Trends over Time in Urinary Glyphosate Levels in California Residents: Mills et al., 2017

Excretion of the Herbicide Glyphosate in Older Adults Between 1993 and 2016

Paul J. Mills, PhD, Izabela Kania-Korwel, PhD, John Fagan, PhD, Linda K.McEvoy, PhD, Gail A. Laughlin, PhD, Elizabeth Barrett-Connor, MD; Journal of the American Medical Association,  October 24, 2017, Volume 31, Number 16, DOI:10.1001/jama.2017.11726.

Why It's Important:

Since the mid-1990s, herbicides containing the active ingredient glyphosate have come to dominant total herbicide use in the U.S. and globally. Across America, enough glyphosate was applied in 2019 to spray about three-quarters of a pound of glyphosate on every acre of cropland in the country! Yet until very recently, almost no effort has been made to track glyphosate exposures in the general public.

In this important paper, a team of University of California scientists reports rising levels of glyphosate from 1993-2016 in urine samples collected from 100 elderly residents living at the Rancho Bernardo retirement community in southern California.

What They Found:

The team reports trends in the frequency of detectable glyphosate and its main metabolite AMPA, and glyphosate and AMPA levels in stored urine samples collected in five time periods between 1993 and 2016.

Over time, mean glyphosate levels increased from a low of 0.024 micrograms/liter (ppb) in 1993-1996 to a high of 0.314 ppb in 2016.  Moreover, the percentage of samples testing positive for glyphosate rose from 12% in 1993 to 70% in 2016.

It is highly likely that the increase in frequency of detections and mean levels were brought about by the growing popularity of pre-harvest, crop desiccation use of glyphosate on wheat, oat, and barley farms.

Glyphosate Levels Over Time in Rancho Bernardo Residents

  • Glyphosate Levels (micrograms/Liter)

Percent of Samples with Glyphosate

1993-1996 12%
1999-2000 30%
2001-2002 43%
2004-2005 38%
2014-2016 70%

See the full paper here, or click the following keywords to pull up more: herbicide use, biomonitoringglyphosate

About Us:

The Heartland Study is focused on birth outcomes in a 13-state region that 72 million Americans call home. Many doctors — and families — worry that it seems to be getting harder for women to get pregnant and carry a healthy child to term.

The Heartland Study is conducting cutting-edge scientific research that explores whether rising herbicide use is part of what is driving more frequent, and/or more serious reproductive problems and birth defects in the Midwest and beyond.