Some 50 million people are at risk of arsenic poisoning from contaminated groundwater in Pakistan’s Indus Valley far more than previously thought, according to a new study. Pakistan is aware of the growing problem, with arsenic levels rising in some areas as people increasingly and indiscriminately draw from the country’s underground aquifers, said Lubna Bukhari, who heads the government’s Council for Research in Water Resources. “It’s a real concern,” she said. “Because of lack of rules and regulations, people have exploited the groundwater brutally, and it is driving up arsenic levels.”
The authors of the study developed a map highlighting areas of likely contamination based on water quality data from nearly 1,200 groundwater pumps tested from 2013 to 2015, and accounting for geological factors including surface slope and soil contents. They determined some 88 million people were living in high-risk areas.
Given that about 60-70 per cent of the population relies on groundwater, they calculated that roughly 50 million maybe even 60 million were potentially affected. That’s equal to at least a third of the 150 million already estimated by the World Health Organization to be drinking, cooking and farming with arsenic-laced water worldwide.
“This is an alarmingly high number, which demonstrates the urgent need to test all drinking water wells in the Indus Plain,” with hotspots around the densely populated cities of Lahore and Hyderabad, said the study’s lead author, Joel Podgorski, of the Swiss Federal Institute of Aquatic Science and Technology, known as Eawag. The findings were published today in the journal Science Advances.
The high-risk area mapped out in the study broadly covers the middle and lower reaches of the Indus River and its tributaries, before they empty into the Arabian Sea. Scientists had expected this area might be affected. Similar geographical areas along the Ganges River in neighboring India and Brahmaputra in Bangladesh also contain pockets of arsenic contamination.
Normally, that arsenic would stay in the ground. But in the last few decades, South Asian countries concerned with pathogen-infused surface water have been pumping enormous volumes of groundwater, causing the water tables to drop drastically and tapping into new water pockets tainted by the colorless, odorless toxin.