title: Glyphosate and aminomethylphosphonic acid are not detectable in human milk.
abstract: BACKGROUND
  Although animal studies have shown that exposure to glyphosate (a commonly used herbicide) does not result in glyphosate bioaccumulation in tissues, to our knowledge there are no published data on whether it is detectable in human milk and therefore consumed by breastfed infants.
  
  
  OBJECTIVE
  We sought to determine whether glyphosate and its metabolite aminomethylphosphonic acid (AMPA) could be detected in milk and urine produced by lactating women and, if so, to quantify typical consumption by breastfed infants.
  
  
  METHODS
  We collected milk (n = 41) and urine (n = 40) samples from healthy lactating women living in and around Moscow, Idaho and Pullman, Washington. Milk and urine samples were analyzed for glyphosate and AMPA with the use of highly sensitive liquid chromatography-tandem mass spectrometry methods validated for and optimized to each sample matrix.
  
  
  RESULTS
  Our milk assay, which was sensitive down to 1 μg/L for both analytes, detected neither glyphosate nor AMPA in any milk sample. Mean ± SD glyphosate and AMPA concentrations in urine were 0.28 ± 0.38 and 0.30 ± 0.33 μg/L, respectively. Because of the complex nature of milk matrixes, these samples required more dilution before analysis than did urine, thus decreasing the sensitivity of the assay in milk compared with urine. No difference was found in urine glyphosate and AMPA concentrations between subjects consuming organic compared with conventionally grown foods or between women living on or near a farm/ranch and those living in an urban or suburban nonfarming area.
  
  
  CONCLUSIONS
  Our data provide evidence that glyphosate and AMPA are not detectable in milk produced by women living in this region of the US Pacific Northwest. By extension, our results therefore suggest that dietary glyphosate exposure is not a health concern for breastfed infants. This study was registered at clinicaltrials.gov as NCT02670278.
authors.affiliation: School of Biological Sciences and Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA; smcguire@wsu.edu.
authors.forename: Michelle K
authors.initials: MK
authors.lastname: McGuire
authors.affiliation: Department of Animal and Veterinary Science and.
authors.forename: Mark A
authors.initials: MA
authors.lastname: McGuire
authors.affiliation: Statistical Programs, College of Agricultural and Life Sciences, University of Idaho, Moscow, ID; and.
authors.forename: William J
authors.initials: WJ
authors.lastname: Price
authors.affiliation: Statistical Programs, College of Agricultural and Life Sciences, University of Idaho, Moscow, ID; and.
authors.forename: Bahman
authors.initials: B
authors.lastname: Shafii
authors.affiliation: School of Biological Sciences and.
authors.forename: Janae M
authors.initials: JM
authors.lastname: Carrothers
authors.affiliation: School of Biological Sciences and.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Lackey
authors.affiliation: Monsanto, St. Louis, MO.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Goldstein
authors.affiliation: Monsanto, St. Louis, MO.
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Jensen
authors.affiliation: Monsanto, St. Louis, MO.
authors.forename: John L
authors.initials: JL
authors.lastname: Vicini
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis / Q000652:urine; D006540:Herbicides / Q000032:analysis / Q000652:urine; D006801:Humans; D007061:Idaho; D007555:Isoxazoles; D007774:Lactation; D057230:Limit of Detection; D008895:Milk, Human / Q000737:chemistry*; D063065:Organophosphonates / Q000032:analysis* / Q000652:urine; D013777:Tetrazoles; D014861:Washington; D055815:Young Adult; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D007555:Isoxazoles; D063065:Organophosphonates; D013777:Tetrazoles; D000097797:Glyphosate; C418233:2-amino-3-(3-hydrox-5(2-methyl-2H-tetrazol-5-yl)isoxazol-4-yl)propionic acid
keywords: AMPA; aminomethylphosphonic acid; breastfeeding; environmental contaminants; glyphosate; human milk; lactation; organic food; pesticide