more from Prof. Dahlberg

Following are excerpts from another excellent article by Prof. Dahlberg.
Additions in brackets are mine.    
Regards,
Shivani

RESEARCH ASSESSING THE IMPACT OF ENVIRONMENTAL AGENTS
By Duane A. Dahlberg


One of the most far-reaching encroachments of 60 Hz energies into the
environment is the
current in the earth associated with the basic design of the entire
electrical distribution system.
Historically the distribution system that supplies electricity to the
consumer was electrically
isolated from the earth and therefore a self-contained system. At some point
in the expansion of
electrical use, a decision was made to connect the electrical distribution
system to the earth and
use the earth to carry some of the current. Of the possible reasons for this
decision, one was to
decrease the loss of electrical energy in the system. Another reason may have
been to increase
the ability to extend the length of the lines and to increase the energy
carried on the lines. The
overall effect is a national electric distribution system in which 65 to 75%
of the current returns
to the substations through the earth rather than through the wires
(Hendrickson 1995, Gonen
1986, Morrison 1963). The earth becomes one terminal of the electrical
distribution system, and
electrical currents are, therefore, present to a greater or lesser degree in
all materials in the
environment. As a result of this environmental change, all living organisms
are conductors of
electricity and in contact with the earth and other materials carrying
electric currents. They are
plugged into the electrical circuitry of the distribution system. Living
organisms are continually
in contact with one terminal of the entire electrical distribution system of
the North American
continent. Human and animals literally stand on one terminal of the
electrical system with no
way of escaping that state. All living organisms become part of the
electrical distribution
system, experiencing electric currents in much the same way as the earth.
For most people, when the electricity reaches the earth, the current is, “out
of sight and
(therefore) out of mind.” When the electrical current was first routed
through the earth, the
amount of electricity in the ground was quite small and in general,
dispersed, so the potential
impact was quite small. The demand for electricity has increased
exponentially, however, and
the number of users has grown in the same way. The consequent growth in the
number and
lengths of the distribution lines and the acceleration in electrical use have
significantly increased
the use of the earth as a current carrying conductor. The quantity of
electric current in the earth
is no longer small, and the potential impact can be expected to increase
accordingly.

. ...On some farms
conducting cables or pipes are placed on the ground surface or dug into the
ground to encircle
the farm buildings. In some cases the current in these conductors is
sufficient to light a small
light bulb.

.... The earth
is a complex electrical structure, similar to an electrical circuit. When a
source of electricity is
disrupted, changes occur in the electrical equilibrium in the earth. These
changes, in turn, can
affect the electrical currents accessing cows in a specific barn, resulting
in the improvement
observed by dairy operators after they have disconnected grounding wires or
deflected the
currents in the earth. With time, however, the earth has a tendency to return
to its long-term
electrical equilibrium, and the stray voltage problem may reappear. Changes
in the equilibrium
can also occur as new sources of electricity enter the earth, and with
changes in the quantities of
current in the earth, the conductivity of the earth, and the impedance of the
ground connection.

..... Field investigations also recognize that currents
can reach the environment of cows by means of wires including the farm
neutral, the utility
neutral, telephone cables, and cable television. In addition to these
sources, however, field work
finds that currents in the earth are also able to reach the cows'
environment. They may originate
from grounding systems near the farm or even far away from the farm. These
currents are
identified as ground currents. [Even the Amish, with no on-property
wiring, experience ground current problems with their dairy herds.]

....In electrical exposure, electric currents traverse the body of living
organisms in direct proportion
to the electric potential and the varied conductivity of the body. These
currents in the body set
up magnetic fields. If electric charge increases at a given point in the
body, a localized electric
field is produced. There may well be mechanisms that could describe
interactions that occur
simply because of the presence of the currents and fields, and these
interactions could cause
biological or health effects. If this is the case, such mechanisms will
certainly be more difficult
to identify, because the electric and magnetic properties of the entire body
of the living organism
have never been mapped. There is no comprehensive model for understanding all
of the
different ways that the body uses electricity for maintaining its integrity,
or for the role of
electricity in all body functions.

....One of the difficulties is
the fact that the physical mechanisms for the biochemical actions of very
weak EM fields are not
understood. From energy principles there is a paradox. This paradox is
especially clear in
research involving low frequency fields. The field energy quantum is
approximately ten orders
of magnitude below the characteristic energy of chemical bonds. There is no
physical
mechanism that can explain biological processes at those field levels (Binhi
2002).
from his research Pressman (1970) has concluded that because physical
mechanisms cannot
define biological effects from EM fields on living systems, a fundamentally
new theoretical
approach to biological effect is needed. His approach is based on information
theory. Applying
this theory he claims that in addition to energetic interactions,
informational interactions have the
dominant role in biological processes. Energetic processes in biological
activity are in response
to information provided. That information can be provided by electrical
stimuli.

..... The fact that materials in the body rectify alternating currents is an
added complication in efforts to
understand the biological effects from electrical exposure. Different
frequencies in the body are
rectified to a greater or lesser degree. Therefore there are direct currents
(DC) in the body from
any and all exposures (Pressman 1970). The work of Nordenstrom shows that
additional DC
affects the naturally-occurring DC that controls functions of the living
organisms (Nordenstrom
1983).

....Stray voltage research has assumed that animal tissue generally behaves
according to the simple
form of Ohm's law: V=IR (electrical potential between two points on the body
of living
organisms is equal to the total current in the body times an average
resistance). This use of
Ohm's law is qualitatively adequate for explaining acute physical response
from a shock current.
If one wishes to study chronic effects, however, it is necessary to know
where the current is
going in the living organism and how it interacts with each part of the
organism. Living
organisms are complex organic systems with ionic components. Resistance of
organic systems is
a complex function of many variables. Consequently a more general form of the
Ohm's law is
required. This form states that the current density in an object is equal to
the conductivity times
the electric field (J=sE). Conductivity, which is the reciprocal of
resistivity, is obviously not a
constant for organic and semiconducting materials. In fact conductivity can
be a tensor when
electrical conductivity has different values for current traveling in
different directions in a
material. In the case of animal tissue, resistivity is dependent on the
direction of current flow,
the direction of the applied electric field, the magnitude of current
density, and frequency. Some
body materials have diode characteristics, and are able to rectify AC. Other
parts may be
piezoelectric and generate electric currents when stressed. In addition there
are orders of
magnitude differences in conductivity of different parts of the body. Fluids,
in general, have
higher conductivity and fibrous materials have lower conductivity.
When electrical potential are applied between two points on the body of an
animal, the fraction
of the current in each part of the body is directly related to the electrical
conductivity of that part.
It is possible to determine what portion of the current is in the nerve
fibers or the vascular
system, for example, but only if the relative conductivity of the entire body
can be mapped.
Since many molecular structures in the body are polar in nature, capacitance
can vary throughout
the body. These many molecular structures also have different magnetic
properties that can,
therefore, have a different inductance. Predicting how current from an
applied AC potential will
vary from one part of the body to another requires knowledge of both
capacitive and inductive
reactance as well as conductivity. These complexities support the need to
take a more general
approach in the investigation of cause and effect from electrical exposure.

....The fact that cows responded differently suggests that there can be
significant individual differences
in observed effects from the same electrical exposure. This is consistent
with the natural
differences that occur in living organisms.

....The stray voltage problem is a classic example of the difficulties that
can occur when a
technological development provides many benefits for humanity throughout the
world, but has
never been examined to determine possible impacts on human and animal health.
Without such
an examination, perceived negative effects experienced by humans or animals
are readily
ignored or denied. Because of the complexities of any research involving
environmental agents,
and because of the power of vested interests in any technological
development, the challenges to
scientific research on the negative effects of electrical exposure are almost
overwhelming.

..... The basic interaction of electricity with living organisms has been
considered to be an energy exchange. In order to be deemed harmful, [it hasbeen
presumed that] the energy must be capable of destroying living tissue, produce
acute and at times chronic effects, or it must be capable of breaking
molecular bonds to cause
chronic health effects. There is another property of electricity that ought
to be recognized,
however. Electricity is the result of a fundamental property of matter called
electric charge, and
moving charges introduce magnetic fields. Since living organisms use this
fundamental property
of matter for the functioning of their systems, electric currents and
electric and magnetic fields
have the potential to directly affect the functioning of those systems. In
proposing mechanisms
of interaction, both the energy itself and the direct effect of fields and
currents deserve attention.

....The real world involves exposure to many different things, and two or
more
elements may work together synergistically, with differing effects from one
organism to another.
Research that is focused narrowly on a single parameter does not provide any
way to account for
possible effects from exposures other than those used in the research.

....Understanding how electricity maintains the appropriate functioning of
systems of living beings
can help us to identify mechanisms of interaction between electrical
exposures and electrical
systems of the body. This understanding can also help to differentiate
between electrical
exposures that can cause negative effects and those that can cause positive
effects. It is also
important to keep in mind that thresholds may not be especially meaningful
measures of possible
effects. There is a real danger that research may not be able to supply
sufficient information
about safe levels of exposure to electricity of all kinds before widespread
damage to human and
animal health has already taken place.



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