Inoue O, Seiji K, Kawai T, Watanabe T, Jin C, Cai S X, Chen Z, Qu Q S, Zhang T, Ikeda M
Tohoku Rosai Hospital, Sendai, Japan.
Int Arch Occup Environ Health. 1993;64(7):533-9. doi: 10.1007/BF00381104.
The correlation between exposure to three xylene isomers and resulting urinary excretion of corresponding methylhippuric acid (MHA) isomers was studied among 175 Chinese workers of both sexes who had been predominantly exposed to xylenes (exposure to xylenes accounting for 70% or more of the total exposure on a ppm basis). Nonexposed controls (281 men and women) were also studied to define the background level of MHAs in urine. The solvent exposure of xylene-exposed workers during their workshift was monitored by diffusive sampling of breathing zone air, and MHAs in shift-end urine were determined by high-performance liquid chromatography. Regression analysis showed that the concentration of each MHA isomer correlated significantly with the time-weighted average intensity of exposure to the corresponding xylene isomer, and therefore the correlation between the sum of three xylene isomers in air and that of three MHA isomers in urine was also significant; the slope of the regression line was essentially the same among the three isomers. The calculated regression line suggested that the urinary MHA level after hypothetical exposure to xylenes at 100 ppm will be somewhat less than the proposed biological exposure index and biological tolerance value. Two social habits of smoking and drinking in combination suppressed the conversion of xylenes to MHAs in male workers.
在175名主要接触二甲苯的中国男女工人（以ppm计，二甲苯接触量占总接触量的70%或更多）中，研究了接触三种二甲苯异构体与相应甲基马尿酸（MHA）异构体的尿排泄量之间的相关性。还对未接触的对照组（281名男女）进行了研究，以确定尿中MHA的背景水平。通过对呼吸带空气进行扩散采样来监测接触二甲苯工人在工作班次期间的溶剂接触情况，并通过高效液相色谱法测定班次结束时尿液中的MHA。回归分析表明，每种MHA异构体的浓度与相应二甲苯异构体的时间加权平均接触强度显著相关，因此空气中三种二甲苯异构体的总和与尿液中三种MHA异构体的总和之间的相关性也很显著；三种异构体的回归线斜率基本相同。计算出的回归线表明，假设接触100 ppm二甲苯后的尿MHA水平将略低于建议的生物接触指数和生物耐受值。吸烟和饮酒这两种社会习惯共同抑制了男性工人中二甲苯向MHA的转化。
