Research into the amount of radiation emitted by mobile phones only tells part of the story of the possible health risks associated with using the devices, according to a theoretical physicist at Warwick University.
After the publication of a study of radiation levels emitted by mobile phones carried out by the National Physical Laboratory for BBC's Panorama, mobile phone manufacturers have insisted the phones are safe to use and comply with UK safety limits. The safety limit stipulates that 10 watts of radiation energy - measured as a specific absorption rate (SAR) of 10 - can be transmitted per kg to the brain, and all the mobile phones emitted radiation levels below the limit.
However, the levels of radiation energy emitted varied considerably. Of eight mobile phones tested, the Motorola Star TAC 70 produced a SAR level of 0.02 (with the antenna extended), while at the opposite end of the scale the Nokia 2110 had a SAR rating of 0.44 (antenna extended) - 20 times higher than the Motorola. The Nokia 5110, with a fixed antenna, had a SAR rating of 0.37 and the Bosch World 718 produced a SAR rating of 0.33 with the antenna retracted.
But Dr Gerard Hyland, of Warwick University, says the research does not address the effects of other aspects of radiation energy on the body when using mobile phones. "The body is sensitive to aspects other than the intensity of microwaves, for example aspects of radiation waves not covered by safety measures. Research has shown they can alter the rate of cell division in the body and cell DNA and this is consistent with reports worldwide."
Dr Hyland insists that more research needs to be carried out to assess the health risks of using mobile phones, such as high incidences of short-term memory loss and insomnia in people living near mobile phone transmitters.
Mobile phone manufacturers Motorola, which fared well in the study, said yesterday they would not use the low SAR rating as a selling-point in future advertising. "We know that our products are safe and we are not surprised by the results," a spokesman said. "The study shows that all the mobile phones are working well below the safety limits that have been set and that's the reassuring thing that the customers should take from this."
Mr Tom Wills-Sandford of the Federation of the Electronic Industry which represents the mobile phone operators, said that despite producing a SAR rating 20 times higher than the Motorola models "the 0.44 phone was 20 times below the safety limit and both were within the guidelines".