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1
Introduction
THE ELF COMMUNICATIONS SYSTEM
IN THE LATE 1950S the U.S. Navy began to investigate the use of extremely
low-frequency (ELF) electric and magnetic fields (EMFs) to communicate with
submerged submarines. In 1969, the Navy completed an experimental facility,
in the Chequamegon National Forest near Clam Lake, Wisconsin. For more
than a decade, this facility was operated intermittently and at less than full
power to test the system and to make engineering evaluations. The Naval
Radio Transmitting Facility (NRTF) in Wisconsin was upgraded and became
fully functional in 1985. About 150 miles to the east in the Copper County
and Escanaba River state forests near Republic, Michigan another facility was
completed by the Navy in 1986. It was operated intermittently beginning in
1986 and became fully operational in 1989.
Today, the Navy's ELF communications system comprises the radio
transmitting facility near Clam Lake, Wisconsin, and the one near Republic,
Michigan (see Figure A-. Each facility consists of a transmitter connected to
long overhead wires (antennas) with ground terminals buried at their ends. The
antennas and terminals are in cleared rights of way in forests. The rights of
way are 70 to 100 feet wide. The Wisconsin facility has two antennas, each
14 miles Tong, perpendicular to each other. The Michigan facility has three
antennas: two are 14 miles long and parallel to each other, and the third is 28
miles long and perpendicular to the other two.
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INTRODUCTION
15
The frequency of the EMFs produced by the ELF communications sys-
tem is modulated between 72 and 80 hertz (Hz) to produce a binary-coded
signal (! or O) that is transmitted to submarines. The most prominent fre-
quency is 76 Hz (Haradem et al. 19941. The transmitters use three ELF EMFs
to broadcast messages to submarines:
.
A magnetic field in the air and the earth that is generated by the
electric current in the antennas and ground terminals.
· An electric field in the earth that results from the combination of
fields induced by the magnetic field and the current flowing from the buried
ground terminals.
· An electric field in the air that is produced as a result of the differ-
ence in electric potential between the antennas and the earth or as a byproduct
of the electric field in the earth.
THE NAVY'S ECOLOGICAL
MONITORING PROGRAM
At the time of the construction of the Wisconsin experimental transmitter,
the Navy provided funds for the U.S. Forest Service and other investigators
to determine whether changes in biologic factors could be observed in re-
sponse to electric and magnetic fields produced by the existing Wisconsin
experimental facility. In 1977, the National Research Council independently
evaluated the studies at the Wisconsin facility and the results of other studies
on effects of ELF EMFs (NRC 1977~. The Navy undertook a similar exercise.
Both the Navy and the Research Council concluded that substantial effects on
organisms in the vicinity of the facility would be unlikely, but recommended
establishment of a biologic monitoring program at the ELF communications
facilities if they became operational. Years later, the American Institute of
Biological Sciences (AIBS) reviewed bioelectromagnetic research and recom-
mended continued ecological research because of the problems of extrapolating
results of highly controlled laboratory studies to complex ecological systems
(AIBS 1985~.
The original plan for the ecological monitoring program was developed
by the Navy in the late 1970s to satisfy such recommendations. This program
included a set of general, statistical, and design requirements. It also required
ambient environmental monitoring and the development of a preconstruction
database. The ecological studies listed included soil microfauna, earthworms,
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ration and reporting.
~ 6 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
small mammals, large mammals, crops, herbs, grasses, trees, periphytic algae,
aquatic insects, fish, pollinating insects, nesting birds, migrating birds in
flight, and human health effects. Data were to be interpreted by principal
investigators, and the monitoring program was to be supervised by a review
committee composed of Navy and state representatives.
The Illinois Institute of Technology Research Institute (ITTRI) received
the contract to manage the ecological monitoring program and provide overall
program technical support. TITRT was in a unique position because of its long
experience of technical support to the ELF project, including work to ensure
that the ELF communications system did not interfere with local power distri-
bution lines or telephone circuits. IITR! had had previous responsibilities for
environmental design, protection planning, and engineering support for bio-
logic studies. Under the ecological monitoring program, ITTRI's management
roles were program coordination, study evaluation and monitoring, subcontract
administration, en.gineerin.g support, and direction of a review of data interpre
, ~ ~ . . ,
UTR} designed a fully developed ecological monitoring program in 1982
based on the original outline from the Navy, input from several state and
federal agencies, the 1977 National Research Council report, and the Navy's
draft environmental-impact statement. The purpose of the ecological monitor-
ing program was to determine whether EMFS produced by the ELF communi-
cations system affected plant or animal populations or otherwise caused impor-
tant ecological community or ecosystem changes. The program was included
in a 1982 request for proposals (RFP) to perform monitoring studies.
The RFP stipulated that subcontracting researchers were to use statistical
methods capable of detecting small changes in measured variables and well-
established techniques, that biologic end points must be sufficiently understood
to ensure confident interpretation, that blind scoring must be used in labora-
to~y analysis, and that field studies should produce only minimal impacts. The
RFP discussed criteria for experimental design, including use of paired plots
(treatment and control), exposure criteria for establishing treatment plots,
requirements for characterizing ELF exposures at control and treatment plots,
and such ambient monitoring as recording of climatic data. Annual reports and
a yearly symposium that was open to the public would be required and would
be used to review the progress of each study.
A preconstruction database was stipulated by the original Navy proposal
and by the RFP. Information obtained from a monitoring program in the
vicinity of the planned Michigan facility was judged to be sufficiently applica-
ble to the Wisconsin facility to obviate further monitoring there. The RFP
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INTRODUCTION
17
stipulated that the preconstruction database include data already available from
federal, state, commercial, and private sources and data from several years of
new field studies.
About 120 proposals were submitted in response to the 1982 RFP and
were reviewed for merit by an independent pane} of scientists; I! were se-
lected for support: wetlands, slime mold, Wisconsin birds, Michigan birds,
small vertebrates, litter decomposition and microflora, upland flora, aquatic
ecosystems, pollinating insects, soil arthropods and earthworms, and soil
amebas. This group of studies included most of the specific flora and fauna
listed in the Navy's original monitoring plan. The studies included collection
of data on physiologic, developmental, behavioral, and ecological measures
from dominant biota in upland, wetland, and riverine habitats near the Wis-
consin and Michigan facilities. TITR] established a group of scientists to re-
view the annual reports of the selected projects and attend the yearly symposia
to discuss the status of the studies.
The studies began in 1982 to 1984. Observations were made before
construction (Michigan only), during intermittent use, and during full opera-
tion of the facilities. Data collection for studies near the Wisconsin facility was
completed in 1989. Data collection for studies near the Michigan facility was
completed in 1993. The final reports of studies near both facilities were com-
pleted and peer reviewed by March 1996. The overall conclusion reported by
TITR! is as follows:
Although some investigators believe that a few biological changes may
have occurred, all acknowledge that there were no consistent, unequivo-
cal effects of ELF System operation on any of the variables they moni-
tored. All conclude that the implications of their results are not indicative
of adverse ecological significance (Zapotosky et al. 1996~.
In 1994, the Navy, believing it essential to have an additional external
evaluation of the ELF ecological monitoring program's activities and findings,
requested that the National Research Council conduct an independent review
and evaluation of the program.
THE COMMITTEE'S CHARGE AND APPROACH
The Committee to Evaluate the U.S. Navy's Extremely Low Frequency
Communications System Ecological Monitoring Program was formed by the
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1 8 EVALUATION OF ELF ECOLOGICALMONITORING PROGRAM
National Research Council in 1995 to evaluate independently the objectives
and design of the monitoring program, data-collection methods, data analysis,
and interpretations. Important evaluation considerations included the following
questions:
To what extent did the physical measurements represent characteris-
tics of EMFS appropriate for assessing possible ecological effects?
· Were proper experimental controls used to enable the detection of
actual differences between exposed and unexposed organisms? Were known
sources of concomitant variation controlled so as not to obscure a real effect?
Were the experimental end points properly chosen?
· Were sample sizes adequate to reveal small effects?
· Was the sensitivity of experimental design, sampling, and analysis
adequate to ensure a reasonable probability that effects, if any, would be
detected?
· Were the experimental and observational techniques, methods, and
conditions objective?
interest?
Was the study internally consistent with respect to the effects of
Are the conclusions reached by the investigators well reasoned and
well supported by the data?
· Are the results able to be confirmed by other investigators?
The ecological monitoring program and the committee's review addressed
the possible effects of ELF EMF exposures resulting specifically from the
Navy's ELF communications system. The monitoring program and the com-
mittee's review did not address effects of ELF EMF exposures in general (that
is, from all sources). The committee did not analyze the data systematically.
In some cases, the committee selectively examined the data in detail and in so
doing uncovered inconsistencies in some of the analyses. The committee did
not determine before its assessment whether any types of effects would be
likely or unlikely, did not attempt to assess possible effects of ELF EMF
exposures beyond the study sites, and did not attempt to determine the possible
effects of variations over time in factors, other than the operation of the ELF
communications system, that might have affected the observations of the eco-
logical monitoring program.
The committee reviewed a large number of relevant documents, including
the original request for proposals, the original proposals, followup proposals,
annual progress reports, reviewer comments, engineering reports, and the final
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INTRODUCTION
19
reports produced for each of the 11 ecological studies. It found that often the
written word did not convey all the analytic thinking and interpretation of the
investigators, so on several occasions it discussed findings with the investiga-
tors for clarification.
The committee examined the responsiveness of study designs to program
objectives, selection of study species and justification, selection of response
variables and justification, the soundness of experiment designs and implemen-
tation from ecological and biophysical perspectives, statistical methods used
for analysis, exposure assessment, presentation of results, and the validity and
uncertainty of conclusions reached by researchers. This report presents the
results of the committee's evaluations (biographic information on the members
of the committee is presented in Appendix A). Although some data from the
monitoring program are presented in this report, it is not intended to provide
a comprehensive summary of the large amount of data contained in the numer-
ous reports from the ecological monitoring program. Documents from the
monitoring program are available to the public from the National Technical
Information Service in Springfield, Virginia.
SPECIFIC THEORIES OF
BIOLOGIC EFFECTS OF EMF EXPOSURE
From the beginning of its review, the committee was fully aware of
scientific controversies surrounding the question of biologic responses to
exposure to low-amplitude alternating EMFs in the ELF range. Scientists who
have studied this question since the 1977 National Research Council report
(NRC 1977) have offered a wide array of opinions (for example, see Wilson
et al. 1989; NRPB 1992; ORAU 1992, 1993; NRC 1997~. Some scientists
believe that biologic responses attributed to EMF exposures have been
reproducibly demonstrated; others are skeptical about the documentation of
such responses; and yet others have expressed the opinion that such responses
violate fundamental laws of physics and are therefore physically and biologi-
cally impossible. It was not within the scope of this committee's work to
resolve such controversies, nor did it attempt to do so. An investigation of the
extent to which controversial responses to low-frequency EMF exposure might
present a hazard to human health was the mandate of the National Research
Council's Committee on Possible Effects of Electromagnetic Fields on Bio-
logic Systems (NRC 1997~.
The present committee decided at the outset that in carrying out its man
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20 EVALUATION OF ELF ECOLOGICAL MONITORING PROGRAM
date, it would be counterproductive to make assumptions about the possibility
or impossibility of biologic responses to ELF EMFs. For example, if the
committee had begun its work with a notion that testing data for consistency
with Theory A of magnetic-field-induced biologic responses was most impor-
tant, it might not have adequately considered data that were not consistent with
Theory A. Tnstead, the committee evaluated all the Navy's experiments in
each project according to criteria that are standard in all branches of scientific
endeavor. According to the committee's charge, the experiments were re-
viewed for the coherence of the hypotheses being tested, the adequacy of the
experimental design to test those hypotheses (including the adequacy of bio-
{ogic species chosen, methods, statistical analysis, and statistical power), and
the soundness of the conclusions that the investigators drew from their obser-
vations. The projects were not evaluated from the perspective of how a dem-
onstrated biologic response to ELF electric-field or magnetic-field exposure
might fit any particular opinion or theory about the plausibility of such re-
sponses. Where biologic responses to ELF EMFs were identified, physical
mechanisms of field interaction with biologic molecules and biologic processes
that might be affected by EMF exposure would necessarily be the subjects of
future experimental investigations.
The ecological monitoring program researchers who conducted the indi-
vidual studies have presented their results in scientific meetings, and some
have been published in the peer-reviewed literature. Voluminous annual re-
ports containing more detailed data are in the public domain. Members of the
scientific community who wish to examine the results of individual experi-
ments are encouraged to do so.
SCOPE OF THE REPORT
Chapter 2 of this report contains introductory material on exposure as-
sessment, including engineering information on TTTRI's measurements and
general information on the concept of dosimetry. Chapter 3 contains evalua-
tions of final reports of the ~ ~ individual ecological studies performed for the
Navy. The committee combined its discussion of studies of Wisconsin birds
and Michigan birds. Chapter 4 discusses common issues that pertained to all
the studies. Chapter 5 summarizes the evaluations and presents the major
conclusions. it also recommends how the Navy might proceed with the infor-
mation that it has received from the monitoring program and on how others
who attempt a similar grand-scale monitoring program might organize its over-
all research and monitoring aspects.
Representative terms from entire chapter:
ecological monitoring
