Fear among consumers about pesticide residues in food, particularly in vegetables and fruit, has been growing over the past few years. Agricultural scientists intimately involved in monitoring these residues assert that this dread is largely the result of either careless use of pesticides or unfounded claims about residual toxicity.
Pesticides, which are duly approved for manufacture and sale, are totally safe if – and this is a critical if – they are used according to the prescribed “good agricultural practices”. It is the improper use of pesticides and a disregard of the suggested precautions that are the main reasons for toxic residues in farm products.
The most common violation of recommended agronomic practices is harvesting the crop soon after spraying the pesticide without observing the vital “waiting period” to allow the effect of the chemical to dissipate. Worse, some farmers, especially vegetable growers, dip the produce in chemical solutions – for instance, cauliflower is dipped in the Malathion – before taking it to the mandi to improve its appearance and get a higher price. Such practices should be curbed by educating farmers, maintains K K Sharma, who heads the all-India network project on residue monitoring run by the Indian Council of Agricultural Research (ICAR). The directorate of this project is located at the New Delhi-based Indian Agricultural Research Institute (IARI).
IARI is also the nodal agency for implementing the agriculture ministry’s scheme for monitoring pesticide residues at the national level. It is assisted by a large number of laboratories and testing centres of various agricultural and scientific research bodies, state agricultural universities and the ministries of agriculture, health, environment and chemicals and fertilisers. These centres collect samples of nearly 25 items, including farm and livestock products, from various markets, agricultural mandis and public distribution system, or PDS, outlets to analyse the presence of toxins.
Of over 29,500 samples examined at 21 laboratories between 2009 and 2011, only 343, or 1.1 per cent, were found to contain residues above the maximum permissible limit. This is not high compared to international standards. The situation in the National Capital Region, however, is worrisome. Of the samples picked up from the Delhi’s Azadpur mandi, one of Asia’s largest agricultural markets, two to three per cent were found to have residues in excess of the allowed limits. Such cases are reported to the agriculture ministry for action against offenders.
However, IARI residue analysts point out that even if a product carries marginally higher than the permissible level of residues, it does not automatically become unsafe to eat. This is because the maximum residue limit is invariably kept far lower than the level at which food becomes injurious to human health. An elaborate procedure is followed to fix the residue limits of a pesticide before granting it registration. A new molecule, developed by a pesticides company after several years of testing, is subjected to multi-location safety trials on the most sensitive animals under ICAR’s all-India network project to assess its “no adverse effect level”. This value is, then, divided by 100, or in other words, lowered to its one-hundredth fraction to arrive at the “acceptable level” of pesticide residue, which forms the basis for fixing the maximum residue limit by the health ministry.
Interestingly, these scientists ridicule the misguided propaganda being carried out by a section of the media, especially a particular TV channel, that vegetables, notably lauki (bottle gourd), are injected with chemicals to increase their size and weight overnight. The chemical often cited in this context is Oxytocin — a milk-enhancing hormone meant for cattle. The experiments conducted at IARI showed no effect of this hormone on lauki or any other vegetable. On the contrary, it spoiled the vegetable. Scientists also decry the common practice of ripening fruit like banana and papaya, among others by exposing them to calcium carbide. This treatment may speed up ripening but lowers the shelf life, they point out.
Thus, there is an urgent need to create awareness among farmers and others involved in marketing farm produce about the safe use of pesticides to tackle the menace of pesticide residues. Wilful defaulters need to be dealt with firmly.