Occupational paraquat exposure of agricultural workers in large Costa Rican farms

Kiyoung Lee, Eun Kee Park, Maria Stoecklin-Marois, Marja E. Koivunen, Shirley J. Gee, Bruce D. Hammock, Laurel A Beckett, Marc B Schenker

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Objective: Paraquat is an herbicide widely used worldwide. This study determined the extent of occupational exposure to paraquat among farm workers in Costa Rica and identified determinants of occupational exposure. Methods: Twenty-four hour urine samples were collected from 119 paraquat handlers and 54 non-handlers from banana, coffee and palm oil farms. Information about herbicide handling operations was also collected. The urinary paraquat levels were determined by an enzyme-linked immunosorbent assay (ELISA) with a limit of quantification (LOQ) of 2 ng/mL. Inhalable dust and airborne paraquat levels were simultaneously measured for a subset of the participants. Results: Urinary paraquat measurements were non-detectable or very low when workers did not handle paraquat. For handlers, 83.3, 47.1 and 63.9% of the samples were below the LOQ on before-, during- and after-paraquat spray days, respectively. The arithmetic mean (±SD) of urinary paraquat level on days when workers handled paraquat was 6.3 (±10.45) μg/24 h. Paraquat exposures among handlers on spray day were significantly associated with the type of crop. Conclusion: Non-handlers had negligible urinary paraquat, while detectable paraquat exposures were observed among handlers on spray day. Urinary paraquat levels were different by crop.

Original languageEnglish (US)
Pages (from-to)455-462
Number of pages8
JournalInternational Archives of Occupational and Environmental Health
Issue number4
StatePublished - 2009


  • Biological monitoring
  • Herbicide
  • Occupational exposure
  • Paraquat

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health


Dive into the research topics of 'Occupational paraquat exposure of agricultural workers in large Costa Rican farms'. Together they form a unique fingerprint.

Cite this