Madhusudankati, West Bengal, India - For decades, Manatosh Biswas - a farmer who lives in the middle of eastern India's so-called "arsenic belt" - had no idea that he was drinking contaminated water.

About 15 years ago, he sought treatment for some lesions on his feet and was told that he was suffering from arsenicosis after having been exposed to the toxic element for years.

Doctors advised him to stop drinking the arsenic-contaminated groundwater from his village's wells, but he could not afford to buy bottled water.

Fortunately for Biswas, last year the Sulabh Safe Drinking Water Project (SSDWP), an initiative run by a New Delhi-based NGO, found a way to provide clean and cheap drinking water to the region.

"This water costing one-third or one-fourth of the other, cheaper packaged water in the market has brought a big relief to all in my village," Biswas told Al Jazeera. "Most of the poor residents in my village, who, for financial constraints, could not access arsenic-free packaged water, are drinking safe water after decades."

While regular bottled water may cost between four rupees (6 cents) and 15 rupees (22 cents) per litre, SSDWP is providing clean water to the villagers for 50 paise (1 cent) a litre.

"Some among us got the Sulabh water tested at some labs and found it free from all contaminants, including arsenic," said Biswas. "Also, it's very cheap. This water has come as a wonderful gift for the poor people in our village."

A recent survey conducted by the NGO running the project found that arsenicosis victims who switched to drinking Sulabh water last year have seen rapid improvements in their health.

A dangerous drink

When the practice of drilling deep tube wells in eastern India began in the 1960s, people were advised to drink groundwater drawn through them to protect themselves from water-borne diseases such as cholera that often trigger epidemics. Later, tens of thousands of shallow tube wells were also sunk in the areas where aquifers lie closer to the ground.

But in the 1990s, high levels of naturally occurring arsenic were detected in water drawn from tube wells in Bangladesh and eastern India. Drinking arsenic-rich water for a long period of time leads to arsenicosis, which causes skin lesions, cancer, and many other diseases.

After scientists and doctors warned that millions of people in West Bengal were drinking the contaminated groundwater, the state government set up a number of groundwater de-arsenification plants.

But most of them failed to effectively remove the arsenic from the water, and many scientists have long suggested that using treated surface water is a better solution to the problem - advice largely ignored by the government.

Towards the end of 2014, Sulabh International Social Service Organisation (SISSO), a New Delhi-based NGO, set up the SSDWP with assistance from 1001 Fontaines, a French NGO.

Managed by Madhusudankati Samabay Krishi Unnayan Samity, a local village cooperative, the project treats pond water using modern filtration technology and has succeeded in mitigating the arsenic problem in some villages, said local residents, doctors, and those running the project.

Kalipada Sarkar, who heads the Madhusudankati village cooperative, said this is the first project in the region to use pond water to produce potable water.

"After running the plant for over a year, we find that our mission to provide clean water in about a dozen villages has been very successful," Sarkar explained, adding that ponds used for the project are fenced off, and that villagers are not allowed to access them to bathe or do their laundry.

"Every month, samples from our plant get tested at the lab of a reputed engineering college [the Indian Institute of Engineering and Science Technology]. They never found arsenic or any other substance, which makes water harmful for drinking, beyond permissible level," said Sarkar.

In an attempt to provide arsenic-free water, the Madhusudankati village cooperative initially set up an arsenic removal plant attached to a deep tube well. But that plant failed to solve the crisis, Sarkar said.

"Safe disposal of the sludge generated at the plant, without contaminating the surface water sources with arsenic, was a very difficult task. Also, with time, we found that the contamination level with arsenic of the groundwater was increasing. The situation was turning unmanageable and we were forced to shut it down," he said.

Since the Sulabh surface water project began functioning, it has been a "big relief" for the mostly poor residents in the dozen villages served, said local doctor, Subal Sarkar (no relation to Kalipada Sarkar).

"Among people who have been using the Sulabh water for some time now, the occurrence of dermatitis, dysentery, some gynecological diseases and other ailments, which are often caused by an overdose of arsenic in drinking water, has dropped considerably.

Even in many cases arsenic keratoses [a type of skin growth] and other arsenic-triggered dark spots are fading away from the skins of the arsenicosis patients who have switched to drinking the Sulabh water," Dr Sarkar told Al Jazeera.

Surface water as a solution

Six years ago, the School of Environmental Studies (SoES) at Kolkata's Jadavpur University reported that in West Bengal, more than five million people were drinking water with arsenic contamination at 50 parts per billion (ppb) - five times the World Health Organisation's permissible limit of 10ppb.

SoES research director Dipankar Chakraborti, who has studied the arsenic problem in South Asia for three decades, said that treating surface water can provide the best solution to arsenic-contaminated groundwater, given the abundance of ponds and small lakes in rural West Bengal.

"We have seen how over the years most of the groundwater arsenic removal plants in West Bengal have failed to supply clean water. It's heartening to know that some organisations have set up a drinking water project sourcing water from a pond," said Chakraborti.

"If they can keep the water finally free from pesticide, insecticide, fertiliser, harmful microbes, etc, the project will succeed to solve a decades-old problem of clean drinking water in some villages of the arsenic-affected region," Chakraborti explained.

Arsenic-rich groundwater is also used in irrigation and food preparation, which poses a threat to public health, the scientist noted.

In West Bengal, SISSO has set up three drinking water projects to provide safe drinking water. While the project at Madhusudankati uses pond water, the other two, located in other districts of the state, use water from the Ganges River.

Bindeshwar Pathak, the founder of SISSO, said the project's success has encouraged him to try to bring safe water to wider areas of the arsenic-risk zone.

"Among our three projects in Bengal, the Madhusudankati project is unique because, in a first among all water projects in arsenic-risk zone of West Bengal, it uses pond water. We have followed the advice of some experts like Dipankar Chakraborti, refrained from drawing groundwater, and have built a successful drinking water project using pond water," said Pathak.

"We are planning to come up with some more such pond water-based water projects across this state, aiming to bring relief to many more arsenic-affected villages in West Bengal."

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