A study carried out by the environmental group Greenpeace India claims to have found evidence that exposure to pesticides is impairing mental development among rural children in India.
Researchers for the organisation tested almost 900 children in six of the country's cotton-growing states, using a range of mental tests designed to measuring analytical abilities, motor skills, concentration and memory.
They found that children living in regions in which pesticides are widely used performed significantly worse in more than two thirds of the tests than children elsewhere.
"Children from regions as diverse as Tamil Nadu and Punjab, who have nothing in common but their exposure to pesticides, [appear to] share an inability to perform simple play-based exercises — such as catching a ball or assembling a jigsaw puzzle — simply because they’ve been exposed to pesticides over a period of time," says Greenpeace India's Sustainable Agriculture Campaigner Kavitha Kuruganti, the study's lead investigator.
Cotton occupies less than five per cent of cultivated land in India, but uses more than half of the total pesticides used in agriculture, according to the study, which has been published under the title Arrested Development.
These pesticides include chemicals such as methyl-parathion and monocrotophos that the World Health Organisation classes as "highly to extremely hazardous to human health" and that the Food and Agriculture Organisation recommends should not be used in developing countries.
The Greenpeace findings echo those of a 1998 study of Mexican children exposed to pesticides that was conducted by Elizabeth Guillette of the University of Florida. This showed that, when compared with children of the same age living elsewhere, such children have decreased stamina, underdeveloped hand-eye coordination, weaker memory and lower drawing skills.
"One can only wonder about the future of any society in which individuals are unable to function at what should be their full potential," says Guillette, who was an advisor for the Indian study.
Greenpeace India is urging the pesticide industry to accept liability and provide compensation for the affected children. It has also called on the Indian government to ban the most hazardous classes of pesticides, and to do more to encourage pesticide-free agriculture, for example by using biological pest-control techniques.
"North Eastern states such as Sikkim and Mizoram have already recognised the risks of using [chemical] pesticides and declared themselves 'organic states'," says K. A. Chandrasekar, director of the Social Initiative for Rural People's Integration, one of study's local coordinators.
In a statement, Bayer CropScience (India) Limited, a leading Indian pesticide manufacturer, declined to comment directly on the Greenpeace allegations.
But it told SciDev.Net that the company "recognises the issue of user safety under specific use conditions, and is committed to the introduction of new products and improved formulations, and the voluntary withdrawal of some application techniques, products or product uses."