Sea-level rise and storms worsen saltwater intrusion into drinking water, but water harvesting might help
LONDON, March 24 (Thomson Reuters Foundation) - Bangladeshis could see a rise in the number of strokes and people with heart disease as salinity levels in drinking water increase due to climate change, a study predicts.
Tropical cyclones that hit Bangladesh lead to incursions of seawater that can “cause a huge flux of salinity in the rivers and drinking water ponds on land for the local people,” said Adrian Butler, co-author of a study by Imperial College in London and the University of Dhaka. Sea-level rise is also raising the risk of worsening saltwater incursions.
Drinking excessive amounts of sodium can increase the risk of hypertension and cardiovascular problems such as strokes and heart disease, the researchers said, during a forum at Imperial College on non-communicable diseases.
The recommended total daily sodium intake is less than 2 grams, according to the World Health Organization. The European Union limit for sodium in drinking water is 200 milligrams per litre.
But a large portion of the population in Bangladesh may be consuming up to 16 grams of salt a day in 2 litres a day of drinking water, according to a previous study by Paolo Vineis, an Imperial College researcher, and colleagues.
Bangladesh, a low-lying country that is largely a vast river delta for the Ganges, Brahmaputra, and Meghna Rivers, is particularly vulnerable to severe weather, including floods, cyclones and droughts.
In November 2007, Cyclone Sidr hit southern Bangladesh, causing more than 2,000 deaths and extensive flooding.
But Bangladesh is also struggling with long-term environmental problems, including soil degradation, increasing soil salinity and river erosion, which are likely to worsen as a result of more extreme weather and rising seas, said Vineis, who has studied climate change and salinity levels in Bangladesh.
The Intergovernmental Panel on Climate Change in its 2014 Fifth Assessment Report predicted that sea-level rise will make worsening salinity of drinking water “a key issue in most coastal areas, particularly in low-income countries,” Vineis said.
“On top of Bangladesh being vulnerable to natural hazards (such as storms), they are also vulnerable to the future effects of climate change and that can exacerbate the natural hazards,” he said.
Butler and his team looked at two sites in Dacope Upazila in southern Bangladesh, studying communal drinking water ponds and efforts to purify salt-contaminated water.
“Currently, government and NGOs are supporting rainwater harvesting as a source of fresh drinking water,” Butler said. “However, often there are very (few) facilities for storage and larger units are expensive.”
One potential solution the researchers are looking into is aquifer storage and recovery. Using that system, people would harvest rainwater from roofs and inject the water in the ground to create a freshwater “bubble”. Then, during the dry season, people could extract water using hand pumps.
However, Butler said the results of these aquifers have been mixed.
“The performance isn’t great because they still have concentrations of saline water, because it’s been difficult to collect enough fresh water (from) a good source for the system,” he said.
Butler said the next step in their research is looking at other solutions to tackle salinity levels in water and at the cost of developing such solutions to tackle health issues associated with high sodium levels in drinking water.
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