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Interaction of Extremely Low–Frequency Electromagnetic Fields
and hand to both feet. Dawson, Stuchly, and Kavet (2004a,b) also estimated the electric
fields in a heterogeneous human body due to electrostatic discharges by the quasistatic
frequency-domain SPFD method.
González, Peratta, and Poljak (2007) and Peratta and Peratta (2010) applied the
human exposure assessment to ELF electric fields using the three-dimensional BEM.
Based on a realistic anatomically based human body, they assessed human exposure
to 60 Hz electric fields generated by transmission lines and a transformer substation.
The human body was modeled through a saline fluid containing a certain conductivity σ of 0.5 S/m. Five different conceptual models were considered: human no arms,
human arms open, human arms up, human arms down, and human internal organs.
They analyzed the influence factors attributed to the relative position of the arms with
respect to the body on the axial distribution of current densities along the body. The
total current densities along the torso and legs showed significant increase as arms
were raised. When exposed to 60 Hz electric fields, the neck was protected due to the
shielding effect of raised arms. This indicates that the brain was protected by the raised
arms. In the case of the transformer substation, the dynamics of current densities were
consistent with those obtained in context of a transmission line. They compared the
results with the basic restrictions established by the International Commission on
Non-Ionizing Radiation Protection (ICNIRP 1998a,b) and found that induced current
densities were lower than the work exposure limit, excluding the neck. Motrescu and
van Rienen (2005) computed the current induced by ELF electric fields in anisotropic
human tissues. In order to compute the induced current densities in the sophisticated
human body model standing under a transmission line, they used the algorithm of the
Finite-Integration Technique (FIT).
4.5.1.3 Coupling with Other Models
Based on results of long-term biological effect research efforts, it has been suggested
that several observed effects are due to induced currents and electric fields triggered in
biological systems. Fear and Stuchly (1998) investigated the behavior of biological cells
with gap junctions exposed to ELF electric fields. They examined the induced transmembrane potential (TMP) in geometrically complex models of various cell configurations by using the FEM. They showed the FEM approach eases the analysis of TMP in
a variety of cell preparations and the examination of parameters such as gap-junction
conductivity in geometrically complex cell cluster models. The approach confirms that
gap junction–connected cells can be treated as a single similarly shaped cell. The gap
influences the potential in the interior of cell configurations, and its effect increases with
gap size and conductivity.
Using both FEM and SPFD calculations, Chiu and Stuchly (2005) presented the
numerically computed result of two models, a cancellous bone model and a bone marrow
stroma cell model, of bone marrow substructures exposed to ELF electric fields. They
used bone marrow to clarify the relationship between EMF and childhood leukemia at
both cellular and subcellular levels. It is well known that bone marrow is responsible for
leukemia. In the cancellous bone model, the enhancement of electric fields was the measure of interest. The enhancement of local electric fields occurred within the cancellous
Interaction of Extremely Low–Frequency Electromagnetic Fields
and hand to both feet. Dawson, Stuchly, and Kavet (2004a,b) also estimated the electric
fields in a heterogeneous human body due to electrostatic discharges by the quasistatic
frequency-domain SPFD method.
González, Peratta, and Poljak (2007) and Peratta and Peratta (2010) applied the
human exposure assessment to ELF electric fields using the three-dimensional BEM.
Based on a realistic anatomically based human body, they assessed human exposure
to 60 Hz electric fields generated by transmission lines and a transformer substation.
The human body was modeled through a saline fluid containing a certain conductivity σ of 0.5 S/m. Five different conceptual models were considered: human no arms,
human arms open, human arms up, human arms down, and human internal organs.
They analyzed the influence factors attributed to the relative position of the arms with
respect to the body on the axial distribution of current densities along the body. The
total current densities along the torso and legs showed significant increase as arms
were raised. When exposed to 60 Hz electric fields, the neck was protected due to the
shielding effect of raised arms. This indicates that the brain was protected by the raised
arms. In the case of the transformer substation, the dynamics of current densities were
consistent with those obtained in context of a transmission line. They compared the
results with the basic restrictions established by the International Commission on
Non-Ionizing Radiation Protection (ICNIRP 1998a,b) and found that induced current
densities were lower than the work exposure limit, excluding the neck. Motrescu and
van Rienen (2005) computed the current induced by ELF electric fields in anisotropic
human tissues. In order to compute the induced current densities in the sophisticated
human body model standing under a transmission line, they used the algorithm of the
Finite-Integration Technique (FIT).
4.5.1.3 Coupling with Other Models
Based on results of long-term biological effect research efforts, it has been suggested
that several observed effects are due to induced currents and electric fields triggered in
biological systems. Fear and Stuchly (1998) investigated the behavior of biological cells
with gap junctions exposed to ELF electric fields. They examined the induced transmembrane potential (TMP) in geometrically complex models of various cell configurations by using the FEM. They showed the FEM approach eases the analysis of TMP in
a variety of cell preparations and the examination of parameters such as gap-junction
conductivity in geometrically complex cell cluster models. The approach confirms that
gap junction–connected cells can be treated as a single similarly shaped cell. The gap
influences the potential in the interior of cell configurations, and its effect increases with
gap size and conductivity.
Using both FEM and SPFD calculations, Chiu and Stuchly (2005) presented the
numerically computed result of two models, a cancellous bone model and a bone marrow
stroma cell model, of bone marrow substructures exposed to ELF electric fields. They
used bone marrow to clarify the relationship between EMF and childhood leukemia at
both cellular and subcellular levels. It is well known that bone marrow is responsible for
leukemia. In the cancellous bone model, the enhancement of electric fields was the measure of interest. The enhancement of local electric fields occurred within the cancellous