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HEALTH HAZARDS FROM WEAK NON-IONISING ELECTROMAGNETIC RADIATION regarding mobile telephony base stations |
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by Roger Coghill MA (Cantab.) C. Biol. MI Biol. MA (Environ. Mgt.) Originally published in March 1998 This report presents the present scientific evidence of adverse health effects from chronic exposure to mobile telephony base stations and other microwave installations. 1.1 Ever since the first deployment of radar in the 1940s there have been persistent reports of adverse health effects from microwave (MW) exposure at weak power flux densities. These include the carcinogenic irradiation of the Moscow US Embassy in the 1950s, reported over-representation of Downs Syndrome children near radar installations in the 1960s, a concerned conclusion by the US Congress subcommittee on Electromagnetic Radiation Management and Control (ERMAC) in the 1970s, and a large scale Chinese study of immune competence among young people living near MW/RF sources in the 1980s (see History section for a fuller account). 1.2 In the 1990s however, with the emergence of broadcast mobile telephony, the issue has begun to dominate both public and scientific agenda. Prior to that time many laboratory studies concentrated on MW frequencies at 2.45GHz., this being the frequency used by domestic microwave ovens. This research reported a wide variety of adverse effects on animals. Aside from one large Polish study published in 1988 and followed up in 1996, and several animal studies of both negative and positive outcome, however, the epidemiology of mobile phone handset usage and base station exposure has been minimal. The $25 million initiative announced by the US Cell phone industry in 1992 fell far short of its declared research objectives, leading to media criticisms. Only in the last year (1997) have large scale research initiatives been announced to address this issue, with new multi-million dollar programmes announced by the EU, WHO, and the Australian Government, though results will take upto five years to report. In the UK a pilot project has just been awarded by the Dept. of Health specifically seeking to establish whether there are adverse effects on human volunteers from mobile telephone handset exposure. 1.3 The thermal effects of MW exposure at levels of field strength sufficient to heat tissue are now well accepted, and form the basis of most but not all present advisory standards, guidelines, and limits. Nevertheless it is also accepted that resonant effects exist below these thermal levels, and this is evidenced by recommendations from the US Environmental Protection Agency (EPA), the World Health Organisation (WHO), The US National Council for Radiological Protection and Measurement (NCRP), and the Federal Drug Administration (FDA). A subcommittee (SC228) of the Institute of Electrical and Electronic Engineers (IEEE) is still considering the scientific evidence. 1.4 The adverse effects of whole body resonance as a concept (between say 40-120 MHz. for human beings) has already to some extent been incorporated into standard-setting, but it is now being appreciated that organ resonance and even smaller corporeal components are vulnerable to "hot spots" at higher frequencies than those involved in whole body resonance. 1.5 This in turn implicates mobile telephone frequencies: the resonant frequency of the human infant skull for example is around 700-800MHz., whereas many mobile phones irradiate at nearby frequencies around 900 MHz. Laboratory studies are beginning to suggest that power density may not be the correct biological effector, but rather that frequency, (particularly when modulated at ELF frequencies) has an important role to play in observed adverse health effects. Damage to hormone synthesis systems as melatonin (MLT), to key enzymes such as ornithine decarboxylase (ODC), to the nuclear DNA macromolecule implicating mutation or solid tumour formation, to the blood brain barrier (BBB), to immune competence and teratogenicity, and in cataract formation are among the studies now in the scientific literature, with some already replicated in several laboratories. 1.6 Some proposed mobile phone base stations consist of three antennae, of undeclared wattage output, but of presumably frequency of 900MHz. and/or 1.8GHz., these being the frequencies usually allocated to mobile telephony. It would be of assistance to have better information in this regard. 1.7 Without knowing the antennae's equivalent radiated power output one cannot calculate the power density at a given metres distance, and in any case this is unlikely to be more than a crude estimate, since it is time-dependant. There is little doubt however that such radiations are far lower than levels which might induce thermal effects. 1.8 Guidelines, standards, and regulatory limits exist in some parts of the world for avoiding thermal effects by occupational groups and the public, though these guidelines differ greatly between authorities (which examples the present uncertainties over the correct metric to be applied). 1.9 There is an increasing body of peer reviewed scientific literature reporting adverse health effects from RF/MW exposures well below thermal limits, particularly when modulated at ELF frequencies. These adverse effects include severe and persistent headache, depressive illness, asthenias, loss of short term memory, Downs syndrome among neonatal exposees, myeloid leukaemias among adults, myalgic encephalomyelitis, and more recently lowered melatonin synthesis, permeabilisation of the blood brain barrier, increased incidence of lymphoma and solid tumours of the brain. Major studies reporting these are attached as an appendix. CONCLUSIONS 1.10 Against a background of increasing scientific concern and new important research endeavours to reach answers sufficient to form a basis for better standard-setting, this report evaluates the latest scientific literature, examines possible effects from installations on vicinal populations, and recommends prudent avoidance by relocation of the masts into adjoining areas such as public parkland. THE SCIENTIFIC BACKGROUND 3.1 Results of major research studies in bioelectromagnetics are reported at the annual meetings of the Bioelectromagnetics Society, the biennial congresses of the European Bioelectromagnetics Assocation, their quinquennial World Congresses, and an increasing number of smaller conferences in different parts of the world, mostly organised by establishment institutions such as the IEE in the UK, The IEEE in the US, or by various Government agencies such as the Dept of Energy Contractors' Review. Anyone pretending competence in bioelectromagnetics should as a prerequisite be familiar with the ongoing dialogues in these fora, or better still be an active presenter of research to this community. It is noteworthy that the NRPB do not routinely attend EBEA meetings, have not attended the latest DoE reviews, and the majority of their publications are not peer reviewed. 3.2 It is also important to recognise that scientists familiar with ionising radiation are part of a quite different set of disciplines whose literature rarely merges, with only a few journals covering both parts of the EM spectrum. Scientists familiar with ionising radiation therefore are not likely to be equally familiar with bioelectromagnetics, and should not be construed as expert. 3.3 There are some 600 members of BEMS and some 300 of the EBEA, with a few dozen belonging to both. These scientists form the core of global bioelectromagnetics research, and it is disappointing that of these only about six EBEA members are from the UK, reflecting a dearth of expertise in that country. BIOLOGICAL MECHANISMS OF INTERACTION 4.1 A recent letter in the Irish Times (18 February 1998) from Professor Philip Walton of Galway University Physics Dept. well illustrates the viewpoint of physicists approaching the issue of mechanisms for the first time without familiarity with bioelectromagnetics literature. Such arguments are by no means new, having been first propounded as early as 1964 (Barnothy, 1964). 4.2 Walton argues that a person exposed to radiation from a typical ESAT base station would experience a temperature rise at the most of 0.004 degrees, less than that of light manual work. Moreover he points out that the human body itself gives out some 0.3 mW/cm2 at 300MHz., three times the base station power flux density. Finally Walton argues that we have been exposed to TV transmissions for over 50 years, often located in built up areas, and then claims that the Dolk 1997 results (which studied 21 TV and RF transmitters in relation to cancer risk) "could find no significant health effect". 4.3 In fact the Dolk studies covering the period 1974 to 1986 reported significant over-representation of adult cancers (principally leukaemias - Odds Ratio 1.83 within 2 km.- skin cancers and cancers of the bladder) with significant declines in risk with distance from four of the transmitters (Sutton Coldfield, Wenvoe, Rowridge and Crystal Palace) and excess risk near two more (Sandy Heath and Winter Hill), and concluded that the two studies gave very weak support overall to the existence of an association between adult cancer exposure. Incidence before 1974 was much lower, and in any case most UHF TV transmitters only began broadcasting in 1965, only about 33 years ago (not over 50 years ago!), only achieving three frequencies by 1971. 4.4 Physicists have been puzzled that such weak energies, too weak to break chemical bonds, clearly have biological effects. They have not taken into acount that Nature has, through evolutionary development, prepared organisms for using electrons, charges, and magnetic fields in a variety of ways. For example the magnetic sensitivity of marine mammals like whales enable them to find their basking grounds across featureless oceans using the geomagnetic field of the earth. The ampullae of Lorenzini in sharks are sensitive to one millionth of a Volt per metre, whereby they can detect their prey, a talent shared by the humble duck-billed platypus, similarly sensitive to worms' electric fields in the topsoil. Indeed, exquisite electromagnetic sensitivity in fishes, birds, insects and mammals, and their application in navigation predation and mating has been reported for some decades (e.g. Lissmann, Machin et al., 1958; Callahan, 1965; Warnke, 1989, etc), even without taking the obvious examples of glow worms and fireflies into account. 4.5 Nearly all the energy normally produced by a human body is achieved via mitochondrial synthesis of adenosine triphosphate (ATP). To judge from oxygen consumption some 40 percent of ATP is made in the brain. The process is dependent on electron transport, and recent studies have shown that imposition of an external electric field depolarises the mitochondrial membrane, lowering ATP production. This kind of effect plausibly explains the asthenias commonly reported by microwave exposed subjects. Moreover positive ions affect blood rheology (Glaser, 1993), and hence the bioavailabliity of molecular oxygen, (which acts as a final electron acceptor in ox-phos pathways). There is evidence that severely lowered oxygen availability is by itself carcinogenic (Warburg, 1936; Goldblatt & Cameron, 1952). 4.6 Furthermore there is also now evidence that exposure to cell phone frequencies lowers daytime melatonin production in human subjects (Burch, Reif et al., 1997), yet another candidate for explaining how such weak fields are influencing organic life. Several laboratories have shown EM field effects on melatonin at a cellular level (Blask, 1988; Liburdy, 1997; Luben, 1997 etc.). 4.7 Another is the radical pair hypothesis advanced by Wallaczek in California and separately by MacLaughlan at Oxford. He suggests that weak magnetic fields may slow down the recombination of electron pairs split during normal chemical reactions sufficiently to create damaging free radicals within tissue, leading to carcinogenesis. In this context it is noteworthy that ubiquinone (an ubiquitous electron transport coenzyme in the Warburg-Dickens ox-phos pathway) operates by temporarily converting to a free radical (ubisemiquinone) during its normal function. 4.8 Furthermore (but by no means finally) it is known that weak electric fields affect intracellular calcium, an important second messenger used in a wide variety of organic processes. For example, the indispensable dehydrogenases early in the ox-phos chain are calcium dependent, and are therefore rate limiting for ATP synthesis, so altered Ca2+ levels in mitochondrial inner membranes will also affect ATP synthesis (Parratt, 1985). 4.9 Given this plethora of natural processes affected by weak non-ionising EM fields and radiation, it is not surprising that no single mechanism enjoys consensus: the truth is likely that the novel exposure of mankind to alternating electric fields and radiation, a feature of evolutionary history unique to this century and now acknowledged far to exceed influences from the earth or the solar system (NRPB, 1992), is an event for which we are not prepared by evolution, with inevitably adverse sequelae. REGULATORY STANDARDS, GUIDELINES, AND LIMITS 5.1 The extent of regulatory uncertainty regarding RF/MW radiation hazard is well illustrated by the variety of uncoordinated standards, guidelines, and limits in force in different parts of the world. The table below sets out some of these where they relate to exposure of the public. In some countries occupational exposures are substantially different from those for public exposure.
Source: Powerwatch, 1998 5.2 It can be seen that there is a great discrepancy between different authorities, with miscellaneous experts advocating far lower limits than the NRPB whose investigations levels are way above those elsewhere in Europe. These experts include The US Environmental Protection Agency and the US Federal Drug administration, who have long argued that thermal limits do not represent adequate protection, and that athermal effects must also be considered. The US National Council for Radiation Protection and Measurements (NCRP) is expected to issue a detailed report on RF/MW frequency health effects and advice in the near future, and sources close to its committee indicate that it will also be advocating limits based on athermal effects. 5.3 Powerwatch point out that the maximal natural thermal background, despite having increased dramatically in the post war period, at 900-1800 MHz. is still only somewhere between 10-30mV/m (equivalent to 20dBmV/m and 30 dBmV/m) based on 20-200 attoWatts/cm2 per MHz. 5.4 The man-made "electrosmog" level is usually below 100mW/m (40dBmV/m), with even very strong broadcast TV transmitter (e.g. at 500MHz.) or FM radio transmitter (e.g. at 100MHz.) signals not exceeding 0.1 V/m (100dBmV/m). The maximum levels in public places from a cell phone base station are usually between 100 and 120dBmV/m (0.03 to 0.3 V/m) though levels near base stations have been measured at upto 140bDmV/m (10 V/m) which would mean peak levels of 20-50V/m due to the pulsed nature of GSM. 5.5 The CENELEC limits of 41 V/m at 900MHz. (58V/m at 1800MHz.) are designed only to protect against thermal effects. In order to approach a practical solution taking into account non-thermal effects Powerwatch of Cambridge suggests a limit of 1V/m between 100MHz. and 2GHz., which should not prove onerous for cell phone companies. 5.6 In placing these emissions in the context of recent literature, it is instructive to read the views of the Expert Group set up by the European Union (see below). PRESENT RESEARCH INITIATIVES 6.1 In response to scientific and public concerns a number of important institutions have announced large research initiatives during the last year. Details of these and others are set out below. The European Commission 6.2 Between January and September 1996 the European Commission-appointed Expert Group prepared a 140 pp. report proposing a research programme to investigate possible health effects related to the use of radiotelephones (mobile phones). Their preface acknowledges that though a large database exists for ELF EM field health effects, there are "far fewer data for radiofrequency (including microwave) fields, and very few indeed related to the emissions and exposures specific to radiotelephones. A comprehensive health hazard assessment requires such data". 6.3 The Expert Group included Professor Bach Anderson from Aalborg University, Professor Kjell Hansson Mild from National Institute for Working Life, Sweden, Dr Bernard Veyret from Bordeaux University and seven others including Dr Alistair McKinlay from NRPB. The timescale envisaged by the group was 1-4 years, with epidemiology likely to exceed this period, and a budget of 23,813,000 ECU (divided 15.6m for biological, 7.5m for epidemiology, and 0.7 m for management.). 6.4 The detailed considerations of the Expert group are too many to discuss here, but clearly identified a number of studies on which their concerns are based, and cited well over 200 scientific studies. For example the Group noted that tube restrained (i.e. stressed) mice exhibit important changes in white blood cells, with leukocyte migration to the skin (Dhabar & McEwan, 1995) and that RF exposure may therefore affect leukocyte competence in near skin tissue. Sleep disturbance and hypersensitivity issues were also raised, but Genetic, Cancer, Immune system and Nervous system studies were the main categories recommended for in vivo biological research. 6.5 The Expert group review of epidemiological studies of brain cancers in relation to RF exposure identified 11 studies, only three of which failed to show an elevated incidence of risk. Four other studies are still ongoing, though results of the first of these to report (a 10,000 questionnaire survey) has been delayed for re-analysis. World Health Organisation (WHO) 6.6 The WHO drafted and agreed a 5 year research proposal, and by June 1996 over 20 countries were actively involved, with funding currently available for only two years, implying an ongoing funding requirement. International Commission on Non Ionising Radiation Protection (ICNIRP) 6.7 This ongoing body is chartered by the International Radiation Protection Association (IRPA) and mainly reviews the compliance of emissions from devices including mobile telephones and base stations with recommended exposure guidelines. Cooperation on Science and Technology (COST 244) 6.8 The research programme currently includes 21 countries and is involved in cooperative research between eastern bloc countries and the West. The first programme having come to an end, it has now been renewed and is now under the umbrella of the EU's Technical Committee for Telecommunications, thereby increasing the emphasis on RF studies. LINK-Interaction of the body with handheld radiotelephones (IBREHT) 6.9 This UK research programme was initiated by the UK Govt.'s Dept of Trade and Industry, and has completed three studies of interactions between phones and the human head, using phantoms and numerical models. 6.10 Other bodies such as Forschungsgemeinschaft Funk (FGF), Wireless Technology Research (WTR), have or are also carrying out research, as well as individual University and private laboratories, but not to any extent on base stations. The Expert Group identified some 49 separate research groups, but none from the UK. Nevertheless, the vastness of the current European research programme alone underscores the importance and uncertainties regarding adverse health effects from exposure to mobile phones and their associated base stations. The outcome of these programmes is not likely to be less than four years from now. WIRELESS TECHNOLOGY RESEARCH: Failure to research? 8.1 In 1992, following intense US media coverage of a legal case where one David Reynard claimed his wife had died of a phone-engendered brain tumour, and mobile phone sales and stocks plummeted, the cell phone industry announced a five year 25 million dollar research initiative. Base stations were not included. 8.2 The research was instituted under a company designated Wireless Research Technology Ltd. and was to be funded by participants from among the US and global mobile phone manufacturing industry. Its directors included Bill Guy, a veteran researcher into RF/MW radiation bioeffects, who had reported increased tumour formation (but few other differences out of 155 parameters) in a large gnotobiotic rat study of long term low level microwave irradiation reported in 1985, but published only in 1992 (Chou, Guy et al., 1992). 8.3 However it gradually emerged during the 1990s that most of the WTR funding, under the direction of George Carlo, had been spent on PR and that funding promises to researchers in the field were not being honoured. This culminated in a 12 minute Canadian TV programme broadcast in September 1997 which savagely indicted the cell phone industry for deceiving the public over health risks. 8.4 Among studies completed by WTR participants (in this case Motorola Inc.) and reported at the 2nd. World Congress (Bologna, June 1997) was a major study (Adey, Byus et al., 1997) of 540 Fischer344 rats exposed in a radial cylinder exposure system to c. 836MHz. The rats were exposed to a speech-modulated FM signal for 2hrs daily (7.5 mins on, 7.5 mins off) from age 35 days for 23 months, then sacrificed and examined for solid tumours of the brain and neck. No "protective" effect was found (a feature suspected in a previous study by the same group) and there were no effects on brain tumour incidence attributable to the FM fields. The exposure system involved a copious supply of oxygen to the rats during exposure inside the cylinders, but the authors did not comment on the possibility that this may also have had a protective effect, since molecular oxygen is a known electron acceptor in ox-phos pathways. 8.5 Another study of 47 young male rats, this time from Japan, reported at Bologna (Shirai, Imaida et al., 1997) investigated chemically initiated liver carcinogenesis followed by partial hepatectomy and found no statistically significant EMF effects on foci numbers or area of hepatoma from six weeks exposure (90 mins/day) at 929MHz.employing a TDMA signal. The reasons for including partial hepatectomy in the protocol were unclear. In summary, the research initiative announced defensively by the US cell phone industry does not appear to have completed its declared objectives, either in terms of studies or timescale. SOME RECENT SCIENTIFIC OPINIONS 9.1 It must be clear to the reader of this report that experts reviewing a highly technical subject such as microwave exposure studies can selectively bias their conclusions, to the disadvantage and confusion of the lay reader. Evidence of this possible bias in the NRPB's literature reviews has already been identified. To balance their opinions a miscellany of recent conclusions from bodies arguably of equal expertise is given here. In January 14 1998 the Federal Drug Administration (FDA) wrote to Congressman Edward Markey stating their belief that additional research in the area of RF exposure is needed. Markey, a member of the House telecommunications subcommittee, had asked a number of questions about the status of this research and the performance todate of WTR. The FDA appears reluctant to endorse a continued role for WTR in investigating health related effects, and WTR itself has announced it will not conduct any further long term animal studies, blaming a lack of funds. By contrast the Swedish Radiation Protection Institute (SSI) issued a flyer in December 1997 concluding that mobile phone base stations do not constitute any risk to health. In Sweden the general population can be exposed to upto 450microW/cm2 . In Australia Dr. Andrew Davidson of Fremantle Hospital proposed in a letter (January 5 1998) to the Australian Medical Journal that a rise in brain cancer in Western Australia between 1982 and 1992 may be linked to the introduction of analogue mobile phones, and a 1992 -1995 decline may reflect the introduction of digital models. He called upon Telstra, Australia's largest phone company, to conduct a full epidemiological survey among users, of which there seems little prospect. Moreover the number of analogue users is still at the same level as 1991, so the argument is not clear cut. In the UK a small (£3000) contract has been awarded to Dr. Alan Preece at Bristol University to investigate psychosocial parameters in a 18 subject human mobile phone user study. This is apparently part of a £100,000 research effort largely being carried out without publicity by scientists at Porton Down, which was leaked to the media in February 1998. Preece does not expect to find any positive results. SUMMARY OF RELEVANT RESEARCH PAPERS 10.1 Daily, 1943: This early and rare clinical study published by the US Navy reported that exposure of 45 laboratory technicians to RF/MW frequencies between 400MHz. and 3000MHz. led to possible nervous system effects. A later study of 65 subjects exposed to 3mW/cm2 at 300-3000MHz. for between 2 - 26 years confirmed these findings (Ginzburg, Sadchikova et al., 1968). 10.2 Harwey, 1960: In the early days of microwaves this study reported the appearance of temporary or permanent sterility when animal (rat) testes were exposed to microwaves. Other 1960s studies reported decreases in germinal epithelial tissue enzymes (Ceciura & Minecki, 1969), and recommended copper mesh protection (Miro & Delahaye, 1967). 10.3 Drohicina, 1965: This early study of 1000 human subjects with more than 5 years exposure to VHF EM fields found as the main symptom an over-representation of asthenovegetative states with EEG alterations in the severest cases. 10.4 Silverman, 1973: This early FDA review in the American J. Epidemiology points out that US studies of MW bio-effects virtually ceased after the 1950s, but discusses the various effects being reported in the Eastern bloc from MW exposure at less than thermal levels, including cataractogenesis, auditory, and olfactory threshold changes, severe neurosis, and astrocytoma of the brain. It quotes nine clinical studies (total n = 1219) of chronic MW exposure from Czechoslovakia, Poland, the USA and Russia. All but one of these found adverse effects, including four showing EEG changes and four neurological effects. 10.5 Lankranjan, Maicanescu et al., 1976: This study from the Bucharest Institute of Hygiene and Public Health reported that gonadic function in 31 workmen with long term occupational exposure to microwaves was significantly impaired when measured by a number of criteria, including spermatogenesis and lowered sexual libido. 10.6: Robinette, Silverman et al., (1980): This negative study compared some 20,000 Korean War personnel during 1950-1954 with possible exposure to radar with a like number with little exposure, but could not establish actual exposure profiles. Using hospital records only one statistical difference was found, namely mental condition, and this was at a higher rate for the low exposed group. The authors stressed the need for better exposure data. 10.7 Lin, Dischinger et al., 1985: This large study examined the EM field and radiation exposure levels of 951 white male Maryland residents who had died of brain tumours between 1969 to 1982. In cases of glioma and astrocytoma (n=519) only those occupationally involved in electrical or electronic engineering showed a statistically significant excess of brain tumours compared with controls. 10.8 Milham, 1986: Registry analysis of leukaemia deaths among 1691 male ham radio operators in Washington State and California between 1971 and 1983 revealed a proportionate mortality ratio of 191, nearly twice the expected level. 10.9 Chiang, Yao et al., 1989: This Chinese tri-university epidemiological study of 1170 young persons living near RF/MW sources used an objective phagocytosis test to measure immune competence. The authors reported that neutrophil phagocytosis was enhanced in the low intensity exposure groups, but reduced significantly at relatively high intensities. The power densities ranged from 0-4microW/cm2 (low) to 42microW/cm2 (high). Moreover, after MW exposure of above 10microW/cm2 the pupils' visual reaction time was slowed and memory test scores were lower. The authors concluded that EM fields may affect the central nervous and immune system in man. 10.10 Salford, Brun et al., 1992: In this study live rats were exposed to microwaves and then assessed for permeability of the blood brain barrier (BBB) by means of a dye. Exposed animals showed more permeable BBBs than non-exposed controls. 10.11 Kues, McLeod et al., 1988; Monahan, Kues et al., 1988: This series of FDA studies found that exposure of monkeys to 2.45GHz microwaves at 10mW/cm2 produced vascular leakage. 10.12 Lai and Singh (1995): Brain cells from rats were exposed to 2.45GHz. radiation at 3mW/cm2 and assessed for DNA single strand breaks. Four hours afterwards the level of single strand breaks was significantly higher in the exposed cells. Single strand breaks in DNA can lead to carcinogenicity, cell death, and ageing. Since the effect was only seen immediately when continuous wave (but not pulsed) microwaves were used, the authors concluded that parameters other than simple power density are at work. 10.13 Szmigielski, 1996: Arguably the largest and most recent occupational study of long term weak microwave exposure, covering some 127,000 Polish military personnel between 1971-1985, the author reported a significant doubling of odds ratio of cancer morbidity among all age groups, with a 6.1 odds ratio for lymphatic malignancy and 1.91 for brain tumours. The largest odds ratio (13.9) was for chronic myeloblastic leukaemia with acute at 8.62, and non-Hodgkins lymphoma at 5.82. 10.14 Kolodynski & Kolodynska, 1996: This Latvian study examined the motor and psychological functions of 966 schoolchildren exposed to large radar surveillance transmitters at Skrunda and compared these with unexposed children behind the beam. They found that the younger children had significantly slower reaction times, ability to remember, and attention span. 10.15 Repacholi et al., 1997: This Australian study of transgenic mice reported a doubling of lymphoma in mice exposed to EM frequencies similar to those used in mobile telephony. 10.16 Dolk, Elliott et al., 1997; Dolk, Shaddick et al., 1997: Twin studies of cancer risk with increasing distance from major TV transmitters found significantly increased risk for adult leukaemias, skin melanoma and bladder cancer with proximity to Sutton Coldfield, Wenvoe, Crystal Palace and Rowridge, and an excess of risk generally within 10 km. of these masts for bladder cancer. Though skin melanoma showed an excess (1.11OR) within 2 km., curiously there appeared a deficit of risk (0.9 OR) for skin melanoma, at 2-10 km. Other transmitters with RF frequencies showed no similar effect. The estimated power densities at these sites range from 0.05 to 1.6 microWatts/cm2. 10.17 Burch, Reif et al., 1997: This new joint study of 142 power utility workers by Colorado State and Washington Universities reported substantially lowered daytime melatonin (MLT) synthesis as recorded by urinary excretion of its metabolite 6-OHMS/cr. among frequent users of mobile phones compared with low or non-users. The significance of this finding is that MLT is an oncostatic (cancer-prevention) hormone, and its lowered synthesis may lead to increased cancer risk. Literature reviews 10.18 ICNIRP ((R. Matthes, Ed) 1996: This collection of papers from the proceedings of the 3rd. International Non-ionising Radiation Workshop, Baden Austria, 1996 covers the entire spectrum, with a section on RF containing four papers including a review of biological effects of RF fields by Saunders (NRPB). This paper concludes that "the effects following exposure to low level radiation have not been well established and are not considered able to provide a basis for restriction on human exposure". 10.19 Mobile Communications Safety, 1997 (Kuster, Balzano, and Lin, eds.): This recent 279pp. book presents 13 papers and covers the ground comprehensively, though without full consensus between authors. For example, Byus and Hawel conclude that weak bioeffects cannot be dismissed out of hand, whereas Bergqvist's review of the epidemiology (which omits several studies referred to in S10 below) concludes that further restrictions are not justified. 10.20 Cherry, 1997: Most of the laboratory and human studies, as well as many others (194 refs.) are reviewed in this paper from Lincoln University, New Zealand, particularly those at power densities below 2microWatts/cm2. The author recommends a limit of 0.1microWatts/cm2 if cancer risk is to be avoided, and that mobile telephony masts be located away from residential areas.. TECHNICAL CONSIDERATIONS 11.1 In the opinion of some scientists (e.g. Powerwatch February 1998)) the biological (as opposed to thermal) limit for human exposure to RF/MW base station emissions should be in the order of 1V/m. Though the precise radiative parameters of the proposed mast at Vicarage Gate have not been submitted in the planning application, typical base stations emissions are set out in the table below: 11.2 Calculated maximum field strengths for Base Stations
Source: European Commission Expert Group, November 1997 11.3 The above table was based on a distance of 58 metres, 10 channels for the digital systems and 40 for the TACS system. It would be sensible to obtain from the proposers the necessary information to calculate field strengths more precisely. 11.4 The present (1988) ICNIRP/IRPA guidelines for 900MHz and 1800 MHz respectively are 41 V/m and 58V/m, based on thermal considerations only. A worst case situation would mean exposures of around 3-4 V/m. at around 50 metres, but actually emissions from most installations at that distance would in practice not often exceed 1V/m., and it could be that the proposed mast might be redesigned and so arranged as to meet these prudent limitations. LEGAL ASPECTS 12.1 The legal implications of mobile telephony base station mast erection near to vicinal residences raises the issue of toxic tort. The research so far carried out by the mobile phone manufacturing industry has almost entirely been confined to handsets, and not to effects from radiation by base stations. Indeed, though similar risk considerations apply to mobile phone handsets, where there is some justification for arguing that while alleged adverse health effects from handsets are being investigated these appliances, arguably the most radiative ever in public use, should carry warning labels in order to comply with section 10 of the provisions of the Consumer Protection Act 1987. 12.2 Attitudes by Local Planning Authorities vary considerably. The most recent (March 1998) planning decision, by Brentwood Council where an application by Orange (Hutchison Telecom) was being considered some 15 metres from a school, was to reject the application by 32 votes to one, with one abstention. The Council passed a motion as follows: 12.3 That the officers should: Refuse on the ground that the presence of two masts in such close proximity to one another would have an unacceptable visual impact within the Green Belt. Write to the Secretary of State demanding an immediate review of PPG8 and in particular to include safety guidelines in a new PPG8. Lobby other Planning Authorities to write to the Secretary of State as in 2. Above. If the Secretary of State does not act in relation to the safety of Telecommunication masts, to examine ways of enforcing the Maastricht Treaty through Europe if necessary. To table a motion at the Local Government Association in respect of the safety concerns relating to Telecommunication Masts. 12.4 This resolution is interesting in that though the grounds for refusal are given as visual impact, which avoids the objection that health and safety are not legitimate grounds for refusal, the remainder of the motion clearly implicates health concerns. EXECUTIVE SUMMARY This report presents the present scientific evidence of adverse health effects from chronic exposure to mobile telephony base stations and other microwave installations. 1.1 Ever since the first deployment of radar in the 1940s there have been persistent reports of adverse health effects from microwave (MW) exposure at weak power flux densities. These include the carcinogenic irradiation of the Moscow US Embassy in the 1950s, reported over-representation of Downs Syndrome children near radar installations in the 1960s, a concerned conclusion by the US Congress subcommittee on Electromagnetic Radiation Management and Control (ERMAC) in the 1970s, and a large scale Chinese study of immune competence among young people living near MW/RF sources in the 1980s (see History section for a fuller account). 1.2 In the 1990s however, with the emergence of broadcast mobile telephony, the issue has begun to dominate both public and scientific agenda. Prior to that time many laboratory studies concentrated on MW frequencies at 2.45GHz., this being the frequency used by domestic microwave ovens. This research reported a wide variety of adverse effects on animals. Aside from one large Polish study published in 1988 and followed up in 1996, and several animal studies of both negative and positive outcome, however, the epidemiology of mobile phone handset usage and base station exposure has been minimal. The $25 million initiative announced by the US Cell phone industry in 1992 fell far short of its declared research objectives, leading to media criticisms. Only in the last year (1997) have large scale research initiatives been announced to address this issue, with new multi-million dollar programmes announced by the EU, WHO, and the Australian Government, though results will take upto five years to report. In the UK a pilot project has just been awarded by the Dept. of Health specifically seeking to establish whether there are adverse effects on human volunteers from mobile telephone handset exposure. 1.3 The thermal effects of MW exposure at levels of field strength sufficient to heat tissue are now well accepted, and form the basis of most but not all present advisory standards, guidelines, and limits. Nevertheless it is also accepted that resonant effects exist below these thermal levels, and this is evidenced by recommendations from the US Environmental Protection. The saga will no doubt continue... |
