An Evaluation of the U.S. Navy's Extremely Low Frequency Submarine Communications Ecological Monitoring Program (1997) / Chapter Skim
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3: Evaluation of Final Reports of Individual Studies
3: Evaluation of Final Reports of Individual Studies
Pages 32-110
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From page 32... ...
The monitoring program studies were designed to compare data collected at control sites with data collected at treatment sites. As discussed in Chapter 2, the paired sites were intended to have matched environmental factors but to be dissimilar in the magnitude of their exposure to the 76-Hz EMFs gener 32
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From page 33... ...
However, control sites had to be close enough to have environmental factors similar to those of their matched treatment sites. Siting criteria called for intensities of the 76-Hz EMFs at treatment sites to be at least 10 times those at control sites, for intensities of the 76-Hz EMFs at treatment sites to be at least 10 times those of the 60-Hz EMFs at treatment sites and control sites, and for intensities of the 60-Hz EMFs at treatment sites to be within 10 times those at control sites (Haradem et al.
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From page 34... ...
The basic null hypothesis of the wetland-monitoring project was that ELF EMFs resulting from the operation of the Navy antenna have no effect on selected ecosystem variables. SYSTEM, SITE, AND SPECIES SELECTION Much of the initial, pilot-study year of this project was spent in establishing study sites and testing methods.
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From page 35... ...
Although the selection of study sites satisfied the criteria established by IITR} and a gradient of exposure from treatment sites to control sites existed, the three treatment sites varied among themselves in terms of EMF intensity. For example, 1987 field measurements showed that the plots within the antenna treatment sites ranged from 0.053 to 0.196 V/m in electric-field intensity and from 6.!
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From page 36... ...
The antennas were capable of operating at full strength from 1985 through 1987, when most of the established protocols were in place; however, the antennas were not on full-time during this period, and it is not certain to what extent the off periods were taken into account in the study. That might be important for response variables that respond instantaneously or in a short term.
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From page 37... ...
That choice essentially eliminated light as one of the independent environmental variables that might have to be considered a covariate in later statistical analyses. Selection of only one species, however, implied the assumption that all other species would respond to ELF EMFs in a similar fashion.
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From page 38... ...
The first used pure cellulose as a substrate, and the second used Labrador tea leaves. The use of pure cellulose was intended to provide a uniform substrate for decomposition.
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From page 39... ...
In a few instances, the models did not agree, and lack of significance within one mode! was selected as the appropriate test of the response variable (i.e., it was not significantly influenced by ELF EMFs)
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From page 40... ...
resistance, could have created analytic difficulties. Field measurements of these very short-term response variables would have had to be timed in coordination with antenna operations to ensure measurement of possible EMF influences that might not be observable when the antenna is off.
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From page 41... ...
1984~. Common comments were related to site characterization, use of specific response variables and timing of measurements, and level of sampling for adequate statistical analysis.
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From page 42... ...
The initial proposal suggested that ANOVA would be the appropriate statistical approach to test the null hypothesis of no difference between or within treatment and control sites. Development of data sets also demonstrated to the researchers that there was a need to attempt to explain the variances of the biologic responses between and within treatments, in addition to assessing them.
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From page 43... ...
. Using stepwise multiple regression to explain the variance of biologic responses, primarily to see whether ELF-EMF principal components might be among the most signif~cant independent variables in the development of the coefficient of determination, they concluded that environmental variables explained more of the variance in the biologic-response variables than did ELF EMFs and not much at that.
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From page 44... ...
However, the spatial variance of exposure levels within treatment and control sites was taken into account. If biologic field measurements were coordinated with ELF-EMF exposure measurements (this
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From page 45... ...
The committee was not asked and did not attempt to determine why.) Second, the natural habitat of Physarum is the forest floor, where it functions with other organisms in recycling organic material, so its relevance to the ecological monitoring program is clear.
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From page 46... ...
SELECTION OF RESPONSE VARIABLES Laboratory studies of possible ELF-EMF effects on slime mold initiated in 1972 had included three measurements: length of the mitotic cycle, rate of respiration, and ATP content. Mitotic-cycle measurements were included in the original proposal and in experimental results reported up to the 1986 annual report, but were eventually replaced with the ATP determination.
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From page 47... ...
were maintained and exposed at each site; the second served as a backup in the case of contamination of the first. Biologic Sampling Techniques Samples were placed at three sites: one control site 7 miles east of the nearest antenna element, one treatment site near the west ground element, and one treatment site near (about 30 ft from)
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From page 48... ...
Because the effects of ELF EMFs on this organism previously reported were stated to be reversible, the protocol, which involved maintenance of cells for 2-3 days before analysis, seems to compromise a firm conclusion. If the EMF has only a small effect, ATP content and respiration rates might well return to control levels during the time of study.
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From page 49... ...
Time of EMF exposure. Study site data were also analyzed using multivariate linear regression; values derived from hourly measurements of the electric-field component of the ELF EMFs, current density, and temperature were included in this analysis.
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From page 50... ...
in laboratory experiments, no attempt was made to duplicate any of the fluctuations in ELF-EMF levels that occurred at the antenna and ground treatment sites. PRESENTATION OF RESULTS The hypothesis tested was that exposure to weak ELF EMFs like those produced by the Wisconsin antenna would result in observable physiologic alterations in Physarum.
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From page 51... ...
For the laboratory cultures, there were unexplained statistically significant differences in the measured values of ATP and respiration rate from year to year. All data before 1985 were omitted from consideration, as is reasonable because the antenna operation was intermittent.
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From page 52... ...
Might some different conclusion have been reached if they had been treated separately? Also, exposure data are plotted starting in the middle of week 6, whereas ATP content levels are shown starting at week 2.
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From page 53... ...
In the ecological monitoring program, the technical aspects of imposing fields were presumably well managed, so it would be good to verify the earlier results and proceed from them. That has not been done, and without a dose-response relationship it is difficult to say that there is no effect.
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From page 54... ...
. ELF-EMF intensity was used to establish treatment and control sites; but in later analyses of the response variables, year served as a surrogate of ELFEMF intensity.
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From page 55... ...
If the EMF changed the treatment sites into demographic "sinks" without dramatically lowering population densities, that would be missed. EXPERIMENT DESIGN AND IMPEEMENTATION The method of walking along transects and counting birds by sight and
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From page 56... ...
Even so, if ROW edge effects developed slowly, they would still be confounded with the onset of antenna operation. Proper design would also require the establishment of matching ROW effects at the control sites.
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From page 57... ...
They indicate no consistent, measurable effects beyond roughly 50-100 m, where magnetic fields in the air have dropped to less than 10% of their magnitude under the antenna. Although control sites were selected by a seemingly adequate randomization procedure, all the control sites in Michigan were southeast of the antenna and treatment sites (Hanowski et al.
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From page 59... ...
Questions about habitat differences across treatments in Michigan resulted in relocation of control sites to match treatment sites better (investigators attempted to deal with this problem in Wisconsin statistically, by using ANCOVA to incorporate habitat differences explicitly)
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From page 60... ...
None of the peer reviews expressed concern about the low intensities of the magnetic field at the treatment sites. PRESENTATION OF RESULTS The reports are very well written, facilitating critical review.
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From page 61... ...
The studies would not have detected any effects within roughly 50-100 m of the antennas. SMALL VERTEBRATES PROJECT PROPOSAE This project attempted to ascertain whether the operation of the Navy's ELF antenna system in Republic, Michigan, had effects on small vertebrates chickadees, tree swallows, chipmunks, and deer mice in an ecological context.
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From page 62... ...
Growth and maturation in deer mice. · Homing in tree swallows.
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From page 63... ...
It produced one of the few positive effects that is not "explained away" in the general discussion: a pattern of earlier eye-opening in deer mice from test plots during periods of full operation than from control plots. The meaning of that effect, if any, for later development, health, or reproductive fitness of deer mice is unclear.
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From page 64... ...
and the homing effect results from antenna operation, it is less important whether there are plot differences, and it is all-important to ascertain whether the antenna leg that intersects the flight path was active during the 4-5 hours that the birds were in flight. Even in years of full antenna operation, there were down periods, and in some cases the legs of the antennas were rotated in their activity.
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From page 65... ...
lLSO) that the antenna operation is highly variable, nearly hourly.
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From page 66... ...
If the use of different strains of chicks can lead to different results, why not the use of different species? MAXIMAL AEROBIC METABOLISM IN CHICKADEES AND DEER MICE This substudy sought to measure the peak metabolic rates (PMRs)
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From page 67... ...
Although many publications have arisen out of the Navy's ecological monitoring program, the only two investigators that had and continue to have distinguished positions in the EMF-effects community are E Goodman and B
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From page 68... ...
The series of experiments presented in this final report (except the homing experiments) failed to ask that question, so the experiment design and statistical analyses are muddled and, in some cases (as in the PMR work)
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From page 69... ...
that EMF exposure affects chronically only the acute response and not the acclimation process. if it did not affect the acclimation process, the animals from test plots and control plots would differ in metabolic capacity on the day they were caught, but no data were collected on that day.
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From page 70... ...
When combined with assumptions about information that would have been obtained in the projects that were dropped, it is clear that the information obtained is severely limited and statistically biased toward not finding an effect even if one was present. That is important for the evaluation of this program for the stated goals of the Navv's ELF monitoring program, and it raises questions about the management of the project.
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From page 71... ...
The reason why studies that have low power and show no effects are not considered informative is that their results will fad! to exclude the null hypothesis in any useful way.
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From page 72... ...
Apart from the lack of an appropriate and hypothesis-driven integration of the ELF-EMF exposure data with the biologic questions, their designs were generally good and the statistical analyses appropriate. However, several of the statistical analyses would have been different had the experiment design taken into account the complexities of EMF dose assessment.
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From page 73... ...
Because of these limitations, it is not clear how informative the study results were in answering the basic question of the ELF monitoring program. Some of the additional analyses proposed in Table 5-!
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From page 74... ...
SPECIES AND SYSTEM SELECTION Litter Decay Red pine, red oak, and red maple are three dominant tree species of the northern hardwood forests of the Upper Peninsula of Michigan and in particular those of the antenna site. Litter from these three species represents the extremes (pine and maple)
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From page 75... ...
Armillaria is a suitable organism for studying the effects of environmental changes on heterotrophic decomposer and disease organisms. SELECTION OF RESPONSE VARIABLES Litter Decomposition Mass loss at various times during incubation was the only response variable selected.
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From page 76... ...
. A red pine plantation was sampled in each treatment site, and a northern hardwood stand was sampled in the overhead-antenna treatment and control sites.
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From page 77... ...
This pseudoreplication problem underlies many other studies in the overall ecological monitoring program. The acceptance of all further conclusions must proceed with this caveat in mind, but the caveat is not clearly stated anywhere in the report.
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From page 78... ...
is meaningless. Sensitivity to and power to detect a statistically significant effect of the ELF EMFs on all response variables were considered, and the usual quality assurance and quality control procedures were used.
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From page 79... ...
where X is percentage of original mass remaining at time t. The authors chose not to pursue fitting the parameters of this equation to the data and evaluating changes in k as the response variable, because the first year's data
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From page 80... ...
The authors conclude that the mode} is not a valid description of the decay process in this study. They then postulate that might be due to changing environmental conditions during the decay process and therefore consider alternatives to include these environmental variables in Eq.
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From page 81... ...
Interpretation The major conclusions reached through the ANCOVA of litter-mass loss, streptomycete populations, and Armitiaria infection rates of red pine seedlings are as follows: . Very small changes in decay rates of each of the three species were statistically detectable between antenna and control sites; these differences were not consistent from year to year.
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From page 82... ...
of each species' litter for each treatment site: In(0.5)
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From page 83... ...
RO, red oak. RP, red pine.
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From page 84... ...
Moreover, the direction of difference between control and antenna sites is inconsistent between species. That is, sometimes litter decays faster in the antenna sites than in the control sites and sometimes slower.
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From page 85... ...
That the effects or lack thereof of the antenna detected in the three sites is not due to other site differences that existed before and during antenna operation and that these effects or lack thereof will be present on any other set of sites under the influence of the ELF EMF generated (the pseudoreplication problem)
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From page 86... ...
. A red pine plantation was sampled in each treatment site, and a northern hardwood stand was sampled in the overhead and control sites.
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From page 87... ...
These problems are discussed further in Chapter 4 in the section on use of exposure data by ecological monitoring teams. Statistical Methods The main effect of interest the effect of the ELF EMFs generated by the
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From page 88... ...
Therefore, the experimental data provide an estimate of variance of response variables within each treatment at one site, but not the variance due to treatments across sites. Treatment is confounded with site.
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From page 89... ...
Accordingly, a model of diameter growth of hardwoods or shoot growth of red pine was constructed to predict expected growth given the selected tree species, size, site factors (mainly climatic) , and presence of competitors.
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From page 90... ...
That these researchers appeared to take peer review seriously might have contributed to their later success in publishing the results in peer-reviewed journals. PRESENTATION OF RESULTS Consideration of Alternative Hypotheses Other factors that might explain differences in response variables between control and treatment sites (climate, soil nutrients, etc.)
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From page 91... ...
, rather than any residual correlation with ELF-EMF strength. CONCLUSIONS Validity Among all the response variables measured (see Table 3-2 of this report)
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From page 92... ...
With some caution, they might be extended to other sites that appear similar (northern hardwood stands and red pine plantations of these densities on sandy haplorthods3 of mixed mineralogy and frigid temperature regimes)
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From page 93... ...
. The abundance, community composition, and movement of fish were examined in the control and treatment sites.
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From page 94... ...
But if the two sites must be on the same stream, it would be far better to have the control site upstream so that "turning on the antenna" is less likely to influence the control sites directly simply through mass movement of water, nutrients, and organisms downstream from the treatment site.
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From page 95... ...
However, three weaknesses detract from it: lack of replication (only one pair of sites was contrasted) ; placement of the control site downstream of the treatment site, which might be expected to show changes at the treatment site and thereby undermine such analyses as BACI; and the fact that many of the response variables were aggregate variables, which might be expected to be poor indicators of change (Carpenter et al.
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From page 96... ...
The validity of the studies for policy-making is severely weakened by the placement of the control site downstream of the treatment site, even though the statistics are quite well done. if one dismisses the downstream problem, the evidence points mainly to a positive effect of ELF-EMF exposure on periphyton productivity and to no other major effects.
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From page 97... ...
The response variables were mostly based on previous results of studies of honeybees exposed to high-voltage transmission lines and generally were highly relevant and well justified. Honeybees show changes in orientation (waggle dances)
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From page 98... ...
EXPERIMENT DESIGN AND IMPLEMENTATION Biologic and Ecological Sampling Techniques Sites were chosen on the basis of required exposure criteria. However, the experimental design has two major flaws.
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From page 99... ...
Their test for statistically significant ELF-EMF effects was based on a significant interaction between treatment-site response variables and levels of antenna operation, which would indicate that differences between the treatment and control sites were greater when the antenna was on full power than earlier, when it was on low or 50% power. However, this is problematic, as recognized, in that such an interaction could indicate either that the treatment and control sites respond differently to the different antenna levels or that the sites were different before antenna operation, but not after, for other reasons.
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From page 100... ...
Exposure Assessment L Measurements of actual ELF-EMF exposures are reported for the treatment and control sites, with maximums and minimums given for one of the two treatment sites for June through August. The 76-Hz magnetic-flux densities at the treatment site were 330 times stronger than at the control site.
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From page 101... ...
Mortality was lower at the treatment site at low antenna power but increased to the level of the control site after full antenna operation.
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From page 102... ...
Overwintering mortality was also found to differ significantly with ELFEMF exposure in a nest-transplant experiment. Nests occupied at a treatment site but moved and overwintered at control site showed lower mortality than nests occupied and overwintered at the treatment site.
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From page 103... ...
The authors' explanations are inadequate for discounting potential ELF-EMF effects and for accepting the null hypothesis of no effect. Given the weak ability of the experiment design to detect ELF-EMF effects, any significant effects should be given careful consideration.
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From page 104... ...
It makes sense to examine the abundances, activity, and demographics of dominant soil animals. This study has six parts: soil and litter arthropod censuses, analyses of surface-active arthropod activity via pitfall traps, analyses of earthworm populations sampled by square cores, analyses of growth and reproduction rates of earthworms incubated in soil bags, analyses of litter inputs sampled by litter traps, and analyses of litter-decomposition rates measured in litterbags.
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From page 105... ...
Litter Decomposition Litter decay is certainly an appropriate system process to examine, especially in the context of concordant measures of earthworm and other macrofauna associated with decomposition. SEEECTION OF RESPONSE VARIABEES Most of the response variables involved counts or densities of individuals by species, an unassailable focus for analysis.
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From page 106... ...
EXPERIMENT DESIGN Biologic and Ecological Sampling Techniques The field design involved a single control site and a single treatment site for all components of the research. Replication is therefore impossible, and the only appropriate statistical analysis uses a before-and-after, control-andimpact (BACT)
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From page 107... ...
No serious effort was made to determine whether those effects were due to ELF EMFs or to some other environmental characteristics associated with the difference between control and treatment sites. Interpretation The interpretations of data seem predisposed to conclude that ELF-EMF
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From page 108... ...
, and it might not be consoling to learn that variation due to ELF EMFs is minor in comparison with the variation caused by a severe drought. SOIL AMEBAS PROJECT PROPOSAL This study, carried out over a period of more than 10 years starting in 1983, records data on populations of soil amebas from two treatment sites near the antenna (one next to the ground terminal and one under the antenna)
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From page 109... ...
EXPERIMENT DESIGN AND IMPLEMENTATION Biologic Sampling Techniques The sampling techniques were well described and appear to have been carried out with professional competence. Similar experimental procedures were used for samples from the control and treatment sites.
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From page 110... ...
The only statistically significant difference found was in conditions before and after antenna operation; there was a small but statistically significant difference in maximal population densities between the control site and ground treatment site, but by the same method of analysis no differences between the control site and the antenna treatment site or between the antenna and ground treatment sites. The study appears to have been carried out carefully and competently.
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