Pollution Assessment of Point and Non-point sources of Buriganga River

Abstract

The objective of this work is to assess the pollution states of point and non-point sources of Buriganga River. Buriganga River is the oldest and important river in Dhaka, the capital city of Bangladesh because Dhaka itself is situated beside this river. There are point and non-point sources of pollutions for this river. In this work, only two sites are assessed. For analyzing water parameter in the laboratories, total three samples are collected. The parameters that have been analyzed are pH, electric conductivity, alkalinity, hardness, BOD5, COD, DO (Dissolved oxygen), ammonia nitrogen. Results obtained from the analysis of point source sample differ from the non-point source. Values of pH, hardness, and alkalinity have been increased a lot in the point source sample. Test for BOD5, COD, DO and ammonia nitrogen has been conducted with non-point source sample only. The value of BOD5 and COD meets the standard requirement but the value of DO and ammonia nitrogen fails to meet the standard. DO level is severely low (0.76 ppm) in the river water which means there is no environment for aquatic lives to live in. Ammonia nitrogen value is almost reached to the maximum standard value which indicates a high pollution level of nitrogen in river water. From the assessment three findings are visible. First is the degree of pollution status in the river in terms of DO and ammonia nitrogen level. Second is the assessment that which source is contributing more pollution in the river. The third is the assessment to find out the reason behind it and its possible mitigation processes.