Columbia University, College of Physicians and Surgeons
Department of Physiology and Cellular Biophysics Telephone: (212) 305-3644
630 West 168 Street Telefax: (212) 305-5775
New York, NY 10032 EMAIL: firstname.lastname@example.org
April 3, 2010
An open letter to the community of El Cerrito, California
Re: Installation of a tower on the Boy Scouts campground
I have been doing research at Columbia University for over twenty five years, studying the biological effects of electromagnetic fields (EMF). I was also one of the organizers of the 2007 Bioinitiative Report on EMF that is available on the Internet. Because of this background, I have been asked to provide information about the potentially harmful effects of EMF on members of the El Cerrito community, especially children who use the campgrounds and the adjacent public playground, that would be exposed to EMF following installation of a proposed tower.
There are now sufficient scientific data about the biological effects of EMF, and in particular about the radiofrequency (RF) radiation transmitted by the tower, to argue against installation tower as a precautionary measure. We can state unequivocally that EMF can cause damage (single and double strand breaks) to DNA at exposure levels that are considered safe under the FCC guidelines in the USA. Since we know that an accumulation of changes or mutations in DNA is associated with cancer, there is good reason to believe that the elevated rates of cancers among persons living near radio and cellphone towers are probably linked to DNA damage caused by EMF. Because of the nature of EMF exposure and the length of time it takes for most cancers to develop, one cannot expect ‘conclusive proof’ such as the link between helicobacter pylori and gastric ulcer. (That link was recently demonstrated by the Australian doctor who proved a link conclusively by swallowing the bacteria and getting the disease.) However, there is enough evidence of a plausible mechanism to link EMF exposure to increased risk of cancer, and therefore of a need to limit exposure.
EMF have been shown to cause other potentially harmful biological effects, such as leakage of the blood brain barrier that can lead to damage of neurons in the brain, increased micronuclei (DNA fragments) in human blood lymphocytes, all at exposure rates well below the limits in the current FCC guidelines. Probably the most convincing evidence of potential harm comes from living cells themselves when they start to manufacture stress proteins upon exposure to EMF. The stress response occurs with a number of potentially harmful environmental factors, such as elevated temperature, changes in pH, toxic metals, etc. This means that when stress protein synthesis is stimulated by radiofrequency or power frequency EMF, the body is telling us in its own language that RF exposure is potentially harmful.
There have been several attempts to measure the health risks associated with exposure to RF, and I can best illustrate the findings with a graph from the study by Dr. Neil Cherry of all childhood cancers around the Sutro Tower in San Francisco between the years 1937 and 1988. Similar studies with similar results were done around broadcasting antennas in Sydney, Australia and Rome, Italy, and there are now studies of effects of cellphones on brain cancer and cancer of the salivary glands. The Sutro tower has antennas for broadcasting FM (54.7 kW) TV (616 kW) and UHF (18.3 MW) signals over a fairly wide area, and while the fields are not uniform, and also vary during the day, the fields were measured and average values estimated, so that one could associate the cancer risk with the level of EMF exposure.
The data in the figure are the risk ratios (RR) for a total of 123 cases of childhood cancer from a population of 50,686 children, and include 51 cases of leukaemia, 35 cases of brain cancer and 37 cases of lymphatic cancer. It is clear from the results that the risk ratio for all childhood cancers is elevated in the area studied, and while the risk falls off with radial distance from the antennas, as expected, it is still above a risk ratio of 5 even at a distance of 3km where the field was 1μW/cm2. This figure is comparable to what has been measured near cellphone towers. The Bioinitiative Report recommended 0.1μW/cm2 as a desirable precautionary level based on this and related studies, including recent studies of brain cancer and cellphone exposure.
As I mentioned above, many potentially harmful effects, such as the stress response and DNA strand breaks, occur at field strengths that do not cause a rise in temperature and are therefore considered safe. It is obvious that the safety standards must be revised down to take into account the established non-thermal biological responses that occur at much lower intensities. Since we cannot rely on the current standards, it is best to act according to the precautionary principle, the approach advocated by the European Union and invoked by the scientists of the Bioinitiative report. In light of the current evidence, the precautionary approach appears to be most reasonable, especially when children are the ones that are most affected.
Martin Blank, Ph.D.
Associate Professor of physiology and cellular biophysics