The assessment methods and application to detect potential hazards of neurotoxicity by environmental chemicals.

目的：了解苯乙烯暴露水平与颜色视觉的关系，特别是与当前暴露浓度和CEI（累积暴露指数）的关系。方法：采用Lanthony去饱和面板D-15测试方法，对74名接触苯乙烯的玻璃钢工厂工人和103名未接触苯乙烯的对照者进行色视觉和其他神经行为测试。当前暴露水平通过末端移位尿曼德酸（MA）、苯基糖酸（PGA）和尿苯乙烯表达。CEI是通过1991年至1997年每年两次测量工人尿扁桃酸的浓度来计算的。结果：尿MA、PGA、苯乙烯终移平均值分别为0.26±0.34、0.11±0.11 g/g肌酐和120.32±146.20μ g/l。平均CEI为7.1±5.9年；暴露工人的颜色混淆指数（CCI）与年龄匹配的对照组相比有显著差异。多元回归分析显示尿MA、PGA浓度与色觉相关。按尿MA+PGA 0.24 g/g肌酐限值将暴露工人分为两组。高暴露组CCI值显著升高。但在低暴露组和年龄匹配的对照组之间，CCI没有显著差异。这项研究的结果表明，高于10 ppm的苯乙烯暴露可能会损害色觉。因此，需要重新评估苯乙烯暴露的安全限值。

Objective : To make clear the relationship between color visual and exposure level of styrene, especially in relation to both current exposure concentration and CEI (Cumulative Exposure Index).Method : Color vision and other neurobehavioral test batteries were examined among 74 workers in a FRP plant exposed to styrene and among 103 non-exposed controls by Lanthony desaturated panel D-15 test. The current exposure levels were expressed by end-shift urinary mandelic acid (MA), phenylglycoxylic acid (PGA) and urinary styrene. The CEI was calculated by concentration of the worker's urinary mandelic acids that were measured from 1991 to 1997 twice yearly.Result : The mean of urinary MA, PGA, styrene at the end-shift were 0.26±0.34, 0.11±0.11 g/g creatinine and 120.32± 146.20μ g/l. The average CEI was 7.1±5.9 years ; CCI (Color Confusion Index) of exposed workers showed a significant difference compared with the age-matched controls. The multiple regression analysis showed the concentration of urinary MA and PGA were related to color vision. Exposed workers were divided into two groups by a limit of urinary MA+PGA of 0.24 g/g creatinine. The CCI value in the higher exposed group was significantly increased. But no significant difference in CCI was observed between the lower exposed group and the age-matched controls. The results of this study suggest that both higher than 10 ppm exposure to styrene might impair color vision. As the consequence, re-evaluation for the safety limit of exposure to styrene is needed.