Rising Sea Levels Increase Threat of Arsenic in Drinking Water, Study Reports – Executive Digest

Rising sea levels will increase the risk of arsenic in drinking water, according to a study published online. 'PLOS ONE'Last January – researchers measured well water levels in Bangladesh, where 97% of the population – 165 million people – rely on this water for drinking.

Arsenic occurs naturally in the Earth's crust, although its levels depend on factors such as geography, fertilization practices or land-use patterns – according to scientists, rising sea levels will increase even modest levels of arsenic. Salt water intrusion.

Seawater can usually only move inland: the meeting point between it and fresh water is called the “salt front”, the 'Bloomberg' publication recalled. However, as sea level rises, this front moves further inland – the heavier salt water pushes the water table upward.

Salt water is better at dissolving certain minerals than fresh water — imagine what a car might look like after being exposed to sea salt — meaning that even small increases in groundwater salinity can lead to more arsenic dissolving.

Bangladesh was not chosen by experts by chance: the importance of groundwater in the country's drinking water supply is huge and floods already occur during the rainy season. Researchers have warned that “tens of thousands of people” in the country are drinking well water with arsenic concentrations higher than the safety limit identified by the World Health Organization.

According to the World Health Organization, countries including Bangladesh, Argentina, China and the United States have naturally high levels of arsenic in their groundwater, leading researchers to confirm that these changes “aren't just happening in Bangladesh,” Professor Seth Frisby said. Emeritus of Chemistry and Biochemistry at Norwich University, United Kingdom. Anywhere there is arsenic in the sediment, “as the water table becomes more saline, we expect more arsenic.”

When arsenic reaches drinking water or food (especially rice), it can make the water unsafe to drink and have negative impacts on the health of those who consume it. Children and adolescents exposed to arsenic may experience cognitive deficits such as difficulty concentrating and problems with memory, verbal comprehension, and reasoning. Long-term exposure in adults is associated with cardiovascular disease, diabetes and several types of cancer.

“Seawater intrusion is something that coastal areas have been thinking about for a long time,” said Holly Michael, director of the University of Delaware's Environmental Institute, adding that salt is generally considered a pollutant. “The question of how climate change and sea-level rise might affect other pollutants remains largely unaddressed.”

He said the release of contaminants such as arsenic “could be a big problem” for parts of the US East Coast, where sea levels are rising and remediation strategies for industrial pollution don't always take into account non-rainfall flooding.
The risks are not limited to arsenic. “There are 76 chemicals in the rocks of the Earth's crust,” Frisbie said, including lead, cadmium and mercury. “Because we're drinking the filtered sludge—that's drinking water—we expect to find 76 of these elements in the drinking water.”