‘High pesticide levels in groundwater’ (The Times of India 18 June 2012)

NEW DELHI: The groundwater that most of Delhi relies on when water shortage leaves taps dry is probably far more contaminated than we can imagine.
A recent study by a team from the civil engineering department of IIT-Delhi on the groundwater quality in the Palla-Burari region has made some alarming revelations. The water samples tested from this area contain moderately high levels of pesticides; some of them residues of long-banned pesticides, such as DDT. This region has close to 80 borewells and five Ranney wells that meet about 15% of Delhi's water needs.
The team tested the water samples for organochloride pesticides (OCP) that breakdown very slowly in the environment. Many of these pesticides disrupt the endocrine system and mimic the body's natural hormones causing havoc in the hormonal system. The study says these pesticides can lead to serious longterm health hazards.
Samples were collected from 21 borewells and tested for 17 varieties of OCPs. Three samples tested positive for all 17 targeted OCPs. The most frequently occurring pesticide residues were of aldrin, a byproduct of insecticide lidane, endosulfan and even DDT. "Yes, we found residues of even pesticides that are banned. It's worrying because these pesticides remain in the environment for very long," said professor Atul K Mittal, who headed the study. The most commonly occurring pesticide in the water samples was aldrin.
Though the concentrations of pesticides were not higher than the standards set by Bureau of Indian Standards (BIS), in many cases the samples had higher concentration of pesticides than the WHO and EU standards. "In case of organochloride pesticides, the concentration is not so much a worry as the fact that we are continuously exposed to them. They stay in our environment for a long time. Such exposure can be directly linked to higher incidence of cancer, reduced fertility, thyroid disruption and other health problems," said Pravin Mutiyar Suthar, one of the researchers in the study.
The same team also conducted a larger study of the entire Ganga basin covering Uttarakhand, UP and Bihar. The results showed that different types of OCPs predominate in different regions depending upon land-use pattern. HCH, a byproduct of insecticide lidane, was detected mostly in the mountainous stretch (Uttarakhand), the water in UP contained more of endosulfan residues and the Bihar region contained more of the aldrin group of pesticides.
Both the Palla-Burari water quality study and Ganga basin study were published in the journal Drinking Water Engineering and Science this year. The team is continuing to test samples from Yamuna and surrounding areas.