Author(s): Mohammed Abed Hossain; Masakazu Hashimoto; Shammi Shawal; Kenji Kawaike; Nozomu Yoneyama; Akiko Matsuyama; Khalequzzamn
Keywords: No Keywords
Abstract: The Tongi Khal marking the northern boundary of Dhaka is highly polluted with industrial and municipal waste. A part of the pollution load reaches the floodplain with monsoon floods increasing the spatial extent and exposure risk, which was investigated for Uttarkhan area located on the right bank of the Tongi Khal opposite to the Tongi industrial area. The inundation modelling for 2017 monsoon showed moderate to high flood depth in the floodplains surrounding the residential establishments investigated. It was found that the floodplain starts to receive polluted water from the river in May while the inundation is highest in Late August. It was seen that the water quality in floodplains is very poor in both May and November indicating accumulation effects of pollutants in floodplains. High ammonia concentration was found in pre-monsoon time which is a serious concern for fisheries and other aquatic life. Household survey reported degradation of floodplain environment through prolonged inundation, and significant number of increase in diseases among adults and young children after dye factory effluents started reaching floodplains. It revealed a general lack of awareness on exposure risk to toxic wastewater. Infrastructure measures and awareness both are needed for averting health crisis for exposed population.