Current Shareware 1994 January/SHAR194.ISO/textfile/magnetic.zip/MAGNET3.TXT

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                    KILLING FIELDS

               THE EPIDEMIOLOGICAL EVIDENCE

          The threat posed by low frequency fields emerged
          initially because a reseacher, looking for
          environmently factors in childhood leukaemia,
          observed a link between low voltage, high current
          power lines and disease occurrence.  Cellular
          evidence now supports the findings but
          epidemiology still leads the argument.

          by: Simon Best

     Today living systems are exposed to a level of man-made electromagnetic
fields (EMF's) in all aspects of modern life to a degree never
experienced before on this planer, most of it resulting from technological
advances over the past 40 years.  Whether at home or at work, EM fields
generated by domestic wiring, overhead high voltage lines and
occupational equipment, as well as other environmental sources such as
radar, microwave communication systems, radio and television broadcasting,
cellular telephones, and the ubiquitous VDT, all contribute to an
indivual's cumulative chronic exposure.

     Growing awareness of this situation has led to the question being
debated and researched, for at least the past 30 years by Western
scientists (and even longer by the Russians), as to whether and to what
extent this chronic exposure is harmful.  The often heated debate
continues but over the past few years there are signs that certain
scientific and legislative authorities, particularly in the United States,
are beginning to accept the need for revised protective regulations and
safety legislation, despite continued official denial or ambivalence in
some quarters, notably in Britian.

     The UK's National Radiological Protection Board (NEPB) recently
published its final guidelines (1) on restricting public and
occupational exposure in both the extremelylow frequency (ELF) 50Hz
power frequency and the much higher frequency RF and microwave parts of
the electromagnetic spectrum.  Although these go further than any previous
such guidelines, they can be criticized on a number of counts, as will be
described below.  Also, they are proposed only as guidelines, with
decisions on new legislation left to the relevant minister; significantly,
no mention of electromagnetic fields was made in the Government's
recent proposed Green Bill.

     Bioelectromagnetics is the study of the effects of electromagnetic
fields on biological systems and an understanding of significant events
and issues in its recent history is necessary to appreciate currend
debate and developments.

     Research on the possible harmful effects of EM fields began to appear
in earnest after the war, partly due to the advent of radar, emerging as
an issue in the 1960's mainly as a result of Russian work (2).

    Observed health problems affecting switchyard workers and others
occupationally exposed to EM fields led the Russians to develop a
standard for public exposure to microwave and RF EM fields that was ,
at 10uW/cm^2, 1000 times lower than that considered safe in America and
other Western countries.

     The Americans, however, developed their guidelines, such as they
were, from a model of human absorption of electromagnetic energy tahat
took account only of the effects of heating body tissue - the so-called
thermal mode.  In the 1950's, Professor Herman Schwan, a physicist who
arrived in the US after teh War and has been based at the University of
Pennsylvania ever since, mainly funded by the Department of Defense,
invented the microwave oven for use in submarines.  Schwan used metal
balls and flasks of salt water to model the human body's ability to
dissipate heat to estimate a danger level of exposure.  Observing that
significant heating only occurred above 100mW, he incorporated a safety
factor of 10 and, in 1953, proposed a safey limit of 10mW/cm^2 for
human exposure.

     By 1957/58 industry and the military had, with little real debate
or further experimentation - and none for nonthermal effects - accepted
the level as an informal guideline.  In 1965 the Army and Air Force
formally adopted the 10mW/cm2 limit and one year later the American
National Standards Institute (ANSI) accepted it as an occupational
exposure standard.  The ANSI decision is remarkable, since Schwan has
consistently maintained that his dosage limit is safe for probably no
more than an hour.

     As will be discussed below, current debate on revising the ANSI
standard is suggesting reductions by between 10 and 100 times.  And it
is the growing and accumulated evidence supporting the reality of
non-thermal effects that has fuelled this debate, much of which, in the
face of opposition and limited funding, has been finally carried out over
the past decade.

     The first well-controlled Western study lining power line fields and
childhood leukaemia was reported by University of Chicago researchers
Drs. Nancy Wertheimer and Ed Leeper in 1979, from a case-control study
of 344 children aged 18 and under in the Denver area (3).  Using a wire
coding and configuration assessment of the high-current electric cables
near the children's homes to indicate 60Hz magnetic-field exposure, they
found a statistically significant increase in childhood cancer in the
exposed children, a relationship tht increase with proximity.

     In the UK in the same year an Albrighton GP, Dr. Stephen Perry,
collaborated with three US researchers in New York to study suicide in
the Shropshire/Staffordshire area.  He measured teh residential
magnetic-field strength outside the front door of homes and found
significantly higher fields (0.1uT or more) at those of suicides as
opposed to controls (less than 0.1ut); the results were published in
1981 (4).  A significant trend in risk of suicide was shown with
increasing field strength.

     A year later Tomenius, in Sweden, reported a two-fold increase in
the incidence of childhood cancers in homes within 150m of visible 200kV
power lines, his work being published in a revised form in 1986 (5).
(As in the UK, Europe uses a 50Hz power frequency.)  At addresses where
the magnetic field exceeded 0.3uT, the relative risk was 2.7 (95% CI 1.2-5.9);
when the sample was restricted to those living at the same address since
birth, the relative risk rose to 5.6 (95% CI 1.8-17.9).

     One year before Wertheimer and Leeper's study, the New York Public
Service Commission reached a decision in a hearing concerning two proposed
765kV lines to run from the Canadian border to locations in New York State.
After an acrimonious hearing the New York Public Service Commission
permitted the lines to be erected but only on two conditions: that the
power utilities involved fund a five-year, five-million-dollar research
project, known as the New York State Power Lines Project (NYSPLP),
to study possible hazards from power-frequency EM fields; and that a
350 feet right-of-way (ROW) corridor either side of the lines be established
within which no human dwelling ws to be permitted, as already existed for
345kV lines.

     Almost simultaneously, a public inquiry in the UK was taking place
into the proposed re-routing of power lines near the village of Innsworth,
Gloucestershire.  Is eventual result, however, was very different, with
the objection being overruled by the two inspectors (one each from the
Departments of Energy and the Environment), but without any independent
medical assessment of the evidence.

     That illustrates the stark contrast between legislative progress in
the US compared to the UK.  Today, 10 years later, despite seven American
states having now adopted similar ROW's to those in New York state, no
such recognition is given in the UK of the need for ROW's around power
lines.

     The results of Wertheimer and Leeper, Perry and Tomenius, as well
as teh setting up of the NYSPLP, led to a growing number of studies of
both residential and occupational exposure to ELF EM fields.  Wertheimer
and Leeper extended their research to adults and observed at least a
two-fold increase in adult leukaemia linked to fields from wires near
the home (6), while others found correlations with occupational groups
exposed to ELF fields, such as electrical and electronics workers and
repairmen, and leukaemia in general; Milham (7) and Stern (8) in the
States, Coleman and colleagues in the UK (9) and Pearche in New Zealand (10).

     Similar occupational studies have linked pharyngeal cancer (11),
eye melanoma (12), and primary brain tumour (13,14).  One of the most
consistent connections was observed with myeloid leukaemia, with studies
from teh UK (15,16), Sweden (17) and the US (18,19) all finding an
elevated risk.

     Some of the results of the occupational studies have been criticized
on the basis that workers might have also been exposed to fumes and
substances (such as PCB's) then used in electrical components or asseblies.
However, in one of the US studies of myeloid leukaemia, Milham (19)
studied radio amateurs and found a greatly increased risk of myeloid and
unspecified leukaemias in both those with and without occupational exposure,
thus supporting the hypotheses that it is the electromagnetic fields
themselves that are the hazard.

     Meanwhile, on the question of residential exposure and cancer, the CEGB
hac, by 1985, caried out only one piece of research, a pilot study of
childhood leukaemia reported at a conference (20), an inconclusive result
which the authors nonetheless admitted had certain shortcomings and of
which a revised version has apparently now finally been submitted for
publication.

     During this time, other laboratory work was confirming the ability
of low-intensity EM fields to cause biological effects below the thermal
level and revealing some frequency-specific actions of modulated fields.
Dr. Ross Adey and his coworkers have demonstrated the effect of specific
modulated frequencies on the efflux of calcuim ions from cats' brains (21,22),
which has been confirmed by Blackman and others (22,23).

     The combination of the highly suggestive epidemiological results and
the growing evidence from animal and cellular studies led, in 1986, to a
landmark pronouncement by the American Advisory Committee on the
Non-Thermal Effects of Non-Ionizing Radiation.

     Reporting to the United States National Academy of Sciences'
National Research Council, it finally accepted the reality of non-thermal
effects and stated that "Abundant fragmentary evidence has been presented
in support of possible biological effects from non-ionizing
radiation, at both transmission and microwave frequencies.  These effects
often appear to be unaccompanied by macroscopic thermal changes" (24).

     The report drew the distinction between a biological effect and the
point at which it becomes a hazard and stopped short of discussing when
this might occure, but the announcement was a significant turning-point
in the continuing debate.

     A further significant event occurred on July 1, 1987 when the New
York State Power Line Project finally reported amid wide media coverage (25)
(a copy resides in the House of Commons library).  Of the 17 funded
studies, 12 reported significant disease and depression . . ." was
reported in those living near the cable.

     A further provocative finding was that, if only those blocks with
underfloor or storage electric heating were considered, the proportion
of cases of "depression" living in flats near the rising cable rose by
82%.  (Wertheimer and Leeper have recently linked increased miscarriage
rates with EM fields from ceiling-cable heating; see below (33).)

     It is interesting that even Perry's lowest measurements of fields
in apartments distant from the cable are 50% above the average residential
fields measured by Bowman, while his average `near' readings were over
three times Bowman's figure.

     It is also worth noting that when Savitz revised and refined his
original data on childhood leukaemia (26), he found that, whereas when
he had used a 0.2uT cutoff for classifying the 60Hz exposed group he had
observed a relatively weak, if two-fold, association between measured
magnetic field and leukaemia, when he increased the cut-off to 0.3uT, the
risk became "... notably larger".

     Thys, Tomenius', Savitz' and Perry's (two) studies together
indicate that there may be a residential level between 0.2 and 0.3uT
at which chronic power-frequency EM field exposure begins to manifest as
a recognised clinical condition; in which case, occupational levels of
between 1uT and 5uT and above, as measured by Bowman, may represent a
considerable hazard, despite exposure being confined only to working hours.

     Currently the NRPB is recommending a level of 2mT for both public and
occupational magnetic-field exposure, approximately 10,000 times above
the levels indicated by Savitz, Perry and others as hazardous.  But what
is equally disquieting is that in 1986, in a set of proposed standards
on which the NRPB invited comments (34), it was suggesting both one set
of standards for workers and two different sets for the public: for
workers (two hours exposure per day), 30kV/m and 1.88mT: for the public,
12kV/m and 0.76mT (up to five hours per day) and 2.6kV/m and 0.174mT for
continuous exposure.

     With the published research after 1986 increasingly pointing to am
EM field hazard both occupationally and residentially, particularly from
magnetic fields as low as 0.2-0.3uT, as outlined above, one must ask on
what basis did the NRPB, three years later, decide to recomment that public
and occupational continuous exposure levels be revised upwards, in the
case of continuous residential exposure to electric and magnetic fields
by, respectively, some five and ten times?

     Following Perry's investigation of depression, a further study of
depression and chronic headache was carried out by another British GP,
Dr. David Dowson, in the Southampton area (35).  Giving a questionnaire
to patients living within various distances of overhead lines and a control
group living three miles away, Dowson found that 15 in the former group
versus one in the latter reported recurrent headaches, the highest
number (10) living at 80-100m from a 132kVline.  Nine patients in the
study group reported depression (seven lived within 40m of the lines),
as against onl one in the control group.  No measurements of electric
or magnetic field were taken.

     In the US, Wertheimer and Leeper, in a study first presented to the
New York Academy of Sciences in 1984, reported theat pregnancies among
couples using electric blankets were more likely to end in miscarriage
than those among couples who did not heat their beds electrically (36).
They found a trend toward slower foetal development among babies born
to parents using electric blankets or water beds, which generate magnetic
fields of 1.0-1.5 and 0.3-0.4uT respectively.

     The researchers observed a clustering of spontaneous abortions from
September to June among electric blanket users; for those using either
electric blankets or water beds the miscarriage rate was significantly
higher during the September-June period.  No such seasonal pattern was
observed among non-users.

     Wertheimer and Leeper implicated electric blankets in a further study
(37) in which they re-analysed the apparently negative results of Stevens
on the incidence of acute non-lymphocytic leukaemia in adults exposed to
ELF fields redidentially, originally funded as part of NYSPLP.

     Using Stevens' data, they were able to assess the chronic use of
electric blankets, waterbed heaters and electric mattress pads.  By
taking these and other refinements into account, Wertheimer and Leeper
calculated that the risk of leukaemia in those exposed to EM fields from
either power lines or electrically heated beds rose 50-90% and, if
exposed to both, by 110-260%.  Most recently, Wertheimer and Leeper, in
an attempt to distinguish heating from EM field effects, have also
linked miscarriage and domestic EM fields from ceiling cable heating (38).

     It has been hypothesized that electric blankets may interfere with
the menstrual cycle by affecting the pineal gland's secretion of melatonin,
which in turn may also led to depressive states in men and women.  A
study is presently under way at the Yale School of Medicine on the
prevalence of electric-blanket use in a group of 4000 pregnant women to
determine the feasibility of studying the growth of children exposed to
EM fields in utero.

     Regarding adult leukaemia, Wertheimer and Leeper have extensively
analysed teh cancer incidence among adults living near high-current power
line in and around Denver, Colorado (39).  They found that certain cancer
subtypes, especially nervous-system cancers, were associated with two measures
of exposure to 60Hz magnetic fields.  Both those exposed occupationally
and residentially showed similarities in the subtypes they contracted.

     In a further memorandum, the researchers discuss a possible
explanation for why some studies have reported no linear increase in
cancer in children with increased intensity of EM field exposure
prenatally (40).  They confirm that, in their own and other studies,
moderate exposure prenatally was associated with increased cancer after
birth, whereas extreme exposure prenatally was not.

     They hypothesise that this occurs because magnetic fields "... can
have an adverse effect on tissue development which, if it is severe and
occurs in the first trimester of pregnancy, may often lead to prenatal
abortion rather than postnatal cancer".

     Clearly, if valid, their suggestion may also help explain some of the
contradictory findings on leukaemia clusters and ionizing radiation
sources in the UK, notably nuclear reprocessing and military installations.
Synergistic interactions between ionizing and non-ionizing radiation
generated around such sites (the latter from the power lines that often
originate from such locations) should also not be overlooked.

     All of which does not apparently, impress the NEPB, whose safety
guidelines are firmly based only on thermal considerations, although
their May 1989 document states that they intend to publish a "... review
of the existing biological and epidemiological evidence in the near
future".

     Not suprisingly, the CEGB tends to hold a similar view regarding the
lack of hazard from power line or domestic wiring EM fields.  However,in
March 1988, possibly galvanised by Savitz' results and the NYSPLP Report
in the previous year, they announced a L500,000 research project on ELF
eM field bioeffects, involving studies of theri own staff, childhood
leukaemian and domestic measurements.  But no results are yet available
and may ot be for some time.

     When evaluating US and UK residential research, on needs to consider
the differences in the distribution of power to homes between the two
countries.  In the US, transmission lines carry up to 765kV, while poles
carry local distribution wires down the streets and at intervals also
carry transformers which step down the 7.6kV area feed to 115vV for
domestic use.

     Indeed, it was the clustering of childhood cancer cases in homes at
certain cistances from these pole-mounted transformers and associated
3-phase wiring which first caught Wertheimer's atention in the mid-1970's.
From these, a single-phase supply then enters the house half way up the
building, very often at or near the bedrooms.  By contrast, in Britain
transmission lines carry 132, 345 or 400kV, with most domestic supply
ariving underground, having been stepped down from the area substation
by smaller local transformers (from 33 to 11kV, and from 11kV to the
domestic 240V).  The cables, carrying the wires in a close, helical
arrangement, thus generating a minimal unbalanced current, then enter
the house through the basement or ground floor to connect to a meter
(except in high-rise blocks, where they run up the side of the building).

     However, this is not always the case, as in parts of Norfolk,
Suffolk and other rural areas, where supply arrives on poles down the
streets, as in the United States.  Nonetheless, with both
methods, significant magnetic fields in the home can be generated by
unbalanced ground return currents.

     Because some have argued that these differences in mode of domestic
supply and associated EM fields may explain the generally more positive
American residential study results against the relatively few but more
megative or ambibalent UK results (20,41), it could be very illuminating
if the CEGN or other researchers were to compare the incidence of major
and minor illness (from cancer, heart disease and immune system problems
to miscarriage, depression and sleeping problems) in samples of both
adults and children living in homes supplied by the two different methods.

     In Myers' preliminary results (20) of childhood cancer in the north
of England, of which a revised update is apparently to be published
shortly, some 7% of the controls lived within 100m of an overhead power
line; the relative risk for those living within 50m was a non-significant
1.25 for leukaemia and lymphoma (95% CI 05.-3.1) and 1.61 for solid
tumours (95% CI 0.6-4.6).  Criticism of the small number of exposed subjects
and other shortcomings must await the final published version.

     McDowell's cohort study (41) of 7631 people living in East Anglia
within 30m of an overhead power line or within 50m of a transformer
substation found a significant excess in lung cancer in women though not
in men, although no smoking data was available.  For those living within
15m of a source, the standardized mortality ratios were higher for
lung cancer, leukaemia and other lymphomas, though numbers of deaths
were small.  The results applied mainly to substations, since only 0.2%
of the sample lived within 30m of an overhead power line.

     The inconclusive results of Coleman and colleagues in the recent
publication of a study, first reported in 1985, of leukaemia in those
living near overhead power lines or substations in four London boroughs (42)
emphasizes the problems of estimating exposure and obtaining a sufficient
sample to provide a meaningful result.  In the study only 0.6% of
subjects lived within 100m of a power line, whereas over 40% lived within
100m of a substation.  Nonetheless, for those under 18 the relative risk
of leukaemia from residence within 50m of a substation was in fact higher
than in adults (RR=1.5, 95% CI 0.7-3.4).

     Besides the problem of sampling, any future residential studies
must now also consider the occupational exposure of the working adults
involved, given the many studies linking electric occupations with
greatly increased risk of various cancers (and vice versa for o
occupational studies).  Exposure to other known environmental hazards
must also be controlled for, including the increasingly recognised hazard
of (ionizing) radon.  The location of a child's school near overhead
power lines or substation would also be significant.

     but the question one still has to ask is whether ther is already
enough suggestive evidence on which to recommend some preventative action.
Epidemiological studies are rarely conclusive, but when teh majority of
occupational and residential studies, despite differences in design and
possible confounding variables, seem to point in the same direction,
perhaps it is time to err on the side of caution and, for example, to
call for a moratorium on the erection of power lines over homes and
schools, and vice versa.

     The CEGB is unlikely to accept such a proposition, particularly
with the implications for its looming privatisation, without some form
of exemption fromlegal liability.  But if a system of no-fault
compensation could be introduced, as exists in countries such as New
Zealand and Sweden, whereby the state accepteed basic responsibility for
treating and possibly compensating people exposed to such a hazard, a
way forward acceptable to the CEGB and local area boards and favourable
to the public might be found.

     With some US and UK researchers publicly stating that they would not
live under a power line, perhaps the CEGN might at least be required to
offer to purchase homes under or very near power lines at market value
to resell to those prepared to take the risk, as a utility in British
Columbia in Canada recently did.

     Certainly, long and expensive litigation, as has occurred in the
US, may only serve to entrench both sides and delay help for those at
risk, though it has definitely brought the issues to the attention of
the public and the media there.  The case need not be that the evidence
is conclusive, merely that it is now sufficient to warrant certain
precautionary measures, both for domestic and occupational exposure.

     Regarding the latter, the Industrial Injuries Advisory Council
(IIAC) will take some persuading, it would seem, judging by their
opinion on the hazards of non-ionizing radiation from various occupational
sources (43).  Their statement that "The available evidence indicates that
chronic low level exposure to non-ionizing radiations appears to be
generally harmless: would be greeted with something approaching derision
by most researchers, even taking account of its date of consideration
in March 1987.

     Whether or not the CEGN disappears, the problem will remain for
the private tranmission and distribution companies, who can no longer
claim ignorance of research findings and will presumably be required
to carry on the CEGB's research in this area.

     Is it worth risking the negative publicity and threat of class-action
litigation in the future tht would cloud privatisation plans, or will the
electricity industry, in conjunction with the Government, consider it
wise to `green' their respetive images and work out some sort of solution
to the problem of electromagnetic fields in the environment which many
now feel pose a growing and chronic threat to their health?
Evidence of electromagnetic bioeffects mounts despite official ambivalence.