Washington, Aug 24: An "alarmingly high" level of arsenic contamination was found in groundwater in Pakistan, putting up to 60 million people at risk of serious diseases including cancer, reveals a US study.
The study, published in the American journal Science Advance on Wednesday, examined groundwater samples collected from nearly 1,200 sites from across the country, reports Xinhua news agency.
Then, a model incorporating topographical, geochemical and hydrological parameters was used to create the first comprehensive "hazard map" of this poisonous element for the entire country.
It showed that many people in eastern Punjab, which includes Lahore, are exposed to a high risk of arsenic contamination.
"In many parts of the densely populated plains along the Indus River and its tributaries, arsenic concentrations in groundwater supplies exceed the WHO (World Health Organisation) guideline of 10 micrograms per liter," the study said.
"Very high concentrations, above 200 micrograms per litre, are found mainly in the south; the highest measured in this study was 500 micrograms per litre."
Altogether, 50 to 60 million use groundwater which very likely contains more than 50 micrograms per liter.
"This is an alarmingly high number, which demonstrates the urgent need to test all drinking water wells in the Indus Plain," first author Joel Podgorski, a geophysicist at the Swiss Federal Institute of Aquatic Science and Technology said on Wednesday.
The researchers called for emergency solutions, including health intervention programs, finding alternative resources of drinking water and evaluating options for removing arsenic.
Arsenic is one of the most common inorganic contaminants found in drinking water worldwide.
This metalloid occurs as a natural component of sediments, with small quantities being dissolved in groundwater as a result of weathering.
The inorganic salts of arsenic are tasteless and odourless, but highly toxic to humans. If ingested over long periods, even low concentrations, can cause damage to health, including skin disorders, lung cancer and cardiovascular diseases.
The WHO estimated that around 150 million people rely on groundwater contaminated with arsenic worldwide.