Germana Carillo It started with scattered spots on people's chests and backs and, for some, even blackening of their toes. Doctors and researchers began noticing patients in Bangladesh exhibiting these types of symptoms as early as the 1980s. And soon everything became clearer: these were classic signs of arsenic poisoning
Health experts have termed it the “worst mass poisoning” of a population in history, with tens of millions of people currently affected. A study has found that approximately 43,000 people die annually in Bangladesh from arsenic-related diseases, and the situation may only worsen.
Recent analyses suggest that the impacts of the human-caused climate crisis—ranging from flooding to rising sea levels (with monsoon rains currently flooding about a fifth of the nation each year, forcing families to abandon their homes, and sea levels predicted to rise half a meter by 2050, covering about 11% of the territory)—are altering the chemical composition of groundwater, further increasing arsenic levels.
Moreover, the issue extends far beyond Bangladesh. Increasing research confirms that global warming could exacerbate the problem of arsenic-contaminated water in other countries, including the United States.
Why arsenic is so dangerous
Arsenic, a known natural toxic metalloid, has a long history as a poison. Arsenic contamination in groundwater and food in Bangladesh, where poor sanitary conditions were already a concern in the 1970s, remains a serious public health issue. Decades after its identification, millions are still exposed to arsenic through drinking water and food.
The negative health effects of chronic arsenic exposure are clear, including arsenicosis, various cancers, neurological disorders, cardiovascular diseases, diabetes, respiratory diseases, and kidney and reproductive diseases.
Arsenic exposure also harms children’s health and development, with maternal exposure during pregnancy linked to increased risks of:
- infant mortality
- spontaneous abortion
- stillbirth
- preterm birth
- low birth weight
- growth retardation
- unhealthy immune system
- lower IQ,
- neurotoxicity
- impaired neurological development.
Arsenic around the world
The World Health Organization (WHO) estimates that around 140 million people in at least 70 countries have drunk water contaminated with arsenic at levels exceeding the recommended limit of 10 micrograms per liter.
A comprehensive study by the British Geological Survey, begun in 1998 and focusing largely on Bangladesh, found that 27% of shallow tube wells exceeded national guidelines, affecting about 35 million people. The study revealed that approximately 57 million people were exposed to levels violating the WHO’s 10 microgram guidelines, about 45% of the population.
Global warming could increase risks
The stakes are rising as humans continue to burn fossil fuels, warming the planet. A recent study clearly shows that the increasingly severe impacts of climate change can alter groundwater chemistry.
This presents additional challenges for Bangladesh, at the forefront of the climate crisis. Located in a low-lying, densely populated area with a long coastline, it faces numerous threats from rising sea levels to flooding: each year, about 20% of the country is virtually submerged.
Research indicates that flooding can prevent atmospheric oxygen from penetrating groundwater, which in turn can increase the release of arsenic from solids and sediments into the water.
Sea-level rise poses another challenge, causing saltwater intrusion into groundwater sources. This not only makes the water saltier but the presence of salt can also increase arsenic concentrations through a phenomenon known as the “salting-out effect.”
And these impacts, scholars say, are not limited to Bangladesh but are seen across the Earth. For example, high levels of arsenic have also been identified in the groundwater in the United States, where at least 43 million people rely on private wells. Hence, it’s a vicious cycle and a serious problem without an easy solution.
