Major drinking water source of Dhaka city is endangered by the Cr pollution from approximately 150 tanneries in Hazaribagh area, in the western side of the capital. Groundwater, surface water and pore water samples, as well as borehole soil samples, were collected in 2012-2013 in order to assess the situation and to describe the Cr behaviour in the soil and groundwater.
Hazaribagh area in Dhaka city, the capital of Bangladesh, is considered one of the hotspots of Cr pollution in the world due to the massive discharge of untreated Cr contaminated waste over decades by approximately 150 tanneries. In 2000-2001, Elevated Cr concentration was observed in the underlying Dupi Tila aquifer which is heavily deployed for drinking water supply of Dhaka city’s population. After 2001, no traceable Cr was observed in the Dupi Tila aquifer while in fact the situation regarding wastewater discharge didn’t change and no remedy measures were initiated.
Due to the importance of Dupi Tila aquifer for its potable water supply for Dhaka city’s population, it is necessary to figure out further risk of groundwater contamination with industrial contaminants like Cr. Therefore, the current study aims to find out the recent situation of Cr contamination in the Dupi Tila aquifer, the risk of spreading, the possible routes of contamination and Cr mobility in the contaminated soil.
To accomplish the aim, groundwater, surface water and pore water samples, as well as borehole soil samples, were collected in 2012-2013. Standard analytical methods were applied to measure total Cr concentration, major ion chemistry and stable water isotopes ratios.
Obtained results show that total Cr concentration in three shallow groundwater samples exceeds the limit (i.e. 0.05 mg/L for drinking water, permitted by Bangladesh environmental conservation rules) but the concentration in deep groundwater samples is below the limit. Results suggest that the recent Cr contamination in the Dupi Tila aquifer has been originated from the nearby Buriganga River and triggered by a recent riverbed excavation work. Results also indicate that vertical leaching of Cr in the contaminated soil is unlikely. But, it is suggested that Cr plume beneath a channel and the channel adjacent lagoon which receive and drain Cr contaminated wastewater, was responsible for the elevated Cr observed in 2000-2001. Rapid declining of groundwater table below the plume depth may be the reason, why no traceable Cr was observed after 2001. This study infers that unless the discharge of untreated tannery waste is stopped, the groundwater is always under threat of Cr contamination even though Cr is relatively less mobile in the environment.
Country, Continent: Bangladesh, Asia
Funding agency: IPSWaT
Years of activity: 2011 – …
Responsible person: Abidur Khan, Prof. Dr Christoph Schüth
Cooperation Partners:
- Bangladesh Water Development Board, www.bwdb.gov.bd/
- University of Dhaka, Bangladesh, www.du.ac.bd/
