Enhanced CNS exposure to glyphosate following inhalation resulting from olfactory uptake

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Project Period: 
Project Investigator(s): 
M. Donovan, Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa
H. Lehmler, P. O’Shaughnessy, Department of Occupational and Environmental Health, The University of Iowa

While glyphosate, the ingredient present in the widely used RoundUp® family of herbicides, has an excellent safety profile following topical and oral exposure, it presents a potential CNS exposure risk if it is able to access the olfactory transfer pathways within the nasal mucosa. These pathways afford the opportunity for molecules to access the brain without needing to cross the blood-brain barrier. This pilot study will evaluate whether glyphosate and several commercial glyphosate herbicide formulations are able to permeate through the olfactory mucosa into the olfactory bulb and nearby brain regions following direct nasal instillation and aerosol exposure. Preliminary results will provide initial quantitative evidence regarding the risk of CNS glyphosate exposure following nasal inhalation and will support further investigations to evaluate the exposure risk along with identifying methods to limit inhalation exposure to herbicide applicators or those in close proximity to spraying operations.     


Xu J, Li G, Wang Z, Si L, He S, Cai J, Huang J, Donovan MD. The role of L-type amino acid transporters in the uptake of glyphosate across mammalian epithelial tissues. Chemosphere 2016 145:487-494