Urinary glyphosate kinetics after occupational exposure

Kanyapak Kohsuwan; Unchisa Intayoung; Supakit Khacha-Ananda; Ratana Sapbamrer; Nut Koonrungsesomboon; Sujitra Techatoei; Klintean Wunnapuk

doi:10.1016/j.ijheh.2022.114021

Urinary glyphosate kinetics after occupational exposure

Int J Hyg Environ Health. 2022 Aug:245:114021. doi: 10.1016/j.ijheh.2022.114021. Epub 2022 Aug 15.

Authors

Kanyapak Kohsuwan¹, Unchisa Intayoung¹, Supakit Khacha-Ananda², Ratana Sapbamrer³, Nut Koonrungsesomboon⁴, Sujitra Techatoei⁴, Klintean Wunnapuk⁵

Affiliations

¹ Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
² Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; Research Center in Bioresources for Agriculture, Industry and Medicine, Chiang Mai University, Thailand.
³ Department of Community Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
⁴ Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
⁵ Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand. Electronic address: klintean.w@cmu.ac.th.

PMID: 35981405
DOI: 10.1016/j.ijheh.2022.114021

Abstract

Glyphosate-surfactant herbicides are the most used and imported herbicide in Thailand. Urinary biomonitoring is a very important tool for evaluating glyphosate exposures and its adverse health effects. However, the data for glyphosate toxicokinetics, especially in Asian populations, is relatively limited. The majority of farmers in Thailand have long term experience with glyphosate use, but they generally follow poor safety practices, including insufficient or incorrect use of personal protective equipment during pesticide handling activities. Therefore, this study aimed to determine the toxicokinetics of glyphosate and its metabolite in urine among maize farmers from the northern region of Thailand. The effects of personal protective equipment usage, as well as farmer behavior during work, on urinary glyphosate levels were also studied. Full-voided spot urine samples were collected over the exposure assessment period (0-72 h). Urinary glyphosate levels were determined by liquid chromatography tandem mass spectrometry. The maximum concentration in urine (uC_max), the time of peak glyphosate levels in urine (uT_max), and the urinary elimination half-life (ut_1/2) were analyzed using the PKSolver program. The median of uC_max were 27.9, 29.2 and 17.1 μg/g creatinine in a one-time spray group, a two-time spray group Day 1 and a two-time spray group Day 2, respectively. The uT_max was 11.0 h in both study groups. The median of elimination ut_1/2 in the one-time and the two-time spray group were 7.0 and 18.1 h, respectively. Although these estimated urinary elimination half-lives may have been impacted by the variation in exposure doses among the participants, it provides the first urinary toxicokinetic data of glyphosate among the Asian population. The toxicokinetic information could be used to increase knowledge and awareness amongst farmers, particularly to minimize the risk of exposure to glyphosate and reduce possible adverse health effects from using pesticide.

Keywords: Elimination half-life; Glyphosate; Herbicide; Occupational exposure; Toxicokinetic; Urine.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Glycine / analogs & derivatives
Glyphosate
Herbicides* / urine
Humans
Kinetics
Occupational Exposure* / analysis

Substances

Herbicides
Glycine