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Safety and Electromagnetic Field Guidelines

of the research indicates that exposure to static and LF feld normally encountered in the environment

does not pose a risk to human health. At high levels, there are established acute efects of static felds

including vertigo and nausea (WHO, 2006). Tere is no established evidence that static felds cause long­

term health efects and the International Agency for Research on Cancer (IARC) has classifed static

felds as not classifable as to their carcinogenicity to humans (Group 3) (IARC, 2002).

Here, a brief overview of the health issues of non-ionizing radiation will be presented. First, several

reviews have been published on the biological and health efects of exposure to static electric and mag­

netic felds (IARC, 2002; ICNIRP, 2009b; WHO, 2006). Static electric and magnetic felds originate from

both natural and man-made sources. Static electric felds are derived from the earth’s atmosphere as a

part of global electric circuit. Te naturally originated static electric feld on earth is highest near the

surface from about 100–150 V/m during fair weather to several thousand V/m under thunderclouds.

Static electric feld depends on the temperature, relative humidity, altitude, and other weather condi­

tions. Te natural static magnetic feld originates from electric current fow in the liquid outer core of

the earth. Tis feld called the geomagnetic feld. Te geomagnetic feld is described by three compo­

nents: total magnetic intensity, declination, and inclination. Te total feld intensity in Japan is around

50 μT. Te geomagnetic feld fuctuates according to diurnal, lunar, and seasonal variation. On the other

hand, man-made sources of static electric and magnetic felds are found everywhere from our day life

to industrial facilities and medical equipment through power transmission systems (WHO, 1987, 2006).

Static electric feld does not penetrate the human body and induces a surface charge. Tis charge may

be perceived through its interaction with body hair and by other phenomena such as discharge (micro-

shock), at sufciently high feld. Te perception in humans is dependent on various factors and can

range from 10 to 45 kV/m. Static magnetic feld is unperturbed by the human body. Tere are three

well-established mechanisms by which static magnetic feld interact with biological systems: magnetic

induction, magneto-mechanical efects, and electron spin efects (ICNIRP, 2009). Based on the evalu­

ation of biological efect research, the WHO carried out the human health assessment of static electric

and magnetic feld (WHO, 2006).

As the scientifc base to develop the rationale for the guidelines, a document published by WHO

(WHO, 2006) on static felds within their Environmental Health Criteria Program, which contains a

review of biological efects reported from exposure to static felds, is referred along with other publica­

tions (ICNIRP, 2003; McKinlay et al., 2004; Noble et al., 2005).

As the scientifc evidence, three established interaction mechanisms with living matter are consid­

ered: magnetic induction, magneto-mechanical, and electronic interactions. For the magnetic induc­

tion, the following types of interaction were evaluated: electrodynamic interactions with moving

electrolytes, and induced electric felds in living tissues. Te electrodynamic interactions with moving

charged particles can lead to an induced electric feld. Te change in electrocardiograms is a well-known

example of this electrodynamic interaction. In the presence of a static magnetic feld, the electrical

potential is induced. In the blood, this is the result of Lorenz force exerted on moving charged particles

(electrolytes). Kinouchi carried out the detailed theoretical treatment if the efects of magnetic felds

on blood fow by using the Navier-Stokes equation (Kinouchi et al., 1996). In the case of magnetic felds

perpendicular to the blood fow, they found a reduction in the fow rate of blood.

For the magneto-mechanical interaction, two types of mechanical efects that a static magnetic feld

can exert on biological objects are evaluated. Te frst type is magneto-orientation. Tis concerns the

orientation of paramagnetic molecules in the high static magnetic feld. Tis efect is involved in mag­

neto-reception in certain species of animals. Te second type of interaction is the magneto-mechanical

translation. Tis occurs in the presence of a feld gradient for paramagnetic or diamagnetic materials

(Ueno and Iwakasa, 1994a,b).

For the electronic interaction, electron-spin interactions are evaluated. Tis interaction can afect

the rate of recombination of pairs of free radicals in chemical reaction intermediates. It seems that this

mechanisms plays a part in the navigation system of certain birds. It was given the excellent review on

the role of free radicals in biology (Hayashi, 2004; Okano, 2008).