低苯暴露人群尿中t，t-MA及S-PMA的生物监测

目的分析职业低苯和环境低苯接触与人体尿液中t，t-MA和S-PMA浓度的相关性。方法选取广州市某制鞋厂钳帮和刷胶工人等苯职业接触人员作为职业低苯暴露人群（职业组），选取非职业苯接触且家庭1年内装修过并已入住半年以上的人员作为环境低苯接触人群（环境组）。采用超高效液相串联质谱联用（UPLC—MS／MS）内标法测定尿中t，t-反式粘糠酸（t，t-MA）及苯巯基尿酸（S-PMA）含量，采用气相色谱法检测空气中苯浓度。结果职业组个体空气暴露的苯浓度（均值±标准差）为（0．16±0．06）mg／m^3，尿中t，t-MA及S-PMA含量分别为（42．7±39．2）和（0．28±0．19）μg／gCr；环境组个体空气暴露的苯浓度中位数（四分位间距）为0．01（0．02）mg／m^3，尿中t，t-MA及S-PMA含量的中位数（四分位间距）分别为20．5（16．2）和0．03（0．04）μg/gCr；经非参数Mann—WhitneyU—test检验分析发现：职业组的个体空气暴露苯浓度及尿中t，t-MA、S-PMA含量均高于环境组（均P〈0．01）。相关性分析结果显示，当空气中苯浓度为0．16mg／m^3时，尿中t，t—MA和S-PMA与空气中苯浓度存在良好的相关性（r=0．499、0．715）。结论t，t-MA及S-PMA可作为生物标记物用于职业低苯和环境低苯暴露的生物监测。

Biological monitoring of t,t-MA and S-PMA in low level exposure to benzene

Objective To analyze the association between the low level occupational and environ- mental exposures to benzene and concentrations of trans, trans-muconic acid （t, t-MA） and s-phenilmerca- pturic acid （S-PMA） in urine collected from exposed individuals. Methods Persons who worked with a shoe-lasting machine and were continuously exposed to glue in shoe factories in Guangzhou City were select- ed as occupational exposure group, and those who lived in newly decorated houses for more than six months were defined as environmental exposure group. Contents of t, t-MA and S-PMA in urine were detected by ultra-performance liquid chromatography tandem mass spectrometry. Airborne benzene was detected by gas chromatography method. Results The concentrations of airborne benzene were （ 0. 16 ±0. 06 ） mg/m^3 （ x ± s ） in occupational exposure group and 0. 01 （ 0. 02 ） mg/m^3 （ M [ ITQ ] ） in environmental exposure group. The concentrations of t,t-MA and S-PMA were （42. 7 ±39.2） μg/g Cr and （0. 28 ±0. 19） μg/g Cr in occupational exposure group and 20. 5 （ 16. 2） and 0. 03（0. 04） μg/g Cr in environmental exposure group, respectively. Mann-Whitney U-test revealed that the concentrations of airborne benzene and t, t- MA, S-PMA were all higher in occupational exposure group than those in environmental exposure group （P 〈0. 01 for all）. Moreover, t,t-MA and S-PMA in urine were correlated with airborne benzene when theairborne benzene concentration was 0. 16 mg/m^3 （ r = 0. 499,0. 715）. Conclusion t, t-M and S-PMA could be taken as biomarkers to apply in monitoring low level occupational and environmental exposures to benzene.