Purified, yet sullied?

with water-borne diseases on the rise, more and more people have been buying commercial domestic water purifier ( cdwp ) systems. However, a recent study indicates that these filters, instead of diminishing the risks, could actually lead to a greater incidence of diseases, especially diarrhoea.

Led by Milind Watve of the department of microbiology, Abasaheb Garware College in Pune, Maharashtra, scientists undertook a year-long survey of 1,195 individuals from 274 urban families residing in various parts of the city. Seventy-three families used commercially-available filters -- porcelain candles, ion exchange and ultraviolet radiation, 63 did not use any treatment and the rest depended on traditional methods like muslin filtration and boiling.

A higher incidence of diarrhoea was noticed among users of cdwp and among those using boiled water. Scientists said that the systems could be colonised by bacteria or could also be inefficient in removing the pathogens. Non-users could have become immune by being continually exposed to infections thereby leading to insignificant diarrhoeal incidences among them.