轨道交通地下站列车驾驶室工频电场强度调查

目的 了解城市轨道交通地下站列车驾驶室的工频电场分布情况。 方法 用电磁辐射分析仪测定某城市轨道交通A、B两型车在运行和停靠状态时,列车驾驶员操作位及相邻位置的工频电场强度,并以柴油检修工程车为对照。 结果 无论停靠还是运行时,A型和B型列车两侧门内外工频电场强度均低于国家职业接触限值要求。两型车驾驶室中部工频电场强度均小于靠近门窗处各检测点(前挡风玻璃下、司机操作位、司机头部),差异有统计学意义(P<0.05)。而在无接触网高电压下运行的柴油工程车驾驶员操作位及周围均未检出工频电场。两种列车在运行及停靠接触网下时,驾驶室中部工频电场强度均低于司机窗外、副驾驶窗外,差异有统计学意义(P<0.01)。在运行时A车驾驶室中部工频电场强度低于停靠时,差异有统计学意义(P<0.05),而B车差异无统计学意义(P>0.05)。两车两侧窗外电场强度在运行时均低于停靠时,差异有统计学意义(P<0.05)。 结论 列车驾驶员工作中接触工频电场,且中心操作位检测数值低于列车靠近门窗侧的数值,职业病危害因素来源于线路接触网。应对工频场可能造成的职业病危害进行进一步研究。     

某市地下轨道供电系统工频电场强度分布特征

目的 了解地下轨道交通供电系统不同等级变压器作业环境工频电场强度差异及相同等级变电站不同站点工频电场强度的分布,为地下轨道交通维检修作业人员是否佩戴专业的工频电场个体防护提供参考依据。方法 通过使用森馥电磁场测定仪对3条地铁线79座站中的不同电压等级变压器进行检测,并且利用SPSS 22.0软件包进行统计学分析。结果 作业人员在日常巡检、维检修过程中,35 kV相同作业点作业人员接触的高压室主变输入端的工频电场数值大于输出端电场强度,差异有统计学意义(χ²=5.652,P<0.05),但均未超过国家职业接触限值的要求(实际上其不超过工频电场接触限制的3%)。结论 该系统正常运行的状态下,不会对巡检作业人员的健康和安全产生影响,无需穿戴防辐射工作服之类的个人防护用品。     

铁路电力牵引工频电磁场对职工健康影响的探讨

目的：探讨铁路电力牵引工频电磁场对不同工种的铁路作业人员的健康影响。方法：以整群随机抽样法，抽取电力机车司机、接触网工、线路工和电力牵引变电所人员192名作为观察组。另抽取非电力牵引铁路职工106名为对照组。检测作业环境的电场、磁感应强度、人体血液学指标、免疫球蛋白水平和外周血淋巴细胞DNA损伤率。结果：电力牵引相关工种作业环境中有不同程度的电磁场强度存在。变电所人员的白细胞数低于对照组，电力机车司机、接触网工、线路工和变电所值班人员淋巴细胞数均低对照组，电力机车司机，接触网工和变电所值班人员外周血淋巴细胞DNA损伤率高于对照组。结论：工频电磁场对不同工种的铁路作业人员的免疫系统和外周血淋巴细胞DNA损伤产生不同的影响。     

铁路电力牵引工频电磁场强度调查

目的 掌握电气化铁路作业环境工频电磁场强度,为评价工频电磁场对人体的影响提供现场资料。方法 对电力机车司机室、牵引变电所、接触网下等电气化铁路作业环境进行环境工频电磁场强度的调查,根据国家卫生标准进行评价。结果 电场强度:接触网下为(1.3±4.3)kV/m,牵引变电所外环境为(2.6±2.8)kV/m,变电所的主控室内和电力机车司机室及机器间均未测出;磁感应强度:接触网下为(0.098±0.06)mT,牵引变电所的主控室为(0.06±0.04)mT,变电所的外环境为(0.14±0.15)mT,电力机车司机室为(0.12±0.10)mT,其机器间为(0.34±0.19)mT。结论 电气化铁路作业环境中的工频电场强度符合GB16203-1996《作业场所工频电场卫生标准》;磁场强度低于国际大电网(CIGRE)会议提出的4.4~5.0mT的接触限值,因此,电气化铁路所产生的工频电磁场对作业人员的健康影响在安全范围内。     

电化铁路高压工频电磁场调查

福州铁路分局永漳段电化铁路全长105Km,列入国宗“七五”规划,为探讨工频50Hz,27.5KV电压对牵引变电所,接触网作业人员健康影响,消除作业人员思想顾虑,采取防护措施提供依据,于1989年11月对永漳段(永安、西洋、麦园、漳     

铁路电力牵引工频电磁场对作业人员淋巴细胞DNA损伤的探讨

[目的]探讨铁路电力牵引对铁路作业人员淋巴细胞DNA损伤情况。[方法]以整群随机抽样法,抽取接触电磁场的136名职工为观察组,非接触电磁场的49名职工为对照组。检测作业环境的电场强度、磁感应强度,对外周血淋巴细胞DNA损伤进行分析。[结果]相关工种作业环境中有不同程度的电磁场强度存在,外周血淋巴细胞DNA损伤率观寨组高于对照组。[结论]铁路电力牵引工频电磁场对作业人员外周血淋巴细胞DNA产生不同程度的损伤。     

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。     

发电厂工频电磁场分布调查

发电厂高压输变电系统存在着工频电磁场辐射,长期暴露在高辐射剂量下可能对人体产生潜在危害。据统计浙江省共有40多个发电厂。本文对浙江省2个火力发电厂的不同区域工频电磁场进行了调查测定和分析,并结合国内外工频电磁场暴露     

某铁路辖区职业卫生与职业健康监护情况调查分析

目的了解某铁路辖区内职业危害现状,客观分析评价职业病防治工作开展情况,为规范开展铁路职业卫生管理工作提供依据。方法对近年辖区内进行职业卫生检测及职业健康监护的情况进行调查分析。结果对车辆系统、机务系统、工务系统、电务系统进行职业病危害因素的检测,合格191个点,合格率81.6%;对771名工人开展职业健康检查,发现职业相关异常71人,异常率9.2%,异常复查率11.3%。结论铁路职业卫生与职业病防治工作尚需进一步加强,包括职业病危害工程防护设施的"三同时"及日常维护,噪声超标岗位人员的个体防护措施,职业健康监护工作中上岗、在岗期间及离岗体检的规范开展,检出职业相关异常者的及时复查等。     

铁路机车驾驶室环境卫生质量调查

了解铁路机车驾驶室环境卫生状况，于2004年12月对提速的DF11G型内燃机车、SS9型电力机车不同运行时段驾驶室环境质量进行了监测，于2005年1月对DF11型内燃机车不同运行时段驾驶室环境质量进行了监测。监测指标包括温度、相对湿度、照度、风速、CO、CO2、噪声、振动，在司机室操作台面或司机室1.5m高度和司机座椅设置监测点。所有列车均采取全程监测，监测时段分为整备阶段（平均2.5h）、始发等待（平均1h）、运行阶段（运行4、8h及特殊路况分别进行监测）及终到阶段。结果显示，SS9型电力机车和DF11型内燃机车驾驶室内风速合格率较低（SS9型为70％，DF11型为48.72％），卡日对湿度均低于国家标准；DF11型内燃机车驾驶室内的温度和风速合格率明显低于其它两型机车（P值均低于0.05）DF11G型机车在各运行时段驾驶室内温度和相对湿度稳定，温度及风速合格率明显高于SS9和DF11型机车。提示DF11G型内燃机车驾驶室整体环境质量较为优良。     

Effects of 50 Hz electric currents on vigilance and concentration

Seventy six male volunteers were studied in a crossover trial to assess the effect on the central nervous system of 50 Hz electric currents. Currents totalling 500 microamperes were passed through electrodes attached to the head, upper arms, and feet, simulating exposure to a vertical electric field of about 36 kV/m. Exposure and sham exposure sessions were assigned using double blind techniques and current passed for about 5.5 hours during the exposure session. A series of psychological tests comprising self reports of mood and performance tests of memory, attention, and verbal skills were administered. The present paper discusses the effects of those currents on vigilance and sustained concentration and examines the hypothesis that electric fields act as stressors. The results indicate that vigilance and concentration were not influenced by exposure, nor do they support the hypothesis of a stress reaction. Although brief reports of sensations at electrode sites compromised the double blind conditions to some extent, the performance changes associated with these reports were independent of exposure per se. Within the vigilance task there were two possible exposure effects on the time taken to identify non-target numbers. Firstly, the non-targets were identified more slowly during the first hour of exposure. Secondly, for subjects not reporting sensations, non-target latencies on the second day were slower in the exposed group--there were no corresponding differences on the first day. The interpretation of this effect is complicated by its apparent restriction to the second day and may indicate some kind of state dependent transfer phenomenon.     

Effects of 50 Hz electric currents on vigilance and concentration.

Seventy six male volunteers were studied in a crossover trial to assess the effect on the central nervous system of 50 Hz electric currents. Currents totalling 500 microamperes were passed through electrodes attached to the head, upper arms, and feet, simulating exposure to a vertical electric field of about 36 kV/m. Exposure and sham exposure sessions were assigned using double blind techniques and current passed for about 5.5 hours during the exposure session. A series of psychological tests comprising self reports of mood and performance tests of memory, attention, and verbal skills were administered. The present paper discusses the effects of those currents on vigilance and sustained concentration and examines the hypothesis that electric fields act as stressors. The results indicate that vigilance and concentration were not influenced by exposure, nor do they support the hypothesis of a stress reaction. Although brief reports of sensations at electrode sites compromised the double blind conditions to some extent, the performance changes associated with these reports were independent of exposure per se. Within the vigilance task there were two possible exposure effects on the time taken to identify non-target numbers. Firstly, the non-targets were identified more slowly during the first hour of exposure. Secondly, for subjects not reporting sensations, non-target latencies on the second day were slower in the exposed group--there were no corresponding differences on the first day. The interpretation of this effect is complicated by its apparent restriction to the second day and may indicate some kind of state dependent transfer phenomenon.     

Effects of 50 Hz electric currents on mood and verbal reasoning skills

Seventy-six male volunteers were studied in a crossover trial to assess the impact on the central system of electric currents such as might be induced by exposure to an intense power frequency electric field. Currents totalling 500 microamperes (50 Hz) were passed through electrodes attached to the head, upper arms, and feet, simulating exposure of and average man to a vertical electric field of about 36 kV/m. Exposure was continuous for a single day (5.5 hours) and the experiment was based on a double blind, counterbalanced, within subject design. A series of psychological tests examining self reports of both stress and arousal (mood checklist) and performance tests of memory, attention, and verbal skills were administered. Although the double blind conditions were compromised to some extent by reported sensations at electrode sites, the duration of these sensations was small in relation to the overall exposure or sham exposure time and did not interact with the effects apparently associated with exposure that were found. No significant difference between the exposed and sham-exposed groups was found on the first day, but on the second day the sham exposed group felt more aroused at the end of the day and their response times had improved more on the complex problems of a syntactic reasoning test. No exposure effects were apparent in self reports of stress or in performance in a semantic reasoning test, although both showed some influence of sensations. Interpretation of the exposure effects is complicated by their apparent restriction of the second test day, which may indicate some type of state dependent transfer phenomenon.     

Real-time recording of neuropsychophysiological parameters during 50 Hz magnetic field exposure

In order to assess the possible effects of occupational levels of 50 Hz magnetic fields (MF) on human performance it is preferable to monitor performance during rather than subsequent to MF exposure. We previously reported studies of heart rate and cognitive behaviour where the issue of contamination was not a serious one. Our present study involves electrophysiological measures, which have a greater capacity to identify the effects and assist in localising them. The contamination of EEG signal by the MF exposure is clearly a problem in this type of study. Previous investigators have not reported these types of measurement concurrent with MF exposure due to the contamination difficulty; but this paper reports means of accomplishing this. Overall a combination of 12 methods for reducing pickup were employed. These were: 1) Distancing recording instruments from the MF source; 2) Shielding the devices and wiring; 3) Appropriate choice of cables; 4) Grounding the instrumentation; 5) Orientation of conduits; 6) Isolation of electrical mains power supplies; 7) Balancing the input impedances; 8) Applying a driven shield technique; 9) Improved electronics design incorporating pre-amplification and circuit impedance level control; 10) Analogue filtering; 11) Signal Averaging; and 12) Post acquisition digital filtering using frequency and time domain techniques.     

Effects of 50 Hz electric currents on mood and verbal reasoning skills.

Seventy-six male volunteers were studied in a crossover trial to assess the impact on the central system of electric currents such as might be induced by exposure to an intense power frequency electric field. Currents totalling 500 microamperes (50 Hz) were passed through electrodes attached to the head, upper arms, and feet, simulating exposure of and average man to a vertical electric field of about 36 kV/m. Exposure was continuous for a single day (5.5 hours) and the experiment was based on a double blind, counterbalanced, within subject design. A series of psychological tests examining self reports of both stress and arousal (mood checklist) and performance tests of memory, attention, and verbal skills were administered. Although the double blind conditions were compromised to some extent by reported sensations at electrode sites, the duration of these sensations was small in relation to the overall exposure or sham exposure time and did not interact with the effects apparently associated with exposure that were found. No significant difference between the exposed and sham-exposed groups was found on the first day, but on the second day the sham exposed group felt more aroused at the end of the day and their response times had improved more on the complex problems of a syntactic reasoning test. No exposure effects were apparent in self reports of stress or in performance in a semantic reasoning test, although both showed some influence of sensations. Interpretation of the exposure effects is complicated by their apparent restriction of the second test day, which may indicate some type of state dependent transfer phenomenon.     

电磁噪声阻断极低频磁场对细胞缝隙连接功能的抑制效应

目的　探讨电磁噪声对 5 0Hz磁场诱导的细胞缝隙连接通讯功能 (GJIC)抑制的干预作用。方法　小鼠成纤维细胞 (NIH 3T3)受 5 0Hz 0 .4mT极低频磁场或磁场加同等强度的电磁噪声联合作用 2 4h后 ,在激光共聚焦显微镜下 ,采用荧光光漂白后恢复技术 (FRAP)测定细胞的GJIC功能。结果　 0 .4mT磁场单独作用明显抑制细胞的GJIC ,其荧光恢复率为 2 7.6 7%± 5 .12 % ,与对照组(45 .5 7%± 9.72 % )相比 ,差异有显著性 (P <0 .0 1) ;而磁场与电磁噪声联合作用 (5 2 .6 1%± 8.30 % )明显拮抗磁场对GJIC的抑制作用 ,与 0 .4mT磁场组的差异有显著性 (P <0 .0 1) ,并与对照组的差异无显著性 (P >0 .0 5 )。结论　电磁噪声对极低频磁场诱导的GJIC的抑制具有阻断作用     

工频磁场对人绒毛滋养细胞凋亡相关基因表达的影响

目的研究50Hz工频磁场对人早孕绒毛滋养细胞凋亡相关基因表达的影响，探索工频磁场对人生殖健康影响的可能机制。方法体外分离培养人早孕绒毛滋养细胞。以50Hz、0．4mT强度的正弦磁场分别辐照处理6、48、72h，同时设立相应的平行对照组，用实时荧光定量逆转录—聚合酶链反应（RT-PCR）方法检测工频磁场辐照对bcl-2、bax、caspase-3、p53、fas基因表达的影响。结果辐照6、48、72h后bcl-2、bax、caspase-3、p53、fas基因表达变化倍数平均值均接近1，暴露组与对照组的差异均没有统计学意义（P〈0．05）。结论72h内，0．4nat工频磁场体外辐照不会影响人早孕绒毛滋养细胞bcl-2、bax、caspase-3、p53、fas等凋亡相关基因的表达水平。     

Cancer from exposure to 50/60 Hz electric and magnetic fields--a major scientific debate

Millions of dollars are presently being spent on both laboratory and epidemiological studies to determine if an association exists between the exposure of humans to 50/60 Hz electromagnetic fields and cancer incidence. This review discusses findings from both of these areas of study and focuses attention on their relevance to the electromagnetic field-cancer debate. So far, the conflicting results from epidemiology have succeeded only in raising the concerns of both occupationally exposed groups and the general public. A few hypotheses have suggested possible mechanisms by which fields could exert biological effects. However the studies on which these hypotheses are based require substantiation and further, there is insufficient evidence to indicate if the biological effects observed in these studies have any relevance to human health. It will be at least another three to five years before there are results from large scale human studies presently being designed or undertaken. From an objective review of existing scientific data it can only be concluded that exposure to 50/60 Hz electric and magnetic fields at levels occurring in our environment have not been established to lead to cancer in humans. Sufficient gaps in our knowledge exist however to recommend that research continue, especially in areas identified in the text. To assist the casual reader of this subject the complex issues of cancer initiation and promotion are considered.