Over 20 banned pesticides under the category of organochlorines (OCPs) have been found in produce in Delhi-NCR in quantities that exceed the internationally defined permissible limits, a study conducted by Jawaharlal Nehru University (JNU) on 52 vegetable samples found.
The study, published in the international journal Environmental Science and Pollution Research, also measured health risk on the basis of annual vegetable consumption, age and body weight. The study found a high lifetime cancer risk in children and adults, which authors said was “serious concern for Delhi population”.
Vegetable samples including radish, radish leaf, cauliflower, brinjal, okra, and smooth gourd were collected from Najafgarh, Mehrauli, Shahadra, Alipur, Faridabad, Ghaziabad, Kanjhawala in 2012, to identify pesticide exposure in root, leafy and fruit type vegetables.
Professor P S Khillare, the corresponding author of the study, said, “The highest contamination was detected in cauliflower, followed by radish leaf, okra, radish, brinjal and smooth gourd in decreasing order. Cauliflower, had the highest exposed area as it is in direct contact with pesticide sprays. It had the highest residual concentrations of these compounds.”
The mean concentration of all 20 OCPs in cauliflower was significantly higher than radish leaves but the levels in the next three vegetables were comparable. This, Dr Khillare said, was possibly because all three are grown identically.
Among the 20 investigated OCPs, 17 were detected in all the vegetable samples with HCH — a combination of pesticides called hexachlorocyclohexane which is a banned category of pesticides — and DDT, which is banned in agricultural products.
“HCH was much higher than DDT because of indiscriminate use of the cheap pesticides,” Sapna Chourasiya, the research scholar who has worked in the study, said.
She said in a survey of pesticides and fertilizers in shops in the areas where the vegetable samples were collected, none of the banned pesticides were identified.
Researchers said direct spray or atmospheric deposition is the most common pathway for contamination. “Vegetables grown in winter have lower photodegradation of pesticides,” Dr Khillare explained.
The cancer risk attributed to OCP exposure is considerable, authors said. Exposure and health risks for children was found to be double that of adults, authors said.
Researchers said more government action is needed on the ground. “The ban seems to be only on paper. Environmental and health safety is directly linked to poverty and the government needs to act on the root cause,” Khillare said.