U.K. Study Examines RF Field Exposure

The final report from the United Kingdom's largest program of research into possible health risks from RF emitted by mobile phones and base stations was published recently and found no evidence of biological or adverse health effects.

The report found no evidence to link exposure to RF emissions from wireless base stations during pregnancy with early childhood cancer development. It also found that use of mobile phones does not necessarily lead to an increased risk of leukemia.

The research not only examined RF exposure, but also the impact of different modulation types and even the impact of low frequency magnetic fields from mobile phones. No effect on cells or tissues was found during any of the experiments for any of the modulation types. The report concluded: “Taken together, we believe that the results from these eight studies constitute a substantial body of evidence that modulation does not play a significant role in the interaction of RF fields with biological systems. This conclusion has extremely important implications as it provides a reasonably high degree of confidence that the results obtained with a modulated signal characteristic of one communications system can be extrapolated to exposures from other systems operating at similar frequencies.”

The introduction to the report of the Mobile Telecommunications and Health Research Programme stated: “Over a period of 11 years, the MTHR Programme has supported 31 individual research projects that between them have resulted in almost 60 papers in peer-reviewed scientific journals. All but one of the research projects is now complete, and the Department of Health has decided that this is an opportune time to bring research on mobile phones and health into its mainstream research portfolio.”

One of the tests I found interesting was the measurement of non-linear response of cells and tissues to RF by measuring the second-harmonic energy generated. A doubly resonant cavity was used to trap any second-harmonic energy generated and very sensitive equipment was used to detect the energy. The stated result was:

“As expected, positioning a Schottky diode within the cavity resulted in the generation of a strong second harmonic response. Similar experiments with seven different cultured cell lines (adherent and non-adherent) and thin slices or sections of eight different tissues did not produce detectable second harmonic responses; all the cells and tissues were tested to show they were still alive at the end of each exposure.”

The study also found that use of a “hands-free kit” reduced exposure.

“The work we supported resolved once and for all the question of whether hands-free kits could be used to reduce exposures. The magnitude of the reduction was sufficiently large relative to differences between individual hands-free kits that we are confident that a general principle has been established. It was also shown that a ferrite bead, correctly positioned around a hands-free cable, would further reduce exposure. The research team responsible for this work kindly made the data available to the appropriate standards committee and we see no need for further work on this issue.”

Regarding the low-frequency magnetic fields, the Report concluded: “The work on low frequency magnetic fields demonstrated that these fields are relatively small, particularly when compared with fields from other appliances held near the head, such as electric razors and hairdryers. We do not see further work in this area as a priority.”

While the study should go a long way in reducing the fear of health impacts from mobile phone use, the Report listed five priority areas for further research:

• Studies of long-term behavioral/neurological outcomes in children and/or adolescents in relation to mobile phone usage

• Provocation studies on children

• Provocation studies to identify neurological mechanisms underlying possible effects of mobile phone signals on brain function, including sleep and/or resting EEG

• Studies in suitable animal models of the effects of early-life and prenatal exposure on development and behavior

• Studies in suitable animal models of effects on aging and neurodegenerative diseases

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.