Physicochemical Status of Sitalakkhya River, an Ecologically Critical Area (ECA) of Bangladesh

The study was conducted to assess the water quality of the Sitalakkhya River, Narayangonj, Bangladesh and observe its temporal changes forthe physicochemical parameters of water from March to May, 2015. The present study showed that the color of water was deep black or black and emittedobnoxious smell. It was found in the study that the temperature, transparency, TDS, EC, pH, DO, alkalinity, hardness, NO3-, Cl- and BOD were ranged from 31.5-34.60C, 15.25-27.30 cm, 291-781 ppm, 558-2664 ppm, 7.57-8.60, 1.4-3.6 ppm, 123-435 ppm, 203-332 ppm, 0-89.13 ppm, 51.68-237.36 ppm and 3.21-17.3 ppm, respectively. Most of the observed parameters have exceeded permissible limits except pH and Cl- indicating higher concentrations of organic and inorganic pollutants present in the river.According to the study,significant strong positive correlations were found in temp. vs pH (r= 0.774, p< 0.05), temp. vsCl- (r= 0.954, p< 0.05), temp. vs BOD (r= 0.747, p< 0.05), TDS vs EC (r= 0.955, p< 0.05), pH vsCl- (r= 0.808, p< 0.05), pH vs BOD (r= 0.864, p< 0.05) and DO vsNO3- (r= 0.758, p< 0.05) in March; temp. vsNO3- (r=0.915, p< 0.05), TDS vs EC (r= 0.949, p< 0.05), TDS vs DO (r= 0.765, p< 0.05) and DO vshardness (r= 0.745, p< 0.05) in April andtransparency vsNO3- (r= 0.906, p< 0.05), TDS vs EC (r= 0.922, p< 0.05), TDS vs pH (r= 0.836, p< 0.05), EC vspH (r= 0.982, p< 0.05) and pH vs hardness (r= 0.764, p< 0.05) in May. Significant strong negative correlations were found in EC vs alkalinity (r= -0.745, p< 0.05), DO vsBOD (r= -0.876, p< 0.05) and NO3-vs BOD (r= -0.765, p< 0.05) in March and TDS vsCl- (r= -0.774, p< 0.05), EC vsCl- (r= -0.758, p< 0.05), hardness vs BOD (r= -0.775, p< 0.05) and NO3-vsCl- (r= -0.763, p< 0.05) in April.The hydrochemistry of the water body has revealed that the water is unsafe for human health, aquatic organisms and also for household, irrigational and industrial uses without proper treatment.