title: Biomonitoring of herbicides in Ontario farm applicators.
abstract: OBJECTIVE
  Biomonitoring of pesticide residues in urine offers the advantages of integrating exposure due to all routes of entry and accounting for individual differences in several factors such as pharmacokinetics. The study was designed to measure the body burden of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA) in farm applicators and to measure compliance with label recommendations regarding the use of personal protective gear and the impact of such use on exposure.
  
  
  METHODS
  Farmers (N=126) from Ontario, Canada, collected a preexposure spot sample of urine and then two consecutive 24-hour urine samples immediately following the farmers' first use of these herbicides during 1996. Details on the pesticides used and handling practices were collected by questionnaire.
  
  
  RESULTS
  For the farmers who reported using 2,4-D, the mean urinary concentration was 27.6 microg/l in the day-1 sample and 40.8 microg/l in the day-2 sample. The comparable figures for MCPA were 44.4 microg/l and 58.0 microg/l, respectively. Adherence to all of the recommended personal protective gear was rare (3%). Wearing goggles or a face shield during mixing and loading was associated with the lowest exposures.
  
  
  CONCLUSIONS
  The urinary concentrations of 2,4-D and MCPA of these farm applicators were of the same order of magnitude as those published in the past decade, but lower than earlier studies, indicating that improvements in education, equipment, and labeling have likely had an impact on the degree of exposure in occupational settings.
authors.affiliation: Biostatistics and Epidemiology Division, Healthy Environments and Consumer Safety Branch, Health Canada, AL 6604C, 2720 Riverside Dr, Ottawa (ON), Canada. Tye_Arbuckle@hcsc.gc.ca
authors.forename: Tye E
authors.initials: TE
authors.lastname: Arbuckle
authors.forename: Donald C
authors.initials: DC
authors.lastname: Cole
authors.forename: Len
authors.initials: L
authors.lastname: Ritter
authors.forename: Brian D
authors.initials: BD
authors.lastname: Ripley
mesh_terms: D004784:Environmental Monitoring; D019983:Guideline Adherence; D006540:Herbicides / Q000652:urine*; D006801:Humans; D009864:Ontario
chemical_list: D006540:Herbicides