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Comments and Mail From Our Readers
January and February 2001
Last modified on:
Friday, March 15, 2002 13:52:50
Copyright © 1994-2008, Information Ventures, Inc.
February 20, 2001
Thank you for your very useful information. I have not been able to find an estimate of a distance that would be relatively safe when building a house near high density power lines. Would 800 feet away from high density lines be considered safe? 1000 feet? 1200 feet? I realize that no one knows the exact answer but any help would be greatly appreciated. Thank you very much.
Reply from Dr. Robert Goldberg: There is no simple formula based on distance since the magnetic field intensity of a source depends on the amount of current a line carries and the configuration of the lines. I am not sure exactly what you mean by high density, but multiphase powerlines that are close together tend to produce a field that drops off more rapidly with distance because the phases cancel. Thus a transmission line right of way with many wires may produce lower field exposures for adjacent areas than a high capacity line with fewer wires. When the geometry and current load of the line is known it is possible to predict the field levels in the vicinity and many utility companies have computer programs to do this, but a guess is just not possible. If you want to learn more about the measurement and powerline risk assessment issues I might suggest a couple of EMF Health Report articles available for purchase on our web site.
Dealing with a risk issue in the face of uncertain evidence is discussed in:
EMF Health Report, Volume 4, Number 5, September/October, 1996 (118 Kb PDF format file) Price $8.00 Title: THREE COMMON QUESTIONS FROM THE REAL WORLD: ONE SCIENTIST'S ANSWERS. Most concerns about EMF are basic and pragmatic. People worry about the purchase of a house near a power transmission line, a cellular phone tower proposed for their child's elementary school, their computer monitor, or industrial EMF sources. This article describes how one scientist responds to practical questions about the safety of EMFs based on ambiguous scientific data.
Magnetic field measurements, what they mean and how they are made, are described in a two-part article:
EMF Health Report, Volume 2, Number 3, May/June, 1994 (85 Kb PDF format file) Price $8.00 Title: POWER FREQUENCY EMFs, Part I: THE SCIENCE BEHIND FIELD MEASUREMENTS. The electric shock you get after scuffing across a carpet on a dry day is caused by an electric charge buildup of thousands of volts. This charge could not power even a small appliance, yet wiring that carries only 100-120 volts powers entire households. Understanding such basic principles of electric and magnetic field behavior helps you understand how EMF can be measured and controlled. Here, in part one of a two part series, we explain voltage and current, magnetic fields, how fields are measured, and how sources of magnetic fields are controlled.
EMF Health Report, Volume 2, Number 4, July/August, 1994 (83 Kb PDF format file) Price $8.00 Title: POWER FREQUENCY EMFs, Part II: EMF MEASUREMENT AND CONTROL IN HOME AND OFFICE In early June, 1994, the Real Estate section of the Philadelphia Inquirer newspaper ran a feature story on the increasing number of home inspections which now include EMF measurements, and the increasing number of real estate agents who find that sales are conditional on finding acceptable magnetic field levels. Although research results are far from conclusive, home owners and buyers want to know the magnetic field levels to which they are being exposed and how to reduce such exposure. Here, in part two of a two part series, we discuss magnetic field measurements, ground currents, shielding and other methods of reducing exposure, and conclude with a recommendation of EMF measurements.
These articles can be purchased on line by clicking the "Online Bookstore" button on the EMF-Link home page and looking under "articles from EMF Health Report." You may also find some of the other material on the site concerning evidence for health risks worthwhile as you consider your options. Regards, Bob
Reader Response: Dear Dr. Goldberg: Thank you very much for responding to my queries. It turns out the house would be 1600-2000 feet from the power lines. We walked the property with a PSEG representative and he measured the EMF at 0.2 - 0.4 mG on most areas of the property. This seems extremely safe to me (he is the company's EMF specialist and said he essentially never sees levels this low). My wife still remains concerned so any thoughts you might have would be greatly appreciated. Thank you again. Sincerely, Jay Geller, MD.
Reply from Dr. Robert Goldberg: Dear Dr. Geller, A survey of 1000 US homes indicated average field levels of about 0.9 mG from external sources, so the PSEG representative is correct in saying the fields measured around your prospective home are relatively low compared with typical exposures in the US. At this point we do not know if such low fields are completely safe, but the most recent summaries of epidemiological evidence suggest that there is no detectable cancer risk with average exposures below about 3-4 mG. If you or your wife are still concerned I can refer you to some of the Health Report articles that discuss the evidence for risk, which will allow you to get a better objective background on the issues and be better able to understand new research as it comes out. As a physician, you may also be interested in the broader range of articles we include in the EMF Health report, including many that deal with medical applications of electromagnetic field exposures. The current issue has a feature article by Dr. Abe Liboff who holds several patents for resonant devices that appear to facilitate bone development for resolving nonunions and speeding recovery following spinal fusion surgery. You can look at the contents of this and earlier issues on our web page under the EMF Health Report button (or directly at http://infoventures.com/emf/hrpt/contents.html). We also cover medical topics in our Database and BENER publications, so you may find topics of professional interest by doing a keyword search from our publications page (at the bottom of the Health Report page) Regards, Bob
January 31, 2001
Discovery of your site while researching RF/EMF exposure is encouraging. I had no idea that working around this sort of thing could be dangerous until I began to experience various symptoms. I worked for a communications company from Oct 1997 through June 2000. About 6 months after beginning work there various physical symptoms such as extreme fatigue (I am usually a very energetic person), burning of the eyes and face, fluctuating blood pressure, insomnia, and finally in January 1999, a burn (hot-spot) on the right top side of my head appeared. There are several transmitting devices in the building where I worked. The company owns several towers with microwave dishes and antennas to provide analog paging, 800mhz radio services for various utilities and governmental agencies, mobile and cellular phone services and other communication services and equipment. There are also 6 large transformers located within 15-20 feet of the building. There was an equipment failure at one of those transformers which remained defective during the 2 year period of my employment. I recently found out that the readings coming from the line outside my office window was -60db. Any technical help you might be able to provide to aid my understanding of how these events could possibly have affected my health would be greatly appreciated.
Reply from Dr. Robert Goldberg: Our company monitors the international scientific literature on electromagnetic field biological effects and our EMF Database contains a dozen or so papers on RF and microwave burns. The more subtle symptoms of fatigue and blood pressure changes which you describe have been associated with microwave exposure in many reports in the literature, particularly from eastern Europe and the former Soviet Union, since the early 1970s. When systematic investigations have been made however it proved impossible to verify the association. In the few instances where there are reports of acute burns when a worker accidentally spends time in front of an active antenna, these are usually sensed immediately and resolved with medical care. There is also a body of research dealing with electrical hypersensitivity which suggests that some individuals experience allergic-type reactions when near an EMF source like a computer terminal. Again this is a disputed area of research because, while the medical effects are clearly real, subjects most often show similar effects when they are exposed to devices that they think are emitting EMFs but which are actually inactive. This research suggests that the physical effects of the EMF may not be directly causing the symptoms, but rather a conditioned response may have developed which is triggered by the stimulus of an EMF-producing device.
We could certainly supply you with references to studies reporting adverse effects and studies that generally find little or no indication of adverse long-term effects. Making a case for occupational injury would be difficult without detailed measurements of your workplace showing abnormally high radiofrequency EMF levels. There is also not much convincing medical evidence of a cause and effect relationship regarding the less immediate symptoms (other than the burn) or effects from lower levels of exposure which fall within existing exposure standards. Perhaps it is of some comfort to know that the reports which claim hypersensitivity and neurological symptoms generally indicate that the symptoms tend to go away after a moderate period of time away from the exposure condition. Regards, Bob
January 26, 2001
Hi, May I have some more informations about the relationship between Cactus and EMF. Does exist some publications, research, articles and where I find it? Thank's in advance.
Reply from Dr. Robert Goldberg: Some of the messages we get are very odd and hard to figure why they were directed to us. In relation to the following, the only EMF connection I know of is the section in a review (BENER number: 11469) that says: "One of the most bizarre products available to VDT users is a 'radiation eating' cactus, Cereus Peruvianus, which, according to its promotion literature, 'holds the answer to all our fears about dangerous radiation emissions from VDT screens.' The cactus is harmless, but has been found to be ineffective."
January 25, 2001
I am seeking clinical trials and treatment for chronic depression (drug resistant). Can you provide me with any info? Any help would be appreciated.
Reply from Dr. Robert Goldberg: We follow the published research literature on electromagnetic field bioeffects, and there have been some 60 papers on treatment of depression with transcranial magnetic stimulation which were added to our EMF Database from the last few years. Earlier papers go back over a decade. Here are some references to published results from the EMF Database which may provide useful contact information for locating a research group currently conducting a trial. Detailed summaries for some of these studies are available for purchase on our web site:
PRELIMINARY EVIDENCE FOR A BENEFICIAL EFFECT OF LOW-FREQUENCY, REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION IN PATIENTS WITH MAJOR DEPRESSION AND SCHIZOPHRENIA. Eng. Feinsod, M.; Kreinin, B.; Chistyakov, A.; Klein, E. Dept. of Psychiatry, Rambam Medical Center and Bruce Rappaport Faculty of Medicine, Technion-Israel Inst. of Technology, P.O. Box 9602, 31096 Haifa, Israel (RR/E.K., B.K.); Dept. of Neurosurgery, Rambam Medical Center and Bruce Rappaport Faculty of Medicine, Technion-Israel Inst. of Technology, Haifa, Israel (M.F., A.C.) Depress Anxiety 7(2):65-68 1998 BENER number: 18946
DOUBLE-BLIND CONTROLLED INVESTIGATION OF TRANSCRANIAL MAGNETIC STIMULATION FOR THE TREATMENT OF RESISTANT MAJOR DEPRESSION. Eng. Loo, C.; Mitchell, P.; Sachdev, P.; McDarmont, B.; Parker, G.; Gandevia, S. Psychiatry Unit, Prince of Wales Hosp., High and Avoca Sts., Randwick, N.S.W. 2031, Australia, e-mail: colleen.loo@unsw.edu.au (RR/C.L.); Mood Disorders Unit, Neuropsychiatric Inst. and Prince of Wales Medical Res. Inst., Prince of Wales Hosp., Randwick, N.S.W., Australia; Sch. of Psychiatry, Univ. of New South Wales, Sydney, Australia Am J Psychiatry 156(6):946-948 1999 Funding: Australian Natl. Health and Medical Res. Council Mood Disorders Unit Program Grant No. 953208; Peter Joseph; William Loewenthal; New South Wales Inst. of Psychiatry (C.L.) BENER number: 19208
REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION AS A NEUROPSYCHIATRIC TOOL: PRESENT STATUS AND FUTURE POTENTIAL. Eng. Post, R. M.; Kimbrell, T. A.; McCann, U. D.; Dunn, R. T.; Osuch, E. A.; Speer, A. M.; Weiss, S. R. B. Biological Psychiatry Branch, Natl. Inst. of Mental Health, NIH, Bldg. 10, Rm. 3N212, 10 Center Dr., MSC 1272, Bethesda, MD 20892-1272 (RR/R.M.P.) J ECT 15(1):39-59 1999 BENER number: 19284
A RANDOMIZED CLINICAL TRIAL OF REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION IN THE TREATMENT OF MAJOR DEPRESSION. Eng. Berman, R. M.; Narasimhan, M.; Sanacora, G.; Miano, A. P.; Hoffman, R. E.; Hu, X. S.; Charney, D. S.; Boutros, N. N. Clinical Neuroscience Unit, Rm. 360, Connecticut Mental Health Center, 34 Park St., New Haven, CT 06519 (RR/R.M.B.); Yale Univ. Sch. of Medicine, Dept. of Psychiatry, 333 Cedar St., New Haven, CT 06510 (M.N., G.S., A.P.M., R.E.H., X.S.H., D.S.C., N.N.B.) Biol Psychiatry 47(4):332-337 2000 Funding: NNB VA Merit Award; NIMH Program Grant; State of Connecticut BENER number: 20566
STUDY AND MODULATION OF HUMAN CORTICAL EXCITABILITY WITH TRANSCRANIAL MAGNETIC STIMULATION. Eng. Pascual-Leone, A.; Tormos, J. M.; Keenan, J.; Tarazona, F.; Canete, C.; Catala, M. D. Lab. for Magnetic Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical Sch., 330 Brookline Ave., Boston, MA 01778 (RR/A.P-L., J.K.); Departamento de Fisiologia, Universidad de Valencia, and Instituto Cajal, Consejo Superior de Investigaciones Cientificas, Valencia, Spain (A.P-L., J.M.T., F.T., C.C., M.D.C.); J Clin Neurophysiol 15(4):333-43 1998 Funding: Spanish Ministerio de Educacion y Ciencia (DGICYT); the Milton Fund; the Stanley Vada Foundation BENER number: 18739
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