US scientists say use of deep aquifers in irrigation could raise arsenic poisoning in S. Asia

WASHINGTON - Researchers of three American universities have warned farmers in Bangladesh and other parts of South Asia not to use deep, uncontaminated aquifers for irrigation, as continuing with the practice could raise levels of arsenic poisoning in ground water and compromise access to clean drinking water.

A report co-authored by groundwater experts Scott Fendorf (Stanford University), Holly A. Michael (University of Delaware) and Alexander van Geen (Columbia University) said: “Every effort should be made to prevent irrigation by pumping from deeper aquifers that are low in arsenic. This precious resource must be preserved for drinking.”

Every day, more than 100 million people are exposed to arsenic-contaminated drinking water in Bangladesh, Cambodia, China, India, Myanmar, Nepal, Pakistan and Vietnam.

The report appears in the May 27 issue of journal Science.

Over the last 10 years, Fendorf, Michael and van Geen have conducted long-term groundwater studies throughout South Asia with the goal of finding low-cost solutions to what the WHO calls the largest mass poisoning in history.

“Our Science report presents an overview of the scientific consensus and continuing uncertainty about the root causes of the arsenic calamity,” said Fendorf, a professor of environmental Earth system science at Stanford.

Unlike most countries in the region, India and Bangladesh have very deep aquifers that typically have low levels of arsenic. In Bangladesh, one of the poorest and most densely populated countries in the world, concerns about arsenic-contaminated rice crops have led farmers to look for safer sources of water deep underground.

Arsenic poisoning was first identified in the early 1980s in West Bengal, India, where health officials linked an outbreak of skin lesions to groundwater pumped from shallow wells.

Today, the WHO estimates that thousands of people from Pakistan to Vietnam die of cancer each year from long-term arsenic exposure. Groundwater containing arsenic also causes cardiovascular disease and inhibits the mental development of children.

The three researchers have recommended use of arsenic filters.

“Many arsenic filters are quite effective at removing arsenic over the short term. However, they should be tested regularly, which doesn’t always happen, and replaced when they begin to fail from disturbance or exhaustion,” Professor Fendorf said.

“We need to be thinking broadly about water options that are available and not focus on a single solution,” he added. (ANI)