Powerfrequency EMF Summary up to 2000
This article has been kept as it is a good indicator as to how long these
issues have been known about and contested in official circles.
- A moratorium should be imposed to prevent NEW residential building
within agreed distances of overhead power lines.
- Local Authorities should be given clear, and positive, guidance.
- We should adopt the precautionary stance set out in the Tamino report
passed by the European Parliament in March 1999
- Electricity Companies should be required to minimise fields from their
overhead and underground cables
- A requirement should be imposed on electricity companies to prove NEED
for new or upgraded cables.
Electromagnetic interactions are now being recognised as the basis of
bio-chemical actions and life itself. In the mid 1980's US scientist Eldon Byrd,
who worked for the US Navy, described their findings:
"We can alter the behaviour of cells, tissues, organs and whole organisms ...
alter the levels of hormones in living creatures, alter the reaction time of
irreversible chemical processes as well as the chemistry itself in a living
cell. We can alter time perception in humans and animals; we can make animals go
to sleep; we can make bone grow and we can stop bone growing; we can start and
stop cell de-differentiation - what that means is that we can make a cell that's
programmed to do one thing, do something else. We can entrain human brain waves.
We can cause up to six times higher foetal mortality and birth defects in
laboratory animals with fields so weak that you can hardly detect them. These
are only some of the results of interactions of weak, pulsed, usually E.L.F.,
magnetic fields and living systems." [1]
The Russian and US military have continued to spend vast sums on
bio-electromagnetics research. [2]
We are not suggesting that these things happen with the normal fields from
mains electricity, but wish to point out that electromagnetic fields can be used
to control life processes.
In May 1994, the European Parliament passed amendments to the proposed
Physical Agents Directive which called on all EU Governments to take initiatives
for regulations and standards to aim at limiting the exposure of workers and the
general public to electromagnetic fields according to the ALARA (As Low As
Reasonably Achievable) principle. This included corridors of land near
high-tension wires where housing would be banned, and the introduction of
systems of indemnification and compulsory purchase of properties with
significantly elevated EM fields. These amendments were not endorsed by the
Commission, and the last Conservative UK Government stated its opposition to the
whole of the Physical Agents Directive, which it saw as an unnecessary burden on
both industry and government.
In March 1999 the European Parliament approved the Tamino Proposals [3]. They
require that stringent basic restrictions and EMF exposure levels must be based
on the best available scientific data and advice. Member States are to lay down
minimum safety distances from electrical equipment, and minimum distances from
public buildings, housing and workplaces for the siting of high-voltage
transmission lines, radar equipment and broadcasting and re-broadcasting
transmitters, including cellular phone base stations.
In the UK the NRPB is responsible for providing guidance on these matters,
together with the Committee on Medical Aspects and Radiation in the Environment
(COMARE). Their advice goes to the Health and Safety Executive who help the
Government produce policy documents, but as these matters cross departmental and
ministerial boundaries it is particularly difficult to draft Policy. The present
Government's Science and Technology Committee is currently reviewing the quality
of advice it receives from the National Radiological Protection Board (NRPB), to
make sure government policies are based on the best available scientific data
and advice (see above).
The Secretary of State for Trade and Industry also has the duty, under the
Electricity Act 1989, to protect the public from the dangers arising from the
generation, transmission or supply of electricity. The NRPB advice was
summarised by Lord Inglewood in Parliament on 23 March 1995 as: "The NRPB ...
has concluded that the evidence does not establish that exposure to
electromagnetic fields is a cause of cancer, although it does provide some
evidence that the possibility exists, which justifies moving forward with
research". Please note: The current UK guidelines for EMFs are not intended
to protect people against chronic health problems, such as cancer, depression,
Alzheimer's Disease, etc.
Dr Roger Clarke, the Director of the NRPB, is on record [4] as saying that if
they did recognise the reality of these effects the Guidance levels would have
to come down by orders of magnitude. In the case of power frequency magnetic
fields by a factor of about 8000, to about 200 nanotesla (0.2 microtesla).
They have admitted that there is "some weak evidence" (1992), "weak
evidence" (1993), "some evidence" (1994), of association, but still
not enough to prove a causal link, between low levels of power frequency
magnetic fields and some types of cancer. It is important to realise that we
still do not actually know the mechanisms by which smoking or asbestos cause
cancer, but that has not stopped us taking appropriate preventative actions.
In a January 1994 BBC1 Panorama programme, Sir Richard Doll stated that
although a few years ago he did not believe that a link would be found, in the
light of the most recent research results he was now much less confident. When
pressed at a conference, Sir Richard, Chairman of the NRPB Advisory committee,
admitted that, if he were on a planning committee and was asked to approve a new
housing scheme and school next to 400kV lines, he said that he thought, as a
planner, that he would have to say: "such a development would not seem very
wise at present". [5]
In 1995 the USA Department of Energy issued a very helpful booklet, free to
all US citizens, entitled "Question and answers about EMF", which looks
in a very open minded way at all the issues, allowing interested individuals to
gain some understanding of the issues and make up their own minds about any
action. Nothing like this level of useful, open minded, information has been
produced by the UK authorities.
The USA debate was dominated by an 800 page draft National Council on
Radiation Protection (NCRP) Report [6 & 8]. The study, based on the first
comprehensive review of the world's literature on low frequency EMF health
effects, calls for strong action to curtail the exposure of the US population to
such fields. It was first reported in the UK in the Powerwatch August 1995
Newsletter.
The committee recommended that:
(a) new day care centres, schools and playgrounds should not have ambient power
magnetic fields above 200nT *;
(b) new housing should not be built where ambient fields exceed 200 nanotesla
(nT) for more than two hours daily;
(c) new lines should not produce fields exceeding 200nT in existing housing.
Additionally new office and industrial environments should be planned with the
aim of reducing exposures to a 200nT level over a frequency range from a few Hz
to 3000Hz (cycles per second).
* 200nT = 0.20 microtesla (uT); (see later for typical domestic levels)
In June 1999 the National Institute of Environmental Health Sciences released
a report in which its Director, Dr. Kenneth Olden, states that epidemiological
data show a "fairly consistent pattern of a small, increased risk of
childhood leukaemia and acute lymphocytic leukaemia in adults with increasing
EMF exposure." Olden concludes that "inexpensive and safe reductions in
exposures should be encouraged, through electric companies measuring fields in
customers' homes and helping them identify sources of high fields". He also
suggested that "the power industry continue the current US practice of siting
power lines to reduce exposure."
Sweden's National Electrical Safety Board (NESB) findings in 1993 and the
1999 NIEHS recommendations reinforce the precautionary principles outlined by
five Swedish authorities in their 1996 pamphlet called: "Low-frequency
Electrical and Magnetic Fields: The Precautionary Principle for National
Authorities - Guidance for decision makers" [7].
The Swedish National Authorities recommend the following precautionary principle:
"If measures generally reducing exposure can be taken at reasonable expense
and with reasonable consequences in all other respects, an effort should be made
to reduce fields radically deviating from what could be deemed normal in the
environment concerned. Where new electrical installations and buildings are
concerned, efforts should be made already at the planning stage to design and
position them in such a way that exposure is limited. The overriding purpose of
the precautionary principle is eventually to reduce exposure to magnetic fields
in our surroundings, so as to reduce the risk of injury to human beings."
They go on to look at what could be deemed to be normal magnetic field
levels. The median values for homes and day nurseries is given as 100 nT (0.1
µT) in major towns and cities, and below 50 nT in smaller towns and
rural areas. They re-iterated the policy that new schools, day-care centres and
play groups should not be located in areas where ambient power-frequency
magnetic fields are above 200 nanotesla (0.2 microtesla).
Some leading multi-national corporations are already specifying
precautionary levels (e.g. 0.1 µT max. in office areas, 0.3 µT max.
in corridors, toilets, etc.) in design criteria for new office buildings.
In signing the Maastricht treaty, the UK government agreed to apply the
precautionary principle in its decision-making. Powerwatch believes that the UK
should now adopt the European Parliament Tamino proposals.
Environmental causes of ill-health are usually first identified by
epidemiological studies investigating patterns of illness.
One of the strongest studies is the 1992 Swedish paper by Feychting &
Ahlbom. It investigated 436,503 people who had lived within 300 metres of a high
voltage power line, and indicated a dose-response relationship with childhood
leukaemia. It showed no effect below 0.1 µT, a doubling in relative risk
by 0.2 µT and, although there were no cases between 0.2 and 0.3 µ, a
tripling over 0.35 µT (microtesla).
A 1995 combined re-analysis of this and a Danish study by Dr Olsen, continued
to show this relationship with childhood leukaemia, with a five-fold increase in
risk for exposures over 0.5 µT, a level 3000 times lower than the current
UK exposure guidelines. Most, but not all, EMF epidemiological studies have
shown elevated risks of childhood leukaemia in the range 1.1 to 4, with some
studies showing even higher relative risk levels.
The USA National Council on Radiation Protection (NCRP) committee of 11 top
scientists charged with assessing published information on these issues has
allowed a version of its epidemiology conclusions to be published [8]. This
states: The weight of evidence supports an association of proximity to power
lines and risk of, at least, childhood leukaemia, and the weight of evidence
supports an association of putative occupational EMF exposure and increased risk
of leukaemia and brain tumours ... In addition, other possible associations
have begun to be examined that are plausible based on laboratory research on
melatonin. These include breast cancer in women and prostate cancer in men ...
Even effects which initially seem implausible in the laboratory may prove to be
causative, as illustrated in the early difficulties in confirming carcinogenic
effects of benzene and inhaled arsenic, known human carcinogens.
The US National Research Council - National Academy of Sciences issued a
report entitled "Possible Health Effects of Exposure to Residential Electric
and Magnetic Fields" [9]. The most important aspect of this report is
that it does establish and agree that even under the strictest possible
standards of proof, there is a reliable, though low, statistical association
between power lines and at least one form of cancer (childhood leukaemia).
This fact in itself shows that we need to do more to find out why this
relationship exists, and take prudent avoidance action in the meantime.
A much acclaimed USA National Cancer Institute (NCI) study by Linet et al,
was published in July 1997. Although some claimed that this was a "negative"
study, it did find an association between childhood leukaemia and measured
magnetic field levels very much in line with earlier studies: an increase in
risk of about 1.4 times over 300 nT (0.3 µT), rising to a six-fold
increase between 0.4 and 0.5 µT [10].
In June 1999 a team, led by Dr Lois Green, at the University of Toronto and
the Hospital for Sick Children reported their findings that children with the
highest exposures to EMFs were 4.5 times more likely to develop leukaemia than
those with the lowest exposures [11].
The weight of evidence does link powerlines and electricity EMFs with
childhood leukaemia, and in a number of studies, with brain tumours.
In 1998 a working group of the National Institute of Environmental Health Sciences
classified power frequency EMFs as a "probable human carcinogen" in the same
category as DDT [12].
The UK Childhood Cancer Study published 'proximity' paper in British Journal
of Cancer in November 2000. "Childhood cancer and residential proximity to power
lines" claims "no association" in the summary, but further reading of the paper
reveals a 42% increase near to 275 kV and 400 kV high-voltage power lines. They
were not able to check out the latest Bristol University findings. The UK NRPB issued what we see as a
scientifically and morally flawed response statement.
Another British Journal of Cancer Paper confirms high power-frequency
magnetic fields ARE associated with a doubling of childhood leukaemia. A
major meta-analysis of the original data from a large number of competent
studies of 3,203 children with leukaemia and 10,338 children without showed that
the few (62) children exposed to residential power-frequency magnetic fields
above 0.4 microtesla (4mG) have TWICE the chance of developing leukaemia
compared with the unexposed control children. Relative Risk = 2.0
(1.27-3.13), p=0.002 showing a high level of confidence in the result.
Yet another meta-analysis, this time of 15 studies, published in the November
issue of Epidemiology finds a 1.7 fold increase in childhood leukaemia
at 0.3 microtesla. There have been too few electric field studies published
to carry out a meaningful meta-analysis, but electric fields are also under
suspicion. These studies are are reported here.
There are various non-cancer effects which have been reported:
Clinical depression and suicide have been repeatedly associated with power line
fields. This work was initiated by a West Midlands GP Dr Stephen Perry in 1981,
and there have been further peer-reviewed studies which indicate an association
of depressive illness and suicide with living in close proximity to power lines.
Magnetic fields around 0.5 µT lower the pineal gland's synthesis of
melatonin. The pineal gland (deep inside our head) first converts an essential
amino acid, tryptophan, to serotonin, and then uses some of this serotonin to
produce melatonin. Studies have shown that lowered levels of serotonin are
associated with clinical depression. This effect could be involved in the
reported association between EMFs, depression, and immune system problems such
as ME / Chronic Fatigue Syndrome. Lowered melatonin has been associated with
sleep problems, lethargy, psychiatric disorders and immuno-deficiency.
Two studies now link EMF exposure to a raised incidence of Alzheimer's
Disease [13]. Several recent studies have shown that field levels of 12 µT
can completely block the growth inhibitory properties of melatonin, the body's
naturally-produced oncostatic agent. They also reported that magnetic field
levels at and above 1.2 µT, prevent the anti-cancer drug Tamoxifen from
inhibiting breast cancer and brain tumour cell growth.
A recent study showed up to a four-fold increase in testicular cancer in men
exposed to moderately high power-frequency magnetic fields [14].
Sources of electric and magnetic fields:
Overhead power lines, although a very visible and obvious source, probably only
account for a few percent of the UK population's EMF exposure. We agree with
National Grid comments that the EMF "Prudent Avoidance" concept includes all
aspects of our generation and use of electricity, especially including house
wiring and electrical appliance design and use.
According to research, including some carried out by National Grid, most
domestic ambient EMFs are caused by underground low voltage distribution cables.
Fields well over 0.2 uT can be found in many houses due to such underground
cables, and Powerwatch has found fields of up to ten microtesla. These are
usually due to what are termed "net" currents. These are "stray" currents either
flowing through the earth, or more usually through the wrong piece of cable or
metal pipework. UK electricity companies inter-connect neutrals from different
substations (allegedly necessary to prevent "over-voltage surges" occurring if
the local neutral becomes broken). This greatly increases unnecessary net
currents, which can be due to equipment or installation faults. This situation
could be prevented relatively easily if the electricity supply industry chose to
tackle the problem.
The background power frequency magnetic field level in a UK house is usually
around 40 nT (0.04 µT), and will generally range from about 15 nT to 90
nT. A number of houses and flats can have fields exceeding 1000 nT (1 µT)
due to underground cables, and some rural overhead low-voltage street
distribution cables also produce high EMFs. About 0.5% of UK homes have ambient
fields above 200 nT (0.2 µT), and VERY FEW houses have regular exposure
levels above 2000 nT (2 µT). European reports show mean domestic levels
between 10 and 70 nT (0.01 to 0.07 µT) for houses, and around 100 nT (0.1
µT) in flats and apartments.
Another common cause of elevated field levels is undetected faults in
internal building wiring. Appliances in the house continue to work correctly,
but cause high magnetic fields throughout large areas of the house. Powerwatch
has found fields as high as 15 uT from this cause. The problem can be prevented
by using "radial and tree" wiring methods instead of the usual UK "ring
circuits".
Powerwatch believes that a measured EMF assessment should be included in
every full building survey. The initial tests could be carried out in about 15
minutes. If high or suspicious readings are found, then a more thorough survey
would be necessary. More detailed information can be obtained by data-logging
EMF measurements over a period of several days.
There is increasing evidence that electric fields may also be a problem. [16,17,18]
A number of scientific studies have found highly significant associations
between higher than normal electric field levels and childhood cancer. Due to
support from the Children with Leukaemia charity, both magnetic and electric
fields are being measured in the landmark UK Childhood Cancer Study, the first
results of which are due to be reported in December 1999.
In the 1996 Ontario Hydro adult worker study conducted by Dr Anthony Miller
of Toronto University [19], when they took both fields into account, the risk of
developing leukaemia rose from 1.6 times to 11.2 times compared with unexposed
workers. It is likely to be a similar risk for children.
In order to minimise electric field levels, building wiring ideally needs to
be enclosed in metal conduit or trunking, or screened mains cable should be
used. Present day electric fields in many domestic properties greatly exceed the
10 volts per metre long term aim of the American NCRP report. We recommend that
people who are concerned about the levels of electric fields in their houses
should measure them.
Powerwatch believes that it would now be prudent to work towards ensuring
that power frequency magnetic fields are below 0.1 µT, and most electric
fields below 10 volts/metre.
A 1998 survey [20] suggested that the presence of overhead powerlines near a
property reduced the number of potential buyers by around 80%, and substations
reduced its desirability for about 57% of purchasers. It might take quite a lot
longer to sell it. Several UK lending institutions consider property with
overhead lines to be unsuitable security for a mortgage. Surveyors and valuers
who responded to the survey believed that property values and marketability were
adversely affected if substations, pylons, overhead or underground power lines
were within 200 metres of a property. The value could be reduced by as much as
30% for a power line within 50 metres, and as much as 20% for substations. Where
power lines go over a property a wayleave or easement is negotiated. A wayleave
is a personal agreement between the electricity company and the landowner and
usually ceases to have effect when the property is sold. It should then be
re-negotiated. [21]
National Grid and the Regional Electricity Companies have paid significant
compensation for loss of development potential of land underneath high voltage
overhead power lines. This compensation is not, however, easy to obtain, and
each case is considered on its merits.
The electricity supply industry is concerned about the various pending
adverse health Court cases and other unfavourable publicity, and is currently in
the process of setting up an £8,000,000 industry fund to help fight future
liability claims. [22]
Measurement of fields
We often suggest concerned people contact the local electricity company and ask
them to measure the house, and to provide a plan showing all nearby underground
electricity cables. A number of Regional Electricity Companies have now stopped
offering this service for free, unless you live next to a substation or overhead
line. Most have allocated a number of staff to deal with customer EMF queries.
Powerwatch believes that every surveyor should carry a small, easy-to-use,
electric and magnetic field monitor in order to make a basic assessment of the
ambient magnetic fields. Typical instruments can vary in price from a few
thousand pounds down to about £130 for small ELF Monitors. [23]
Powerwatch hires hand-held meters which measure both electric and magnetic
fields at £30 per week (as of 03/2000), including instructions and advice
as to what measured readings might mean. Many people find this an inexpensive
way of finding out whether or not they need to be concerned about EMF levels in
their homes and workplaces. We also have advanced EMF data-loggers for use when
a problem has been identified and readings need to be recorded at regular
intervals.
It is important that professional EMF surveyors are adequately trained -
there is more to carrying out a complete assessment than simply walking about
with a hand held EMF meter.
Conclusions and recommendations
Powerwatch believes that it is inexcusable to continue to ignore the evidence
that there are ill health effects associated with high voltage power lines, and
almost certainly with other forms of electricity use.
It is quite iniquitous for commercial electricity companies to be able to
make changes at will as 'permitted developments'. ALL significant electric cable
changes should be subject to planning controls, with appropriate appeals
procedures, and with requirements on the companies and Local Planning
Authorities to inform all affected residents.
A moratorium should immediately be imposed to prevent NEW building within
agreed distances of overhead power lines.
Some lines need greater distances (up to 250m), some are acceptable at much
closer distances, depending on a number of technical considerations. Lines
approaching these distances should have their electric and magnetic fields
measured. Field minimisation should be achieved by enforcing the reduction of
net currents from local substations and "balancing" overhead and underground
lines for optimum magnetic field cancellation.
Electric fields in houses should be reduced by returning to the old practice
of using earthed metal conduit (as is still done in public buildings). This
would add little to the total cost of a new house. Radial wiring should replace
the present "ring-main" system of wiring, to avoid generating large magnetic
fields.
References
[1] Living with Electricity pp 51-2
[2] Powerwatch Network Newsletter, No 11, November 1996>
[3] European Parliament, Proceedings, COM(98)0268-C4-0427/98-98/0166(CNS)
voted on 10.03.99 item 19.
[4] BBC Panorama, 31st January 1994
[5] EMF Conference Oct.'94.BICS 0171 336 7703
[6] Microwave News,
July / August 1995
[7] "L.F.Electrical and Magnetic Fields: The Precautionary Principle for
National Authorities"
Swedish Radiation Protection Institute, 171 16 Solna. Tel:08
729 7100, Fax: 08 729 7108
[8] Ch.7 in the Handbook of Biological Effects of Electromagnetic Fields, Eds.
Polk & Postow,
CRC Press, Second edition, 1996 ISBN 0 8493 0641 8
[9] US National Research Council - National Academy of Sciences report, 31st
October 1996,
"Possible Health Effects of Exposure to Residential Electric
and Magnetic Fields"
[10] Linet et al., "Residential exposure to magnetic fields and childhood ALL",
N.Eng.J.Med 1997:337(1)
[11] Dr L. Green et al., "A case-control study of childhood leukaemia in S
Ontario, Canada, & exposure to
magnetic fields in residences," Int. J. of Cancer June 1999
[12] Dr C.J. Portier et al., "Assessment of Health Effects from Exposure to
Power-Line Frequency Electric &
Magnetic Fields" ( NIEHS working group report) 16-24 June 1998
[13] Microwave News, July
/ August 1994
[14] Stenland & Floderus, Cancer Causes and Control (8, pp184-191, 1997)
[15] "Killing Fields
in the Home?"
[16] D.Henshaw, et al., "Enhanced Deposition of Radon Daughter Nuclei in the
Vicinity of Power Frequency
Electromagnetic Fields"; Internat. J. of Radiation Biology,
69, pp25-38, January 1996.
[17] A.Miller, et al., "Leukemia.....Utility Workers", Am.J.Epidemiology, 144,
pp150-160, July 15 1996.
[18] R.Coghill, J.Steward & A Philips, "ELF Electric and Magnetic fields in
the bedplace of children
with leukaemia: a case control study"; European J. of Cancer
Prevention,V.5,No.3,June 1996
[19] Dr A Miller et al., Am.J.Epidemiology, July 15th 1996, Vol 144 pp 150-160
[20] P. Dent & S. Sims, "Electricity Distribution & Residential Property
Values" 1999, Oxford Brookes University
[21] C.Gell, "Shocking Overheads", Estates Gazette, 2 August 1997, Issue 9731, pp 93-95
[22] Financial Times, front page, 11/Oct/1996
[23] Contact Perspective Scientific,
100 Baker St, London, W1M 1LA. Tel: (+44) 0207 486 6837
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