Effects Of Water Pollution In Bangladesh

Introduction

Bangladesh is a country in Asia, roughly the size of Iowa. The climate is tropical, with mild winters, hot, humid dry summers from March to June, and a warm rainy monsoonal season from June to October. The terrain is mostly flat, composed primarily of alluvial sediments, with hilly terrain dominating the southeastern portion of the country. Prior to 1970, surface water was the country’s primary drinking water source. The highly polluted surface waters pressed the need to find an alternative drinking water source. The introduction of irrigation ~30 years ago caused a steady increase in groundwater extraction to support the growing agricultural industry; with rice, jute, tea, and wheat being the main crops7. According to the Central Intelligence Agency (CIA), in 2008, total freshwater extraction was 35.87 cu km/yr, with 88% of extracted water being for crop irrigation and 12% sourced for drinking water.

Water quality concerns have plagued the country for decades. During monsoonal flooding events, surface waters become contaminated with waterborne diseases and runoff from commercial pesticides. Conversely, groundwater is contaminated by naturally occurring arsenic, leaving the 166,280,712 inhabitants at risk of arsenic poisoning and cancer7. Reports of arsenic poisoning are concentrated in the Ganges Brahmaputra Delta (GBD) region of Bangladesh.

Today Bangladesh relies heavily on groundwater as the main drinking water supply, despite the contamination from naturally occurring arsenic. Arsenic is an odorless and tasteless semi-metal. It contaminates groundwater when sorbed arsenic enters the aqueous phase and gets mobilized as a direct result of the influx of carbon caused by human actions7. The affected aquifer is a ...

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...ow of anthropogenic carbon, the mobilization probably occurred from a complex combination of redox changes. The organic carbon influenced the microbially mediated dissolution of Fe-oxyhydroxides and freed surface bound arsenic. As(V) is not the stable form of dissolved arsenic in highly reducing conditions, so it’s quickly reduced to the more mobile and toxic As(III). Future remediation efforts may utilize iron, aluminum and manganese oxides or microbial communities as As(III) remediation techniques. But before remediation efforts begin, a more complete understanding of arsenic mobilization is needed. Future studies need to focus on the rate that As(V) is desorbed from surface binding sites of Fe-oxyhydroxides. Quantifying the rate will confirm or disprove whether dissolution reduction Fe-oxyhydroxides play a major role on the arsenic concentrations in groundwater.