New research from the Agricultural Health Lab at Boise State University measured pesticide exposure in pregnant women living in agricultural areas. Cynthia Curl is an associate professor in the School of Public and Population Health at Boise State University and the lead researcher on the study.
“In our lab, we're interested in ensuring that agricultural production methods are protective of the workers who grow our food, people who live in ag communities, and the general public,” Curl said.
Her latest research examined glyphosate exposure in pregnant women living in agricultural communities.
“Glyphosate is a non-selective herbicide, which means it can basically kill any plant,” Curl said.
Glyphosate, the active ingredient in RoundUp, has become widely used in the past two decades due to genetic modification of crops, Curl said.
“So, when you hear the phrase Roundup Ready, that means that somebody has made corn or soy or cotton, alfalfa,... able to resist glyphosate. Now you can broadcast apply or even aerially apply herbicides across the entire field and your crop will not be harmed, but the weeds will be killed. And that's a lot more efficient. But it does lead to an increase in herbicide use,” Curl said.
Whether glyphosate has negative impacts on human health is under debate, Curl said.
“The World Health Organization's International Agency for Research on Cancer has declared glyphosate a probable human carcinogen. And the cancer that they connect it to is non-Hodgkins lymphoma,“ Curl said.
Other health effects that have been associated with glyphosate exposure include adverse birth outcomes, like preterm birth. However, Curl said, the health impacts of glyphosate exposure in humans are still unclear.
“Most regulatory bodies worldwide, including the EPA say that it is not likely to be a human carcinogen,” Curl said.
Curl’s most recent study was exclusively an exposure assessment, she said.
“So we enrolled 40 pregnant women, half of whom lived very close to agricultural fields and half of whom lived further away. We collected urine samples beginning at enrollment, which was in their first trimester, all the way through their delivery, each week,” Curl said.
Unlike some older pesticides including DDT, glyphosate does not accumulate in human tissue.
“And so, a single urine sample really represents your exposure from like yesterday,” Curl said.
By measuring levels of glyphosate in the urine samples, the researchers were able to look at trends over time, as well as the differences based on where the women lived.
“The women who lived close to agricultural fields had significantly higher glyphosate levels during the spray season, so May through August, than the women who lived further away. They also had much higher levels during that time of year than they did during other times of year,” Curl said.
Chronic exposure to glyphosate occurs when people regularly consume food to which glyphosate was applied, or, as this study demonstrates, when people live near agricultural areas that use glyphosate as an herbicide.
“I do want to be really clear that the dose makes the poison, just because you test positive for having glyphosate in your urine doesn't mean there's a health effect associated with that,” Curl said.
Still, with possible links to cancer and adverse pregnancy outcomes, Curl said glyphosate needs to be studied further. While eating an organic diet can reduce glyphosate exposure, Curl said that she is reluctant to recommend individuals switch to organic food.
“I'm a public health person. So I'm always going to advocate for societal and policy-based changes and not putting everything on the individual to have to do — not everyone has equal access, finances, ability to buy organic food… I mean, I think that if there's something in our food supply that is harmful, we should get it out of our food supply for everyone,” Curl said.
