Reassuring Quantitative Analysis of Glyphosate and Aminomethylphosphonic Acid Levels in Breast Milk Using Liquid Chromatography Mass Spectrometry

Purpose: The World Health Organization's International Agency on Research for Cancer has determined that glyphosate is "probably carcinogenic to humans." There is a great public interest to investigate whether glyphosate are detected in breast milk. Thus, the goal of this study was to assess the concentration of glyphosate and its main metabolite in breast milk. Materials and Methods: Liquid chromatography was performed at 25°C using a Luna NH₂, 50 × 2 mm, 3⎛ m (Phenomenex) analytical column. Electrospray ionization mass spectrometry was collected using negative ionization mode. The calibration curve for glyphosate ranged from 10 to 250 ng/mL. The detection limit was 1 ng/mL. Results: Breast milk samples were collected from 74 women, which included vegans (n = 26), vegetarians (n = 22), and nonvegetarians (n = 26). One of the 74 milk samples contained a detectable concentration of glyphosate and an additional 7 were found to contain aminomethylphosphonic acid. Conclusions: In breast milk samples collected mainly from women residing in urban regions of the United States, glyphosate detection was rare. Consistently, breastfed infants have a low or minimal risk of being exposed to glyphosate through ingestion of mother's milk. It is possible that the presence/absence and/or level of concentration of milk glyphosate depend on a place of residency and time of breastfeeding vis-à-vis time of its agricultural application.