Pregnant women living near farm fields show “significantly” increased concentrations of glyphosate weedkiller in their urine during periods when farmers are spraying their fields with the herbicide, according to a new scientific paper published on Wednesday.
The research team said the findings were concerning, given recent studies that have found gestational exposure to glyphosate is associated with reduced fetal growth and other fetal problems. Glyphosate separately has been linked to cancer and other health problems.
“If the developing fetus is especially vulnerable to glyphosate, it is critical to understand the magnitude and sources of exposure during this critical developmental period,” the new paper states.
The authors include researchers from the University of California, Berkeley; the University of Washington; Boise State University; and the US Centers for Disease Control and Prevention (CDC).
Glyphosate is the world’s most widely used herbicide and is the active ingredient in products sold around the world, including the widely used Roundup brand developed by Monsanto and now owned by Bayer after Bayer’s 2018 acquisition of Monsanto.
The results of the study were considered somewhat surprising because none of the women studied worked with glyphosate or other herbicides or had a household member who worked with weedkillers, said Cynthia Curl, associate professor at Boise State and lead author on the paper.
“What is going on? Is it drifting more than we think? Is it adhering to soil particles which then blow around and end up in people’s house dust? Is it drinking water? Until we figure that out we can’t suggest the right interventions,” Curl said.
Curl said follow-up research will collect household dust and water samples to try to determine routes of exposure.
To evaluate the exposure, the research team collected 453 urine samples biweekly from 40 pregnant women in southern Idaho from February through December 2021. Women were considered to be living near a farm field if they resided less than 0.5km, or roughly 0.3 of a mile, from an actively cultivated field.
In those living near the fields, glyphosate was detected both more frequently and at much higher concentrations during the months when farmers were spraying glyphosate than during the periods when they were not spraying. Those participants living farther away still showed glyphosate in their urine, but the frequency and concentrations stayed relatively unchanged throughout the year.
“Sadly, I am not surprised that pregnant women who live near fields sprayed with glyphosate have elevated levels of glyphosate in their bodies during the spraying season,” said Philip Landrigan, director of the Program for Global Public Health and the Common Good at Boston College. “This situation is analogous to the elevated exposures to benzene, 1,3-butadiene and other toxic plastics chemicals that have been documented in women who live in ‘fenceline’ communities.”
Though glyphosate has been on the market for more than 50 years, it is only within the last few years that researchers have started to document the extent of human exposure.
In 2022, a unit of the CDC reported that out of 2,310 urine samples collected, more than 80% were laced with detectable traces of glyphosate. And in a recent population-based survey in France, glyphosate was found in 99% of urine samples collected from close to 7,000 participants.
This story is co-published with the New Lede, a journalism project of the Environmental Working Group
