职业接触二甲基乙酰胺工人尿中甲基乙酰胺生物限值研究

Biological limit value for occupational exposure to N, N-dimethylacetamide

目的研制我国职业接触二甲基乙酰胺（DMAC）工人尿中甲基乙酰胺（NMAC）的生物限值。方法选择3家氨纶生产企业201名接触DMAC工人，应用个体采样器采集工作周末工作日的车间空气样品，用气相色谱法检测个体DMAC接触水平，同时收集当日工人班末尿样，应用气相色谱法测定尿中NMAC浓度以评价DMAC接触工人内暴露水平。通过内外剂量的回归方程、百分位数和相对内暴露（RIE）指数计算，推荐我国职业接触二甲基乙酰胺工人尿中NMAC生物接触限值。结果201名DMAC接触工人中接触浓度符合我国DMAC接触限值133名，占66．2％，接触浓度范围在0．40．300．12mg／m^3，几何平均浓度为19．4mg／m^3。工作周末班未尿中NMAC浓度范围为1．30—189．42mg／g Cr，几何平均浓度为23．7mg／g Cr。尿中NMAC浓度与个体DMAC外暴露浓度有相关性（F=188．872，R^2=0．487，P〈0．001），回归方程为log（NMAC mg／g Cr）=0．685＋0．455 log（DMAC mg／m^3）。以我国DMAC职业接触限值PC—TWA为20mg／m^3推算，尿中NMAC浓度为18．92mg／g Cr。当工作场所空气中DMAC〈20mg／m^3时，90％的工人尿中NMAC水平为23．9mg／g Cr。按RIE指数推算的尿中NMAC为19．0mg／g Cr。结论参考国外DMAC生物接触限值标准，建议我国DMAC生物接触限值为工作周末班未尿中NMAC20mg／g Cr。

Objective Toestablish BiologicalLimit Value （BLv） for N, N-dimethylacetamide （DMAC）. Method 201 workers in 3 spandex factories exposed to DMAC were recruited. Air samples were collected using personal air samplers, and urine samples from each works were collected at the end of shift at end of workweek. The urinary metabolite NMAC and air samples of DMAC were determined by gas chromatography （GC）. Percentile and relative internal exposure （RIE） were analyzed and proposed a BLV for DMAC. Results The number of workers who exposure to DMAC below OELs were 133 （66.2%） among 201 workers monitored. Geometric mean （range） concentration of DMAC in air was 19.4 （0.40-300.12） mg/m3, and that of NMAC in urine was 23.7 （1.30-189.42） mg/g Cr. A linear correlation was found between the personal air DMAC and creatinine-adjusted NMAC levels in urine collected at the end of shift at end of workweek （F=188.872, R2= 0.487,P〈0.001）. The relationship can be described by the equation Log （NMAC mg/g Cr）= 0.685＋0.455 log （DMAC rag/m3）. According to the equation the current China OELs value of 20 mg/m3 would lead to a mean NMAC concentration of 18.92 mg/g Cr. The 90th percentile biomonitoring result below 20 mg/m3 8-hour TWA is 23.9 mg MMAC mg/g Cr, and that of NMAC in urine calculated by relative internal exposure （RIE） was 19.0 mg/g Cr. Conclusion A BLV of 20 mg/g Cr NMAC in urine at the end of shift at end of workweek for DMAC was recommend by reference to official values from other countries.