Effect of Extremely Low Frequency (ELF) Electromagnetic Fields on Human Health

Introduction

In day-to day living the general public, including children and adolescents, is exposed to low-intensity magnetic fields.  In fact, extremely low frequency (ELF) electromagnetic fields are found in proximity to any electric current: electric wires, cables, household wiring, various electrical appliances, and any infrastructure or installation connected to an alternating current electricity grid.

What are electromagnetic fields?

Charged electrical wires produce an electric field. The higher the voltage, the stronger the electric field at a given distance from the wire. When the electric charges flow through the wire (i.e., there is an electric current), a magnetic field is created. Electric fields exist even when there is no current flowing through the wire, while magnetic fields are only produced when the current flows and cease to exist once the current is switched off.   

The strength of both types of fields - electric and magnetic – is highest close to their origin and rapidly decreases at greater distances from the source. 

For further reading on electromagnetic fields

The effect on public health of prolonged exposure to low-intensity electromagnetic fields has been studied for over 30 years, since Nancy Wertheimer and Ed Leeper found in 1979 an increased risk for developing leukemia among children up to 19 years of age in whose homes a relatively strong electric current had been measured, and related this observation to the magnetic field created by the electric current. 

Most studies that investigated the health effects of prolonged exposure to -intensity magnetic fields focused on the possible association between this type of exposure and the development of childhood leukemia.  Other studies have investigated other types of cancer in children, cancer in adults, the effect on pregnancy outcomes (miscarriage, birth weight), behavioral effects, influence on cognitive function, hormonal effects, sexual dysfunction, developmental problems, changes in the immune system, effects on the nervous system, degenerative nerve diseases (such as Alzheimer's disease), and cardiovascular (heart) diseases.

In 2002, on the basis of epidemiological studies published up to 1999, the International Agency for Research on Cancer (IARC) classified extremely low frequency magnetic fields as possibly carcinogenic to humans (category 2B). This conclusion was established following pooled analyses, which were based on population studies that investigated the possible association between residence in proximity to high-voltage powerlines and the incidence of leukemia.  The results of these studies indicated that prolonged exposure to relatively high levels of magnetic fields (above 0.3-0.4 microtesla, equivalent to 3-4 milligauss), increases the risk of developing leukemia by a factor of 1.5-2.  It should be noted that most experimental studies on tissue cultures or animal models have failed to confirm the existence of such an association.  Moreover, no biophysical process known to date can unequivocally explain the association observed in the epidemiological studies.

It should be noted that the report of a World Health Organization working group published in 2007 (Environmental Health Criteria), and reviews by the European Commission published in 2009 – SCENIHR – (pdf document available for downloading), and in 2012 – EHFRAN – (pdf document available for downloading), supported the conclusions of the IARC.