Provikmo Occupational Health Services, Dirk Martensstraat 26/1, B-8200 Bruges, Belgium.
Occup Environ Med. 2012 Feb;69(2):93-8. doi: 10.1136/oem.2011.064840. Epub 2011 Jul 1.
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.
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 n° 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.
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 μg TDA/l (post-shift minus pre-shift concentration) corresponds to an exposure of 5 ppb (37 μg/m(3), the current American Conference of Governmental Industrial Hygienists threshold limit value) during the shift.
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.
甲苯二异氰酸酯（TDI）用于制造聚氨酯（PU）泡沫，是职业性哮喘的强效诱导剂。本研究的目的是评估空气中总 TDI（2,4-和 2,6-TDI）暴露与相应水解尿中总 TDA（2,4-和 2,6-TDA）浓度之间的相关性。目的还在于提出尿液中总 TDA 的适当生物暴露限值。
对来自生产 PU 泡沫的两家工厂两条生产线的 9 名工人进行了研究。通过主动空气采样方法（用 1-(2-甲氧基苯基)哌嗪浸渍的过滤器）监测工人在四个代表性生产班次期间的 TDI 个人暴露情况，并通过高效液相色谱和二极管阵列检测（NIOSH n° 2535、5521）进行定量。同时，从暴露工人采集班前和班后尿液样本，并用碱性水解后气相色谱-质谱法测定 TDA 浓度。所有样本均在四个测量日采集：两个星期五（工作周结束）和两个星期一（工作周开始），间隔一个无暴露的周末。
观察到个人空气总 TDI 浓度与尿中相应总 TDA 生物标志物水平之间存在强烈相关性（r=0.816）。班后与班前尿液中 TDA 浓度增加 18.12μg/L（18.12μg/L）对应于班内暴露 5ppb（37μg/m³，目前美国政府工业卫生学家会议的阈限值）。
班内 TDA 的增加是同一班内 TDI 暴露的合适生物标志物。需要进一步研究评估尿中每周开始或结束时的 TDA 作为生物标志物的使用，因为 TDA 在工作周内会积累，因此采样时间显然会影响结果。
