Arsenic-free water

A way to provide arsenic-free water to people in South Asia who are exposed to high levels of the poison in groundwater has been developed by UK researchers.

Researchers at Queen’s University Belfast have helped develop a way to provide arsenic-free water to millions of people in South Asia who are exposed to high levels of the poison in groundwater.

Currently over 70 million people in Eastern India and Bangladesh experience involuntary arsenic exposure from consuming water and rice, which is the main staple food in the region. This includes farmers who have to use contaminated groundwater from minor irrigation schemes.

It is estimated that for every random sample of 100 people in the Bengal Delta, at least one person will be near death as a result of arsenic poisoning, while five in 100 will be experiencing other symptoms.

Leading an international team, Queen’s researchers have developed a trial plant in Kasimpore, near Calcutta, which offers chemical-free groundwater treatment technology to rural communities for all their drinking and farming needs.

The idea behind the plant is based on recharging a part of the groundwater, after aeration, into a subterranean aquifer (permeable rock) able to hold water. Increased levels of oxygen in the groundwater slows down the arsenic release from the soil. At higher dissolved oxygen levels, soil micro organisms, as well as iron and manganese, reduce the dissolved arsenic level significantly.

Dr Bhaskar Sen Gupta of Queen’s, coordinator of the project, said: ’Arsenic poisoning is behind many instances of ill-health in Southern Asia, including a rising number of cancer cases. Developing a low cost method of decontaminating ground water that is laced with high levels of arsenic is a key challenge for sustainable agriculture there.

’While there are some techniques available for treating relatively small quantities of water, there has, until now, been no viable technology available for decontaminating groundwater on a large scale that can ensure safe irrigation and potable water supply.’

The project is part of the EU-funded Asia Pro Eco Programme which is dedicated to the improvement of environmental performance in Asian economic sectors, known as TiPOT (Technology for in-situ treatment of groundwater for potable and irrigation purposes).

The new plant will be maintained and operated by local village technicians. To help apply the idea to other areas in the South Asian region, the World Bank has given a grant of $200,000 (£109,000) to the TIPOT consortium to set up six more subterranean water treatment plants in the Gangetic plains of West Bengal.

In June 2008, Queen’s, along with the Indian partners BESU and IEMS, won the prestigious DELPHE award of the British Council to set up another treatment plant and run awareness programmes for arsenic poisoning in India.