摘要：
目的 研究铅的接触、效应及易感性标志物间的关系,探讨其用于评估低水平职业性铅接触人群健康危害的敏感性和实际应用价值.方法 应用职业卫生检测方法测定江苏省某铅酸蓄电池生产企业作业场所中铅烟、铅尘浓度,对该企业233名职业性铅接触工人和76名非职业性铅接触工人采用石墨炉原子吸收光谱法测定血铅(Pb-B),血液荧光计法测定锌原卟啉(ZPP),分光光度计法测定血δ-氨基乙酰酮戊酸脱水酶(ALAD),Taqman荧光探针实时定量聚合酶链反应测定ALAD基因多态性,用石墨炉原子吸收光谱法测定尿铅(Pb-U),分光光度测定方法测定尿δ-氨基乙酰丙酸(ALA-U),多元线性回归法分析上述指标的相关关系.结果 18个铅烟与30个铅尘检测点浓度分别为0.002～0.019 mg/m3和0.004～0.013 mg/m3;233名职业性铅接触工人Pb-B与Pb-U、ZPP呈正相关(r值分别为0.62、0.47,P＜0.01),与ALAD呈负相关(r=-0.77,P＜0.01);218人(93.6％)Pb-U≤70 μg/L,其中15人(6.9％)Pb-B≥400μg/L;Pb-B＜190 μg/L时,Pb-B与ZPP不相关(r=0.18,P=0.068);Pb-B≥190 μg/L时,Pb-B与ZPP呈正相关(r=0.36,P＜0.01);Pb-U与ALA-U、ZPP呈正相关(r值分别为0.49、0.47,P＜0.01);ZPP与ALAD呈负相关(r=-0.19,P＜0.01),与ALA-U呈正相关(r=0.27,P＜0.01);ALAD与ALA-U不相关(r=-0.11,P＞0.05);ALAD1-2基因型工人的Pb-B、ZPP水平和ALAD活力与ALAD1-1基因型工人差异无统计学意义(P＞0.05).76名非铅接触工人中,两种基因型工人的Pb-B水平差异无统计学意义(P＞0.05),ALAD1-2基因型工人ALAD活力低于ALAD1-1基因型工人,ZPP平均水平高于ALAD1-1基因型工人,差异均有统计学意义(P＜0.01).结论 在低水平职业性铅接触人群中,ZPP与Pb-B相关的阈值为190 μg/L,ALAD可作为低Pb-B水平的效应标志物;ALAD基因多态性对职业性与非职业性铅接触人群的Pb-B水平及其毒性效应的影响作用不同.%Objective To investigate the lead exposure,its effects,and the relationships between biomarkers of susceptibility in the workers with low-level occupational lead exposure,and to explore its sensitivity and practical value to evaluate the health hazard.Methods The concentrations of lead fume and lead dust in workplaces of a lead acid storage battery enterprise in Jiangsu Province,China,were measured by occupational health monitoring method.The blood samples of 233 workers with occupational lead exposure and 76 non-occupational lead exposure were collected to measure the blood lead (Pb-B) level using graphite furnace atomic absorption spectrometry (GFAAS),the zinc protoporphyrin (ZPP) level with blood fluorescence assay,and the delta-aminolevulinic acid dehydratase (ALAD) concentration by a spectrophotometer,and to determine the gene polymorphism of ALAD with TaqMan real-time polymerase chain reaction.At the same time,their urine samples were collected to measure urine lead (Pb-U) concentration with GFAAS and delta-aminolevulinic acid (ALA-U) concentration with a spectrophotometer.The correlations between the above indices were analyzed by multiple linear regression method.Results The concentration of lead fume in 18 testing sites and the concentration of lead dust in 30 testing sites were 0.002～0.019 mg/m3 and 0.004～0.013 mg/m3,respectively.Pb-B level was positively correlated with Pb-U concentration (r=0.62,P＜0.01) and ZPP level (r=0.47,P＜0.01) and was negatively correlated with ALAD concentration (r=-0.77,P＜0.01) in 233 workers with occupational lead exposure.Among 233 workers,218 (93.6％) had ≤ 70 μg/L Pb-U,and 15 (6.9％) had ≥ 400 μg/L Pb-B.Pb-B level was not correlated with ZPP level as Pb-B level was ＜ 190 μg/L (r=0.18,P=0.068),while Pb-B level was positively correlated with ZPP level as Pb-B level was ≥ 190 μg/L (r=0.36,P＜0.01).Pb-U concentration was positively correlated with ALA-U concentration (r=0.49,P＜0.01) and ZPP level (r=0.47,P＜0.01).ZPP level was negatively correlated with ALAD concentration (r=-0.19,P＜0.01),and was positively correlated with ALA-U concentration (r=0.27,P＜0.01).ALAD concentration was not correlated with ALA-U concentration (r =-0.11,P＞0.05).And in 233 workers with occupational lead exposure,there were no significant differences in Pb-B level,ZPP level,and ALAD activity between the workers with ALAD1-2 genotype and the workers with ALAD1-1 genotype (P＞0.05).In 76 workers with non-occupational lead exposure,there was no significant difference in Pb-B level between the workers with ALAD1-2 genotype and the workers with ALAD1-1 genotype (P ＞0.05).The workers with ALAD1-2 genotype had a significantly lower ALAD activity,and a significantly higher ZPP level compared with those ALAD1-1 genotype (P＜0.01).Conclusion In the workers with low-level occupational lead exposure,ZPP level is positively correlated with Pb-B level when Pb-B level was ≥ 190 μg/L.ALAD could be used as an effect biomarker of low Pb-B level.ALAD gene polymorphism shows different effects on the Pb-B level and the toxic effects between the workers with occupational lead exposure and the workers with non-occupational lead exposure.
