Mei Yong, Song Shi-Zhen, Chen Si-Qi, Ye Yu-Jie, Ye Fang-Li
Department of Occupational Health, College of Medicine, Wuhan University of Science and Technology, Wuhan 430065, China.
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2009 Nov;27(11):641-3.
To establish the biological exposure limit values of urinary S-phenylmercapturic acid (SPMA) for assessing occupational exposure to benzene.
Study participants were selected from 55 workers of benzene exposures below 32.5 mg/m(3). The concentration of personal exposure to benzene was measured by gas chromatography and sampled with personal sampler. The urine samples were collected at the end of work shift and individual internal exposure level was evaluated by determination of SPMA in urine by HPLC/MS method. Comparison of external and internal exposure was assessed by the relative internal exposure (RIE) index.
The benzene exposure level ranged from 0.71 to 32.17 mg/m(3) (geometric mean 6.98 mg/m(3), median 7.50 mg/m(3)). The urinary SPMA at the end of the work shift were significantly correlated with benzene exposure, (microg/g Cr) = -8.625 + 18.367X (mg/m(3)), r = 0.8035, (P < 0.01). According to the occupational exposure limit for benzene in China and calculation of regression equation, the expected value of urinary SPMA was 101.58 microg/g Cr. Mean level of biotransformation of per mg/m(3) benzene to urinary SPMA was 18.23 microg/g Cr and the metabolic efficiencies of benzene transformation to urinary SPMA decreased with benzene exposure increased.
Based on abroad documents and data, biological limit value for occupational exposure to benzene in China is recommended as follows: 100 microg/g Cr (47 micromol/mol Cr) for SPMA in the urine at the end of shift.
建立尿中S-苯基巯基尿酸（SPMA）的生物暴露限值，用于评估职业性苯暴露。
研究对象选自55名苯暴露浓度低于32.5mg/m³的工人。采用气相色谱法测定个人苯暴露浓度，并用个人采样器进行采样。在工作班结束时收集尿液样本，采用高效液相色谱/质谱法测定尿中SPMA来评估个体内暴露水平。通过相对内暴露（RIE）指数评估外暴露与内暴露的比较。
苯暴露水平范围为0.71至32.17mg/m³（几何均值6.98mg/m³，中位数7.50mg/m³）。工作班结束时尿中SPMA与苯暴露显著相关，（μg/g Cr）=-8.625 + 18.367X（mg/m³），r = 0.8035，（P < 0.01）。根据我国苯的职业接触限值及回归方程计算，尿中SPMA的预期值为101.58μg/g Cr。每mg/m³苯转化为尿中SPMA的生物转化平均水平为18.23μg/g Cr，且苯转化为尿中SPMA的代谢效率随苯暴露增加而降低。
根据国外文献和数据，建议我国职业性苯暴露的生物限值如下：工作班结束时尿中SPMA为100μg/g Cr（47μmol/mol Cr）。
