Assessment of soil and groundwater contamination at a former Tannery district in Dhaka, Bangladesh

摘要

The uncontrolled and unplanned development of leather processing industries in Bangladesh has contaminated land and water, prompting concerns for public health. Hazaribagh, located in the southwestern part of Dhaka, has been the city's principal leather processing zone since the 1960s. In order to alleviate the environmental contamination and public health risks to citizens of Hazaribagh and downstream, a relocation project was launched to remove the tanning industry. However, soil and groundwater quality conditions of the former industrial sites must be assessed and/or remediated for commercial and residential use. Soil was collected from ten sites and tested for concentrations of potentially toxic metals (Pb, Cr, Zn, Cu, Ni and Cd), and groundwater was collected from six sites and analyzed for physiochemical parameters and potentially toxic metals. Concentrations of soil Cr, Zn and Cu exceeded the European Union maximum permissible concentrations. Deep groundwater Cr concentration in one location exceeded the Bangladesh DoE maximum limits; however, deep groundwater is overall of good-to-excellent quality. Spatial variations of soil and groundwater contamination in Hazaribagh indicate that contaminants have not spread laterally. Based on local conditions, current technologies, contamination level, time and cost, and ease of operation, it is suggested that soil flushing, electrokinetics and/or phytoremediation could be options for remediation of affected soil and groundwater in the Hazaribagh district.