Department of Experimental and Applied Medicine, Section of Occupational Health and Industrial Hygiene, University of Brescia, Brescia, Italy.
Med Lav. 2012 Sep-Oct;103(5):361-71.
Despite its advantages over environmental monitoring, biological monitoring of exposure to 2,4-:2,6-toluene diisocyanate (TDI) mixtures is still underused. The present study was designed in order to evaluate the feasibility and reliability of biological monitoring in a factory producing polyurethane foam blocks.
Airborne TDI isomers were sampled by both static and personal pumps and determined by HPLC with fluorimetric detection. Specific metabolites 2,4- and 2,6-toluenediamine (TDA) were determined by gas chromatography-mass spectrometry on hydrolysed urine samples collected from 16 workers at the beginning of the workweek and both before (BS) and at the end (ES) of the 4th workday. Additional samples were collected at the end of the 1st half-shift and at the beginning of the 2nd half-shift in 5 workers.
In the foam production shop, TDI values were on average about 20 microg/m3, with higher levels in the 2nd half-shift and peak levels in workers operating along the polymerization tunnel. Average TDI levels were significantly correlated with ES TDA concentrations (p < 0.0001). TDA showed a fast urinary elimination phase leading to progressively higher TDA levels either during the shift (5 workers) and at the end-of-shift. A slower elimination phase with a weekly accumulation was demonstrated by values at the beginning of the workweek (higher than in unexposed subjects) and by their elevation in subsequent BS samples.
The study demonstrates the feasibility and reliability of biological monitoring in workers exposed to 2,4-:2, 6-TDI mixtures. This approach can provide information about both the daily and weekly exposure levels.
尽管生物监测在暴露于 2,4-:2,6- 甲苯二异氰酸酯（TDI）混合物方面具有优势，但仍未得到充分应用。本研究旨在评估在生产聚氨酯泡沫块的工厂中进行生物监测的可行性和可靠性。
通过静态和个人泵采集空气中的 TDI 异构体，并通过 HPLC 与荧光检测法进行测定。在工作周开始时，从 16 名工人的尿液中采集水解尿液样本，通过气相色谱-质谱法测定特定代谢产物 2,4-和 2,6-甲苯二胺（TDA），并在第 4 个工作日之前（BS）和结束时（ES）进行测定。在 5 名工人中，在第 1 个半班结束时和第 2 个半班开始时采集额外的样本。
在泡沫生产车间，TDI 值平均约为 20μg/m3，在第 2 个半班更高，在沿聚合隧道操作的工人中达到峰值。平均 TDI 水平与 ES TDA 浓度呈显著相关（p <0.0001）。TDA 显示出快速的尿液消除相，导致在轮班期间（5 名工人）和轮班结束时 TDA 水平逐渐升高。通过工作周开始时的值（高于未暴露的工人）和随后的 BS 样本中的升高，证明了较慢的消除相，具有每周积累。
该研究证明了在暴露于 2,4-:2,6-TDI 混合物的工人中进行生物监测的可行性和可靠性。这种方法可以提供关于每日和每周暴露水平的信息。
