Waveform magnetic field survey in Russian DC and Swiss AC powered trains: a basis for biologically relevant exposure assessment.

Recent epidemiological studies suggest a link between transport magnetic fields (MF) and certain adverse health effects. We performed measurements in workplaces of engineers on Russian DC and Swiss AC powered (16.67 Hz) electric trains using a computer based waveform capture system with a 200 Hz sampling rate. MF in DC and AC trains show complex combinations of static and varying components. The most probable levels of quasistatic MF (0.001-0.03 Hz) were in the range 40 microT. Maximum levels of 120 microT were found in DC powered locomotives. These levels are much higher than the geomagnetic field at the site of measurements. MF encountered both in DC and AC powered rail systems showed irregular temporal variability in frequency composition and amplitude characteristics across the whole frequency range studied (0-50 Hz); however, more than 90% of the magnetic field power was concentrated in frequencies

[Myocardial infarct and geomagnetic disturbances: analysis of data on morbidity and mortality]. / Infarkt miokarda i geomagnitnye vozmushcheniia: analiz dannykh o zabolevaemosti i smertnosti.

Relationships between different parameters of the geomagnetic activity and medical statistical data on myocardial infarction were investigated anew, because previous results in this field have been often inconsistent. The data are daily numbers of myocardial infarction incidence rates (15,543 cases) and number of deaths for infarction (3,065 cases), abstracted from registries of the 14 biggest hospitals of St. Petersburg (1989-1990). The analysis showed a statistically significant increase in myocardial infarction rate during big geomagnetic disturbances, defined by the days of the descending phase of cosmic ray Forbush decreases. An overall estimation of the average increase in infarction incidence rate during big geomagnetic storms, (10.5 +/- 1.2)%, has been computed by taking into account previous results [1-3]. In contrast, morbidity data did not show any significant correlation with geomagnetic disturbances. It was found also that the infarction incidence rate appears to be rather constant from Monday to Friday and to decrease sharply by a factor approximately 1.25 on Saturday-Sunday and mid-week festivities. This effect is associated with different exposure during work days and week-ends to man-made magnetic field environment mainly produced by electrified transport. Such effect was not observed in mortality data. The results and their methodological aspects are placed in the context of studies on possible health effects of low frequency magnetic fields both natural and man-made origin.

Coronary heart diseases: assessment of risk associated with work exposure to ultralow-frequency magnetic fields.

The present analysis was stimulated by previous findings on the possible influence of natural ultralow-frequency (ULF; 0.001-10 Hz) geomagnetic field variations on the cardiovascular system and indications of an effect of man-made ULF magnetic fields on the rate of myocardial infarction. In the present study, we considered the occupational health hazards of the strongest ULF magnetic fields in densely populated urban areas. Measurements of ULF magnetic field fluctuations produced by trains powered by DC electricity were performed by means of a computer-based, highly sensitive, three-component magnetometer. We found that the magnitude of magnetic field pulses inside the driver's cab of electric locomotives (ELs) could be > or = 280 microT in the horizontal component perpendicular to the rails and up to approximately 130 microT in the vertical component, and, in the driver's compartment of electric motor unit (EMU) trains, they were approximately 50 and 35 microT, respectively. We have investigated the relationships between the occupational exposure to ULF magnetic field fluctuations produced by electric trains and cardiovascular diseases (CVDs) among railroad workers in the former Soviet Union. We have analyzed medical statistical data for a period of 3 years for approximately 45,000 railroad workers and 4,000 engine drivers. We have also analyzed 3 years of morbidity data for three subgroups of engine drivers (approximately 4,000 in each group) operating different types of trains. We find that EL drivers have a twofold increase in risk (2.00 +/- 0.27) of coronary heart diseases (CHDs) compared with EMU drivers. Because our analysis of major CVDs shows that the examined subpopulations of drivers can be considered to have had equal exposure to all known risk factors, the elevated CHD risk among EL drivers could be attributed to the increased occupational exposure to ULF magnetic fields.