DOI: 10.36347/sajb.2018.v06i02.017

Pages: 230-238

The present study was carried out to determine the water quality of three most important Lakes in Dhaka city of Bangladesh in terms of physicochemical and microbiological properties. The study reported highest number of microorganisms in Gulshan Lake followed by Banani and Uttara Lake. The average MPN/100 ml water in Gulshan Lake were 452.8 which were higher than that of the Banani Lake (260.8) followed by Uttara Lake (43.33). Among physiochemical parameters, the lowest Dissolved Oxygen (DO) was recorded from Gulshan Lake which was approximately 5 lower than the recommended value of the Department of Environment (DoE). However, the DO value in Uttara Lake ranged from 3.50 to 7.50 mg/l with the average value of 5.00 mg/l which was very closure to the DoE standard. The average Biological Oxygen Demand (BOD5) value was ranged from 180 to 329 mg/l in Gulshan Lake, 96 to 270 mg/l in Banani Lake, whereas in Uttara lake the average BOD5 value was found 111.56 mg/l. The average Chemical Oxygen Demand (COD) value was found 200 mg/l in Gulshan Lake which was significantly correlated with BOD5 (0.825**). Both BOD5 and COD value of water in Gulshan Lake exceeded the permissible limit of DoE standard. The COD value of the water samples in Banani Lake was ranged from 42.55 to 200.00 mg/l and showed a significant correlation with BOD5 (0.652**) which was also much higher than the DoE standard. In case of Uttara Lake the COD value ranged from 42.55 to 127.65 mg/l which had significant correlation with BOD5 (0.847**) and similarly higher than DoE standard. However, the EC and TDS values were within safe limit according to DoE standard in all three lakes water. The study concluded that the water in all three lakes water was highly polluted in terms of microbiological and physicochemical properties. Therefore preventive and safety policy is an immediate demand for health and well-being of the people and environment of Dhaka, the capital city of Bangladesh.