TPS 623: Exposures to pesticides, Johan Friso Foyer, Floor 1, August 26, 2019, 3:00 PM - 4:30 PM Background/Aims: To date, very few studies have evaluated the extent and amount of human exposure to glyphosate, a broad-spectrum herbicide and desiccant whose use is growing and widespread since 1974. To fill this gap, we reviewed existing publications on glyphosate levels in workers occupationally exposed and in the general population. Methods: We conducted a review of scientific publications on glyphosate levels in humans, and identified 20 studies: 5 reported on occupational exposure to glyphosate, 11 reported the exposure in general populations, and 4 reported on both. Results: Nine studies reported urinary glyphosate levels in 509 occupationally and para-occupationally exposed subjects; 15 studies reported glyphosate levels in various biofluids, including urine, on 3336 subjects from the general population. Among those with detectable glyphosate levels, average urinary levels in occupationally exposed subjects ranged from 0.26 to 73.5 μg/L, urinary levels in the general population ranged from 0.16 to 7.6 μg/L. The limits of detection in these studies ranged from 0.02 to 100 μg/L in urine, meaning that subjects who would have been detectable in some studies were missed in others, making it difficult to determine how common detectable exposure to glyphosate is. Two studies measuring temporal trends in exposure showed an increasing proportion of individuals with detectable levels of glyphosate in their urine over time. Conclusions: This current review highlights the scarce amount of data on glyphosate levels among individuals exposed occupationally, para-occupationally, or environmentally to this herbicide. It is therefore challenging to fully understand the extent of overall exposure in the general population, in vulnerable populations particularly children, and populations occupationally exposed to glyphosate. Further work to evaluate exposure across populations and geographic regions is highly recommended, including apportion the exposure sources (e.g., occupational, household use, food residues), as well as more investigations to understand temporal trends.