Water Quality of a Canal Adjacent to Alternative Shrimp-Paddy Culture Plots in Khulna, Southwest Coastal zone of Bangladesh

Abstract

A study was conducted to observe the water quality of Telegati canal, near Kathaltala, Dumuria, Khulna district, which acts as a source of inlet and outlet water for surrounding shrimp fanning and agricultural activities. Three stations of the canal were selected to check and compare water parameters both at high and low tide during Shrimp culture (April to July, 2004) and Agriculture period (August to December, 2004). In Shrimp culture period, the average values of Dissolve Oxygen (DO), Biochemical Oxygen Demand (BOD). pH, Alkalinity, and Free C02 were 3.867±0.583mg/l, 1.352±0.469 ppm, 7.5±0.387, 137.&57±27.367 CaC03mg mg/l, 6.914±2.l77 mg/l at low tide and 4.0±O.864 mg/l, 1.295±O.591 ppm, 7.533±0.409, 128. 809±24.393 CaC03 mg/l, 7.752±3.818 mg/l at high tide. On the other hand, in Agriculture period, the average values of DO, BOD, pH, Alkalinity and Free C02 were 3.867±0.575mg/l, 1.113±0.464 ppm, 7.393±0.409, 134±22.038 CaC03mg/l, 6.013±2.120 mg/l at low tide and 3.867±0.609, l.087±0.467 ppm, 7.4±0.382, 141.167±21.083 CaC03 mg/l, 5.867±2.074 mg/l at high tide. It is apparent that all the parameters were within the optimum level except DO which found less than standard and indicates a clue for pollution in the study area. Statistical analysis revealed that tidal inundation playing a significant role over the canal water quality instead of shrimp or agriculture activities particularly.