Ong C N, Kok P W, Lee B L, Shi C Y, Ong H Y, Chia K S, Lee C S, Luo X W
Department of Community, Occupational and Family Medicine, National University of Singapore.
Occup Environ Med. 1995 Aug;52(8):528-33. doi: 10.1136/oem.52.8.528.
To evaluate the relations between environmental benzene concentrations and various biomarkers of exposure to benzene.
Analyses were carried out on environmental air, unmetabolised benzene in urine, trans, trans-muconic acid (ttMA), and three major phenolic metabolites of benzene; catechol, hydroquinone, and phenol, in two field studies on 64 workers exposed to benzene concentrations from 0.12 to 68 ppm, the time weighted average (TWA). Forty nonexposed subjects were also investigated.
Among the five urinary biomarkers studied, ttMA correlated best with environmental benzene concentration (correlation coefficient, r = 0.87). When urinary phenolic metabolites were compared with environmental benzene, hydroquinone correlated best with benzene in air. No correlation was found between unmetabolised benzene in urine and environmental benzene concentrations. The correlation coefficients for environmental benzene and end of shift catechol, hydroquinone, and phenol were 0.30, 0.70, and 0.66, respectively. Detailed analysis, however, suggests that urinary phenol was not a specific biomarker for exposure below 5 ppm. In contrast, ttMA and hydroquinone seemed to be specific and sensitive even at concentrations of below 1 ppm. Although unmetabolised benzene in urine showed good correlation with atmospheric benzene (r = 0.50, P < 0.05), data were insufficient to suggest that it is a useful biomarker for exposure to low concentrations of benzene. The results from the present study also showed that both ttMA and hydroquinone were able to differentiate the background level found in subjects not occupationally exposed and those exposed to less than 1 ppm of benzene. This suggests that these two biomarkers are useful indices for monitoring low concentrations of benzene. Furthermore, these two metabolites are known to be involved in bone marrow leukaemogenesis, their applications in biological monitoring could thus be important in risk assessment.
The good correlations between ttMA, hydroquinone, and atmospheric benzene, even at concentrations of less than 1 ppm, suggest that they are sensitive and specific biomarkers for benzene exposure.
评估环境苯浓度与苯接触的各种生物标志物之间的关系。
在两项现场研究中，对64名接触苯浓度为0.12至68 ppm（时间加权平均值）的工人的环境空气、尿中未代谢苯、反式，反式-粘康酸（ttMA）以及苯的三种主要酚类代谢物（儿茶酚、对苯二酚和苯酚）进行了分析。还对40名未接触者进行了调查。
在所研究的五种尿生物标志物中，ttMA与环境苯浓度的相关性最佳（相关系数，r = 0.87）。当将尿酚类代谢物与环境苯进行比较时，对苯二酚与空气中苯的相关性最佳。尿中未代谢苯与环境苯浓度之间未发现相关性。环境苯与班末儿茶酚、对苯二酚和苯酚的相关系数分别为0.30、0.70和0.66。然而，详细分析表明，尿酚在5 ppm以下的接触水平时并非特异性生物标志物。相比之下，即使在浓度低于1 ppm时，ttMA和对苯二酚似乎也是特异性和敏感的。尽管尿中未代谢苯与大气苯显示出良好的相关性（r = 0.50，P < 0.05），但数据不足以表明它是低浓度苯接触的有用生物标志物。本研究结果还表明，ttMA和对苯二酚均能够区分未职业接触者和接触低于1 ppm苯者的背景水平。这表明这两种生物标志物是监测低浓度苯的有用指标。此外，已知这两种代谢物参与骨髓白血病的发生，因此它们在生物监测中的应用在风险评估中可能很重要。
即使在浓度低于1 ppm时，ttMA、对苯二酚与大气苯之间的良好相关性表明它们是苯接触的敏感和特异性生物标志物。
