NEW DELHI: If the costly packaged water bottles bearing ISI marks have been found to contain residues of harmful pesticides then how bad must the raw groundwater, that is treated to fill those bottles here, be?

On Wednesday, after releasing the study on dirty bottled water, Centre for Science and Environment (CSE) director Sunita Narain had said: “The bigger issue is that of groundwater contamination.”

A large number of Delhiites are either totally dependent on the sub-soil reserves or use it in addition to the meagre Delhi Jal Board (DJB) supply. Moreover, all bottling units in Delhi are totally dependent on groundwater for filling up their bottles. According to DJB chief P K Tripathi, not a single unit has sought DJB connection till date.

In January 2000, the Central Ground Water Board (CGWB) and the Central Pollution Control Board (CPCB) had conducted a joint study to find how bad the Delhi’s groundwater was.

CGWB’s Delhi unit incharge S B Singh said: “The biggest problem was found to be that of excessive salinity, nitrate and fluorosis content.” Traces of hard metal and other contaminants were also found in some samples.

Fluorides come mainly from sub-soil clays and rocks and nitrates from untreated sewage, leaking septic tanks, human faeces and leaching at the landfill sites.

Residues of pesticides were detected from samples drawn from places near agricultural areas like Alipur, Kanjhawala, Najafgarh and Mehrauli.

But the contamination seems to have worsened in the past two years. The CSE study drew samples from the tubewells of bottling units located in places like Okhla, Shivaji Marg and Burari. And pesticides were found in all of them.

“A major factor for this is the indiscriminate spraying of pesticides like DDT and malathion for checking spread of malaria,” CPCB chief Dilip Biswas said.

Such is the condition of groundwater that Tripathi said: “DJB water is the safest bet for people as its primary source is river water.”

He said the DJB is even planning to send its samples to CSE for verifying the “total safety” claim.