Q In WDDTY vol 5 no 3, your cover story on power lines gave evidence that exposure to electromagnetic fields was harmful to people, particularly children. I was wondering whether electromagnetic fields are the same as the electromagnetic radiation transmitted from mobile phone masts. I live in the centre of Warminster practically next door to a B7 building. They have recently installed four mobile phone masts on the roof of their building, and plan to install several more over the next few months.
Does WDDTY know of any research which shows these masts to be harmful? - AP, Wiltshire
A Are you sitting comfortably? Then we'll begin. We spoke to the UK's acknowledged electropollution and magnetotherapy guru Roger Coghill, founder of Coghill Research Laboratories (www.cogreslab.co.uk), whose family coat-of-arms motto is 'Non dormit qui custodit' (roughly translated as 'No peace for the guy looking after the place'), which seems rather appropriate.
'The difference between electromagnetic fields [EMFs] and electromagnetic radiation is that, with the field, the energy doesn't actually leave the source whereas, with radiation, the energy forms a closed loop that leaves the source entirely. That's the basic difference,' he says, 'so that radio frequencies (radiation) completely escape the transmitting antenna.
'But the thing is that these antennae don't only emit radio frequencies, they emit a cocktail of frequencies which include very long (or extra-low) frequencies [ELFs],' he adds. 'These are the components in the signal so, in that case, a radio mast of the kind used in cellphone telephony comprises both a field and a signal. Both of these are imposed upon anyone within a kilometre or two (in the case of radio frequencies) or hundreds, if not thousands, of kilometres (with ELF fields).'
The Missouri-based American EMF guru Roy Beavis (http:/emfguru.org), says the difference between the EMF of power lines, and the electromagnetic radiation of cell phones and their towers is a difference of frequency (wave length). So, does that 'difference' introduce any significant health risks? 'We don't know for sure,' he says. 'Perhaps - and, if so, it seems likely to be as a matter of degree mainly. They both have the same physical or radiation characteristics. There has been more study of power-line exposures than of cellphone towers, though I regard the present evidence as sufficiently convincing in the case of cellphones per se (the sets we hold in our hands to our ears). I am not so sure about the risk from the much weaker signals we get from the towers. Much more study is needed on the tower exposures.'
Radio waves, microwaves, visible light and X-rays are all examples of electromagnetic waves which are produced by the motion of electrically charged particles. These waves are also called 'electromagnetic radiation' because they radiate out from electrically charged particles. They travel through empty space as well as through air and other substances.
Children in the home are at particular risk from EMFs. Several studies have established a link between childhood cancer and exposure to electromagnetic radiation (Am J Epidemiol, 1979; 109: 273-84; Lancet, 1990; 335: 1008-12).
But adults are at risk too. Overhead power lines can concentrate pollutants in the air, raising the risk of cancers of the lungs and skin (Am J Epidemiol, 1996; 143: 841; Int J Radiat Biol, 1999; 75: 1505- 21, 1523-31).
Professor Denis Henshaw, of Bristol University's Human Radiation Effects Group, took 2000 field measurements and found that the toxic effects of EMFs could extend up to more than 100 yards (91 metres) on either side of power lines. He also proposed a theory as to how EMFs could cause cancer. According to Henshaw, living near power lines, where radiation levels are dozens of times the legal limit, may increase the concentrations of carcinogenic airborne particles that are produced naturally in the soil and as a result of local traffic pollution (Int J Radiat Biol, 1999; 75: 1505-21). This hypothesis is consistent with earlier research showing potentially toxic interactions between alternating EMFs surrounding power lines and radioactive breakdown products of naturally occurring radon gas (Int J Radiat Biol, 1996; 69: 25-38).
However, in the case of base stations, the government recently (March 2003) extended its lb7.4 million initiative to investigate the possible health hazards of cellphone technology to include the base stations as well, following the publication of a report by the Independent Expert Group on Mobile Phones, part of a project called the Link Mobile Telecommunications and Health Research Programme (MTHR), which was set up to look into the possible impact of mobile telecommunications on health.
This initiative includes an epidemiological study of early childhood leukaemias and other cancers near to mobile-phone base stations. As far as we know, this is the first programme of such research into this area of concern.
The government's Stewart Report highlighted public concerns and uncertainty regarding the health effects of mobile telephony, including base stations. Although levels of RF (radio frequency) radiation associated with mobile-phone base stations were thought to be low (and, in some cases, indistinguishable from background radiation), the Stewart Report noted that 'the possibility of harm from [base station] exposures insufficient to cause important heating effects of tissues cannot yet be ruled out with confidence.'
The MTHR study will determine whether or not childhood cancer cases occur more frequently near mobile-phone base stations than would be expected from the national distribution of births. But this information on its own will not be able to say whether any excess risk near mobile-phone base stations is causally linked to base-station emissions.