Suzy B Software 2/Suzy B Software CD-ROM 2 (1994).iso/nasa/emf/emf.rtc

Text File | 1995-05-02 | 26KB | 605 lines

GEnie Space and Science Roundtable Science RTC          July 18, 1993
Transcript copyright (c) 1993 Dave Zimmerman

Guest:  Dr. John Moulder
        Radiation Biology Group
        Medical College of Wisconsin
        Milwaukee, WI
        Internet: [e-mail]

  [Editor's note: For more details and a reference list on the EMF
  issue, see Dr. Moulder's summary appended to the transcript. -- FR]

<FRANK.REDDY> Our guest tonight is Dr. John Moulder, a radiation biologist
with the Radiation Biology Group of the Medical College of Wisconsin in
Milwaukee. He's an expert on radiation bioeffects and hazard evaluation.
He has given invited talks on the connection between power lines and cancer
to the Wisconsin State Medical Society, the Wisconsin Safety and Health
Congress, the Milwaukee Area Medical Directors Association, has reviewed
grant proposals for the National Cancer Institute and papers for scientific
journals, and testified on the issue in state and federal courts. Thanks
for joining us!

<FRANK.REDDY> Just to start things off, what's the latest in the "power
lines caused my cancer" court cases?

<[john] SPACE.GUEST> San Diego -- plaintiff claimed distribution lines has
caused childhood cancer -- jury didn't buy it.

<FRANK.REDDY> This was the first of three cases, I recall.

<[john] SPACE.GUEST> Yes -- next property value cases in Michigan where
plaintiff claimed that "fear of lines should be compensatable" -- still in
litigation.

<[Dave] SPACE> (Oh boy....  I can see it -- a parallel case for the midwest
-- fear of sewer lines will be compensatable. <G>)

<JOHNMOSHER> What voltage, and at what distance?

<[john] SPACE.GUEST> Answer re San Diego case -- distance was very short,
voltage was low (distribution not transmission).

<[james] J.BRYAN> Excuse me for interrupting :), but what is the danger of
a house being say 100 feet away from high power electrical lines.

<[john] SPACE.GUEST> Those who claim that there is a risk (I'm not one of
them) would put the boundary at 100 to 300 ft.

<C.POOLEY> Is discussion re e-fields?

<[john] SPACE.GUEST> No, more re magnetic fields, (e)-fields are easy to
shield.

<C.POOLEY> Frankly, I'm suspicious of all this--green plot...

<JOHNMOSHER> What are 35 kV and 65 kV lines considered? The 4 kV local
lines are easily distribution, and the 500 kV are transmission.

<[john] SPACE.GUEST> Those who believe that there is a problem attribute it
to the magnetic field.  Magnetic fields depend on the current, not the
voltage, thus the voltage is not important. A low-voltage distribution line
in your alley may have a higher field than a much more visible long-haul
transmission line.

<JOHNMOSHER> Is there a correlation to the EMF/cancer problem then?

<[john] SPACE.GUEST> To many people, power lines *are* the emf-cancer
problem.

<FRANK.REDDY> Let me try to get some background in here . . . John, what is
the primary evidence that power frequency fields have any health
association, and is this backed up by lab work?

<[john] SPACE.GUEST> 1) Epidemiological studies that suggest childhood
cancer near distribution lines; 2) (epi)demiological studies suggesting
cancer in people who work with electricity; 3) lab studies give no support
for the connection.

<[james] J.BRYAN> Are underground power lines safer than above ground power
lines?

<[john] SPACE.GUEST> Underground lines have lower fields

<JOHNMOSHER> What kind of cancers?

<[john] SPACE.GUEST> Leukemias and brain tumors are the types most often
associated with power-frequency exposure

<[john] SPACE.GUEST> BTW: Any future questions, I'm not on GEnie, but I'm
[e-mail] on Internet.

<JOHNMOSHER> What about Ozone and Ion production by high-voltage lines?

<[john] SPACE.GUEST> Should not be enough to cause problems - also, studies
showing excess cancer risks in USA are for distribution systems - no ozone.

<FRANK.REDDY> There is some disagreement even between the epi studies,
right? They don't all find a link -- especially those that take actual
dosimetry into account?

<[john] SPACE.GUEST> The epi studies are very contradictory and uneven - one
points to one cancer one to another and the next to nothing. That's why the
lab stuff is so important - if we could show a problem in an experimental
system we'd know where to go.

<C.POOLEY> Is evidence correlated with magnetic, or elect. field?

<[john] SPACE.GUEST> If there is a problem, its got to be the magnetic
field, the electrical field does not penetrate.

<[james] J.BRYAN> Are there any studies linking computer displays to eye
problems, or any type of cancers?

<[john] SPACE.GUEST> RE VDTs. That's a different issue -- I'll defer to
another time or if we get bored with power lines.

<JOHNMOSHER> Humidity plays a big part in the ion effect, has that been
checked?

<C.POOLEY> The e-field question is important to me because it should be zero
for underground due to shielding, and means to cope with it depends on
which type is problem.

<[john] SPACE.GUEST> There is no practical way to shield power-frequency
magnetic fields.

<C.POOLEY> Putting lines close together, like underground will reduce
magnetic field.

<[john] SPACE.GUEST> BUT: underground lowers fields are  more expensive.

<[john] SPACE.GUEST> To C.Poole: yes, crossed messages (-:

<C.POOLEY> Any environmental solution is expensive :)

<[john] SPACE.GUEST> Priorities are the issue! We cannot afford a 100%
underground solution.

<JOHNMOSHER> Underground also eliminates O3 and ion generation.

<FRANK.REDDY> Where is the push for these concerns coming from, John? I
know some of the epidemiologists have become quite vocal -- but that seems
odd given that the studies are hardly uniform and that there's no lab
support.

<[john] SPACE.GUEST> Pardon the cynicism - but there is big $$$ in
litigation.

<C.POOLEY> How do we know the epidem. evidence isn't due to economics--in
better neighborhoods, houses are further from ugly overhead power lines?

<[john] SPACE.GUEST> The idea that the power line cancer connection is due
to socioeconomics is not new. For those of you not into it, the kind of
cancer you get depends on your race and social class.  Also, power lines
follow roads, roads produce exhaust fumes, benzene is a carcinogen.

<JOHNMOSHER> If it is social/class related, diet seems more of a "cause".

<[john] SPACE.GUEST> Different topic, but not all socioeconomic cancer
trends are due to diet.  Many are due to what we call "life style choices."

<JOHNMOSHER> Like refrigeration Air Conditioning?

<[john] SPACE.GUEST> How about smoking as a socioeconomic risk? How about
living near carcinogen-producing industry as a socioeconomic risk?

<C.POOLEY> Let's see how the greens do with this when they push electric
cars.

<[john] SPACE.GUEST> You're not a <green>, I am on some things (-: If ya
wanna decrease your exposure, disconnect from the grid (-:

<C.POOLEY> John: I'm not a 'green' and I do believe that technology, on the
whole, has contributed greatly to health, longevity...

<[Dirk] D.TERRELL> What do these people have to say about the Earth's 0.6
gauss field?

<[john] SPACE.GUEST> The standard answer is that it is a static field, and
they are worried about AC fields, but I hear you.

<JOHNMOSHER> What I am trying to get a feel for is if the EM fields aren't
the problem, but the discharge from the lines bay be producing carcinogenic
compounds.

<C.POOLEY> Discharge from lines--you mean that sizzling I hear especially on
foggy mornings?

<JOHNMOSHER> Yes, the corona discharge makes all kinds of nasty things.  I
have 190 feet of 35 kV lines ~40 high through my property!

<[john] SPACE.GUEST> The best evidence for a problem is associated with the
distribution lines that run in your back yard (here) or street (other
places). They don't have enough voltage to produce corona discharge.

<[john] SPACE.GUEST> Corona - high voltage transmission. High magnetic
fields - local distribution lines.

<[james] J.BRYAN> To <Johnmosher>: What kind of carcinogenic compounds are
we talking about?

<JOHNMOSHER> #1 is ozone.

<[john] SPACE.GUEST> Ozone is an issue for high-voltage lines. The epi
evidence (such as it is) points to distribution lines.

<FRANK.REDDY> Hang on a sec -- I think we're getting a bit scattered here.
John has said that the best case for any cancer association is with the
distribution lines, which do not have a corona discharge (correct me if I'm
wrong here), but they do have high magnetic field.

<[john] SPACE.GUEST> Right - high current = high magnetic field.

<JOHNMOSHER> These are 636 MCM lines that carry about 500 amps.

<[john] SPACE.GUEST> These are low current compared to your local
distribution system!  Have we bored everyone to death (-:

<JOHNMOSHER> Wait a minute, the distribution is on #8 and is <100 Amps @ 4
KV.

<C.POOLEY> On magnetic. fields--the net current along a set of lines is zero--
right? So field is due to current in each wire and separation between
lines.  This will fall off with cube of distance, so range of effect will
be very short.

<[john] SPACE.GUEST> Pooley:  yes the fall off if very fast. But in
distribution systems, ground returns mess up things, the current mismatch
rises, and so do the fields.

<C.POOLEY> In 'far field' situation--distance from a set of lines being
greater than several times separation between lines--both e-field and
magnetic field will decrease with cube of distance.  That's one of
the reasons I've been dubious about all of this.

<[john] SPACE.GUEST> To Pooley: Yes, more than 100 ft from a power line
fields in homes are dominated by electricity used in the homes, not by the
lines.

<JOHNMOSHER> Has there been any study of DC transmission lines?

<[john] SPACE.GUEST> Yes, there are a couple around, one in Minnesota. No
AC magnetic field.

<C.POOLEY> John--ok, but in homes, the wiring tends to be in line pairs--
even extension cords etc--so the net current is zero, and because the wires
are very close together, the fields at low freq should be VERY low

<[john] SPACE.GUEST> C.POOLEY: Yes, if wiring was the only issue, but AC
motors cause big fields, plus the wiring is not perfectly paired.

<C.POOLEY> John--yes, motors do, but except for refrigeration, we don't
spend that much time near running motors--especially me, who doesn't vacuum
often.

<[john] SPACE.GUEST> Re: house field: Still, internal field exceeds
external (power line) fields within several hundred feet of a high-voltage
line.

<C.POOLEY> What is the field strength, John?

<[john] SPACE.GUEST> Typical magnetic-field strengths in homes -- 1-10 mGauss.

<C.POOLEY> John--doesn't sound like much to me. BTW, TV will produce quite
a bit at 15.75 kHz, and 60 Hz.  Any study done on that?

<[john] SPACE.GUEST> TV not that different from computer terminal.

<FRANK.REDDY> A couple of pending questions -- RE VDT and associated
problems and any results from the DC transmission studies . . .

<[john] SPACE.GUEST> RE: VDTs -separate subject, other frequency, ergonomic
issues, etc.  Re: DC lines - haven't seriously looked into, but field small
versus earth's field.

<FRANK.REDDY> Well, looks like it's getting time to wrap things up here.
Last questions for our guest?

<C.POOLEY> john--true, and since we sit nearer to term. than TV, effect
might be more--any evidence? GA

<[john] SPACE.GUEST> Nothing strong on VDT, what there is related to
pregnancy outcome.

<C.POOLEY> No worry for me, then :)

<FRANK.REDDY> On a rather different issue, but one that made the press
earlier this year, how about cellular phones? :)

<[john] SPACE.GUEST> Cell phones -- no scientific issue, very little power.

<[Dave] SPACE> So you're saying that the whole "my wife's cell phone gave
her brain cancer" thing was bogus from the start?

<[john] SPACE.GUEST> My opinion based on the scientific literature is yes,
it's bogus.

<[john] SPACE.GUEST> Doesn't mean that the plaintiff and their lawyer don't
believe it though.

<[Dave] SPACE> Ok.  <G>  (I've been saying the same thing, BTW)

<FRANK.REDDY> Well, thanks for coming, John!

<[Dirk] D.TERRELL> Yes, thank you John

<[Dave] SPACE> Yes!  Many thanks for spending time with us.

<FRANK.REDDY> I know it's an, ah, unique, method of communication :)

<[john] SPACE.GUEST> Unique, yes. Confusing, yes.

<FRANK.REDDY> Yeah :(. I'll send you a copy of the cleaned-up transcript,
too.

<[Dave] SPACE> Yes to both. <G>

<[john] SPACE.GUEST> Its interesting though, I'm more used to the Internet
system where flame wars take days to develop.

<FRANK.REDDY> Do you get flame wars on sci.med.physics?  Stupid question, I
suppose -- I _have_ seen Usennet :)

<[john] SPACE.GUEST> Not as bad as some, but it gets interesting.

-- END RTC TRANSCRIPT ----------------------------------------------------


MOULDER'S EMF Q&A

*Introduction

Most of the concern about power-frequency fields and cancer stems from two
sets of epidemiological studies.  Laboratory studies have shown no link
between power-frequency fields and cancer.

A very good review of the area has just been published by Oak Ridge
Associated Universities.  It is titled "Health Effects of Low-Frequency
Electric and Magnetic Fields".   It costs $25 and is available from National
Technical Information Service (ARAU 92/F-8) and the US Government Printing
Office (029-000-00443-9).

---------------------------

*To summarize the state-of the-art

- People living near power lines:
A number of studies have shown that children (but not adults) living near
certain types of powerlines (high current distribution lines and transmission
lines) have higher rates of leukemia, lymphomas and brain cancers (Refs 1-3).
 The results must be interpreted with caution. Several other studies have
shown no such correlations (Refs 4-8).  In addition, the correlation is not
strong, and none of the studies have shown dose-response curves.  What is
even more curious is that when power-frequency fields are actually measured,
the correlation vanishes (not surprising since the major sources of power-
frequency fields within dwelling comes from power usage inside the house).

- People working in "electrical occupations":
Several studies have shown that people who work in electrical occupations
have higher cancer rates (see refs 9-11 for reviews).  Most of the cautions
listed for the residential studies apply here also: many negative studies,
weak correlations, no dose-response curves.  An additional problem
interpreting these studies is that they are based on job titles - very little
actual dosimetry has been done.

- Laboratory studies
Power-frequency fields shown none of the classic signs of being carcinogens -
they do not cause DNA damage or chromosome breaks, and they are not mutagenic
(refs 12-15, 19-22).  No studies have shown that animals exposed to power-
frequency fields have increased cancer rates.  On the other hand, numerous
studies have reported that power-frequency fields do have "effects",
particularly at high field strength (refs 15,16).  Even among the scientists
who believe that there may be a connection between power-frequency fields and
cancer, there is no consensus on possible mechanisms (refs 15, 17, 18).

---------------------------

*What about the new "Swedish" study.

Actually there are four studies, residential and occupational from both
Sweden and Denmark.  None have been published in full, but translations of
the preliminary reports have been circulated.  It is the Fleychting & Ahlbom
study that is getting the most attention.

- Fleychting & Ahlbom, Magnetic fields and cancer in people residing near
Swedish high voltage powerlines.

This is a case-control study based of everyone in Sweden who lived on a
property within 300 meters of 220 or 400 kV powerlines between 1960 and 1985.
For children all types of tumors were analyzed, for adults only leukemia and
brain tumors were studied.  "Exposure" was assessed by spot measurements,
calculated retrospective assessments, and distance from powerlines.

No increased overall cancer risk was found for either children or adults.  An
increased risk for leukemia in children was found for *calculated* fields at
the time of diagnosis.  No significantly elevated cancer risks were found for
measure fields or proximity to powerlines.

Below are the relative risks with 95% CIs, based on calculated field greater
than 2 mG at time of diagnosis.
Childhood Leukemia   2.7 (1.0 - 6.3)
Childhood Brain      0.7 (0.1 - 2.7)
All childhood cancer       1.1 (0.5 - 2.1)
Adult Leukemia   1.0 (0.7 - 1.7)
Adult Brain      0.7 (0.4 - 1.3)

- Olsen and Nielson, Electromagnetic fields from high-power electricity
transmission systems and the risk of childhood cancer.

Case control study based on all childhood leukemia, brain tumors and
lymphomas diagnosed in Denmark between 1968 and 1986.  This would be most but
not all childhood cancer.  "Exposure" was assessed on the basis of calculated
fields over the period from conception to diagnosis; details on the exposure
metric are very sketchy.

No overall increase in cancer risk was found, but the risk of lymphoma was
elevated.  No increase in childhood leukemia or brain was found.

- Guenel et al.  Cancer incidence among Danish persons who have been exposed
to magnetic fields at work.

Case-control study based on all cancer in actively employed Danes between
1970 and 1987 who were 20-64 years old in 1970.  All were coded by job title
and industry.  Each occupation-industry combination was coded on the basis of
putative 50-Hz magnetic field exposure.  No appreciable increases in risk
were seen for breast cancer, malignant lymphomas or brain tumors.  Leukemia
incidence was elevated among men in the highest "exposure" category, with a
relative risk of 1.6 (1.2 - 2.2), women in similar exposure categories showed
no risk, but the numbers were small.

-Floderus et al, Occupational exposure to electromagnetic fields in relation
to leukemia and brain tumors.

Case control study of leukemia and brain tumors of men, 20-64 years of age in
1980 who were employed and living in mid-Sweden. "Exposure" calculations
were based on the job held longest during the 10-year period prior to
diagnosis.  Work places were actually visited and measurements were taken
using a contemporary person whose job was most similar to that of the person
in the study. About two thirds of the subjects in the study could be assessed
in this manner.

Age-adjusted relative risks (with 95% confidence intervals), based on
exposure in longest-held job above 2.9 mG
     Leukemia    1.6 (1.1 - 2.4)
     Brain       1.4 (0.9 - 2.1)

Within leukemias the elevated relative risk is principally for chronic
lymphocytic leukemia.

-------------

Granted that power-frequency fields are not genotoxic, that is that they
don't damage the genetic material, aren't there carcinogens that are not
genotoxic?

There are agents that influence the development of cancer without being
genotoxic.  It has been suggested that power-frequency EMFs could either
promote cancer or influence the progression of cancer.   A promoter is an
agent that increases the cancer risk in an animal already exposed to a
genotoxic carcinogen.  A progression effect would be one that increased the
growth rate of an existing tumor.

Over the last few years, numerous studies of the ability of power-frequency
EMF to influence promotion and progression have been done.  The promotion
studies have been uniformly negative (Refs  21, 23-26).  The studies of
progression have been mixed: 75% show no effects on tumor growth; the rest
are about equally mixed between studies showing increased growth and studies
showing decreased growth (Refs 13, 22, 24, 26, 27).

-------------------

* My professional opinion on the subject:

- Epidemiological studies of populations exposed to power frequency
electromagnetic fields do not show that such fields cause cancer.

- Epidemiological studies of occupational groups exposed to power frequency
electromagnetic fields do not show that such fields cause cancer.

- Epidemiological studies of human exposures to power frequency
electromagnetic fields allow one to speculate that these fields might in some
way influence cancer risks.

- Laboratory studies relevant to the issue of whether power frequency
electromagnetic fields are carcinogenic provide little evidence to support
the speculation that power frequency electromagnetic fields might influence
cancer risks.

- Laboratory studies relevant to the issue of whether power frequency
electromagnetic fields have effects on biological systems provide evidence to
support the idea that these fields can interact with biological systems.

- There is no consensus within the scientific community as to the mechanism
or mechanisms through which power frequency electromagnetic fields could
influence biological systems.

-----------------------
*References:

1) N Wertheimer, E Leeper. Electrical wiring configurations and childhood
cancer. Amer J Epidemiol 109:273-284, 1979.

2) DA Savitz, H Wachtel, et al. Case-control study of childhood cancer and
exposure to 60-Hz magnetic fields. Amer J Epidemiol 128:21-38, 1988.

3) SJ London, DC Thomas, et al. Exposure to residential electric and magnetic
fields and risk of childhood leukemia. Amer J Epidemiol 134:923-937, 1991.

4) MP Coleman, CMJ Bell, et al. Leukemia and residence near electricity
transmission equipment: a case-control study. Br J Cancer 60:793-798, 1989.

5) JP Fulton, S Cobb, et al. Electrical wiring configurations and childhood
leukemia in Rhode Island. Amer J Epidemiol 111:292-296, 1980.

6) ME McDowall. Mortality of persons resident in the vicinity of electrical
transmission facilities. Br J Cancer 53:271-279, 1986.

7) L Tomenius. 50-Hz electromagnetic environment and the incidence of
childhood tumors in Stockholm County. Bioelectromag 7:191-207, 1986.

8) A Myers, AD Clayden, et al. Childhood cancer and overhead powerlines: a
case-control study. Brit J Cancer 62:1008-1014, 1990.

9) M Coleman, V Beral. A review of epidemiological studies of the health
effects of living near or working with electrical generation and transmission
equipment. Int J Epidemiol 17:1-13, 1988.

10) JR Jauchem, JH Merritt. The epidemiology of exposure to electromagnetic
fields: an overview of the recent literature. J Clin Epidemiol 44:895-906,
1991.

11) DA Savitz, EE Calle. Leukemia and occupational exposure to
electromagnetic fields: Review of epidemiological studies. J Occup Med 29:47-
51, 1987.

12) AM Khalil, W Qassem. Cytogenetic effects of pulsing electromagnetic field
on human lymphocytes in vitro: chromosome aberrations, sister-chromatid
exchanges and cell kinetics. Mutat Res 247:141-146, 1991.

13) GK Livingston, KL Witt, et al. Reproductive integrity of mammalian cells
exposed to power frequency electromagnetic fields. Environ Molec Mutat 17:49-
58, 1991.

14) M Rosenthal, G Obe. Effects of 50-Hertz electromagnetic fields on
proliferation and on chromosomal aberrations in human peripheral lymphocytes
untreated and pretreated with chemical mutagens. Mutat Res 210:329-335, 1989.

15) TS Tenforde. Biological interactions and potential health effects of
extremely-low-frequency magnetic fields from power lines and other common
sources. Ann Rev Publ Health 13:173-196, 1992.

16) R Goodman, A Shirley-Henderson. Transcription and translation in cells
exposed to extremely low frequency electromagnetic fields. Bioelec Bioenerg
25:335-355, 1991.

17) JRN McLean, MA Stuchly, et al. Cancer promotion in a mouse-skin model by
a 60-Hz magnetic field: II. Tumor development and immune response.
Bioelectromag 12:273-287, 1991.

18) RB Goldberg, WA Creasey. A review of cancer induction by extremely low
frequency electromagnetic fields. Is there a plausible mechanism? Medical
Hypotheses 35:265-274, 1991.

19) J.C. Murphy, D.A. Kaden, J. Warren, and A. Sivak, Power frequency
electric and magnetic fields:  A review of genetic toxicology, Mutation
Research 296:221-240, 1993.

20) J. Nafziger, H. Desjobert, B. Benamar, J.J. Guillosson, and M. Adolphe,
DNA mutations and 50 Hz electromagnetic fields, Bioelectrochemistry and
Bioenergetics 30:133-141, 1993.

21) A. Rannug, T. Ekstrm, K.H. Mild, B. Holmberg, I. Gimenez-Conti, and T.J.
Slaga, A study on skin tumor formation in mice with 50 Hz magnetic field
exposure, Carcinogenesis 14:573-578, 1993.

22) R. Zwingelberg, G. Obe, M. Rosenthal, M. Mevissen, S. Buntenktter, and
W. Lscher:  Exposure of rats of a 50-Hz, 30-mT magnetic field influences
neither the frequencies of sister-chromatid exchanges nor proliferation
characteristics of cultured peripheral lymphocytes.  Mutation Research 302:39-
44, 1993.

23) A. Rannug et al: Rat liver foci study on coexposure with 50 Hz magnetic
fields and known carcinogens.  Bioelectromag 14:17-27, 1993.

24) M.A. Stuchly et al: Modification of tumor promotion in the mouse skin by
exposure to an alternating magnetic field.  Cancer Letters 65:1-7, 1992.

25) M.R. Scarfi et al: Spontaneous and mitomycin-C-induced micronuclei in
human lymphocytes exposed to [ELF] pulsed magnetic fields, Biochem Biophys
Res Comm 176:194-200, 1991.

26) J.R.N. McLean, et al: Cancer promotion in a mouse-skin model by a 60-Hz
magnetic field:  II.  Tumor development and immune response.  Bioelectromag
12:273-287, 1991.

27) S. Baumann et al: Lack of effects from 2000-Hz magnetic fields on mammary
adenocarcinoma and reproductive hormones in rats.  Bioelectromag 10:329-333,
1989.

28) R.A.E. Thomson et al: Influence of 60-Hertz magnetic fields on leukemia.
Bioelectromag 9:149-158, 1988.

John Moulder ([e-mail])                Voice: 414-266-4672
Radiation Biology Group                              FAX: [phone]
Medical College of Wisconsin, Milwaukee