A new study out of the United States has found links between agricultural pesticides used in Australia and attention-deficit hyperactivity disorder (ADHD).
Monitoring American-Mexican families in the major horticultural area of the Salinas Valley in California, the research found that children exposed to organophosphate pesticides in utero are more likely to display signs of attention disorders before they reach school age, with more noticeable effects in boys.
The researchers from the National Institute of Environmental Health Sciences found a direct correlation between the presence of metabolites in a mother’s urine during pregnancy that confirmed exposure to organophosphate pesticides and increased instances of attention disorders in their children at age five.
Professor of toxicology at the University of New South Wales, Chris Winder, says that these kinds of pesticides are widely used on agricultural crops in Australia, and are known to affect the brain.
"While the development of the brain occurs early in pregnancy, its growth and differentiation continues throughout pregnancy and even after birth as the complex interaction of brain and behaviour emerges," he says.
It is not surprising then, Professor Winder says, to see symptoms of preschool ADHD arise in children known to be associated with exposure to the pesticides before birth.
Associate professor Irina Pollard from Macquarie University points out that the reason behind these negative impacts is clear.
Pesticides are human-made, synthetic hormone disruptors, she says, that “are known to impair the immune system, disrupt endocrine and reproductive function."
Scientists say the findings are a pertinent reminder that children’s exposure to pesticides should be minimised.