title: Recruiting strategy and 24-hour biomonitoring of paraquat in agricultural workers.
abstract: The objectives of this study were to recruit agricultural workers in Costa Rica to participate in a 24-hour urine collection for paraquat exposure assessment and to compare the 24-hour sampling to end-of-shift sampling. The authors recruited 187 handlers and 54 nonhandlers from coffee, banana, and palm oil plantations. The completeness of 24-hour urine samples collected (a total of 393 samples) was confirmed by questionnaire and urinary creatinine level. For a subset of 12 samples, the absorbed paraquat level was determined in 24-hours and end-of-shift spot urine samples. The participation rate for handlers was approximately 90%. The completeness of 24-hour urine collections was verified as the overall average of creatinine levels from 393 urines (1.11+/-0.50 g/L). A total of 92.4% to 96.7% of urine samples were considered within the acceptable range of urinary creatinine, whereas 94.7% of the samples were described as "complete" from the questionnaire. Measured creatinine correlated well to predicted values (r=.327, p=.0024, 95% CI .12-.51). Detected paraquat levels in spot urine samples had a sensitivity of 96.9% at the high specificity of 100% compared to 24-hour urine samples as the gold standard. There was a significant (p<.0001) correlation between spot and 24-hour urine paraquat levels (r=.7825, 95% CI .61-.88). The recruiting strategy was successful in getting 24-hour urine samples from a farm worker population. Comparison between the paraquat levels in spot and 24-hour urine samples demonstrated that for this compound, end-of-shift spot urine samples would be an appropriate substitute for 24-hour collections.
authors.affiliation: Department of Public Health Sciences, Cancer Research Center, University of California, Davis, CA 95616, USA.
authors.forename: Eun-Kee
authors.initials: EK
authors.lastname: Park
authors.forename: Hector
authors.initials: H
authors.lastname: Duarte Tagles
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Gee
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hammock
authors.forename: Kiyoung
authors.initials: K
authors.lastname: Lee
authors.forename: Marc B
authors.initials: MB
authors.lastname: Schenker
mesh_terms: D000328:Adult; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D009784:Occupational Diseases / Q000139:chemically induced* / Q000652:urine*; D016273:Occupational Exposure; D010269:Paraquat / Q000652:urine*; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires
chemical_list: D003404:Creatinine; D010269:Paraquat