红细胞中铬含量作为铬盐接触者生物标志物的研究

Chromium content in erythrocytes serving as the exposure biomarker for workers exposed to soluble chromate

目的通过对职业接触可溶性铬盐劳动者红细胞中铬浓度的研究，了解红细胞中铬浓度与个体环境可溶性铬盐接触之问的相关性及其在职业人群中分布的特点、影响因素，探讨其作为职业接触可溶性铬盐接触性生物标志物的可行性。方法采用横断面现场研究，对山东省济南市某铬盐生产企业进行了流行病学调查。接触组选择重铬酸钾制造业铬盐作业劳动者114名（男74名、女40名）；年龄范围25～52岁，平均年龄（35．83±6．14）岁；工龄1～37年，平均工龄（14．20±6．77）年；接触铬盐年限范围0．5～28年，平均接触铬盐年限（9．80±5．97）年。对照组为无毒物接触史的健康人员30名（男22名，女8名），年龄范围25～47岁，平均年龄（36．13±6．17）岁。接触组与对照组两组人群在年龄、性别和吸烟状况等方面相匹配。通过问卷调查了解研究对象的一般情况、职业接触情况、吸烟饮酒情况、既往疾病史、个人防护情况等。作业环境铬盐浓度的测定：采用双滤膜个体采样器8h工作日连续采样，滤膜铬盐含量采用火焰原子吸收分光光度法测定；红细胞中铬浓度测定采用石墨炉原子吸收分光光度法；血浆还原能力测定采用二苯碳酰二肼分光光度法；总维生素C、还原型维生素C含量的测定采用2，4-二硝基苯肼法。用SPSS10.0统计软件进行单因素统计分析和多元回归分析。结果职业接触可溶性铬盐劳动者红细胞中铬浓度为（15．79±31．01）μg／L，高于对照组的（3．21±2．20）μg／L，差异有统计学意义。当空气中个体铬盐暴露浓度小于106．00μg／m^3时，职业接触可溶性铬盐劳动者红细胞中铬浓度随个体铬盐接触水平的增加而增加，并呈明显的剂量．反应关系。相关分析结果表明：红细胞中铬浓度与空气中个体铬盐暴露水平之问呈显著的正相关。多元回归证实：在α=0．10水平，血浆中维生素C、血浆六价铬的还原能力可以作为可溶性铬盐接触氧化应激水平的指标，并可影响红细胞内铬的摄取。结论红细胞中铬含量可以作为可溶性铬盐职业接触者的有效接触性生物标志物，尤其适于个体低剂量铬盐接触的评价。

Objective To explore biological exposure markers, we investigated the chromium content in peripheral erythrocytes from occupational population with broad ranges of soluble chromate exposure, as the candidate biomarker may provide the scientific evidence for health risk assessment in occupational chromate-exposed population. Methods A cross-sectional study was conducted in chromate exposed workers employed at a chromate factory in a district of Jinan city, Shandong Province. The studied population contained 114 workers from different processes of the chromate plants, which included 74 males and 40 females, with an age range from 25 to 52 years old, averaging at （35.83±6.14） years old; the length of service was ranging from 1 year to 37 years, an average of （14.20±6.77） years. In addition, 30 farmers in the countryside one hundred kilometers away from the factory, without exposure to chromate matched with exposed subjects by age, gender and smoking status were identified as a control group, which included 22 men and 8 women, with age ranging from 25 years old to 47 years old, having an average age of （36.13±6.17） years old. Personal information on age, chromate exposure, medical history, smoking habit and alcohol consumption was obtained at an interview. The air concentration of personal exposure was determined by individual sampling for 8 hours per day as shift work, and chromium was assayed by atomic absorption spectrometry. The chromium content in the erythrocytes from peripheral blood was determined by graphite furnace atomic absorption spectrometry. The potential plasma reduction capacity was determined by dibenzene anthracoamid dihydrazine spectrophotometry. The content of total vitamin C and reductive ascorbic acid were determined by 2, 4-dinitrobenzene hydrazine. The data were analyzed by SPSS10.0 software for statistical significance. Results （1） The results showed that the chromium levels in erythrocytes in the exposed group [（15.79±31.01） μg/L] were significantly higher than those in the control group [（3.21±2.20） μg/L] （P 〈 0.01）. （2） There existed a dose-response relationship between the personal airborne chromate concentration and the chromium content in erythrocytes. As airborne chromate concentration lowered to 106.00μg/m^3, the chromium content in erythrocytes increased, depending on the air concentration of chromate. （3） Correlation analysis showed that there was a significant positive correlation between airborne chromate concentration and the chromium content in erythrocytes （P 〈 0.01）. （4） In multiple regression analysis, it was found that the potential plasma reduction capacity and reductive ascorbic acid may be a good indicator for oxidative stress produced by chromate exposure and be used to evaluate the effects on intracellular uptake of chromium （Ⅵ）. Conclusion Our findings suggested that the chromium content in erythrocytes should be used as an effective exposed biomarker in the risk assessment for occupational chromate-exposure.