title: Total body burden arising from a week's repeated dermal exposure to N,N-dimethylformamide.
abstract: BACKGROUND
  Hazardous chemicals and their metabolites may accumulate in the body following repeated airborne exposures and skin contact.
  
  
  OBJECTIVE
  To estimate the contribution of skin absorption to total body burden of N,N-dimethylformamide (DMF) across a working week in two groups with similar levels of respiratory exposure but dissimilar skin contact.
  
  
  METHODS
  Twenty five workers in a synthetic leather (SL) factory, 20 in a copper laminate circuit board (CLCB) factory, and 20 age and sex matched non-DMF exposed subjects, were recruited. Environmental monitoring of DMF exposure via respiratory and dermal routes, as well as biological monitoring of pre-shift urinary N-methylformamide (U-NMF), were performed for five consecutive working days.
  
  
  RESULTS
  Environmental and biological monitoring showed no detectable exposure in controls. The average airborne DMF concentration (geometric mean (GM) 3.98 ppm, geometric standard deviation (GSD) 1.91 ppm), was insignificantly lower for SL workers than for CLCB workers (GM 4.49, GSD 1.84 ppm). Dermal DMF exposure and U-NMF values, however, were significantly higher for SL workers. A significant pattern of linear accumulation was found across a five day work cycle for SL workers but not for CLCB workers.
  
  
  CONCLUSIONS
  Dermal exposure to DMF over five consecutive days of occupational exposure can result in the accumulation of a significant DMF body burden. The long term exposure response under both repeated and intermittent conditions of substantial skin exposure is worthy of note.
authors.affiliation: Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan. h7154@mail.ncku.edu.tw
authors.forename: H-Y
authors.initials: HY
authors.lastname: Chang
authors.forename: C-Y
authors.initials: CY
authors.lastname: Tsai
authors.forename: Y-Q
authors.initials: YQ
authors.lastname: Lin
authors.forename: T-S
authors.initials: TS
authors.lastname: Shih
authors.forename: W-C
authors.initials: WC
authors.lastname: Lin
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000032:analysis; D001822:Body Burden; D004126:Dimethylformamide / Q000493:pharmacokinetics*; D004784:Environmental Monitoring / Q000379:methods; D005542:Forearm; D005559:Formamides / Q000493:pharmacokinetics; D006225:Hand; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D012869:Skin Absorption
chemical_list: D000395:Air Pollutants, Occupational; D005559:Formamides; D004126:Dimethylformamide; C002950:methylformamide
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