ABSTRACT
Human exposure to electromagnetic fields (EMFs) continues to rise with the general increase in applications of electrotechnical devices. Man-made fields differ very greatly in strength and temporal distribution from those that occur in nature, such as the earth’s magnetic field and the electric fields and disturbances that arise in the atmosphere. It is therefore inevitable that society should need to examine whether there is any detriment to human health that results from exposure to these artificial fields. The range of man-made frequencies extends from static fields through power, audio and radio frequencies up to microwaves. From a simple physical point of view, there is little to suggest that the EMFs to which people are generally exposed could have any effect on their health. This is quite different from the situation with ionising radiations (x-rays, alpha-particles etc.) where their intrinsic energy is sufficient to change molecular structure (e.g., by breaking DNA) and where the connection between the induction of genotoxic damage and the causation of cancer and heritable defects seems fairly clear. However, some epidemiological studies have indicated a possible correlation between EMF exposure and the incidences of certain types of cancer, although other studies have failed to confirm an association. At the present time, research continues to examine whether there are any real risks and, if so, what are their magnitudes. The aim is to provide the facts needed for regulation, risk management and public information. Current research is on three main fronts: epidemiology, animal studies and cellular studies. This combination of approaches is required to establish whether there is evidence of a health effect in exposed populations, whether the magnitude or incidence of any effect relates to the level and/or duration of exposure and whether there is a candidate mechanism for any effect. To establish a cause-and-effect relationship, clear evidence of all three of these aspects is required. The study reported in this chapter investigates previous work published by others which has indicated that the mutagenic effect of ionising radiation on cells in culture can be enhanced by exposing them to power-frequency EMFs. Thus this work had further suggested that the level of genotoxic damage present in the population due to natural and man-made ionising radiation exposures, as well as from other processes known to cause damage to DNA, might be amplified by EMF exposure and lead to an increase in cancer. For reasons set out below, the uncertainties associated with studies of the type reported previously are considerable. The purpose of the present study was to repeat independently some aspects of the earlier work and so help to verify whether or not the reported amplifying effect of EMF was reproducible and significant.
