Purifying the purifier

A consumer looking for a water purifier is most likely to be confronted with a fusillade of quality claims. K J Nath, president, Institution of Public Health Engineers in Kolkata is not sure about their veracity. "A lot of the tall claims by private players cannot be substantiated scientifically,' he says.

Down To Earth asked a few manufacturers about the standards they adhere to. Most produced lab reports and rolled of terms like certified by nsf international usa, endorsed by the Indian Medical Association (ima), tested by university of Minnesota, bis certified, member of the Water Quality Association, usa.

What about the testing criteria at these national and international laboratories? We wondered. Our investigations revealed that these varied and were sometimes even irrational. A consumer needs to know the contaminant challenge, the quality and source of water, for which the purifier was certified. But consider, for example, a 2006 report by Spectro Labs Delhi. It stated that a model manufactured by Kent cleansed to packaged drinking water standards: IS 14543: 2004. Heavy metals were within limits stipulated by this standard, the report noted. But most heavy metals were within prescribed limits in the untreated water itself. So, the purifier had actually done precious little. It had only removed microbial contaminants, tds and salts. IS 14543: 2004 standards also stipulate that there should not be any pesticide in water. But the Spectra Labs report made no mention of pesticide levels in the treated water.

We then decided to check on certificates issued by the Indian Medical Association. Were they also indifferent to the contaminant challenge? A certificate given by the association to Eureka Forbes in 2004 came as a revelation. It showed that the association actually does not test water purifiers. The certificate said, "Endorsements