AMS ALAM*, MA ISLAM, MA RAHMAN, E. AHMED

Bangladesh having an area of about 144000 sq. km with a population of more than 120 millions is situated in the northeastern part of the south Asia subcontinent and a vast area to the south in the Bay of Bengal. The largest delta in the world has a large catchments area of about 1554000 sq. km spread over five countries namely Bhutan, Nepal, China, India and Bangladesh. Environmental pollution usually refers to biological, chemical and physical materials introduced largely as a result of human activities. Water is one of the main sources of the environmental pollution and the contamination of water by the metal ions at the trace levels is generally occurred through natural processes or anthropogenic sources. Buriganga, Sitalaksma, Karnafully, Bramhaputra and Jamuna were selected for the present study. The toxic metal ions concentration in water samples of various region of different rivers were determined by AAS and GFAAS. The highest amount of As was found in the Karnafully river at KAFCOO (34.6±1.2 µg/L) in the dry season and lowest in the Buriganga river at Badamtoli (5.3±0.1 µg/L). The highest amount of Pb was found in the dry season at Kalurghat (13.4±0.05 µg/L) in Karnafully river. The highest amount of Cd was found in the river of Karnafully at KAFCOO (27.2±0.4 µg/L) in dry season. These observations demand the need of regular monitoring of toxic metal ions concentration in different rivers especially Buriganga, Sitalaksma and Karnafully. The concentration of As, Pb and Cd determined in this study is below the recommended values of WHO (World Health Organization) and EQS (Environmental Quality Standards of …