title: Contributions of inhalation and dermal exposure to chlorpyrifos dose in Egyptian cotton field workers.
abstract: OBJECTIVE
  Chlorpyrifos exposures were assessed in 12 Egyptian cotton field workers.
  
  
  METHODS
  3,5,6-trichloro-2-pyridinol (TCPy) was measured in 24-hour urine samples to estimate absorbed dose. Workshift air samples were used to calculate chlorpyrifos inhalation dose.
  
  
  RESULTS
  Patches on legs had the highest chlorpyrifos loading rates among body regions sampled. Geometric mean chlorpyrifos air concentrations were 5·1, 8·2, and 45·0 μg/m(3) for engineers, technicians, and applicators, respectively; peak TCPy urinary concentrations were 75-129, 78-261, and 487-1659 μg/l, respectively; geometric mean doses were 5·2-5·4, 8·6-9·7, and 50-57 μg/kg, respectively, considering TCPy excretion half-life values of 27 and 41 hours. All worker doses exceeded the acceptable operator exposure level of 1·5 μg/kg/day. An estimated 94-96% of the dose was attributed to dermal exposure, calculated as the difference between total dose and inhalation dose.
  
  
  CONCLUSIONS
  Interventions to reduce dermal exposure are warranted in this population, particularly for the hands, feet, and legs.
authors.affiliation: University of Washington, Seattle, WA, USA. rfenske@uw.edu
authors.forename: Richard A
authors.initials: RA
authors.lastname: Fenske
authors.forename: Fayssal M
authors.initials: FM
authors.lastname: Farahat
authors.forename: Kit
authors.initials: K
authors.lastname: Galvin
authors.forename: Ellis K
authors.initials: EK
authors.lastname: Fenske
authors.forename: James R
authors.initials: JR
authors.lastname: Olson
mesh_terms: D000383:Agriculture; D000395:Air Pollutants, Occupational / Q000032:analysis* / Q000493:pharmacokinetics / Q000652:urine; D004390:Chlorpyrifos / Q000032:analysis* / Q000493:pharmacokinetics / Q000652:urine; D004534:Egypt; D003368:Gossypium; D006207:Half-Life; D006801:Humans; D019570:Inhalation Exposure; D007306:Insecticides / Q000032:analysis* / Q000493:pharmacokinetics / Q000652:urine; D016273:Occupational Exposure; D012869:Skin Absorption; D013997:Time Factors
chemical_list: D000395:Air Pollutants, Occupational; D007306:Insecticides; D004390:Chlorpyrifos