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Here is yet controversial issue. The EPA stated that EMF and EMR (electromagnetic radiation) pose no threat to human health, but other studies claim equally fervently that it does! EHSO's opinion is - common sense - living under a high power line for 20 years can't possibly be good for youthen neither is selling your home at a $20,000 loss to move quickly. Balance the risks and costs and try to avoid prolonged exposure.
Typical scenario: My family and I are thinking about buying a house that is positioned approximately 600 feet away from a high tension wire. Are there any adverse health effects associated with the long term exposure to electromagnetic fields? Is there a government-designated "safe distance" from the source of electromagnetic fields?
Note: This answer comes from Robert B. Goldberg, Ph.D. of EMF-Link, Information Ventures, Inc. ( http://infoventures.com/ )
Answer: There are now close to 100 larger and smaller epidemiologic studies that address the long-term exposure issue. I refer you to EMF-Link (1-800-643-4794) - ask about the Epidemiology Studies chapter in the Status Report prepared for the State of Maryland, as a basic reference ( http://infoventures.microserve.com/emf/maryland/cover.html ). In brief, there is a suggestion which has appeared in many (but not all) studies of children living near power lines that such exposure can approximately double the risk of leukemia and/or brain tumors. Evidence is less clear for adults, but suggests the possibility of similar risks. Risks of breast cancer, depression, and other negative health effects are based on much more limited evidence and are even more speculative. There is enough information to have some concern, but not enough to set exposure standards. There is also a lack of clear evidence from laboratory evidence from laboratory experiments to indicate what protective measures (if any) would be appropriate or to demonstrate to everyone's satisfaction a mechanism which could explain such an effect of powerline fields.
The question of a "safe distance" is, at least in my opinion, a complete unknown. The epidemiologic studies indicated above used a "cut off point" of 2 or 3 mG (average magnetic field level) to define people as "exposed," but you should realize that this is somewhat arbitrary level. If you set the cut off point too low, the exposed group is not really much different from the group you are comparing them to, and if you set it too high you will never find enough people in the exposed group to allow statistical analysis. These experiments cannot really give an indication of safe levels: you would need a very clear effect, show a sharp change in effect over a small difference in exposure. Given the current state knowledge, I don't think anyone can indicate safe or unsafe levels, only magnetic field levels which are unusually high compared to what most of us are exposed to. Many people adopt a "prudent avoidance" position where they reduce personal exposure levels to 1 or 2 mG if it doesn't cost a lot to do so. In doing this you are not establishing "safe" conditions (because we don't really know what is safe), but are establishing conditions which do not expose you to an unusually high magnetic field.
Now, read both sides and make up your own mind
Although not a chemical, electromagnetic radiation (also called EMR) has been linked with numerous health effects, including immune system problems. EMR has many sources and includes overhead power lines, radio broadcast towers, telephone/television microwave transmission and computer equipment. EMR is invisible radiowave energy that in some circumstances can change biological function. For instance, it is well known that microwaves can heat human tissue, thereby causing damage. However, even small amounts of microwave energy has been found to cause oscillation (vibration) of the DNA and genes without our cells. This research was conducted in 1984 at the National Center for Devices and Radiological Health at the Food & Drug Administration in Rockville, Maryland. According to Dr. Earl Prohofsky at Purdue University in Indiana, "That's worrisome because that's about the worst place in the body you'd want resonant absorption (vibration) - right in the DNA." Other research has shown that microwave energy can actually cause the chromosomes to uncoil.
In tests with laboratory rats at the Veterans Administration Hospital in Loma Linda, California, as little as 60 hertz of nonionizing energy (about what escapes from a leaky microwave) adversely affected immune response.
EPA Admits Problem
A 1984 EPA report stated there was a detrimental link between radiation and immunity including negative changes in blood count, immunity and overall health among animals exposed to radio waves.
Neutrophils Lose Effectiveness
The U.S. government has set standards allowing the public to be exposed to microwave levels of 10 milliwatts per square centimeter. Many European countries permit far less than this to their public. In a 1979 Soviet study, very low intensity microwaves about 60 times less than what the U.S. government allows, caused "inhibition of neutrophils phagocytic activity." This means that the neutrophils were not consuming foreign substances in the blood as effectively as before the microwave exposure.
Overhead Power Lines Weaken Natural Killer Cells
Another type of EMR is called "extremely low frequency" magnetic fields, which are produced by high voltage power lines. Several studies have linked high voltage power lines with increased cancer risk for children. Research from the University of North Carolina in Chapel Hill and the University of Colorado found a five-fold increase in childhood cancer, particularly leukemia, in those homes near the highest level of extremely low frequency fields. Homes showing increased cancer risk were within 48 feet of power line wires designed to carry very high electric currents and within 22 feet of power lines designed to carry lower currents.
In helping to explain why this could be happening, Dr. Jerry Phillips, director of biochemical research at the Cancer Therapy and Research Center in San Antonio, Texas, conducted research into this problem. Dr. Phillips experiments have shown that exposure to extremely low frequency electric fields causes an abnormal increase in the growth of cancer cells. His research of the immune system found that natural killer T-cells were also 60-70% less effective in killing the cancer cells.
NIEHS PR #9-99
ENVIRONMENTAL HEALTH INSTITUTE REPORT CONCLUDES EVIDENCE IS 'WEAK' THAT ELECTRIC and MAGNETIC FIELDS CAUSE CANCER
After six years of accelerated, Congressionally mandated research, the National Institute of Environmental Health Sciences today announced it has concluded that the evidence for a risk of cancer and other human disease from the electric and magnetic fields (EMF) around power lines is "weak."
NIEHS' review and analysis of the existing data came in a report to Congress, released today. The report applies to the extremely low frequency electric and magnetic fields surrounding both the big power lines that distribute power and the smaller but closer electric lines in homes and appliances.
While sections of the report say EMF exposure "cannot be recognized as entirely safe," the report concludes: "The NIEHS believes that the probability that EMF exposure is truly a health hazard is currently small. The weak epidemiological associations and lack of any laboratory support for these associations provide only marginal scientific support that exposure to this agent is causing any degree of harm."
Research continues on some "lingering concerns," the report says, and efforts to reduce exposures should continue.
NIEHS said that the "strongest evidence" for health effects comes from statistical associations observed in human populations with childhood leukemia and chronic lymphocytic leukemia in occupationally exposed adults such as electric utility workers, machinists and welders. "While the support from individual studies is weak," according to the report, "these epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia than for childhood leukemia."
However, laboratory studies and investigations of basic biological function do not support these epidemiological associations, according to the report. It says, "Virtually all of the laboratory evidence in animals and humans and most of the mechanistic studies in cells fail to support a causal [cause and effect] relationship."
NIEHS Director Kenneth Olden, Ph.D., said, "The lack of consistent, positive findings in animal or mechanistic studies weakens the belief that this association is actually due to EMF, but it cannot completely discount the epidemiological findings. For that reason, and because virtually everyone in the United States uses electricity and therefore is routinely exposed to EMF, efforts to encourage reductions in exposure should continue. For example, industry should continue efforts to alter large transmission lines to reduce their fields and localities should enforce electrical codes to avoid wiring errors that can produce higher fields." An interagency committee established by the President will make a subsequent report to Congress about the findings of this report and whether any remedial actions are needed to minimize exposures.
Dr. Olden said NIEHS would continue to support some research on EMF, though not at the high levels Congress provided in special legislation and appropriations.
The NIEHS report follows a six-year research program and a two-year review by the institute and by outside scientists. For the effort, Congress appropriated $23 million that the electrical industry matched. The industry had no control over what research was conducted. The funds were administered by the Department of Energy and a portion was transferred to NIEHS, targeted for health effects research. NIEHS also added $14 million of its own appropriated funds to support additional research. The total expenditure was about $60 million.
The studies reviewed and conducted by NIEHS and its grantees focused on the possibility of a link to cancer - a reaction to a leukemia study in Denver, Colo., in 1979, and to subsequent attempts to duplicate or refute it in Denver and elsewhere. But the report said NIEHS also found inadequate evidence of any link to such non-cancer diseases as Alzheimer's, depression and birth defects. Christopher Portier, Ph.D., the associate director of the Environmental Toxicology Program at NIEHS who coordinated the evaluation effort, said, "This risk assessment gains strength and reliability from the conduct of extensive new research focused to support the evaluation and through obtaining the opinion of hundreds of scientists who participated in the evaluation. The novel methods used in this risk assessment can serve as a blueprint for resolving other difficult issues."
To assist NIEHS in reaching its conclusions, several panels of scientists reviewed the data in open, public hearings. A major panel of scientists - many of them EMF researchers - was assembled in a suburb of Minneapolis, Minn., last June to advise NIEHS. The panel rejected EMF as a "known" or proven, or even "probable" carcinogen but a majority of the panel said a role in cancer could not be ruled out and so it should be regarded as "possible" carcinogen. The NIEHS report today also recommends that the fields continue to be recognized as a "possible" cancer hazard, but emphasizes the weakness of the data and the low risk that may be involved. The NIEHS report says the evidence does not seem to meet the standard for listing as a known or even "anticipated" human carcinogen in the National Toxicology Program's Report on Carcinogens .
NIEHS is one of the National Institutes of Health. NIEHS' headquarters and laboratories in Research Triangle Park, N.C., are also the headquarters of the National Toxicology Program, and they have the same director.
NIEHS Report on EMF - (PDF Format) , (HTML Format) , Press Release (released June 15, 1999)
Actually, it seems that no one is saying that long term EMF exposure is safe. Here's one of the few I found: