Pakistan’s Indus Valley is at risk of arsenic poisoning from contaminated groundwater risking lives of around 50 million people, the risk is far more than thought.

Lubna Bukhari, heads the government’s Council for Research in Water Resources said that people are fully aware of arsenic levels rising in some areas because they extensively draw underground aquifers.

“This is a real concern of lack of rules and regulations that have subjugated the groundwater cruelly, and is increasing arsenic levels.”

The study highlighting contaminated area based on water quality data from approximately 1,200 groundwater pumps tested from 2013 to 2015, and accounting for geological factors like surface slope and soil contents and estimated 88 million people living in areas of high risk.

They roughly calculated 50-60 million people were potentially affected that is 1/3rd of the 150 million estimated by the World Health Organization to be drinking, cooking and farming with arsenic contaminated water worldwide.

“Alarmingly high number that demands urgent call to test all drinking water wells in the Indus Plain,” particularly populated cities of Lahore and Hyderabad, said Joel Podgorski, of the Swiss Federal Institute of Aquatic Science and Technology, known as Eawag, lead author of study, published in the journal Science Advances.

Arsenic stay in the ground normally but pumping enormous volumes of groundwater, causing the water tables to drop drastically and tapping into new water pockets tainted by the colourless, odourless toxin.

The WHO considers arsenic concentrations above 10 micrograms per liter to be dangerous and many of Pakistan’s  wells test showed 5 times or much higher.

“The study is of critical importance because it draws attention to an unnoticed problem affecting the health of millions of villagers,” said geochemist Alexander van Geen of Columbia University’s Lamont-Doherty Earth Observatory.

Abida Farooqui, assistant professor of environmental sciences at Quaid-i-Azam University Islamabad, said that the sample size of study may be too small to draw clear conclusions. “The study exposed an emerging problem of arsenic in Pakistan,” Farooqui said. But in the whole Indus Valley only 1,193 samples have been used to foresee the condition, which is impractical.”

This is an acute problem for those who have no access to clean water and rely on what the government supplies.

“It is job of government to provide clean drinking water, but have to travel to find clean water,” Ali Hasan said while filling a large plastic jug to take home, resident of Islamabad.

Nearly 80 % of water sources were unsafe to drink in 2,807 villages across 24 districts were contaminated with bacteria or other pollutants suggested from survey submitted to parliament of Pakistan last year.

“The presence of arsenic in drinking water is flattering a prevalent health problem,” said Luis Rodrguez-Lado, a chemist with the University of Santiago de Compostela in Spain.

Bukhari said that for Pakistan the problem is now imperative. in the worst-affected areas her department is already working to provide cheap anti-arsenic water filters to poor villagers with the United Nations Children’s Fund.

“We should discourage the indiscriminate ground water exploitation,” she said, knowing that even residents of city with municipal water access were digging tube wells “to have a lavish supply of water.” There is a need to test countless tube wells and identify arsenic possibly determining which depths might be safer, she said. If researchers can find a depth where “there is no arsenic, wells dig to depth that stop before the water is contaminated,” Bukhari said.