Young brains appear at risk from exposure to popular weed killers

By Carey Gillam

Exposure to two widely used weed killers could be harming the brain function of young people, impacting their memory and learning abilities, according to a study published Wednesday.

The study looked specifically at glyphosate, the active ingredient in Roundup herbicide and scores of other brands, and also at 2,4-D – a long-used, weed killing chemical that has seen a surge in use in recent years and has increasingly been combined with glyphosate to kill tenacious weeds.

Concerns about impaired brain function were associated with both chemicals, particularly with 2,4-dichlorophenoxyacetic acid (2,4-D), according to the study, which was led by researchers at the Herbert Wertheim School of Public Health and Human Longevity Science at University of California San Diego and published in the journal Environmental Health Perspectives.

“This herbicide (2,4-D) has gone mostly under the radar and more studies aimed at understanding the health effect of herbicide exposures are needed,” said Jose Ricardo Suarez, director of the Climate and Environmental Health Research Program at the University of California San Diego.

“This builds on the growing knowledge that not just insecticides – pesticides that are designed to be neurotoxins – can affect brain processes,” Suarez said. The study showed that as herbicide exposures increased, neurobehavioral performance decreased, he said.

The researchers analyzed urine samples taken from 519 young people ages 11-17 who lived in farming communities in Ecuador where herbicides and other pesticides were sprayed. They then assessed the neurobehavioral performance of the youth, testing them on their attention/inhibitory control, memory/learning, language, visuospatial processing, and social perception.

Glyphosate was detected in the urine of 98.3% of the study participants and 2,4-D in 66.2%. Glyphosate was associated with problems with social perception, while 2,4-D was associated with attention/inhibition, language and memory/learning skills.