Why we need prudent avoidance of exposure to elevated levels of magnetic fields associated with the electricity supply


- Opinion -   Professor D. L. Henshaw   04/09/02


There is now a clear case for prudent avoidance of exposure to elevated levels of magnetic fields such as those associated with high voltage powerlines but also associated with the electricity supply generally. Here, we summarise the latest scientific information concerning exposures to power frequency magnetic fields and adverse health outcomes, and the steps that some countries are taking either by legislation or by recommendation to avoid unnecessary exposures.

Three Bodies, the US National Institute on Environmental Health Sciences (NIEHS), the International Agency for Research on Cancer (IARC) and the UK National Radiological Protection Board Advisory Group on Non-Ionising Radiation (AGNIR) now agree that magnetic fields are a possible carcinogen. Their conclusion is based on the pooled analyses of epidemiological studies which show a doubling of childhood leukaemia risk associated with magnetic field exposures above 0.4 microtesla, µT (Ahlbom et al, 2000 and Greenland et al, 2000). Full reference to these and related papers

In July 2001, the California Health Department issued a major EMF report for public discussion citing an added risk of miscarriage, childhood leukaemia, adult leukaemia, adult brain cancer and amyotrophic lateral sclerosis (ALS), a form of motor neurone disease as some of the health risks associated with exposure to electric and magnetic fields such as those that radiate from powerlines. The final version of the California Report is about to be published and details have already been discussed in a report in Microwave News, July/August 2002 and on CNN



1. The final Report confirms the findings of the earlier report.


Several studies have suggested an increased risk of depression and suicide associated with magnetic field exposures above 0.2 µT. These are mentioned in the IARC and California reports and are discussed in more detail in a recent paper in the journal Medical Hypotheses (Vol. 59, 39-51, 2002). At the same time magnetic fields as low as 0.2 µT have been shown to reduce the nocturnal production of melatonin in the pineal gland in human populations (Davis et al, 2001; others).   1.2 µT fields have been shown to inhibit the oncostatic action of melatonin on breast cancer cells in vitro (Ishido et al, 2001; others). Such fields have also been shown to reduce the effectiveness of Tamoxifen, a drug widely used in the treatment of breast cancer (Liburdy & Harland, 1997; others). Here is a summary of adverse health effects associated with magnetic field exposures.


2. The case for strict limits on exposure to elevated levels of power frequency magnetic fields

Magnetic fields are measured in units called Tesla. Domestic levels are most usually microtesla. These are written µT. So 1 µT should be read as “one microtesla”.

Physics definitions of Magnetic Field Strength, Magnetic Flux Density and Tesla

Below is a summary of current regulations and advisory exposure limits to magnetic fields. Some countries, notably Sweden, Switzerland and parts of Italy have already moved to introduce either advisory or regulatory limits of exposure for new installations. There is also a recent court decision in Queensland, Australia which some argue may set a precedent in Australia.

- UK National Radiological Board, NRPB 1600 µT
- International Commission onNon-Ionising radiation Protection, ICNIRP   100 µT
- 1996 Swedish Advisory Bodies suggest power distribution should avoid above
   average exposures
  0.2 µT*
- Swiss Government 1999 limit for new installations.
   Explanatory notes and Ordinance
    1 µT
- 2000 Three Italian Regions: Veneto, Emilia-Romagna and Toscana - limit for
   new installations §   Full details
  0.2 µT
- 2002 New substation in Queensland, Australia: Energex Ltd settle out of court.
   Full details
  0.4 µT
- 2003 California Education Department exposure limit for schools
   (under discussion) Full details (PDF File: 218 KB)
  0.01 µT



* Some scientists have called for an across-the-board limit of 0.2 µT
§ These regional government decisions are not currently endorsed by the Itallian government in Rome

October 2001
The World Health Organistation (WHO) endorsed a policy of prudent avoidance of exposure to elevated levels of EMF's




3. Health implications of exposure to magnetic fields from the electricity supply


September 2002
Levels of exposure to magnetic fields that are associated with certain biological effects and health conditions:

Miscarriage1 1.6 µT
Suppression of the 'anti-cancer' action of melatonin on cancer cells2 1.2 µT
Childhood leukaemia3 0.4 µT
Adult leukaemia3 0.4 µT
Depression of nocturnal melatonin4 0.2 µT
Suicide5 0.2 µT
Depression and depressive symptons6 0.1 µT
1  California Health Department report, Chapter 13 and Appendices 5 and 6
2  Ishido et al(2001)
3  California Health Department Report, Chapter 8
4  Davis et al(2001) and Levallois et al (2001)
5  California Health Department Report, Chapter 18. On current evidence, a link with EMFs was considered 10-50% likely

References


1

California Health Department Report, 2001. An evaluation of the possible risks from electric and magnetic fields (EMFs) from powerlines, internal Wiring, electrical occupations and appliances. Summary or Full report

Li, D., Odouli, R., Wi, S., Janevic, T., Golditch, I., Bracken, T.D., Senior, R., Rankin, R. and Iriye, R., 2002. A population-based prospective cohort study of personal exposure to magnetic fields during pregnancy and the risk of miscarriage. Epidemiology, 13, 9-20.

Lee, G. M., Neutra, R. R., Hristova, L., Yost, M. and Hiatt, R. A., 2002. A nested case-control study of residential and personal magnetic field measures and miscarriages. Epidemiology, 13, 21-31.



2

Ishido, M., Nitta, H. and Kabuto, M., 2001. Magnetic fields (MF) of 50 Hz at 1.2 µT as well as 100 µT cause uncoupling of inhibitory pathways of adenylyl cyclase mediated by melatonin 1a receptor in MF-sensitive MCF-7 cells. Carcinogenesis, 22 (7), 1043-1048.

Liburdy, R. P., 1992. Calcium signalling in lymphocytes and ELF fields. FEBS Lett, 301, 53-59.

Liburdy, R. P., Sloma, T. R., Sokolic, R. and Yaswen, P., 1993. ELF magnetic fields, breast cancer, and melatonin: 60 Hz fields block melatonin’s oncostatic action on ER + breast cancer cell proliferation. Journal of Pineal Research, 14, 89-97.

Blackman, C. F. and Benane, S. G., 1998. The influence of magnetic fields on inhibition of MCF-7 cell growth by tamoxifen. Paper at the 20th Annual Meeting of the Bioelectromagnetics Society, St Pete Beach, FL.

Luben, R. A. and Morgan, A. P., 1998. Independent replication of 60 hz, 1.2 µT EMF effects on melatonin and tamoxifen responses of MCF-7 breast cancer cells in vitro. Paper at the 20th Annual Meeting of the Bioelectromagnetics Society, St. Pete Beach, FL.

Morris, J. E., Chrisler, W. B., Miller, D. L., Sasser, L. B. and Anderson, L. E., 1998. In vitro exposure of MCF-7 human mammary cells to 60 Hz magnetic fields. Paper at the 20th Annual Meeting of the Bioelectromagnetics Society, St. Pete Beach, FL.



3

Liburdy, R. P. and Harland, J. D., 1997. Magnetic Fields, Melatonin, Tamoxifen, and Human Breast Cancer Cell Growth. In: Stevens R. G., Wilson B. W., Anderson L.E. (Eds). The Melatonin Hypothesis - Breast Cancer and Use of Electric Power. Battelle Press, Columbus, Richland 1997: 669-700.

Harland, J. D. and Liburdy, R. P., 1997. Environmental magnetic fields inhibit the antiproliferative action of tamoxifen and melatonin in a human breast cancer cell line. Bioelectromagnetics, 18, 555-562.

Harland, J., Engstrom, S. and Liburdy R., 1999. Evidence for a slow time-scale of interaction for magnetic fields inhibiting tamoxifen’s antiproliferative action in human breast cancer cells. Cell Biochemistry & Biophysics, 31(3), 295-306.

Blackman, C. F., Benane, S. G. and House, D. E., 2001. The influence of 1.2 µT, 60 Hz magnetic fields on melatonin and tamoxifen-induced inhibition of MCF-7 cell growth. Bioelectromagnetics, 22(2), 122-128.



4

California Health Department Report, 2001. An Evaluation of the Possible Risks from Electric and Magnetic Fields (EMFs) from Power Lines, Internal Wiring, Electrical Occupations and Appliances. http://www.dhs.ca.gov/ehib/emf/RiskEvaluation/riskeval.html

Ahlbom, A., Day, N, Feychting, M., Roman, E., Skinner, J., Dockerty, J., McBride, M., Michaelis, J., Olsen, J. H., Tynes, T. and Verkasalo, P. K., 2000. A pooled analysis of magnetic fields and childhood leukaemia, British Journal of Cancer, 83(5), 692-698.

Greenland, S., Sheppard, A. R., Kaune, W. T., Poole, C. and Kelsh, M. A., 2000. A pooled analysis of magnetic fields, wire codes and childhood leukaemia. Epidemiology, 11, 624-634.

National Radiological Protection Board, 2001. Power lines and cancer. Radiological Protection Bulletin, No. 230.

IARC Monographs of the Evaluation of Carcinogenic Risks to Humans, 2002. Non-Ionizing Radiation, Part 1: Static and Extremely Low-Frequency (ELF) Electric and Magnetic Fields. Volume 80, 19-26 June 2001, IARC Press, 150 cours Albert Thomas, F-69372 Lyon cedex 08, France.



5

Davis, S., Kaune, W. T., Mirick, D. K., Chen, C. and Stevens, R. G., 2001. Residential Magnetic Fields, Light-at-Night, and Nocturnal Urinary 6-Sulfatoxymelatonin Concentration in Women. American Journal of Epidemiology, 154 (7), 591-600.

Levallois, P., Dumont, M., Touitou, Y., Gingras, S., Mâsse, B., Gauvin, D., Kröger, E., Bourdages, M. and Douville, P., 2001. Effects of Electric and Magnetic Fields from High-power Lines on Female Urinary Excretion of 6-Sulfatoxymelatonin. American Journal of Epidemiology, 154 (7), 601-609.

Wilson, B.W., Wright, C.W., Morris, J.E., Buschbom, R.L., Brown, D.P., Miller, D.L., Sommers-Flannigan, R. and Anderson, L.E., 1990. Evidence for an Effect of ELF Electromagnetic Fields on Human Pineal Gland Function. Journal of Pineal Research, 9, 259-269.

Pfluger, D.H. and Minder, C.E., 1996. Effects of exposure to 16.7 Hz magnetic fields on urinary 6-hydroxymelatonin sulfate excretion of Swiss railway workers. Journal of Pineal Research, 21, 91-100.

Burch, J.B., Reif, J.S., Yost, M.G., Keefe, T.J. and Pitrat, C.A., 1998. Nocturnal excretion of a urinary melatonin metabolite among electric utility workers. Scand. J. Work Environ. Health, 24(3), 183-189.

Burch, J. B., Reif, J. S., Noonan, C. W. and Yost, M. G., 2000. Melatonin metabolite levels in workers exposed to 60 Hz magnetic fields: Work in substations and with 3-phase conductors. Journal of Occupational and Environmental Medicine, 42(2), 136-142.



6

IARC Monographs of the Evaluation of Carcinogenic Risks to Humans, 2002. Non-Ionizing Radiation, Part 1: Static and Extremely Low-Frequency (ELF) Electric and Magnetic Fields. Volume 80, 19-26 June 2001, IARC Press, 150 cours Albert Thomas, F-69372 Lyon cedex 08, France.

California Health Department Report, 2001. An Evaluation of the Possible Risks from Electric and Magnetic Fields (EMFs) from Power Lines, Internal Wiring, Electrical Occupations and Appliances. Summary or Full Report

Henshaw, D. L., 2002. Does our electricity distribution system pose a serious risk to public health? Medical Hypotheses, 59, 39-51






Three Italian regions: limits for new installations

The regulations are given here in their original Italian version (PDF file: 283 KB)
For the region of Tuscany (Toscana), the limit for new installations of 0.2 µT is given on pages 3 & 4 (Art 3, paras 2 & 3).
For the region of Emilia-Romagna, the limit for new installations of 0.2 µT is given on page 18 (Art 13, para 4).
For the region of Veneto, the magnetic field limit for new installations of 0.2 µT is given on pages 21 & 22 (Art 1, paras 1 & 2). Note that there is also an electric field limit of 0.5 kV m-1.
In general the regulations apply to new installations near nurseries, schools, hospitals, houses and places where people spend more than four hours per day.




Australian court imposes 0.4 µT exposure limit on substation development

The Planning and Environment Court of Queensland has imposed a magnetic field exposure limit of 0.4 µT on a new electricity substation development at Tanah Merah. This decision follows an appeal by the power company Energex Ltd, against an earlier decision of the court. The case was officially closed on the 18th March 2002. The judgement was based on the findings of the NRPB AGNIR Report of April 2001 that exposure to magnetic fields above 0.4 µT is associated with a doubling of the risk of childhood leukaemia. The court accepted that while there was no absolute proof that exposure to magnetic fields caused an increased risk of childhood leukaemia, nevertheless the policy of "prudent avoidance" should apply. The health issues are discussed on pages 13-19. Details of the judgement are given on pages 19-23. Full judgement (PDF file: 495 KB)