Electric And Magnetic Fields Research Articles

Childhood leukemia, electric and magnetic fields, and temporal trends

During the past 25 years concern has been raised about the possible health effects of extremely low frequency (ELF) electric and magnetic fields (EMFs), particularly regarding childhood leukemia. Comparison of changes in electricity consumption (a surrogate for exposure) to changes in childhood-leukemia rates, known as ecologic correlation, have been used to argue both for and against the association between magnetic fields and childhood leukemia. In this paper we explore what can be learned from such an ecologic approach. We first examine separately the evidence on trends in exposure to EMFs and on trends in leukemia rates, and then compare the two. Both incidence rates and exposures have increased, but there are so many approximations and assumptions involved in connecting the two trends that we cannot regard the ecologic evidence as providing any meaningful evidence for or against a causal link.

Melatonin in pathogenesis and therapy of cancer

Melatonin is a neuroendocrine hormone secreted by the pineal gland to transduce the body's circadian rhythms. An internal 24 hour time keeping system (biological clock) regulated by melatonin, controls the sleep-wake cycle. Melatonin production is a highly conserved evolutionary phenomenon. The indole hormone is synthesized in the pinealocytes derived from photoreceptors. Altered patterns and/or levels of melatonin secretion have been reported to coincide with sleep disorders, jetlag, depression, stress, reproductive activities, some forms of cancer and immunological disorders. Lately, the physiological and pathological role of melatonin has become a priority area of investigation, particularly in breast cancer, melanoma, colon cancer, lung cancer and leukemia. According to the 'melatonin hypothesis' of cancer, the exposure to light at night (LAN) and anthropogenic electric and magnetic fields (EMFs) is related to the increased incidence of breast cancer and childhood leukaemia via melatonin disruption. Melatonin's hypothermic, antioxidant and free radical scavenging properties, attribute it to an immunomodulator and an oncostatic agent as well. Many clinical studies have envisaged the potential therapeutic role of melatonin in various pathophysiological disorders, particularly cancer. A substantial reduction in risk of death and low adverse effects were reported from various randomized controlled trials of melatonin treatment in cancer patients. This review summarizes the physiological significance of melatonin and its potential role in cancer therapy. Furthermore, the article focuses on melatonin hypothesis to represent the cause-effect relationship of the three aspects: EMF, LAN and cancer.

Developing Policy in the Face of Scientific Uncertainty: Interpreting 0.3 μT or 0.4 μT Cutpoints from EMF Epidemiologic Studies

There has been considerable scientific effort to understand the potential link between exposures to power-frequency electric and magnetic fields (EMF) and the occurrence of cancer and other diseases. The combination of widespread exposures, established biological effects from acute, high-level exposures, and the possibility of leukemia in children from low-level, chronic exposures has made it both necessary and difficult to develop consistent public health policies. In this article we review the basis of both numeric standards and precautionary-based approaches. While we believe that policies regarding EMF should indeed be precautionary, this does not require or imply adoption of numeric exposure standards. We argue that cutpoints from epidemiologic studies, which are arbitrarily chosen, should not be used as the basis for making exposure limits due to a number of uncertainties. Establishment of arbitrary numeric exposure limits undermines the value of both the science-based numeric EMF exposure standards for acute exposures and precautionary approaches. The World Health Organization's draft Precautionary Framework provides guidance for establishing appropriate public health policies for power-frequency EMF.

The Effects of Electromagnetic Fields From Power Lines on Avian Reproductive Biology and Physiology: A Review

Electrical power lines are ubiquitous in the developed world and in urban areas of the developing world. All electrical currents, including those running through power lines, generate electric and magnetic fields (EMFs). Electrical power lines, towers, and distribution poles are used by birds for perching, hunting, and nesting. Therefore, many bird species, like humans, are exposed to EMFs throughout their lives. EMFs have been implicated in adversely affecting multiple facets of human health, including increasing the risks of life-threatening illnesses such as leukemia, brain cancer, amyotrophic lateral sclerosis, clinical depression, suicide, and Alzheimer’s disease. A great deal of research and controversy exists as to whether or not exposure to EMFs affects the cellular, endocrine, immune, and reproductive systems of vertebrates. Laboratory work has used mice, rats, and chickens as models for this EMF research in an effort to understand better the possible implications of EMF exposure for humans. However, EMF exposure of wild birds may also provide insight into the impacts of EMFs on human health. This review focuses on research examining the effects of EMFs on birds; most studies indicate that EMF exposure of birds generally changes, but not always consistently in effect or in direction, their behavior, reproductive success, growth and development, physiology and endocrinology, and oxidative stress under EMF conditions. Some of this work has involved birds under aviary conditions, while other research has focused on free-ranging birds exposed to EMFs. Finally, a number of future research directions are discussed that may help to provide a better understanding of EMF effects on vertebrate health and conservation. We dedicate this paper to Professor Ross Adey whose exceptional talents as a researcher and mentor will be greatly missed. We thank Ross Adey and Bob McGivern for advice about the physiological effects of EMFs and with respect to avian fertility. K. J. Fernie thanks Hydro Québec, Elliot Block and Dave Bird for logistical support and/or advice during her EMF research, as well as the Canadian Wildlife Service during her current research. We also thank Wolfgang Wiltschko and Roland Prinzinger for access to literature. Financial support for EMF work by K. J. Fernie has been provided by McGill University, Hydro-Québec, the Department of Natural Resource Sciences, the John K. Cooper Foundation, the Wilson Ornithological Society, the Province of Québec Society for the Protection of Birds (P.Q.S.P.B.), the International Osprey Foundation, and the Orville Erickson Memorial Scholarship. Financial support for S. J. Reynolds has been provided by the Natural Environment Research Council, the National Science Foundation, the University of Memphis, and the University of Birmingham.

Research Strategies for Magnetic Fields and Cancer

Widespread concerns about whether electric and magnetic fields (EMF) could adversely affect human health have been raised in epidemiologic studies reported since the 1980s. Possible EMF health effects have been widely publicized in the popular press since that time. We consider here three possible mechanisms of action of EMF on childhood leukemia. We identify the first as "magnetic fields": this hypothesis relates the average level of magnetic field to the incidence of childhood leukemia. We identify a second, recently proposed, mechanism as "contact current": this hypothesis relates the low voltage and consequent current that occurs on the domestic water pipe, due to U.S. grounding practices, as a source for exposure of children. The third hypothesis is that the relationship observed is spurious. Using a modified example taken from the work of Von Winterfeldt and Keeney, we use Decision Analysis to estimate the value of information for distinguishing between the three hypotheses. We believe that this improves on the usual process for deciding on research budgets. Depending on which hypothesis we favor a priori, the value of being informed ranges from US 101 dollars to US 233 dollars per "problem household." Since there could be as many as 2 million such households, the value of information for resolving this issue could approach half a billion dollars! We find that there is no value of information for finding the odds ratio given the contact current hypothesis. In writing this article, we have consciously kept the computations as simple as possible so as to engage the reader's attention and interest. In a penultimate section, we suggest numerous possible extensions for a group interested in discussing and deciding on the value of research on the relationship between magnetic fields and cancer.

Exposure chamber for determining the biological effects of electric and magnetic fields on dairy cows

An exposure chamber was designed to study the effects of electric and magnetic fields (EMF) on oestrous cycles, hormonal profile during gestation, pineal function, quantity and quality of milk production, feed intake, and central nervous system of dairy cattle. The chamber was 15 x 10 x 3 m; and the control system was fully computerized so that the field intensities can be varied and monitored continuously, on site or remotely. During exposure to EMF, milk production, feed consumption, and health were monitored closely and blood and cerebral spinal fluid were continuously sampled. The chamber characteristics allow use of a wide range of exposure such as electric fields (0-30 kV/m) and magnetic fields (0-100 microT) at frequencies ranging from 45 to 3000 Hz.

THE EFFECT OF 17 DAYS EXPOSURE TO STATIC MAGNETIC FIELDS ON THE HYPOTHALAMIC-PITUITARY-GONADAL AXIS IN THE MALE RAT

Power stations produce a range of magnetic fields more than 20 mT which are harmful to those working or living around them. Several investigators have reported an increased health risk due to exposure to electric and magnetic fields (EMF) at 50 and 60 Hz. Several studies have been reported especially with increased tumor incidence, effects on reproduction and development, and neural and behavioral changes. This study evaluated the possible effect of static MFs 50 Hz on the secretion of Testosterone, LH and FSH hormones in male rats. Forty eight Wistar male rats (same range of age and weight) were randomly divided into four groups. Animals in group 1 were used as a sham exposure group. After one-week adaptation they were placed in exposure to three MFs for 40 minutes daily for 17 days. Group 2, 3 and 4 were exposed with 6, 12 and 24 mT static MFs at 50 Hz respectively. After experiments animals were killed and their bloods were collected in separated tubes and their serums were separated using a centrifuge with 3500 RPM for 15 min. Hormones were measured using gamma counter equipment with RIA and IPMA methods. The results were analyzed by ANOVA statistical method. Our results show that testosterone, LH and FSH have not changed significantly (p< 0.05) using these static MFs intensities. therefore it can be concluded that at least the static MFs used in this study (with these intensities and duration) can not affect the secretion of hypothalamic-pituitary-gonadal hormones.

Blood melatonin and prolactin concentrations in dairy cows exposed to 60 Hz electric and magnetic fields during 8 h photoperiods.

Two experiments were conducted to test the hypothesis that electric and magnetic field (EMF) exposure may result in endocrine responses similar to those observed in animals exposed to long days. In the first experiment, 16 lactating, pregnant Holstein cows were assigned to two replicates according to a crossover design with treatment switchback. All animals were confined to wooden metabolic cages and maintained under short day photoperiods (8 h light/16 h dark). Treated animals were exposed to a vertical electric field of 10 kV/m and a horizontal magnetic field of 30 microT (EMF) for 16 h/day for 4 weeks. In a second, similar experiment, 16 nonlactating, nonpregnant Holstein cows subjected to short days were exposed to EMF, using a similar protocol, for periods corresponding to the duration of one estrous cycle. In the first experiment, circulating MLT concentrations during the light period showed a small numerical decrease during EMF exposure (P < .05). Least-square means for the 8 h light period were 9.9 versus 12.4 pg/ml, SE = 1.3. Melatonin concentrations during the dark period were not affected by the treatment. A similar trend was observed in the second experiment, where MLT concentrations during the light period tended to be lower (8.8 pg/ml vs. 16.3 pg/ml, P < .06) in the EMF exposed group, and no effects were observed during the dark period. Plasma prolactin (PRL) was increased in the EMF exposed group (16.6 vs. 12.7 ng/ml, P < .02) in the first experiment. In the second experiment, the overall PRL concentrations found were lower, and the mean plasma PRL concentration was not affected by treatment. These experiments provide evidence that EMF exposure may modify the response of dairy cows to photoperiod.

Association of residential magnetic fields with contact voltage.

The US National Electrical Code's (NEC) requirement to ground a home's electrical service to the residential water line results in a voltage between the water line and earth, V W-E. The voltage may result from ground return current that flows into the earth via the water line or from inductive effects from other sources of magnetic fields, such as transmission lines. This voltage can, in turn, serve as a source for Vbath, the voltage between the water fixtures and conductive drain pipes sunk into the earth beneath a residence. Vbath can be a source of contact current exposure to a child touching a water fixture while bathing. Previous research has suggested that exposure to these currents could be the basis for the association between power-frequency magnetic fields and childhood leukemia. In this study, we assessed the association between measured Vbath and VW-E with the average spot-measured magnetic field, Bavg, in a sample of 191 single-family residences in the Denver metropolitan area. This area was the source of cases and controls for previous studies of electric and magnetic field (EMF) and childhood cancer. The association of both Vbath and VW-E with Bavg had upward trends across magnetic field strata (<0.1 microT (reference); 0.1-<0.3 microT; and > or = 0.3 microT). In addition, VW-E was associated with Vbath. Without further study, these results cannot be applied to multi-dwelling residences or to electrical systems prevalent in other nations. Nonetheless, when combined with the finding that contact current is a far more plausible candidate than the residential magnetic field for mediating biological effects on the basis of comparative dose to bone marrow, these associations indicate that contact current exposure deserves further study.

Occupational magnetic field exposure and myocardial infarction incidence.

Studies on healthy volunteers have seen reduced heart rate variability after exposure to extremely low-frequency electric and magnetic fields (EMF). Because reduced heart rate variability has been linked to cardiovascular disease risk, it has been hypothesized that exposure to EMF might increase the risk of cardiovascular disease. One epidemiologic study has shown increased mortality from cardiovascular conditions in utility workers with elevated exposure to magnetic fields, but several other epidemiologic studies have failed to confirm this result. We tested the hypothesis that occupational EMF exposure increases the risk of myocardial infarction in a large population-based case-control study of myocardial infarction, with detailed information on potential confounders. We used data from the SHEEP study, which is a population-based case-control study of acute myocardial infarction in Stockholm. Occupational EMF exposure was based on job titles 1, 5, and 10 years before diagnosis. We used 2 approaches to classify exposure: first, specific individual job titles with presumed elevated EMF exposure, and second, classification of subjects according to a job-exposure matrix. We found no increased risk of myocardial infarction in subjects classified as having elevated EMF exposure. For the highest exposure category of > or = 0.3 microT according to the job-exposure matrix, the adjusted relative risk was = 0.57 (95% confidence interval = 0.36-0.89). The results of this study do not support the hypothesis that occupational EMF exposure increases the risk of myocardial infarction.

Daubert and the Exclusionary Ethos: The Convergence of Corporate and Judicial Attitudes towards the Admissibility of Expert Evidence in Tort Litigation*

The article traces the way admissibility jurisprudence following Daubert has come to emphasize the importance of strict judicial gatekeeping; making it more difficult for plaintiffs to succeed in tort and product liability litigation. This exclusionary ethos appears to have been shaped by a range of values and interests which appear closely aligned to the perspectives promoted by corporate‐sponsored proponents of tort and evidence reform. The effects of the exclusionary ethos are explored through an example of judicial gatekeeping in recent mobile telephone litigation and a review of judicial surveys of post‐Daubert attitudes toward expert evidence. The role of corporate‐sponsored amicus briefs in the influential Supreme Court Kumho Tire Co. Ltd. v Carmichael appeal, extra‐legal mobilization by conservative think tanks in litigation around electric and magnetic fields (EMF), and a qualitative citation analysis of federal court judgments, are then used in a preliminary attempt to trace the influence of corporate lobbying and social problem rhetorics on judicial attitudes and practice.

Presenting electromagnetic theory in accordance with the principle of causality

A method of presenting electromagnetic theory in accordance with the principle ofcausality is described. Two ‘causal’ equations expressing time-dependent electric andmagnetic fields in terms of their causative sources by means of retarded integrals are usedas the fundamental electromagnetic equations. Maxwell’s equations are derived from these‘causal’ equations. Except for the fact that Maxwell’s equations appear as derivedequations, the presentation is completely compatible with Maxwell’s electromagnetictheory. An important consequence of this method of presentation is that it offers newinsights into the cause-and-effect relations in electromagnetic phenomena and results insimpler derivations of certain electromagnetic equations.

Lymphoblastoid cells exposed to low-frequency magnetic fields: study by atomic force microscopy.

AbstractSince the appearance of the first pioneering article in the 1970s, particular efforts have been made to study the effect of exposure to electric and magnetic fields (EMFs) on living matter (1–10). The initial interest in radio frequency and microwaves has shifted to include the nonthermal, and essentially magnetic, effect of extremely low frequencies (ELF, 1–300 Hz), in particular the 50 and 60 Hz of the electric power system (3,4,9). The density of normal ELF fields is usually below 0.1 μT, but values of 0.5 μT may be found in front of television sets and computer monitors (11) as well as at a distance of 50 m from 300-kV high-voltage power lines (12). Values up to two to three orders of magnitude higher can be found near some domestic appliances or in some industrial processes, and pulsed magnetic fields in the range 1–10 mT are used in nuclear magnetic resonance imaging and for the therapy of soft tissue or nonhealing bone fractures (1).The increasing interest in ELF fields has been partially motivated by epidemiological reports of an increase in some types of cancer and leukemia in children (13,14) and workers exposed to high levels of ambient fields. Carcinogenesis is considered to be a multistep process consisting of initiation-promotion-progression stages (15). Although ELF magnetic fields are not considered sufficiently energetic to interact with DNA and initiate a cancerous process, they could, by acting on cellular receptors, affect cell proliferation and modulate the promotion or progression stage. KeywordsAtomic Force MicroscopyRaji CellPulse Magnetic FieldCell HeightNuclear Magnetic Resonance ImagingThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

50-60 Hz electric and magnetic field effects on cognitive function in humans: a review.

This paper reviews the effect of 50-60 Hz weak electric, magnetic and combined electric and magnetic field exposure on cognitive functions such as memory, attention, information processing and time perception, as determined by electroencephalographic methods and performance measures. Overall, laboratory studies that have investigated the acute effects of power frequency fields on cognitive functioning in humans are heterogeneous, in terms of both electric and magnetic field (EMF) exposure and the experimental design and measures used. Results are inconsistent and difficult to interpret with regard to functional relevance for possible health risks. Statistically significant differences between field and control exposure, when they are found, are small, subtle, transitory, without any clear dose-response relationship and difficult to reproduce. The human performance or event related potentials (ERPs) measures that might specifically be affected by EMF exposure, as well as a possible cerebral structure or function that could be more sensitive to EMF, cannot be better determined.

Micronucleus induction in cells co-exposed in vitro to 50 Hz magnetic field and benzene, 1,4-benzenediol (hydroquinone) or 1,2,4-benzenetriol ☆

The generation, transmission (e.g. power lines, transformers, service wires, and electrical panels), and use (e.g. home appliances, such as electric blankets, shavers, and televisions) of electrical energy is associated with the production of weak electric and magnetic fields (EMF) which oscillate 50 (Europe) or 60 (USA) times per second (power-line frequency), falling in the extremely-low frequency (ELF) region of the electromagnetic spectrum. Epidemiological reports suggest a possible association between exposure to ELF-EMF and an increased risk of cancer (e.g. childhood acute leukaemia). Benzene is an established human leukomogen. This xenobiotic, which is unlikely to be the ultimate carcinogen, is metabolized in the liver to its primary metabolite phenol, which is hydroxylated to hydroquinone (1,4-benzenediol) and 1,2,4-benzenetriol. In this in vitro approach, to test the genotoxic and / or co-genotoxic potency of ELF-EMF, the cytokinesis block micronucleus (MN) method with Jurkat cells has been used. A 50 Hz magnetic field (MF) of 5 mT field strength was applied for different length of time (from 1 to 24 h), either alone or with benzene, 1,4-benzenediol, or 1,2,4-benzenetriol. Our preliminary results show that, after 24 h exposure, the frequency of micronucleated cells in MF-exposed cultures is 1.9 fold higher than in sham-exposed (control) cultures. Benzene exposure does not show any cytogenetic activity, whereas 1,4-benzenediol or 1,2,4-benzenetriol alone significantly affect the number of MN in Jurkat cells, as compared to untreated cultures. Moreover, co-exposure to ELF-MF does not seem to affect the frequency of micronuclei induced by benzene, 1,4-benzenediol, or 1,2,4-benzenetriol.

DEPRESSIVE SYMPTOMS IN WOMEN LIVING NEAR A 735 KV LINE

Objectives 735 kV powerlines increase residential exposure to electric and magnetic fields (EMF) for people living nearby. Some studies have suspected effect of EMF on depressive symptoms and there is plausibility for such an effect via the melatonin pathway. Recently, we found that aged and overweight women living near high power lines had lower sulfatoxymelatonin excretion (Levallois et al 2001). The objective of this study was to compare symptoms of depression in women living near and far away from a high transmission line. Methods In the Quebec city area, 221 women living within 200 meters of a 735 kV line and 195 women living at least 400 meters from any power lines were recruited. Participants, aged between 20 and 74, were required to wear an EMDEX Lite meter for at least 36 hours to measure personal exposure to extremely low frequency magnetic field. Residential exposure to extremely low frequency electric field was assessed by spot measurements. Depressive symptoms in the last week were evaluated with the Center for Epidemiologic Depression scale (CESD) and, for a subsample of participants, with the Diagnostic Intervention Schedule (DIS). Information on risk factors for depression and lifestyle was gathered by questionnaire. Results Mean magnetic field exposure over 24 hours was three times higher for women living near a power line than women living farther away (p < 0.001) and residential electric field intensity was nearly twice in those living near the line (p < 0.001). Proportion of participants with high CESD score (>16) was similar in the two groups (p = 0.63) and the adjusted Odds Ratio for the presence of depressive symptoms in the exposed group was 1.01 (95%Cl: 0.61–1.66). Results were similar when considering higher CESD cut-off scores (19 and 25). In addition, there was no dose response relationship with either electric or magnetic field measurements. There was no modification effect of age or BMI. The DIS results will available at the conference. Acknowledgements Hydro-Québec and Electricité de France supported the melatonin study from which these results are derived.

Comparison of Electrical-Environment Characteristics Between Two Different Types of EHV Transmission Lines

This paper represents the analysis results by comparison of characteristics on electrical environment between different EHV transmission lines, such as AN (Audible Noise), RI (Radio Interference), TVI (Television Interference), EMF (Electric and Magnetic Field). In Korea, the transmission lines with nominal voltage of 765-kV have been operating since 2002, and Hungary energized a 750-kV line in 1978. However both EHV transmission lines have different line configuration, Korea is a prime example of the first double circuit 765-kV line in the world, and Hungary has been operating one of the single circuit 750-kV.

Foreseeable Health Risk of Electric and Magnetic Field Residential Exposures

Exposure to electric and magnetic fields (EMFs) emanating from the generation, distribution and utilization of electricity is widespread. The major debate in recent years has been the possibility that EMFs influence various effects on the human body especially development of cancer. Epidemiologists were the first scientists to publicize this fact through human population studies. Current investigations into this topic split up over diverse areas of research. This paper provides a review of information on health risk of EMF residential exposure. Four major areas have been considered for evaluating the possible risks with emphasis on recent studies. These include safety standards for EMFs, residential field measurement surveys, biological and epidemiological studies of diseases with foreseeable association with EMFs including childhood leukemia, breast cancer, and pregnancy adverse outcomes. On the basis of review findings, it is difficult to provide a robust conclusion about health risk of EMFs, raising the significance of researching this area further. No policy advise is offered, however, as a voluntary precautionary measure, public health professionals, regulatory authorities, standard setters, electric utilities, and individuals are encouraged to advocate minimizing EMF exposures wherever possible.

Improvement of the lightning shielding performance of overhead transmission lines by passive shield wires

This paper addresses a numerical electromagnetic analysis of the influence of installing passive shield wires "extra ground wires" (EGW) underneath the bottom phase conductor on the lightning shielding performance of 765-kV, 3-phase, double-circuit transmission lines. The method of moment (MOM) is employed to model the whole structure in three dimensions except the lightning channel. The lightning channel is simulated by the well-known transmission-line model (TLM), where the influence of the lightning-channel-generated electric and magnetic fields (EMF) are taken into account. The lightning shielding performance with and without EGW is introduced and discussed, without ac energization and due to three distinct lightning strokes, namely, the negative first, the negative subsequent and the positive strokes. The produced voltages and currents in the phase conductors and ground wires as well as the voltage across the insulators are computed, with and without the EGW, due to different lightning current waveforms, locations and inclination of the lightning channel, and return-stroke velocities. The introduction of such EGW results in a significant improvement of the shielding effectiveness by reducing the lightning-produced voltages and currents in the phase conductors as well as the voltage across the insulators. Accordingly, much lower transient overvoltages can be expected with less inadvertent outages of the lines, where the probabilities of flashover and back-flashover decrease, and the reliability enhances.

Responses of the estrous cycle in dairy cows exposed to electric and magnetic fields (60 Hz) during 8-h photoperiods

To study the effects of exposure to extremely low frequency (ELF) electric and magnetic fields (EMF) on the estrous cycle of dairy cows under short-day photoperiod, 16 non-lactating, non-pregnant Holstein cows were exposed to a vertical electric field of 10 kV/m and a horizontal magnetic field of 30 μT for 16 h per day in a cross-over design consisting of two sequences. Each sequence included three periods, and each period corresponded to the duration of one estrous cycle. All animals were maintained under short photoperiod (8 h light/16 h dark) during the trial. Exposure to EMF had an impact on the duration of a complete estrous cycle ( P<0.01) and on the duration of the luteal phase ( P<0.01). The mean duration of one cycle was 19.5±0.4 for the control and 21.3±0.4 days for the exposed animals, respectively. The mean duration of the luteal phase was 15.4±0.4 days for the control and 17.2±0.4 days for the exposed group. The total area under the progesterone (P 4) curve, the amplitude of the curve or the slope of the P 4 rise at the onset of the luteal phase were not affected by EMF exposure. Results indicate that exposure to EMF may increase the duration of the estrous cycle.