Urinary glyphosate biomonitoring of sprayers in vegetable farm in Thailand

Abstract

In Thailand, glyphosate is popular herbicide to control pests in the agricultural sector. This study aimed to measure glyphosate exposure concentrations through inhalation, dermal contact, and urinary glyphosate concentrations among 43 vegetable farmers spraying glyphosate in Bungphra Subdistrict, Phitsanulok Province. Four types of spraying equipment were used, manual pump backpack (n = 3), motorized spray backpack (n = 22), battery pump backpack (n = 16), and high pressure pump (n = 2). Breathing zone air samples were collected using glass fiber filters; dermal contact samples were collected using 100 cm² cotton patches attached on 10 body locations and urine samples were collected at 3 time points: morning void urine the day before spraying, the end of spraying event, and the morning void urine the next day of spraying. The results showed that the geometric mean (GM; geometric standard deviation [GSD]) of breathing zone concentrations of glyphosate exposure were 9.37 (10.17) µg/m³. The GM (GSD) of total dermal patches exposure concentrations were 7.57 (0.01) mg/h. The legs, back, and arms were the most exposed body areas. The GM (GSD) of urinary glyphosate was found highest among vegetable farmers using manual backpack 46.90 (1.35) µg/g creatinine. Farmers should wear masks and boots to reduce glyphosate exposure by inhalation and dermal contact.

Keywords:

• glyphosate
• vegetable farmers
• dermal and inhalation exposures
• biomonitoring

Acknowledgments

We are appreciative of the Center of Excellence on Environmental Health and Toxicology (EHT), for supporting laboratory facilities and equipment. We thank all participants and all research assistants in Bungphra Health Promoting Hospital in Phitsanulok Province, Thailand.

Additional information

Funding

This research was financially supported by the University of Phayao and the CWEND GEOHealthHub supported by the NIH Fogarty International Center, National Institutes of EnvironmentalHealth Science and the Center for Disease Control under Award Numbers U01 TW010091.