New research suggests that the effects of climate change will increase the likelihood of cancer from polluted well water for millions of individuals in Bangladesh.

Scientists warn that as the climate continues to warm, there will be an increase in sea level, unpredictable flooding, and extreme weather events. This will lead to a faster release of harmful levels of arsenic into the nation’s drinking water.

According to the researchers, the outcome will be a worsening of an existing public health emergency in the country. Millions of individuals are already suffering from skin, bladder, and lung cancers due to arsenic poisoning.

Dr. Seth Frisbie, a retired chemistry professor from Norwich University and lead researcher, emphasized in a recent presentation that the issue of long-term arsenic poisoning from drinking water is not just a theoretical concern, but a pressing reality. He shared an example of a village he visited where the average lifespan was only 30 years due to this issue.

The issue of arsenic contamination in water in Bangladesh can be traced back to the 1970s. During this time, the country had a high rate of infant deaths due to the presence of pollutants in surface water.

UN aid agencies and NGOs sponsored a vast programme of deep tube well boring to provide clean water for domestic use, crop irrigation and fish farming. The new wells reduced rates of child deaths by curtailing the spread of waterborne diseases, but by the 1990s it became clear that water drawn from sedimentary rocks beneath Bangladesh contained high levels of naturally occurring arsenic.

The initial instance of long-term exposure to arsenic through consumption of well water was identified in Bangladesh in 1993. The World Health Organization later deemed it to be the most extensive poisoning of a community in history.

According to Frisbie, arsenic is a naturally occurring element that is carried by water and sediment from the Himalayan mountains. This means that the sediment in rivers such as the Ganges, Brahmaputra, Meghna, Irrawaddy, and Mekong basins contain high levels of arsenic.

Drinking surface water used to be safe because it is exposed to oxygen in the atmosphere, which prevents arsenic from dissolving and removes it from the water. However, deep well water does not have as much contact with oxygen, leading to a sudden increase in health problems when people are given access to these wells.

Long-term exposure to arsenic can result in the accumulation of this toxic substance in the bodies of those affected. This can manifest through the hardening of skin on the hands and feet, known as keratinisation. Internally, similar processes occur, leading to the buildup of arsenic in the lungs and other organs, which can ultimately result in cancer.

During his research, Frisbie discovered that approximately 49% of wells had drinking water with arsenic levels higher than the WHO’s recommended limit of 10 parts per billion. Additionally, around 45% of wells had water with at least five times that amount of arsenic. One well that Frisbie tested had an extremely high concentration of 448 parts per billion.

Frisbie stated that his approximate calculation suggests that 78 million individuals in Bangladesh are at risk, and he predicts that approximately 900,000 of those individuals will succumb to lung and bladder cancer.

The issue of climate change could be exacerbated by the breakdown of natural systems. Bangladesh, located on a large river delta, faces a heightened risk of flooding as ocean levels rise. This could lead to a chemical reaction called “reduction” that would cause increased levels of arsenic to be released from the sediment in the underlying aquifer.

Simultaneously, the intrusion of seawater into the aquifer caused by sea level rise will lead to a higher salinity level. This chemical alteration will also escalate the rate of arsenic infiltration into the water through a phenomenon referred to as “the salt effect”.

Frisbie and colleagues state in their study, published in the journal Plos One on Wednesday, that modifications in the chemistry of aquifers are likely to lead to a rise in the presence of arsenic in Bangladesh’s drinking water from wells. This heightened exposure to arsenic is expected to result in higher rates of mortality and illness due to chronic arsenic poisoning.

The consequences of alterations in the chemical makeup of aquifer water due to climate change will extend beyond Bangladesh to the rest of the globe. According to Frisbie, these chemical reactions have a global impact. For example, there is a decrease in arsenic levels in Manchester and a salt effect in Louisiana caused by floods such as Hurricane Katrina. Therefore, this is a worldwide issue due to the universal nature of these chemical processes.

Source: theguardian.com