铁路电力牵引工频电磁场现场职业卫生学调查

目的 探讨铁路电力牵引工频电磁场对职工健康的影响。方法 对铁路电力牵引接触网和变电所周围环境进行工频电场和磁场强度的测定，通过问卷对工人的症状和体征进行调查，同时采集静脉血，进行血液学分析、免疫球蛋白水平测定和外周血淋巴细胞DNA损伤分析。结果 铁路电力牵引接触网和变电所周围环境均存在不同强度的工频电场和磁场。接触组工人白细胞、淋巴细胞数目及IgA和IgG水平明显低于对照组，外周血淋巴细胞DNA损伤率则明显高于对照组。结论 铁路电力牵引工频电磁场可影响工人的免疫功能，可能与工频电磁场引起淋巴细胞DNA损伤、从而启动细胞凋亡有关。

Occupational health study in extremely-low-frequency electromagnetic field

Objective To study the health effects of workers exposed to extremely low frequency electromagnetic field (ELF EMF) in the environment of contact system and transformer substation for electric traction in railways. Methods The intensity of electric field and magnetic field in the work environments were measured, at the same time, 196 male wokers who worked in the environment with ELF EMF and 106 male workers who worked in the environment without ELF EMF were recruited and the peripheral blood were collected to examine the number of blood cells, the levels of immunoglobulins and the levels of DNA damage of lymphocytes. Results The results showed that the electric field intensity ranged from 0 to 12.0 kV/m, and the magnetic field intensity ranged from 0.01 to 0.92 mT in the environment of contact system and transformer substation for electric traction in railways. The blood examination showed that the number of white blood cells and lymphocytes in the exposure groups were lower than those in the control groups ( P <0 05). The levels of IgA and IgG were also lower in the exposure groups than those in the control groups ( P<0.05). Single cell gel electrophoresis analysis showed that the percentage of lymphocytes with DNA damage were higher in the exposure groups (8.41%) than that in the control group ( 3.72%, P <0 05). Conclusion ELF EMF would be harmful to workers' immunology system, and would speculate that ELF EMF might cause DNA damage of lymphocyte in the workers, then induce the apoptosis of these cells, and further cause the decrease of number of lymphocytes and levels of immunoglobulins.