Drinking water crisis in parts of the country is feared to deepen further as the climate-induced sea level rise is expected to increase release of arsenic into Bangladesh's drinking well water by the salt effect.
"This exposure to a potent carcinogen is a significant threat to public health," says a new study published in the peer-reviewed journal Plos One, a journal covering research within science and medicine.
As the sea levels continue to rise and floods and cyclones in Bangladesh increase in area and duration, the underlying aquifer can become more saline and more reducing, said the study published on Wednesday.
The study "data strongly suggest that these chemical changes can increase the release of arsenic into Bangladesh's drinking well water."
Around 97 per cent of Bangladeshis drink well water and approximately 49 per cent of Bangladesh's area has drinking well water with arsenic concentration that exceeds the 10 micrograms per liter (?g/L) World Health Organization (WHO) guideline, it said.
Alluvial sediments deposited in Bangladesh's lowlands during the Holocene epoch (11,700 years ago to the present day) have minerals that often contain arsenic.
These minerals release arsenic into Bangladesh's groundwater, it explains.
The study hypothesised that "these consequences of climate change can increase the release of arsenic from sediments into Bangladesh's drinking well water."
This study suggests that arsenic is also released from sediments into water by the salt effect.
The intrusion of saltwater caused by sea level rise can increase the salinity of the country's coastal aquifers and can further degrade the drinking water quality.
The mixing of sewage with floodwater can also degrade the drinking water quality, the study explains.
Bangladesh's low-lying coastal topography, annual monsoon, and frequent cyclones are expected to be severely impacted by flooding as sea levels continue to rise.
From 1968 to 2012, the water level of the Ganges-Brahmaputra-Meghna River delta in Bangladesh increased by about 3 millimeters per year.
At the same time, this increase was slightly faster than the mean sea-level rise at about 2 millimeters per year, according to the study.
The principal human-made factor contributing to this subsidence is most likely the withdrawal of groundwater, especially near Dhaka, the capital of Bangladesh.
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