneous seasonal variation in different bacterial counts and detection of heavy metals in water and shrimp of the Karnaphuli River, Bangladesh

Objective The present study aims to demonstrate whether there is a simultaneous seasonal (wet season and dry season) variation in different bacterial counts and detection of heavy metals in shrimp and water of the Karnaphuli River which is one of the major rivers of Bangladesh. Methods We collected water and shrimp samples from the river and studied the physicochemical parameters (for water only), different bacterial counts and detection level of heavy metals of both sample types. We analysed our data among and within the samples. Results We found that some of the physicochemical parameters of water of the river are significantly varied seasonally. We did not find the bacteriological count to vary significantly in both shrimp and water samples, except the total viable bacterial (TVB) count during the wet and dry seasons for water samples. We found that lead (Pb) significantly increased during the dry season in water samples. Also, there was a slight increment of Pb in shrimp samples during the dry season. However, in other analysis, we also found a seasonal variation in heavy metals individually for shrimp and water samples but not both. Conclusion The present study failed to identify a simultaneous increase or decrease in bacterial counts and detection of heavy metals in water and shrimp samples of the Karnaphuli River. Further large-scale analysis would be required to understand an association of pollution between shrimp and water of the river.