Introduction
1.1 Background Of The Study
For the general public, Council Recommendation of 12 July 1999 (2) on the limitation of exposure of the general public to electromagnetic fields (0 Hz to 300 GHz) fixes basic restrictions and reference levels to electromagnetic fields (EMFs). These restrictions and reference levels are based on the guidelines published by the International Commission on Non Ionising Radiation Protection (ICNIRP)3(3). The ICNIRP guidelines had been endorsed by the Scientific Steering Committee (SSC)(4) in its opinion on health effects of EMFs of 25–26 June 1998(5).
The motivation for this work is derived from the increasing exposure to EMF consequent to the further growth in the use of electricity, from the continuous development of the telecommunications industry, and to a rapid increase in the installation of transmitter masts used as radiotelephone base stations. In addition to domestic, industrial and medical electrical appliances and devices, the high voltage overhead transmission lines (and to a lesser extent underground cables) are major sources of exposure to Extremely Low Frequencies (ELF) in the environment. The CSTEE opinion “on Possible effects of Electromagnetic Fields (EMF), Radio Frequency Fields (RF) and Microwave Radiation on human health”(8), of30 October 2001, concluded that the information that had become available since the SSC opinion of June 1999 did not justify revision of the exposure limits recommended by the Council(9).
A substantial number of scientific publications and reviews on the possible health effects of EMF (focusing mostly on mobile telephones) have become available since the CSTEEopinion of 2001, for example the 2002 Dutch report(10) the 2003 AGNIR report(11) and the 2004 British National Radiological Protection Board (NRPB) report on “Mobile phones and health”(12) which is the most recent of them. The NRPB provided a detailed review of the recent literature and useful contribution to the discussions on whether there are health effects related to the use of mobile phones. The report concluded that there is no hard evidence at present that the health of the public is being adversely affected by mobile phone technologies but uncertainties remain and a continued precautionary approach is recommended until the situation is clarified.
Additional results are expected shortly from Community funded research and development (R&D) activities, from national programmes, and from work within the International EMF Project of the World Health Organisation (WHO).
As part of its mission to protect public health and in response to public concern over health effects of EMF exposure, WHO established the International EMF Project(16) in 1996 to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. The EMF Project encourages focused research to fill important gaps in knowledge and to facilitate the development of internationally acceptable standards limiting EMF exposure.
1.2 Statement Of The Problem
It is well recognized that there are established biophysical mechanisms that can lead to health effects as a consequence of exposure to sufficiently strong fields. For frequencies up to, say, 100 kHz the mechanism is stimulation of nerve and muscle cells due to induced currents and, for higher frequencies, tissue heating is the main mechanism. These mechanisms lead to acute effects. Existing exposure guidelines, such as those issued by ICNIRP, protect against these effects. The current issue is the possibility that health effects occur at exposure levels below those where the established mechanisms play a role and in particular as effects of long term exposure at low level. No further consideration is given to thermal effects.
1.3 Aims And Objectives Of The Study
The objective of this project is to:
- To have an overview of the scientific literature concerning the health effects of EMF;
- To draw attention to significant new scientific findings;
- To provide a review of the literature in the light of significant new evidence;
- To determine Possible effects of Electromagnetic Fields (EMF), Radio Frequency Fields (RF) and Microwave Radiation on human health
1.4 Research Questions
In reviewing and evaluating the studies on the potential health effects of EMF, the study seeks to answer the following questions:
- What is the nature of EMF studies, i.e., epidemiology, laboratory biology (in vivo vs. in vitro), clinical examinations (heart function, sleep electrophysiology, immune system, blood chemistry, hormones including melatonin, etc.), and theory;
- What is the characterization of risks, in particular, nature and magnitude of damage, likelihood of occurrence (expressed preferably in terms of natural frequencies rather than probabilities), uncertainty, geographical distribution, persistence over time, reversibility, delay, possible violation of equity, potential for public mobilization etc.; and
- How is the identification and physical characterization of existing and foreseeable sources of exposure to EMF, e.g., electromagnetic vs. magnetic including magnetic resonance imagery (MRI), from AC vs. DC current, new frequency ranges, higher transmission power, etc.
1.5 Significance Of The Study
The purpose of this study is in respect to whether or not exposure to electromagnetic fields (EMF) is a cause of disease or other health effects. Recommendations regarding exposure guidelines or other risk management tools, including application of the precautionary principle are beyond the scope of the opinion. The methods that were used for the preparation of the opinion are explained below.
1.6 Scope And Limitations Of The Study
Following the CSTEE general principles, only studies published in peer reviewed journals have been considered. The section is divided into four sub-sections according to frequency (f) range: radio frequency (RF) (100 kHz < f ≤ 300 GHz), intermediate frequency (IF) (300 Hz < f ≤ 100 kHz), extremely low frequency (ELF) (< f ≤ 300 Hz), and static (0 Hz) (only static magnetic fields are considered in this opinion). These frequency ranges are discussed in order of decreasing frequency, RF, IF, ELF, and static. For each frequency range the review begins with a description of sources and exposure to the population. This is followed, for each frequency range, by a discussion that is organized according to outcome. For each outcome relevant human, in vivo, and in vitro data are covered.
Table 1 below illustrates some typical artificial sources of electromagnetic fields with frequency and intensity. Natural sources like the magnetic field of the earth are not included. Note, however, that big variations occur. For an explanation of some of the terminology used please be referred to the next chapter.
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