MOBILE PHONES – ARE THEY SAFE?
THERMAL VERSUS NON-THERMAL EFFECTS
The whole of the debate over mobile phones – and indeed over other sources of non-ionizing radiation such as VDUs, power lines, etc – centres on the evidence for and against thermal versus non-thermal biological effects. A thermal or heating effect on tissue is the currently accepted way that most orthodox scientists in this area consider that electromagnetic fields (EMFs) can pose a significant hazard to the body and thus all guidance, both national and international, continues to be based on this assumption. Even the Stewart Report has not basically challenged this view.
However, a growing body of evidence and opinion over the last decade indicates that effects can occur at levels well below that at which tissue begins to heat up and that these non-thermal effects can pose significant risk. But to assess this research, it is important to understand basically how a mobile phone works.
HOW A MOBILE PHONE WORKS
Digital (as opposed to the older analogue) mobile phones use a frequency of approximately 900 MegaHertz (MHz) for the GSM (Global System Mobile) system used by Vodafone and Cellnet, and 1800 MHz for the PCN (Personal Communication Network) system used by Orange and One2One. Both fall in the microwave region of the electromagnetic spectrum, but phones for one system cannot be used with the other.
Besides the general evidence for the potential hazards of microwave radiation (which is used as a weapon system by both the Russians and the West), there is a further reason for concern: the mobile phone signal is ‘pulsed’. This means that the main frequency ‘carries’ another signal – in this case at 217 Hz -which generates a regular, low-frequency pulsing effect into the brain. In fact, there are further subtle, harmonic pulses and fields to which the user is exposed. It is these, as well as other parameters of the signal, that are causing concern and which are not properly taken into account in current guidance advice.
The proposed new TETRA system (Truncated Terrestrial Radio), to be used mainly for the emergency services, some corporate networks and the London Underground, is especially alarming in this respect since it uses not only a 420 MHz signal (producing a waveform that maximizes radiation absorption for 3-6 year-olds!) but also a pulse at 17 Hz, right in the brain’s beta rhythm!! This, despite a complete lack of research on possible health effects! BT has awarded a £2.5bn contract to Motorola to roll out the system across the UK, which will require in the order of 25,000 new masts. It is also promoted by Dolphin Telecom, which is owned by the Canada-based giant TIW, one of the winners of the licenses’ auction.
RECENT RESEARCH FINDINGS
In 1998 Dr Kjell-Hansson Mild at the National Institute of Working Life in Umea, Sweden, reported a study of 11,000 users in Norway and Sweden comparing symptoms according to duration of use of both analogue and GSM phones.3 Concentrating on the latter (since they represent 95% of phones sold in the UK), he found a significant dose-response relationship between reported symptoms (fatigue, headache, warmth behind or on ear, burning skin sensation) and duration of use, covering less than 2 minutes, 2-15 minutes, 15-60 minutes and over 1 hour. For example, those Swedes using a phone for more than an hour were 22 times more likely to report an increase in warmth behind the ear than those using them for less than 2 minutes; the equivalent figure for Norwegians was 16-fold (see Table 1). These results clearly show that a heating effect does occur, although how far it penetrates into the brain and whether this effect itself is responsible for all the reported symptoms, is still unclear.
Other research, also in Sweden by Professor Leif Salford at Lund University, has shown that radiation at mobile phone frequency can change the blood-brain barrier that normally allows certain chemicals to cross and keeps others out. He observed that after only 2 minutes’ exposure to mobile phone intensities, rats displayed changes in the permeability of the blood-brain barrier.4 This is clearly a worrying finding that suggests a non-thermal effect. Work by Prof. Ross Adey in the US, a world leader in research with over 35 years’ experience, has shown that calcium efflux in brain cells can occur when exposed to low-level microwave radiation near mobile phone frequencies.
Another American researcher, Professor Henry Lai, at the University of Washington in Seattle, has reported increased strand breaks in DNA in rats’ brains, although some are claiming not to be able to replicate the effect.
Back in the UK Dr Alan Preece at Bristol University reported in April 1999 that he had observed an effect of mobile phone radiation on human cognition – specifically the speeding up of a choice reaction test.b However, given that he used 15 different tests on only two groups of 18 subjects exposed for two sessions of 30 minutes, the finding may easily have been a chance result. Also the signal used did not exactly match that produced by a GSM phone, a deficit not helped by the derisory grant from the Department of Health of a mere £3,000!
By contrast, Dr John Tattersall, based at Porten Down Chemical and Biological Defence base in Wiltshire, funded to the tune of £113,000 by the DoH, recently reported effects of RF radiation of rats’ hippocampal brain sections at non-thermal levels well below current NRPB guidelines. He observed changes in the electrically evoked potentials and in long-term potentiation that were not due to heating.
Aside from his results one has to ask why the DoH choose to give such a sum to Porton Down rather than awarding it on the open university market place where one can be reasonably assured that all results will be fully published.
Meanwhile at Nottingham University Dr David de Pomerai has exposed nematode worms to microwaves from a Nokia 2110 phone and found that their cells produce high levels of ‘heat shock proteins’ (HSPs), at levels that did not produce a measurable temperature rise. HSPs are so-named because they were first observed to be produced in response to a considerable rise in temperature (at least 2°C) but in fact are produced whenever cells start to experience any damage to the protein structure in DNA and RNA.
Table 1. Adjusted Odds Ratios (p<0.05) for calling time using GSM phone with reference to reported symptom. Reference category is calling time less than 2 minutes a day (K-H Mild et al, 1998)
Symptom 2-15 min/d 15-60min/d >60 min/d
Fatigue 1.10 1.55 4.14
Headache 1.94 2.69 6.31
Warmth behind ear 1.68 2.93 16.0
Warmth on ear 1.65 3.94 8.37
Burning skin 1.56 3.48 8.42
Fatigue 1.25 1.80 1.40
Headache 1.49 2.50 2.83
Warmth behind ear 2.63 9.00 21.9
Warmth on ear 2.73 10.2 22.4
Burning skin 1.06 2.34 2.77
It is research such as the above that is causing a growing number of researchers and others to be concerned over non-thermal effects and to question the real safety of any guidance based solely on limiting thermal increases.
NRPB GUIDANCE BASED ON SAR
Current NRPB and international guidance is based on the SAR, which is a measure on how much radiation is absorbed per gram of tissue over a given time. The NRPB focuses purely on preventing temperature rises exceeding 1°C and bases its guidance on keeping any heating to less than 10 watts per kilogram (10 W/kg) in any 10 grams of tissue averaged over 6 minutes. By contrast, the International Committee on Non-Ionizing Radiation (ICNIRP) uses 2 W/kg – five times lower (the US uses 1.6 W/kg but in I gram of tissue). The Stewart Report recommended that the UK fall in line with Europe and adopt the ICNIRP levels in place of current NRPB guidelines, which is at least a step in the right direction but an embarrassment to the NRPB -particularly as this was also recommended in September 1999 by a House of Commons Select Committee Report ,9 but rejected at the time.
However, the whole basis of using SAR as a reliable measure of exposure, given the complexities of the signal, has been questioned. At a special seminar held at the House of Commons in June 1999, with speakers from overseas (including Prof. Lai from the US) and the NRPB (including Professor Richard Doll) and attended by MPs and pressure groups, Professor Michael Kundi, of the Institute of Environmental Health at the University of Vienna, presented five basic assumptions in using an SAR for mobile phones that can be scientifically challenged.l0 As Kundi pointed out, the use of an SAR is only valid if a continuous wave applies (as in a microwave oven), but where the signal is modulated as with the pulsed mobile phone signal this measure is not appropriate because of the stronger effect such a signal has been shown to have on biological membranes.
Although SARs may enable a useful, crude comparison of phones’ emissions, many argue that their actual value as indicators of relative safety may be misleading. The Stewart report recommended that new research should aim to elucidate this issue. In the meantime one can take measures to reduce exposure from both types of radiation.
PROTECTIVE DEVICES – BEWARE THE SCARE – WHICH? PROJECT!
The Stewart Report recommended that an independent assessment be made of the efficacy of protective devices on the market. According to the DTI, they have already commissioned independent tests of hands-free kits and will publish the results shortly.
Although the NRPB tends to dismiss the need for or efficacy of protective devices, the BMA, in its evidence to the above House of Commons Committee, called for ‘prudent avoidance’ and recommended that consumers should have access to protective devices to reduce radiation. One of the possible ways of achieving the latter is to use a remote, hands-free earpiece that significantly reduces radiation into the head.
However, this year’s April issue of Which? published a report (pp. 11-17) claiming that research it had carried out showed that hands-free headsets tripled EMF exposure www.which.net. However, the claimed results have been strongly criticized and Which? has been less than forthcoming in releasing its data and methodology. The research was actually carried out by ERA Technology in Leatherhead, Surrey, which tested only two phones but refuse to discuss their findings. They did not do a full SAR test but instead took a single set of readings of the electric and magnetic fields 4 cm inside a simulated skull. This was criticized by Dr Alan Preece at Bristol University who said they should have done at least three measurements.
Having finally been pressured into releasing the full report, it transpires that what the Which? test actually found was that the electric field was three times higher if the phone was connected to the earpiece compared to when placed next to the model head – but only when the phone was vertically below the head (as when strapped to the user’s belt). When placed horizontally, the field was unchanged. In either situation the magnetic field was also unchanged.
By contrast, tests carried out for Vodafone by Dr Camelia Gabriel, of Microwave Consultants in London and a director of SARTest, which specializes in developing ‘phantom’ heads to test SARs, have found no such increased exposure. Indeed, even in a worst-case situation, SAR reductions of more than 80% were measured (for full results, see www.sartest.com). Her results strongly challenge the validity of Which?’s results and methodology, which in turn casts some doubt over other tests they have performed.
Previous tests by others, such as Alasdair Philips of the consumer information group Powerwatch, have found only a 15-30% increase into the ear in a worse case scenario. Thus, these devices are useful for keeping the phone away from the body and only emphasize advice to keep calls as short as possible.
Of other devices on the market, the two with the most research and testing are the Microshield and Tecno AO Antenna. The former is a barrier shield that tests show does reduce radiation into head significantly, depending on what level of power the phone is using. The Tecno device aims to boost the body’s ability to cope with the radiation and aims to reduce the effects of the 217Hz pulse, which tests show it does mitigate. Both provide research to back up their claims.
Given the evidence that already exists, the research yet to be done, and the considerable uncertainty over the validity of current guidance, some sort of protection, especially for young people, is wise, as well as keeping calls as short as possible. Considering the organs involved I would strongly suggest it is worth erring on the side of caution: you are talking about cumulative, pulsed RF radiation into your head, eyes and other organs possibly every day for the rest of your life! For children, especially, that will hopefully – be a very long time.
1. Mobile Phones and Health. IEGMP (Chair: Sir William Stewart), 2000. Full report at website: www.iegmp.org.uk. Also available from the NRPB, price f20; ring (01235) 831600.
2. R. Coghill. Mobile Phones and Health: why the missing evidence? Electromagnetic Hazard & Therapy (I ).I I. 2000.
3. Comparison o(analogue and digital mobile phone users and symptoms. A Swedish Norwegian epidemiological study. Kjell-Hansson Mild et al, National Inst. Of Working Life, Umea, Sweden, Arbetslivsrapport 23. 1998. Email:firstname.lastname@example.org for details and cost.
4. Salford L et al. Permeability of the blood-brain barrier by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50, 200 Hz. Microsc. Res Tech. 27:535-42. 1994.
5. Lai H & Singh N. Single- and double-strand DNA breaks in rat brain cells after acute exposure to radiofrequency electromagnetic radiation. Intern J Radiat Biol. 69:513-21. 1996.
6. Preece A et al. Effect of a 915MHz simulated mobile phone signal on cognitive functioning man. Intern] Radiat Biol. 75(4):447-56. 1999.
7. Tattersall J et al. The effects of radiofrequency electromagnetic felds in the electrophysiology of rat brain slices in vitro. EE Science meeting, 28 June 1999, London, ref: 99043. CBD Porton Down.
8. Daniells C, de Pomerai D et al. Transgenic nematodes as bio-markers of
9. Mobile Phones and Public Health, Select Committee report, House of Commons (no 489). Either ring 0345 023474 (credit card) or write to: Stationery office, Box 276, Publications Centre, London SW8 STD. In two volumes, approx. f20. Also website: www.parliament.uk/commons/selcom – go to Science and Technology Committee.
10. Report in Electromagnetic Hazard & Therapy I-2:3. 1999.
About the Author
Simon Best MA is the editor of Electromagnetic Hazard & Therapy News Report. Simon Best has a background in psychology and is coauthor, with biophysicist Dr Cyril Smith of Salford University, of Electromagnetic Man: health and hazard in the electrical environment (Dent, 1989), which won the Journal of Alternative & Complementary Medicine Book of the Year award in 1990. Although currently out of print in English (available in libraries and via the authors) it is published in French and Italian. Since the book, he has edited and published for 10 years the quarterly news report Electromagnetic Hazard & Therapy which covers all aspects of electromagnetic pollution as well as the positive uses of electromagnetism in various therapies.