Biological monitoring of exposure to 1,5-naphthalene diisocyanate and 4,4'-methylenediphenyl diisocyanate.
OBJECTIVE
Biological monitoring of occupational sensitizers, such as 1,5-naphthalene diisocyanate (NDI) and 4,4'-methylenediphenyl diisocyanate (MDI) is of high importance. In this study, 1,5-naphthalenediamine (NDA) and 4,4'-methylenedianiline (MDA) in hydrolysed urine and plasma were evaluated as biomarkers of exposure to NDI and MDI, respectively.


METHODS
The air exposure to NDI and MDI was monitored for 30 exposed workers at four different plants. In parallel, urinary as well as blood plasma samples were collected. Biomarker levels were determined in hydrolysed urine and plasma by means of gas chromatography-mass spectrometry.


RESULTS
Air exposure to both MDI and NDI was correlated to their corresponding urinary and plasma biomarkers. The correlation coefficients for the associations between air and biomarker levels were in the range of 0.51-0.65 and 0.53-0.96 for MDI and NDI, respectively. For NDI, but not for MDI, the significance and correlation coefficients were increased by adjusting the urinary biomarker levels for creatinine content or density.


CONCLUSIONS
Biomarker and air levels of MDI and NDI were correlated, but there was a large individual variation.
Sennbro
C J
CJ
Institute of Laboratory Medicine, Division of Occupational and Environmental Medicine, University Hospital, 221 85, Lund, Sweden.
Lindh
C H
CH
Mattsson
C
C
Jönsson
B A G
BA
Tinnerberg
H
H
D000395:Air Pollutants, Occupational / Q000032:analysis* / Q000097:blood / Q000652:urine; D015415:Biomarkers / Q000097:blood / Q000652:urine; D004784:Environmental Monitoring; D006801:Humans; D017953:Isocyanates / Q000032:analysis* / Q000097:blood / Q000652:urine; D016273:Occupational Exposure; D001559:Benzhydryl Compounds
D000395:Air Pollutants, Occupational; D015415:Biomarkers; D017953:Isocyanates; C023446:1,5-naphthylene di-isocyanate; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds