Source: eurekalert.org
Herbicides are the most used class of pesticides worldwide, with uses in agriculture, homes and industry. Exposures to two of the most popular herbicides were associated with worse brain function among adolescents, according to a study led by researchers at the Herbert Wertheim School of Public Health and Human Longevity Science at University of California San Diego.
In the Oct. 11, 2023 online issue of Environmental Health Perspectives, the researchers reported measuring metabolite concentrations of two commonly used herbicides — glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) — and the insect repellent DEET in urine samples collected in 2016 from 519 adolescents, aged 11 to 17, living in the agricultural county of Pedro Moncayo, Ecuador. Researchers also assessed neurobehavioral performance in five areas: attention and inhibitory control, memory and learning, language, visuospatial processing, and social perception.
“Many chronic diseases and mental health disorders in adolescents and young adults have increased over the last two decades worldwide, and exposure to neurotoxic contaminants in the environment could explain a part of this increase,” said senior author Jose Ricardo Suarez, M.D., Ph.D., M.P.H., associate professor in the Herbert Wertheim School of Public Health.
Among the findings:
- Glyphosate, a nonselective herbicide used in many crops, including corn and soy, and for vegetation control in residential settings, was detected in 98 percent of participants.
- 2,4-D, a broadleaf herbicide used on lawns, aquatic sites, and agricultural crops, was detected in 66 percent of participants.
- Higher amounts of 2,4-D in urine were associated with lower neurobehavioral performance in the domains of attention and inhibitory control, memory and learning, and language.
- Glyphosate concentration in urine was associated with lower scores in social perception only, while DEET metabolites were not associated with neurobehavioral performance.
Following the introduction of genetically modified, glyphosate-resistant “Roundup-ready” crops in 1996 and 2,4-D resistant crops in 2014, there have been substantial increases in glyphosate and 2,4-D use, making them the most widely used herbicides in the world, wrote the authors….