John Moore (04/17/91)
Subject: Re: High Tension Wire Hazards?
Date: 16 Apr 91 19:55:52 GMT
References: <17100012@inmet> <1991Apr12.213951.10825@markets.amix.com> <1991Apr16.141601.573@news.larc.nasa.gov>
Organization: San Diego State University Computing Services
Lines: 33
In article <1991Apr16.195552.13826@ucselx.sdsu.edu> Shahad Naqvi writes:
]>>the government (she refered to "Bush administration") is "holding up" the
]>>release of the study. I sincerly hope this is not true (both the results of
]>>the study and any government action to delay its release). But nonetheless,
]>>if such a study existed I'd like to hear about it.
]>
]>I have seen a couple of studies pointing out a higher incidence of cancer
]>among people who lived close to 3 KV distribution lines. However, there
]>was no causation indicated anywhere. Perhaps the higher cancer rate was
]>caused by the huge number of herbicides used near the lines, or the fact
]>that more power lines tend to occur in built up areas. But I have not seen
]>any studies involving the very high voltage long lines.
]I have written a paper on the effect of Low frequency Electromagnetic
]fields [LF/ELF] which are produced by high volatge transmission lines
]and power transformers. There is an increasing evidence of the correlation
]between the 60 Hz EM fields and various kinds of cancer. Childhood leukemia
]is one of the major ones. The 1st extensive research was done in the the
]1970's when the relationship b/w leukemia incidence and the proximity
]of the victims to the nearby power transformer was determined.
]The US govt, for some reason or another continues to say that the evidence
]is inconclusive. It is not hard to imagine why. [I'll leave you some food
]for thought]. The evidence is fairly alarming but little is being done about it
][I can provide the recent statistics and research if required]
I think that would be of considerable value to the net.
Some comments here (replying to the several posters quoted above):
(1) The government did NOT hold up the study, contrary to what the nurse
said. There was controversy over whether the results indicated a problem
or not, and there were allegations that the "government" pushed for
the "no problem" conclusion.
(2) All of the evidence that I am familiar with deals with the biological
effects of ELF MAGNETIC fields, not electric fields. These are likely
to be most significant, to most people, from low voltage sources such as
house wiring, electric blankets, appliances, etc. Physics will show
you that low frequency magnetic fields penetrate tissue far better than
electric fields - the body is essentially a short circuit to electric
fields, since it is a good conductor (once through the skin).
(3) (replying to the person in a previous post who argued that because
we cannot come up with a physical explanation, there must be no
effect). I cannot buy the argument. I am aware that the E-field
forces should be many orders of magnitude below naturally occurring
forces. However, we are talking about B field forces here (which should
also be low). There are several ways that extremely low (below the
noise level) forces could cause effects:
-resonance (which acts to raise the SNR by reducing the "bandwidth")
-chaotic amplification - a highly nonlinear system may be susceptible
to very low level forces, and may show unusual resonances.
-larger than expected forces: there may be magnetic particles in the
body that are large enough to experience larger forces than predicted.
In any case, to deny the existence of the phenomenon on the basis that
we don't understand it (and we THINK that we can rule it out on known
physical principles, but without serious analysis) is specious. As another
poster pointed out, it has taken a long time to reach a significant
understanding of the carcinogenesis mechanism of cigarette smoke, but
the hazard was recognized well before the mechanism was even vaguely
understood. At the very least, an examination of the evidence is in
order.
(4) Evidence includes:
-Epidemiological studies showing correlations between ambient magnetic
field strengths (at 60Hz) and childhood leukemia. The herbicide
explanation fails to explain this - there is no reason to expect,
in the study that was done in Denver, that herbicide application
would correlate with residential neighborhood field strengths. However,
it may be that PCB exposure would - the highest fields were nearest the
transformers, which may have contained PCB's. I would be interested if
some knowledgeable person on the net could respond to the PCB
conjecture.
-Experimental studies showing tissue response to ELF magnetic fields.
Dr. Ross Adey has been doing these for decades, and other researchers
have also. A lot of work has been done to rule out artifact in these
studies - precisely for the reason that the physical mechanism is
not yet known. Other researchers have also done these sorts of
studies. In order to throw out the EM-leukemia conjecture, you have
to explain these studies.
(5) We are talking about a very WEAK effect here. By that I mean that the
risk is very small. I realize that to someone whose child develops
leukemia, this is small comfort. However, a 1.5x increase in child
leukemia rates in some areas is still a relatively small risk. In fact,
if it were a large risk, there would be little debate about this
issue, since the evidence would be obvious. As a society (perhaps as
an organism) we tend to overemphasize small risks relative to large
risks. The child exposed to relatively high EM fields is still in much
more danger from automobile trips than anything else. This doesn't mean
we should ignore the issue - it does mean we shouldn't do anything
rash.
(6) There is a popular book out that covers this controversy. It is by
Paul Brodeur, and the name escapes me right now. It has interesting
data in it, although I should caution that it is, too me, irresponsibly
sensationalist and alarmist - and FAR from scientific. It does, however,
give pointers to where to find the real scientific literature.
(7) Brodeur and others allege coverups by government and the electic
producers. I should point out that much of the research that has
purported to show the effect was funded by EPRI - The Electric Power
Research Institute. They do not seem to be suppressing the results.pierson@cimcad.enet.dec.com (Dave Pierson) (04/18/91)
In article <4023@anasaz.UUCP>, John Moore writes an, in my opinion, EXCELLENT, summary of the situation, from which i quote, in part: > (2) All of the evidence that I am familiar with deals with the biological > effects of ELF MAGNETIC fields, not electric fields. Second this. And the studies showing effects, in lab settings, are much stronger than the links to electric fields. > (4) Evidence includes: > -Epidemiological studies showing correlations between ambient magnetic > field strengths (at 60Hz) and childhood leukemia. The herbicide > explanation fails to explain this - there is no reason to expect, > in the study that was done in Denver, that herbicide application > would correlate with residential neighborhood field strengths. However, > it may be that PCB exposure would - the highest fields were nearest the > transformers, which may have contained PCB's. I would be interested if > some knowledgeable person on the net could respond to the PCB > conjecture. There are a couple of interesting things i have heard from professional studies of the Denver (and similar Southern California studies). I do not have sources, but the speakers were professionals: 1) As John points out, the Denver correlation was weak. I believe it was one case away from being statistically insignificant. 2) In the case of the Denver studies (Wertheimer(?) et al) no field strength measurements (electric or magnetic) were done. When, after the fact, (some years after the fact) a seperate study revisited the same locations to measure the fields (magnetic only) they found no correlation between the (later) field strengths and the earlier leukemia rates. This is not, obviously, "cast iron", it is intriguing. What is curious is that the "California" study found the same effect, with much less time lag between measurement of field and diagnosis of leukemia: A weak correlation between postion of wiring and leukemia. NO correlation between measured field strength and leukemia. > (5) We are talking about a very WEAK effect here. By that I mean that the > risk is very small. I realize that to someone whose child develops > leukemia, this is small comfort. From memory, the strongest correlation found was a doubling of the risk. By comparison, the first study of smoking and cancer showed a ten times increase. > (6) There is a popular book out that covers this controversy. It is by > Paul Brodeur, and the name escapes me right now. It has interesting > data in it, although I should caution that it is, too me, irresponsibly > sensationalist and alarmist - and FAR from scientific. It does, however, > give pointers to where to find the real scientific literature. Currents of Death. I have not read it, but assume it covers the same ground as Brodeur's extended three-parter in June, 1990 issues of New Yorker. I was less than overwhelmed by the New Yorker article. As to pointers, Brodeur, interestingly, fails, I understand, to mention the existence of a professional journal (name escapes me...) dedicated to the field. Curious omission. If it hasn't been mentioned, the Office of Technolgy Assessment, an arm of the US Congress, prepared a survey, ca 100 pages, ca 1989. The exact title escapes me (Biological effects of ELF Fields, perhaps?), about $8 from the US Government Printing office (if its in print, it was last summer). Value for money, with extended footnotes and bibliography. This is not the "delayed" report. thanks dave pierson |the facts, as accurately as i can manage, Digital Equipment Corporation |the opinions, my own. 600 Nickerson Rd Marlboro, Mass 01752 pierson@cimnet.enet.dec.com "He has read everything, and, to his credit, written nothing." A J Raffles
will@rins.ryukoku.ac.jp (will) (04/18/91)
Acually, I really think that this study is a JOKE.. The Russians did this same study years ago, I read about it in fact 11 years ago, in a book written on this exact topic, I don't remember the Name, but I may be able to find out. The book was written by some American researchers that were following the Advances of the Soviets in EMP studies and their effects on people. In fact, I haven't seen the document you guys are refering to. But I would bet it is a word for word copy of the Soviets research. Another worthless effort by Americans, always re-inventing the wheel and wasting money that can best be used else-were. Will.....
will@rins.ryukoku.ac.jp (will) (04/18/91)
Pardon me, elf not emp, I must be going crazy. Will......
dadams@cherry10.cray.com (David Adams) (04/19/91)
Yesterday I heard a report on the radio about a study on the Hazards of living near high tension wires. The study involved, the report pointed out, was not scientific! In order to perform a valid scientific study on the subject we would have to obtain a random sample of children, randomly assign half of them to live near high tension wires and the other half away from high tension wires. Then we follow the progress of these children over the course of many years and measure the proportions which develope cancer, etc. We cannot do this in a democratic society. So what the researchers did was to find a group of people who had developed some disease. (I don't remember what disease was involved.) Then they tried to find a *similar* group of people who did not develope the disease. Then they looked back to the childhood histories of these people to see how many of each group lived near high tension wires. This is not a good scientific method. It was pointed out, for example, that it may well be that more affluent people were willing to volunteer for the study, and that fewer of these were likely to have lived near high tension wires. When you set out to find a *similar* group, it is entirely impossible to consider all of the variables that might be involved. This is one of the reasons that randomization is so critical. When I see so many people begin to believe conclusions that come from bogus studies, it really makes me stop and think. We need to learn to be critical when we read, or evaluate a study like this one. This doesn't mean that High Tension Wire Hazards do not exist, but we cannot use the conclusions of experiments like these as evidence that they do. David Adams Statistical Analyst Cray Research Inc.
ankleand@mit-caf.MIT.EDU (Andrew Karanicolas) (04/19/91)
In article <236@rins.ryukoku.ac.jp> will@rins.ryukoku.ac.jp (will) writes: > > Acually, I really think that this study is a JOKE.. The Russians did JOKE? Which? >this same study years ago, I read about it in fact 11 years ago, in a book >written on this exact topic, I don't remember the Name, but I may be able to >find out. The book was written by some American researchers that were following >the Advances of the Soviets in EMP studies and their effects on people. > > In fact, I haven't seen the document you guys are refering to. But I >would bet it is a word for word copy of the Soviets research. Another worthless >effort by Americans, always re-inventing the wheel and wasting money that can >best be used else-were. > > Will..... Are you serious? One of the cornerstones of science is substantiation of hunches or other vague thoughts. Clearly, you demonstrate remarkable ability to jump to conclusions without any proof. I would recommend that you post such rubbish elsewhere in order not to drag sci.electronics to the low level that is consistent with your posting. By the way, I ordinarily do not get too serious about anything posted on this or any other networks. However, you are crossing the bounds of what is tolerable. Newsgroups you should try instead include alt.flame. There, you do not need to be concerned with thinking. Finally, if you are going to attempt to discourse the topic concerning American research, then you had better be prepared with facts or you will be torn to pieces. Sci.electronics is not the forum to deal with this. That is all. -- Andrew Karanicolas MIT Microsystems Technology Laboratory ankleand@caf.mit.edu
John Moore (04/19/91)
In article Message-ID: <112256.27482@timbuk.cray.com> dadams@cherry10.cray.com (David Adams) writes: >Yesterday I heard a report on the radio about a study on the >Hazards of living near high tension wires. > >The study involved, the report pointed out, was not scientific! >In order to perform a valid scientific study on the subject >we would have to obtain a random sample of children, randomly >assign half of them to live near high tension wires and the >other half away from high tension wires. Then we follow the >progress of these children over the course of many years and >measure the proportions which develope cancer, etc. This is not true. In order to perform an OPTIMAL experiment on the subject, we might have to do as you say, but valid science is often done with skimpy data. > >We cannot do this in a democratic society. So what the researchers >did was to find a group of people who had developed some disease. >(I don't remember what disease was involved.) Then they tried to Childhood Leukemia - if you are referring to the Denver study. >find a *similar* group of people who did not develope the disease. >Then they looked back to the childhood histories of these people >to see how many of each group lived near high tension wires. Not high tension wires - simple backyard distribution wires - with different levels of ELF magnetic fields. >This is not a good scientific method. It was pointed out, for example, >that it may well be that more affluent people were willing to >volunteer for the study, and that fewer of these were likely to have >lived near high tension wires. When you set out to find a *similar* >group, it is entirely impossible to consider all of the variables >that might be involved. This is one of the reasons that randomization >is so critical. >When I see so many people begin to believe conclusions that come >from bogus studies, it really makes me stop and think. We need to >learn to be critical when we read, or evaluate a study like this one. >This doesn't mean that High Tension Wire Hazards do not exist, but >we cannot use the conclusions of experiments like these as evidence >that they do. Self selection is always a risk in epidemiological studies. It does not mean that the study is incorrect - it does mean that the results may not be as conclusive as would be with the sort of experiment that you admit cannot be run. It does not mean we should simply ignore the studies or not try to run them. Modern medical science would be seriously crippled -where without these studies. I would point out that your criticism also applies to most smoking-->cancer/smoking-->heart_disease studies. Try to eliminate self selection from a risk of smoking epidemiological study! Does that mean that we are foolish to believe them, or that we should not act upon them? While the best statistical results come from a pre-designed, randomized, multiple-blind study, we are not always in a position to do such a study. Sometimes we have to use what data is available, with recognized corresponding degradation in experimental accuracy. One of the most powerful challenges in science is designing statistically valid experiments under these conditions - and some people are amazingly good at these experimental designs. None of what I say above means that I take these studies uncritically. The Denver study in particular was just barely statistically significant (like a lot of cold-"fusion" studies were!). It may be wrong. It may also be right. It is backed up by some other epidemiological studies (also perhaps flawed) and some experimental lab work (that is a lot more solid).
dadams@cherry10.cray.com (David Adams) (04/24/91)
In article <4045@anasaz.UUCP>, John Moore writes: |> In article Message-ID: <112256.27482@timbuk.cray.com> dadams@cherry10.cray.com (David Adams) writes: |> |> >Yesterday I heard a report on the radio about a study on the |> >Hazards of living near high tension wires. |> > |> >The study involved, the report pointed out, was not scientific! |> >In order to perform a valid scientific study on the subject |> >we would have to obtain a random sample of children, randomly |> >assign half of them to live near high tension wires and the |> >other half away from high tension wires. Then we follow the |> >progress of these children over the course of many years and |> >measure the proportions which develope cancer, etc. |> |> This is not true. In order to perform an OPTIMAL experiment on the |> subject, we might have to do as you say, but valid science is often |> done with skimpy data. |> |> > |> >We cannot do this in a democratic society. So what the researchers |> >did was to find a group of people who had developed some disease. |> >(I don't remember what disease was involved.) Then they tried to |> |> Childhood Leukemia - if you are referring to the Denver study. |> |> >find a *similar* group of people who did not develope the disease. |> >Then they looked back to the childhood histories of these people |> >to see how many of each group lived near high tension wires. |> |> Not high tension wires - simple backyard distribution wires - with |> different levels of ELF magnetic fields. |> |> >This is not a good scientific method. It was pointed out, for example, |> >that it may well be that more affluent people were willing to |> >volunteer for the study, and that fewer of these were likely to have |> >lived near high tension wires. When you set out to find a *similar* |> >group, it is entirely impossible to consider all of the variables |> >that might be involved. This is one of the reasons that randomization |> >is so critical. |> |> >When I see so many people begin to believe conclusions that come |> >from bogus studies, it really makes me stop and think. We need to |> >learn to be critical when we read, or evaluate a study like this one. |> >This doesn't mean that High Tension Wire Hazards do not exist, but |> >we cannot use the conclusions of experiments like these as evidence |> >that they do. |> |> Self selection is always a risk in epidemiological studies. It does not |> mean that the study is incorrect - it does mean that the results may |> not be as conclusive as would be with the sort of experiment that you |> admit cannot be run. It does not mean we should simply ignore the |> studies or not try to run them. |> We can't help but look at the conclusions with a jaundiced eye. |> Modern medical science would be seriously crippled -where without these |> studies. I would point out that your criticism also applies to most |> smoking-->cancer/smoking-->heart_disease studies. Try to eliminate self |> selection from a risk of smoking epidemiological study! Does that mean that |> we are foolish to believe them, or that we should not act upon them? |> We are foolish if we act on that study alone, or on a group of similar studies, especially when most of these studies are marginally significant. Many of the studies done on smoking probably are weak. I am not the first to level such criticism. This does not imply that smoking does not cause cancer/heart_disease etc, and it doesnot mean that we should not act to prevent a forseeable danger. Furthermore, the evidence in the case of smoking, I beleive, is much stronger than for magnetic fields. Has any one preformed randomized experiments with magnetic radiation with animal subjects, at doses that are comparable to those received by humans? Again it may be a jump to make inferences from rabbits, mice, and mink, to humans, but the significance levels can at least be established. If we could see studies of this nature, that corroborate those studies which have been done, we might be on a *little* firmer ground. |> While the best statistical results come from a pre-designed, randomized, |> multiple-blind study, we are not always in a position to do such a study. |> Sometimes we have to use what data is available, with recognized corresponding |> degradation in experimental accuracy. One of the most powerful challenges |> in science is designing statistically valid experiments under these |> conditions - and some people are amazingly good at these experimental |> designs. |> The problem is that people don't recognize the corresponding degradation in experimental accuracy, in fact mathematicians can't even tell what it is! (Ie. If you forget to randomize can you say that you are 80% confident instead of 95% confident? No! You can't say anything about confidence at all!) Yet people make very serious decisions on the basis of such weak conclusions, not even knowing the weakness was there. |> None of what I say above means that I take these studies uncritically. The |> Denver study in particular was just barely statistically significant (like |> a lot of cold-"fusion" studies were!). It may be wrong. It may also be |> right. It is backed up by some other epidemiological studies (also |> perhaps flawed) and some experimental lab work (that is a lot more solid). None of what I say above means that I do not believe that hazards from electromagnetic radiation exist. Perhaps some of these other studies are on firmer ground? I am not familiar with them. To date, I do not believe that any of the studies I have heard of *should* affect property values.
John Moore (04/25/91)
#define SRPCPY(to, from) \
safecpy(to, client_srp.from, sizeof(client_srp.from), blank)
#define SIZE(field) \
sizeof(client.field) - 1
Article 788 of sci.electronics:
Path: micquis!anasaz!asuvax!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!cs.umn.edu!uc!shamash!timbuk!dadams
Newsgroups: sci.electronics
Subject: Re: Re:High Tension Wire Hazards
Message-ID: <113351.25560@timbuk.cray.com>
Date: 23 Apr 91 17:33:15 GMT
References: <4045@anasaz.UUCP>
Reply-To: dadams@cherry10.cray.com (David Adams)
Organization: Cray Research, Inc.
Lines: 105
In article <113351.25560@timbuk.cray.com> David Adams writes:
]We can't help but look at the conclusions with a jaundiced eye.
Agreed. I am quite suspicous of the epidemiological studies that I have
read about.
]a forseeable danger. Furthermore, the evidence in the case of smoking, I
]beleive, is much stronger than for magnetic fields. Has any one preformed
]randomized experiments with magnetic radiation with animal subjects, at doses
]that are comparable to those received by humans? Again it may be a jump to
Yes, this in fact has been done. Some interesting results were obtained,
but I don't know if excess cancers was among them.
]make inferences from rabbits, mice, and mink, to humans, but the significance
]levels can at least be established. If we could see studies of this nature,
]that corroborate those studies which have been done, we might be on a *little*
]firmer ground.
Like I say - there are SOME animal studies. There are also tissue studies.
These studies are interesting because:
-They are easily repeatable
-They are just as hard to explain as the epidemiological results - the
same criticisms (weak forces involved) apply.
]
]None of what I say above means that I do not believe that hazards from
]electromagnetic radiation exist. Perhaps some of these other studies
]are on firmer ground? I am not familiar with them. To date, I do not
]believe that any of the studies I have heard of *should* affect property
]values.
Property values are affected by all sorts of silly stuff. Whether they
"should" be or not is another matter :-(