Domestic filters, best defense in arsenic affected areas

KOLKATA, INDIA, Apr 1 - Authorities in West Bengal, India have found that household treatment of contaminated water by domestic filters may be the best possible immediate solution to tackle problems of arsenic poisoning.

The government of West Bengal has explored possibilities in developing user-friendly and affordable arsenic removal domestic filters with the support of UNICEF, to provide safe drinking water to those communities affected, faster than any other scheme.

And, the quicker the better, for investigations so far suggest that ground water drawn through tube wells in 75 blocks of eight districts in this state have arsenic content above the permissible level of Indian government standards. The standards set by the Bureau of Indian Standards are 50 parts per billion (ppb), while the World Health Organization (WHO) sets the standard at 10 ppb.

"Thousands have already been affected by arsenic related illnesses with over 13.8 million people estimated to be at risk in the districts," said Prof K. J Nath, Chairman of the Arsenic Task Force for West Bengal. Though some of the worst cases have been reported from different parts of Asia like Nepal, the Gangetic basin affecting West Bengal and Bangladesh far surpasses any of these.

"It is important to provide safe drinking water to the people," he said. According to him piped water systems, with treated surface water mainly from rivers, have been provided to a few hundred villages. Such surface water projects are already under way in the arsenic affected districts of Malda, South 24 Parganas and North 24 Parganas. "However, these schemes are expensive and require larger implementation time," said Prof Nath.

As arsenic-free water is required for drinking and cooking, so arsenic contaminated tube well water can be used for other household purposes. Recently, a domestic arsenic removal unit has been developed which is very cheap and effective in removing arsenic and fluoride. The approximate cost of the filter is Indian rupees 400 (Rs 640).

Som Nath Basu of the UNICEF office in Kolkata said that these filters would be distributed at primary levels. "The filters will be distributed through social marketing and the authority will be given to non-governmental organizations," said Basu.

The filter has two parts connected with a circular rubber gasket. Raw water is placed in the upper chamber for filtration. The water is then filtered by an iron removal chamber, which can be made locally, and then flows through an aluminum tube. The arsenic-free water is then collected in the lower chamber. The unit can filter three liters per hour of water.

Already 3000 arsenic removal units have been distributed. However, Prof Nath adds that in the long run there is no escape to developing permanent solutions.

Kazal Kumar Dey, Engineer of the Sanitation Cell of the Ram Krishna Mission - which is developing these filters at Narendrapur said that he has sold quite a few of these filters but most have been distributed for free. "There is still more work to be done on awareness. Once, this is developed there will be demand for these filters," he said.