Urinary biomarkers of occupational N,N-dimethylformamide (DMF) exposure attributed to the dermal exposure.
OBJECTIVE
To evaluate whether the dermal exposure to N,N-dimethylformamide (DMF) exerts significant effects and to determine the unit increment of dermal exposure on the total body burden of two biomarkers in urine: metabolism-required N-methylformamide (U-NMF) and non-metabolized DMF (U-DMF) in actual occupational environments.


METHODS
Exposure via respiratory and dermal routes was assessed on an individual basis for 75 workers from four DMF-related factories directly exposed to DMF. Respiratory exposure was determined by breathing-zone sampling for a full-work shift, and dermal exposure was assessed on the palms and forearms of both hands by an adhesive tape-patch method. U-NMF and U-DMF collected immediately postshift were measured.


RESULTS
The average concentrations of airborne DMF, DMF on hands and on forearms, U-NMF, and U-DMF (GM) were 1.51 ppm, 0.04 microg/cm(2), 0.03 microg/cm(2), 0.47 mg/l, and 0.38 mg/l, respectively. In multiple linear regression tests, only airborne DMF and DMF on hands remained significantly (P<0.001) associated with U-NMF and U-DMF. Based on model estimates, the unit increment of hands' exposure (microg/cm(2)) could contribute to 0.53 and 0.46 mg/l of the increment of U-NMF and U-DMF, respectively, given a daily occupational airborne exposure to DMF at about 1.5 ppm.


CONCLUSIONS
Dermal exposure provides a substantial contribution to the total body burden of DMF. A control remedy such as the enforcement of wearing impermeable gloves by workers occupationally exposed to DMF should be implemented with the highest priority.
Chang
Ho-Yuan
HY
Graduate Institute of Environmental and Occupational Health, College of Medicine, National Cheng Kung University Medical College, 138 Sheng-Li Road, Tainan 704, Taiwan. h7154@mail.ncku.edu.tw
Tsai
Ching-Yi
CY
Lin
Yu-Qun
YQ
Shih
Tung-Sheng
TS
Lin
Yun-Chin
YC
D000279:Administration, Cutaneous; D000328:Adult; D016902:Air Pollution, Indoor / Q000032:analysis; D001822:Body Burden; D004126:Dimethylformamide / Q000493:pharmacokinetics*; D005559:Formamides / Q000032:analysis*; D006225:Hand; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D016273:Occupational Exposure; D016482:Urinalysis
D005559:Formamides; D004126:Dimethylformamide; C002950:methylformamide