Open AccessA Case Study On Predicting The Environmental Impacts Of Untreated Effluent Generated From Tannery Industrial Estate In Dhaka, Bangladesh
Author(s) -
Shakil Masum,
Md. Sultan-Ul Islam
Publication year - 2020
Publication title -
geography, environment, sustainability
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.316
H-Index - 8
eISSN - 2542-1565
pISSN - 2071-9388
DOI - 10.24057/2071-9388-2019-127
Subject(s) - effluent , arsenic , cadmium , environmental science , contamination , pollution , environmental chemistry , environmental engineering , chromium , chemistry , ecology , organic chemistry , biology
Significant amounts of heavy metals in the directly discharged wastewater released from the newly built tannery industrial site in Dhaka, Bangladesh are reported. Despite their detrimental impacts on public health and natural ecosystem, no environmental impact study is yet conducted. Therefore, information on safe discharge rates are not available. In this study, the extent of pollution around the industrial site is investigated for four representative trace metals. Temporal and spatial distributions of chromium (Cr), lead (Pb), cadmium (Cd) and arsenic (As) have been predicted using a numerical model with the aim to estimate safe discharge of these metal contaminants. From multiple simulation runs it has been estimated that a discharge of0.026 m 3 of wastewater per day can lead to high levels of Cr and Pb accumulation, exceeding the regulatory standard limits, in the study area. Whilst As and Cd concentrations remain below the advised limits in most cases at this rate. However, an order of magnitude reduction in the total discharge rate, i.e.,0.0026 m 3 per day, results into the metal accumulation below the recommended guidelines in all cases. Elevated concentration of Pb is found to be limited to the top 0.5 m of the soil as compared to Cr, As and Cd, which exhibit larger spread along the depth of the soil. The relative dominance of the metal contamination follows the sequence: Pb>Cr>As>Cd as sorbed concentration in soil aggregates and Cr>Pb>As>Cd as aqueous concentration in soil porewater. Further investigations that are essential for a comprehensive environmental impact assessment have been highlighted.