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Electromagnetic Fields in Biological Systems
long nerve cell (King and Wu 1998). King (1999a) analyzed the interaction between currents and electric fields induced in the organs of the human body by external electric
and magnetic fields and those involved in the propagation of a signal along a nerve axon.
His calculation showed that incident 60 Hz electric fields near high-voltage transmission line did not induce large enough currents and electric fields in a nerve axon in the
leg. The long-term study on the electric fields and currents induced in the organs of the
human body exposed to 50-/60 Hz transmission line and 10- to 30 kHz high-power
transmitters are summarized (King 1998b). King’s research results are limited by the
simplistic human model with electrically homogeneous cylinder.
Bottauscio and Conti (1999) developed a 1.8-m-tall human model with internal
organs such as the heart, brain, and liver in order to evaluate the induced currents
in complex biological structures after exposure to 50 Hz electric and magnetic fields.
The numerical model is based on BEM. In addition, using three-dimensional BEM,
Bottauscio, Chiampi, and Zilberti (2009) evaluated the currents induced inside the reference human body proposed in the International Electrotechnical Commission (IEC)
standards exposed to ELF EMF. The validation of the model is performed by comparison with analytical methods and FEM. After the confirmation between the numerical
and analytical computations, the authors applied this method to calculate the induced
current densities in two conditions: an operator is placed nearby a three-phase 50 Hz,
380-kV line voltage bus bar system and the human body is placed both 2 m from the
closer phase (position A) and below the central bar (position B). The current density
contributions due to the electric fields are always predominant, and the presence of the
magnetic fields gives rise to an increase in the maximum value of the induced currents
of ~20% in position A and ~30% in position B.
Using three-dimensional BEM, Min and Song (2006b) analyzed the induced current
densities inside a human model working close to the 60 Hz, 765-kV double-circuit transmission line. Their human model consisted of several organs (brain, heart, lung, liver,
and intestine) and other various parts, and it was spheroidal or cylindrical. They had
two calculations of the human body model located inside and outside the lowest phase
of 765-kV transmission line. The maximum induced current densities in all organs were
less than 10 mA/m 2 for the human model working outside. However, if the worker stayed
inside the multiconductor bundle, the induced current densities inside the human body
increased to 20.4 mA/m 2 and exceeded the safe level proposed by ICNIRP. In this case,
the worker was recommended to locate his legs at lower subconductors.
Myung et al. (2002) calculated the induced currents of a human head model with
1.27-cm resolution due to 60 Hz magnetic fields around a 765-kV transmission line using
IM. Before the calculation of induced currents, they estimated the three-dimensional
magnetic field profile around the transmission line with an analytic solution. The
induced current in the human head model with 1.27-cm resolution was estimated. The
simulated maximum current density in the human head model was 0.10 mA/m 2 when
the head was exposed to the magnetic field of 1.67 μT. With these results, they found that
there is a high eddy current intensity around the eyes of human head.
Matsumoto and coworkers computed the induced currents in the homogeneous
spherical and prolate spheroid models exposed to 60 Hz electric and magnetic fields
(Matsumoto, Hayashi, and Isaka 1997, 1999; Matsumoto et al. 2000, 2001). After the