Levels of the herbicide glyphosate have soared in older Americans in 23 years

San Diego Union Tribune  October 24, 2017

Levels of the herbicide glyphosate have soared in older Americans in 23 years, according to a study led by University of California researchers.

The study wasn’t designed to detect any potential harm from the increased exposure, but it will help with future studies to determine if any such link exists, said Paul J. Mills, a UC San Diego professor of family medicine and public health.

The study used data from the long-running and influential Rancho Bernardo Study of Healthy Aging, established in 1972. It was published as a research letter Tuesday in the Journal of the American Medical Association. The study can be found at j.mp/roundupucsd.

Environmental activists have attacked the widespread use of glyphosate as causing cancer and other diseases. Some studies have suggested a potential link, but none have actually demonstrated a causal effect in humans. Other studies have found no correlation.

Opponents say animal research shows the potential for harm.

“There's a lot of animal work, but few if any on people,” Mills said. “And I was surprised to see that, given how much the chemical is in the environment, and that's what inspired us to just start researching it so we can fill in that gap.”

Unlike other studies on glyphosate, the data from the Rancho Bernardo study has been collected for decades, providing a time window to examine glyphosate exposure and any effects in individuals. Also importantly, glyphosate levels were directly measured; other studies relied on interviews to assess exposure.

The study examined urinary levels of glyphosate in 100 people from 1993 to 2016. Very few had detectable levels in 1993, but by 2016 70 percent had detectable levels, Mills said. Of those with detectable amounts, in 1993-1996, the average level was 0.203 nanograms per liter. By 2014-2016, the level had risen to 0.449 nanograms per liter.

Ongoing research at UCSD is conducted at the Herbicide Awareness & Research Project. Go to j.mp/ucsdharp for more information.

Glyphosate is widely available as the active ingredient in Roundup, sold by Monsanto, a St. Louis-based agricultural company. Roundup is considered safe by federal regulators within normal levels of use. It enables farmers to quickly kill weeds without using more toxic herbicides. Monsanto also sells crops seeds that are genetically modified to resist Roundup.