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Comments and Mail From Our Readers
March to July, 1999

Last modified on: Thursday, September 12, 2002 08:22:56
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July 3, 1999
USA I just enrolled my 4 year old daughter in a preschool which is adjacent to a substation. The attached readings are consistent over 4 years. I have a few questions. Do readings change? What is your assessment of these readings? What are some remedies, herbs, diet, etc. to counter act these emf's. Here are excerpts from the letter: ...Data sheet that summarizes the results of the electromagnetic field survey performed on October 29, 1998 at ....Day Care. The readings were measured using the EMDEX SNAP magnetic field meter. This meter has a resolution of 0.1 milligauss and an accuracy of (+/-) 1-3%. On average, the readings were nearly the same as measured in 1992. Moonbeam room - (Inside 1.0, Lights on 0.8) Nap room - (Inside 1.7, Lights on 1.8) Cloud nine - (Inside 1.3, Lights on 1.5)
Reply from Dr. Robert Goldberg: The readings you have provided are not atypical of a home and are relatively low for a commercial space, like an office. We sometimes give the figure of 1 mG as an average level for magnetic fields from outside sources like power and distribution lines and transformers, taking that figure from a survey of 1000 US homes. The 1 mG average was based on minimal fields from wiring inside the home (they were made with all appliances in the house turned off), so your daycare levels are close to average. A better way to judge the effect of the substation would be to map the field from the direction of the substation and see if a decrease is evident as you move into rooms further from the substation location. I suspect from the figures you provide that there will be little influence from the substation unless the "nap room" is closest and "moodbeam room" is most distant from the substation location. The magnetic field from the substation will be highest when electricity demand is greatest, so if you decide to make any more measurements you may want to time your measurements in relation to peak power use for the area served by the transformer. I have seen no information that suggests that herbs or protective devices that claim to correct the effects of electromagnetic fields have any value. No clear information and objective tests of effectiveness have been provided by marketers of these products and the research community has had very little interest in investigating them, so there is no basis for recommending any alternative approach to making sure the field levels are as low as possible. Regards, Bob

June 29, 1999
USA I am in sales and use my digital service cellular phone over 1500 minutes per month. I have been experiencing headaches and am concerned over the EMF issue. Is there anything I need to look for when purchasing a phone that makes it safer than another? Also, would using an earpiece and microphone (hands-free) make using a cellular any safer? Please advise. Thank you. Nancy
Reply from Dr. Robert Goldberg: Dear Nancy, Many people have expressed some concern about cell phone use but at present there is very little scientific evidence on which to base a decision. However, a recent preliminary study from Sweden and Norway documented a significant increase in the type of symptoms you describe (heachache, dizziness, warmth sensations in the ear, fatigue, difficulty concentrating, memory loss, burning skin sensation) which appear to be unrelated to the type of phone system (digital or analog) being used. Using an earpiece should reduce radiofrequency (RF) radiation exposure to the head since the antenna is no longer located near the skull, provided it is designed correctly and the cord has an RF filter. If you use a phone in your car frequently, an outside antenna will greatly reduce your exposure because not only is the antenna no longer placed near your head, but the hand-held phone is shielded by the car body and operates at higher power when you are making your calls from inside. Regards, Bob

June 6, 1999
USA I am hoping you can provide some specific information regarding power lines, EMFs and the risk to adults. I am considering buying a new townhome that is fairly close to power lines; a huge pole is located adjacent to the property, and I hear occasional buzzing and cracking as power is being transferred (I think?). I know that research has not been conclusive, so I am looking for some educated opinions: 1. Living within what distance to the power pole would be a risk? I see the article on your site specifies 131 feet for cancer in children studies. 2. Does the type of home construction and roofing have any affect on minimizing risk? Any other info you can provide will be greatly appreciated. I need info quickly as I must make a decision on the purchase within five days. Thank you very much.
Reply from Dr. Robert Goldberg: The questions you asked seem simple, but get into some large areas of unknowns. I'll give you some brief answers to the questions you raised. (1) It is very hard to tell for sure about exposure from distribution lines near a home without knowning more about them. Wire coding, which you may have read about in some epidemiologic studies, tries to make a better guess at magnetic field exposure from the factors like the thickness of the wires and the number of homes served by the section of line, but those are indirect estimates. The primary factors in magnetic field exposures are the current carried in a line and the distance from it (in a direct line of sight). As you describe the line near your prospective town house it could produce relatively high exposures or not. The best approach would be to get some measurements made and decide if those levels are a concern to you. Any home you look at is likely to have some measurable level of exposure from external power distribution: a level of about 1 milligauss from external sources like powerline and transformers is about average for homes in the US. You may want to measure before deciding on a purchase or make the purchase conditional on the field measurements if you are worried. You can then determine if the exposures are greatly above the US average level or not, and decide if living in a house with that level would worry you. (2) Knowing distance, or even milligauss levels, doesn't really give you an accurate indication of cancer risk. The epidemiologic studies suggest that children with higher than average residential exposures to powerlines (living near them) tend to have a twice the incidence of leukemia, but the average exposure level of 2-3 milligauss really just describes that "exposed" residential situation: it doesn't mean that fields at that level are dangerous or those at lower levels are safe. In part, a milligauss level chosen as a "cut off" for exposed/unexposed homes is established for practical purposes and is almost arbitrary: if the level were set too low there would be little difference between exposed and unexposed residences, and if it were set too high there would be so few exposed people there would be no way to do statistics on them. In occupational studies where investigators look at much higher exposures there is no clear relationship between higher average (milligauss) levels and greater risk of disease. So I would say that even if the studies of childhood cancer and residential magnetic field exposure are correct (and some scientists believe that the effect will go away as better studies are done) they do not say that a particular average magnetic field level is dangerous, only that there is some association with something related to living near a power line. (3) Building construction materials do have an effect on electric field levels or higher frequency (radiowave or microwave) electromagnetic fields, but have no real effect on magnetic field levels. For example, buildings with a conductive metal covering (e.g., aluminum siding and metal screening) that is grounded will effectively block electric fields, so that many office buildings with steel frame construction will effectively block out radio signals into the interior of the building. In situations where there is some need to reduce power frequency magnetic field levels, they usually shield, reduce, or reconfigure the source rather than shielding the exposed area because shielding a building against magnetic fields is expensive and difficult. Regards, Bob

May 18, 1999
USA I am doing research on the effects of radiation from computer monitors on one's body. I worked in front of computer monitors for 25 or 30 years and I was diagnosed with chondro sarcoma. This is a cancerous tumor that attached under my sternum and part of my sternum and some ribs on both sides had to be removed. A 9" gortex plate was placed inside of me. This occured about one and a half years ago. I was wondering if you have done any research or have heard of research that has been done on this subject. My concern is that my cancer occured from computer monitors. There is no significant cancer in my family at all. This is a somewhat rare form of cancer. Any information you may have would be very helpful to me, and any information that I can give you I will give it freely.

May 6, 1999
Laura, USA Would it be possible to get a milligauss reading of between 6-22 mg at a distance of about 300 feet from a 138kv transmission line. There are also several distribution lines on the pole? Help me to understand this. Thanks so much, Laura
Reply from Dr. Robert Goldberg: Dear Laura, Many people do not realize that magnetic field levels depend only on the current flowing though a line, not on the voltage of the line. While many high voltage lines carry a lot of current, they are often mounted high to avoid accidental discharge and therefore produce smaller magnetic field exposures for people living near the line than closer distribution lines operating at lower voltage. Where there are multiple lines on the same pole, they are more or less additive except to the extent that individual lines are out of phase and produce cancellation of the field levels. The listing of typical levels from powerlines in the "Questions and Answers about EMF" booklet produced by NIEHS and DOE indicates mean magnetic field levels of 0.2, 0.8, and 1.4 mG from 115 kV, 230 kV, and 500 kV lines, respectively, at 300 feet from the line. The 6-22 mG reading you report from a 138 kV line therefore seems rather high, even considering the variation with time of day that the booklet reports (up to about twice the mean level in their example of a 500 kV line). There are a couple of possible answers that come to mind: (1) Magnetic fields drop off very quickly with distance from the line so if your estimate of distance is off it could add a big error factor. The field intensity usually decreases with the square of the distance from the line on a direct line of sight so, using an example from the booklet, a 230 kV line produces only 0.8 mG at 300 feet but 7.1 mG at 100 feet and 19.5 mG at 50 feet. (2) Inexpensive gauss meters often do not have very precise frequency windows and so often detect higher frequency signals (like high frequency transient or even radiowave or microwave transmissions) and misread them as much stronger than they actually are. If you are near a high frequency source like a TV broadcast tower you could get apparently very high readings. (3) The large range of readings you are getting could indicate an electronic malfunction in the meter (you would know if repeated readings in the same location give very different results, or the pattern of readings with distance from the line doesn't show the characteristic drop off in intensity). Finally, (4) there could be some other closer source of magnetic fields like a buried distribution line that you are picking up (again, you would know if the field reading varies greatly with small changes in position). If the levels are of concern to you it might be good to get a second opinion with some readings made by a utility professional with a high quality meter. Regards, Bob
Reply from Laura: Dear Bob: I can't thank you enough for your extremely helpful information. You are so knowledgeable in this field. I am so fortunate to have found you. I am going to take your advice and call my utility company. However, I am a little concerned that they always have low readings so there isn't a panic among residents living near these lines. The utility companies have always downplayed the health concerns of EMF. How do you feel about that? I just want to mention one more thing. This pole is located at the end of a cul de sac and down a hill about 200 feet from the end of the street. Therefore the transmission lines are closer to the ground than they would be if the pole were located more level with the road. Would that make a difference? Could a transmission box located on the property cause high readings? At what distance from the box would levels drop off to 1 milligauss or below? Are utility companies required to bury the lines at a certain distance? Thank you for your time. Laura
Reply from Dr. Robert Goldberg: Dear Laura, Here are some answers to your last set of questions. Many people are concerned about trusting their utility company to do measurements, but in my experience, when utility companies are willing to do magnetic field measurements they generally do them accurately and fairly. Perhaps it's because utility engineers are skeptical about any possible health effects and see no reason to minimize readings that they see as very low anyway, but I think that most feel that if there is a problem they want to know about it and adjust their actions accordingly. There is a valid reason not to undertake expensive revisions to a line, paid for by the customers eventually, if there is no evidence that it is harmful. I think in most cases that the risk is "downplayed" because that is the honest professional assessment of the utility engineers. The magnetic field levels drop off sharply with increasing distance from the line. The distance we are concerned with is a direct line of sight. If the line is sagging lower at a point near you, or if your property is on a hill so that the house is closer to level with the line, the exposure may be greater. A location at the end of a street or cul de sac would suggest lower field levels since that portion of the line serves few additional houses and therefore carries less current. There are some other factors so measurements are always better than guessing. A transformer box would have fairly high readings right at the box itself (because of the current it carries) but the windings of the transformer allow for a lot of field cancellation so that field levels should decrease very quickly as you move away from the transformer. The drop off is generally more rapid than from power lines (roughly, power lines decrease with the square of the distance and transformers with the cube of the distance). It is hard to specify an exact distance, but most are down to background level (below 1 mG) 6-10 feet away, some as little as 3 feet away. As far as I know the decision to bury lines is left to the individual utility companies and yours may or may not have a fixed policy. Burying lines is usually done for a combination of reasons including avoiding damage and aesthetics (almost never just to reduce field levels). Regards, Bob

May 3, 1999
Chili I am in the Department of Biología Marina in the University Arturo Prat. in Iquique, Chile. I carry out a seminar on the effect of the electromagnetic field on Espirulina sp. that it is a microalga cianobacteria. I want to know if you could send some information in particular on this area or in anyone that involves magnetic fields and you plant, any information will be well received. Thank you. Pd: also information on where I can find a teslametro of low cost.
Reply from Dr. Robert Goldberg: There has been limited exploratory work on the effects of elecromagnetic fields on prokaryotes. I have attached an abstract from a Yugoslavian group working on blue-green algae that may help you get started. Of course, the type of electromagnetic field you are interested in is an important variable since there may be information in other organisms that relates to your study. Magnetic field meters (here they are known as gauss meters) are used to measure time-varying magnetic fields. They are available from many sources and range from $30.00 for a very simple device up to thousands of dollars for devices that are able to measure in a narrow frequency range and record readings over time. Devices that measure static fields or radiofrequency fields are more complex and expensive. A number of Internet sites list sources of inexpensive gauss meters. One listing is on the Bridlewood site (http://www.ncf.carleton.ca/bridlewood-emfinfo/). It may be easier for you to find a source in Chile or to build a simple meter with the help of someone from the physics department in your university. Regards, Bob
Here is the reference: THE EFFECT OF THE PEMF ON CIANOBACTERIA (MEETING ABSTRACT). Eng. Obreht, Z.; Pekaric-Nadj, N.; Dosen, V. Faculty for Natural Sciences, Inst. for Biology, 21000 Novi Sad, Vojvodina, Yugoslavia (Z.O., V.D.); Faculty of Technical Sciences, Univ. of Novi Sad, 21000 Novi Sad, Vojvodina, Yugoslavia (N.P-N.) Bioelectromagnetics Society, 16th Annual Meeting, 12-17 June, Copenhagen, Denmark, p. 137-138 1994 BENER number: 10464

April 16, 1999
USA Sir, I am trying to find information on the relationship between health (eg. Leukemia/etc) and overhead power lines. I am looking at a number of houses, the best of which has a major overhead power line running near the back of the house. I have 2 sons (1 & 3) and I am sure some work has been done on this area, but cannot recall the outcome. Any advice / information gratefully received (for example, in my situation, would YOU buy this house?) Yours Sincerely.
Reply from Dr. Robert Goldberg: At present there is stronger evidence that increased risk of childhood leukemia may be associated with living in proximity to electric power transmission and distribution lines than for any other population group or cancer type, but even that evidence is limited, and the reality of the risk is very uncertain. Basically, epidemiologic studies have repeatedly shown a doubling of risk of this rare cancer that is near the limits of statistical significance: too small to be sure it is a real risk, but coming up too often to be sure there is no risk either. Our website (EMF-Link) has a lot of information on the research that gives rise to the concern and the evidence is too complicated to be easily summarized in a few sentances. My suggestion for people in your situation is to first find out what sort of field levels you are dealing with in the prospective home (by having magnetic field measurements made). Everyone in our society is exposed to EMF to some degree. On average, homes in the US are exposed to about a milligauss from outside sources like power lines and transformers. If the house you are looking at has substantially higher levels, you will have to decide if concern about the possibility of adverse effects and the unease it might cause you overrides any advantages of this house compared to others you are considering. Regards, Bob

March 7, 1999
USA I live in a wood frame house approximately 100 years old. Since moving in 1 and 1/2 years ago, my wife and I have been experiencing health problems related to dust, mold, and other unknown air pollutants. We recently had the furnace (crawl space) and duct work cleaned and a vapor barrier put down. This has greatly improved our reoccurring health problems. I recently purchased a small ionizer that purportedly eliminates pet odors and cleans air. This ionizer seems to clean the air. Because of this improvement, I am thnking about purchasing a larger ionizer, and in my research have learned that this equiment is used in "clean rooms." Query: Are there any health effects that I should be aware and would an ionizer remove airborne pollutants (harmful or otherwise)? I would appreciate your reply.
Reply from Dr. Robert Goldberg: The allergy/mold problems you describe are very common and are a good reason to consider controlling humidity and air flow in homes. After that first step, an electrostatic air cleaner should help improve air quality but may not produce as much improvement as what you already did. As far as I know there are no recognized adverse effects from air ionizers. I have also used room units when doing tissue culture work to pull dust, bacteria, mold spores, etc. out of the air. These devices work by putting a (negative) charge on the particles in the air that attracts them to a screen or filter. You get a similar effect on your TV or computer monitor screen where the electrostatic charge attracts dust from the air. In theory, very little charge leaves the filter but, as with any electrical appliance, there will be some fields produced by the device itself. There may also be some air ions that "escape" during this process, but the beneficial or harmful effects of air ions are speculative at most. There were some animal studies on long-term exposure to much higher concentrations of air ions related to DC transmission lines that were designed to find any possible harmful effects and they showed little or nothing. Regards, Bob
Reply from Reader: Thanks Bob, I appreciate the timely advice. If you become aware of any further developments in this area, I would appreciate more information.

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