Febrero 2003

Radiation shields for mobile phones again shown to be ineffective

In the July 2002 edition of "What's New" and in FAQ #21, we discuss the ineffectiveness of shields that are promoted to block radiofrequency radiation (RFR) emitted from mobile phones. Oliver and colleagues at Motorola Research Laboratories have tested nine such devices and found that they did not reduce the location of the peak SAR or the 1g. peak spatial average SAR.

Reference: Oliver JP, Chou CK, Balzano Q (2003): Testing the effectiveness of small radiation shields for mobile phones. Bioelectromagnetics 24:66-69.

Cell phones in enclosed areas

In the June 2002 "What's New" we discussed the subject of simultaneous use of multiple cell phones in enclosed areas such as trains. Hondou had suggested that this could create a level of exposure to electromagnetic fields that could exceed the guidelines of the International Commission on Non-ionizing Radiation Protection (ICNIRP). Now Toropainen from the Nokia Research Center in Finland refutes that suggestion with calculations that show that it would be "highly improbable" that the exposure from simultaneous use of cell phones in enclosed spaces, such as trains, elevators, or cars, could exceed the guidelines.

Reference: Toropainen A (2003): Human exposure by mobile phones in enclosed areas. Bioelectromagnetics 24:63-65.

Radio Science Bulletin on-line

The Radio Science Bulletin is now on-line and is found at www.ursi.org/RSB.htm . It is published by URSI (Union Radio-Scientifique Internationale), which is a non-governmental and non-profit agency under the International Council for Science. URSI is responsible for stimulating and coordinating studies, research, applications, scientific exchange, and communication in the fields of radio science. The September and December 2002 issues contain articles by Dr. James Lin of the University of Illinois. The September paper deals with "Health and Safety associated with personal wireless telecommunications base stations", and the December one with "The auditory perception and hearing of microwaves".

Review of mobile phones and the nervous system

The January 2003 issue of Bioelectromagnetics contains a review of the effects of EM radiation of mobile phones on the central nervous system. It is an update by Hossmann and Hermann of an earlier review in 1997. They state:

"Most of the reported effects are small as long as the radiation intensity remains in the nonthermal range, and none of the research reviewed gives an indication of the mechanisms involved at this range".

Reference: Hossmann K-A, Hermann DM (2003): Effects of electromagnetic radiation of mobile phones on the central nervous system. Bioelectromagnetics 24:49-62.

EMFs from mobile phones alter cerebral blood flow and EEG tracings

In the February 2000 and November 2000 editions of "What's New" we discussed studies from a Swiss group that examined the effect of RF radiation on EEG tracings. This group has now reported a further study. They again found some EEG changes in the exposed group compared with sham-exposed individuals, but only when pulse modulated electromagnetic fields were used. The changes were not seen with continuous wave exposure. The authors also found increase in regional blood flow in the cerebral cortex on the same side as the EMF exposure. As with the EEG findings, the blood flow increase was only seen with pulse modulated EMF. For more on this study, see "Research - Clinical Experiments - EEG, and Cognitive function".

Reference: Huber R, Treyer V, Borbely AA, Schuderer J, et al. (2002): Electromagnetic fields, such as those from mobile phones, alter regional cerebral blood flow and sleep and waking EEG. J Sleep Res 11:289-235.

Report of nerve cell damage in rats after RF radiation exposure

A group of Swedish researchers have reported that exposure to microwaves from a GSM mobile phone caused nerve damage in rats. The rats were exposed for 2 hours to electromagnetic fields of varying strength. The whole-body SARs were said to range from 2 to 200 mW/kg. The brains of the rats were examined 50 days after exposure and there was evidence of leakage of albumin through the blood-brain barrier and of nerve cell damage.

Some critical details of the experiment are lacking. For more, see "Toxicological Experiments - brain function". It will be important for this study to be replicated.

Salford LG, Brun AE, Eberhardt JL, Malmgren L, et al. Nerve cell damage in mammalian brain after exposure to microwaves from GSM mobile phones. Environmental Health Perspectives, Online January 29, 2003 (www.ehponline.org)

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