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Title
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Air exposure assessment of TDI and biological monitoring of TDA in urine in workers in polyurethane foam industry
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Author
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Abstract
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| Objectives Toluene diisocyanate (TDI) is used in the manufacturing process of polyurethane (PU) foams and is a potent inducer of occupational asthma. The objective of this study was to evaluate the correlation between the exposure to total TDI (2,4- and 2,6-TDI) in air and the corresponding biomarker concentration of total TDA (2,4- and 2,6-TDA) in hydrolysed urine. The aim was also to propose an appropriate biological exposure limit for total TDA in urine. Methods 9 workers from two production lines in a PU foam producing plant were studied. Personal exposure to TDI during four representative production shifts was monitored by an active air sampling method (filter impregnated with 1-(2-methoxyphenyl) piperazine) and quantified by high-performance liquid chromatography and diode array detection (NIOSH no 2535, 5521). In parallel, pre-shift and post-shift urinary samples were collected from the exposed workers, and TDA concentrations were determined by gas chromatography-mass spectrometry after alkaline hydrolysis. All samples were collected on four measuring days: two Fridays (end of workweek) and two Mondays (start of workweek) separated by a weekend without exposure. Results Strong correlations between the personal air concentrations of total TDI and the corresponding biomarker levels of total TDA in urine (r=0.816) were observed. An increase of 18.12 mu g TDA/l (post-shift minus pre-shift concentration) corresponds to an exposure of 5 ppb (37 mu g/m(3), the current American Conference of Governmental Industrial Hygienists threshold limit value) during the shift. Conclusions The increase in TDA during the shift is a suitable biomarker for exposure to TDI during the same shift. Further research is needed to evaluate the use of start of week or end of week post-shift TDA in urine as biomarker since TDA was found to accumulate during the working week and thus the moment of sampling will clearly influence the result. |
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Language
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English
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Source (journal)
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Occupational and environmental medicine / British Medical Association. - London
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Publication
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London
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2012
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ISSN
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1351-0711
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DOI
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10.1136/OEM.2011.064840
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Volume/pages
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69
:2
(2012)
, p. 93-98
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ISI
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000299307700003
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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