Radiofrequency electromagnetic fields in swedish radio stations and tall FM/TV towers

Radiofrequency electric and magnetic fields have been measured around 11 large broadcast stations and tall FM/TV towers in Sweden. The results show that operating personnel may be exposed to fields exceeding by several times the present standard for occupational exposure to RF radiation. Maintenance personnel are especially vulnerable to exposure when climbing energized towers. The present study indicates that the transmitters should be switched off during the performance of certain tasks on the tower. Safe passage of maintenance personnel near energized antennas of certain types is impossible without a drastic reduction of the transmitted power. In the stations, the RF leakage radiation was generally low, but when work was done with the cabinet doors of the transmitter open, high field strengths were found in the vicinity of the transmitter even though it was switched off. It was found that the transmitter acted as a tuned receiver of energy from the other transmitters.     

Effects of mobile phone electromagnetic fields on an auditory order threshold task

The effect of acute exposure to radio frequency electromagnetic fields (RF EMF) generated by mobile phones on an auditory threshold task was investigated. 168 participants performed the task while exposed to RF EMF in one testing session (either global system for mobile communication (GSM) or unmodulated signals) while in a separate session participants were exposed to sham signals. Lateralization effects were tested by exposing participants either on the left side or on the right side of the head. No significant effect of exposure to RF EMF was detected, suggesting that acute exposure to RF EMFs does not affect performance in the order threshold task.     

Radio‐transmitters do not affect seasonal mass change or annual survival of wintering Bicknell's Thrushes

ABSTRACT Studies of the effects of transmitters on passerines have provided mixed results, but many have revealed no negative impacts. Most such studies have been conducted during the breeding season and, as a result, little is known about the possible effects of transmitters on wintering birds. We examined the effects of transmitters on Bicknell's Thrushes (Catharus bicknelli) wintering in the Dominican Republic. We used long‐term mark‐recapture data to compare birds with radio‐transmitters (N= 5 years, 64 individuals) to birds banded, but not radio‐tagged (N= 10 years, 164 individuals). For a subset of birds in each category, we measured the change in mass between early‐winter and late‐winter and, for all birds, we calculated return rates and modeled annual survival by sex and age classes. Return rates of radio‐tagged (16%) and banded‐only individuals (17%) did not differ, and survival models including the effect of transmitter attachment were poorly supported. We also found no sex or age‐specific effects of transmitter attachment. Radio‐tagged and banded‐only birds did not differ either in the proportion of birds gaining mass during the winter or amount of mass gained. Our results indicate that attaching light‐weight transmitters (<5% of body mass) to wintering Bicknell's Thrushes did not adversely affect either body condition or annual survival.     

Summary of measured radiofrequency electric and magnetic fields (10 kHz to 30 GHz) in the general and work environment

We have plotted data from a number of studies on the range of radiofrequency (RF) field levels associated with a variety of environmental and occupational sources. Field intensity is shown in units of volts/meter (V/m) for electric field strength and amps/meter (A/m) for magnetic field strength. Duty factors, modulation frequencies, and modulation indices are also reported for some sources. This paper is organized into seven sections, each cataloging sources into appropriate RF frequency bands from very-low frequency (VLF) to super-high frequency (SHF), and covers frequencies from 10 kHz to 30 GHz. Sources included in this summary are the following: Coast Guard navigational transmitters, a Navy VLF transmitter, computer visual display terminals (VDTs), induction stoves or range tops, industrial induction and dielectric heaters, radio and television broadcast transmitters, amateur and citizens band (CB) transmitters, medical diathermy and electrosurgical units, mobile and handheld transmitters, cordless and cellular telephones, microwave ovens, microwave terrestrial relay and satellite uplinks, and police, air traffic, and aircraft onboard radars. For the sources included in this summary, the strongest fields are found near industrial induction and dielectric heaters, and close to the radiating elements or transmitter leads of high power antenna systems. Handheld transmitters can produce near fields of about 500 V/m at the antenna. Fields in the general urban environment are principally associated with radio and TV broadcast services and measure about 0.1 V/m root-mean-square (rms). Peak fields from air traffic radars sampled in one urban environment were about 10 V/m, 300 times greater than the rms value of 0.03 V/m when the duty factor associated with antenna rotation and pulsing are factored in. Bioelectromagnetics 18: 563–577, 1997. Published 1997 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Investigating short-term exposure to electromagnetic fields on reproductive capacity of invertebrates in the field situation

Organisms are exposed to electromagnetic fields from the introduction of wireless networks that send information all over the world. In this study we examined the impact of exposure to the fields from mobile phone base stations (GSM 900?MHz) on the reproductive capacity of small, virgin, invertebrates. A field experiment was performed exposing four different invertebrate species at different distances from a radiofrequency electromagnetic fields (RF EMF) transmitter for a 48-h period. The control groups were isolated from EMF exposure by use of Faraday cages. The response variables as measured in the laboratory were fecundity and number of offspring. Results showed that distance was not an adequate proxy to explain dose-response regressions. No significant impact of the exposure matrices, measures of central tendency and temporal variability of EMF, on reproductive endpoints was found. Finding no impact on reproductive capacity does not fully exclude the existence of EMF impact, since mechanistically models hypothesizing non-thermal-induced biological effects from RF exposure are still to be developed. The exposure to RF EMF is ubiquitous and is still increasing rapidly over large areas. We plea for more attention toward the possible impacts of EMF on biodiversity.     

Challenges and prospects in the telemetry of insects

Radio telemetry has been widely used to study the space use and movement behaviour of vertebrates, but transmitter sizes have only recently become small enough to allow tracking of insects under natural field conditions. Here, we review the available literature on insect telemetry using active (battery‐powered) radio transmitters and compare this technology to harmonic radar and radio frequency identification (RFID) which use passive tags (i.e. without a battery). The first radio telemetry studies with insects were published in the late 1980s, and subsequent studies have addressed aspects of insect ecology, behaviour and evolution. Most insect telemetry studies have focused on habitat use and movement, including quantification of movement paths, home range sizes, habitat selection, and movement distances. Fewer studies have addressed foraging behaviour, activity patterns, migratory strategies, or evolutionary aspects. The majority of radio telemetry studies have been conducted outside the tropics, usually with beetles (Coleoptera) and crickets (Orthoptera), but bees (Hymenoptera), dobsonflies (Megaloptera), and dragonflies (Odonata) have also been radio‐tracked. In contrast to the active transmitters used in radio telemetry, the much lower weight of harmonic radar and RFID tags allows them to be used with a broader range of insect taxa. However, the fixed detection zone of a stationary radar unit (< 1 km diameter) and the restricted detection distance of RFID tags (usually < 1–5 m) constitute major constraints of these technologies compared to radio telemetry. Most of the active transmitters in radio telemetry have been applied to insects with a body mass exceeding 1 g, but smaller species in the range 0.2–0.5 g (e.g. bumblebees and orchid bees) have now also been tracked. Current challenges of radio‐tracking insects in the field are related to the constraints of a small transmitter, including short battery life (7–21 days), limited tracking range on the ground (100–500 m), and a transmitter weight that sometimes approaches the weight of a given insect (the ratio of tag mass to body mass varies from 2 to 100%). The attachment of radio transmitters may constrain insect behaviour and incur significant energetic costs, but few studies have addressed this in detail. Future radio telemetry studies should address (i) a larger number of species from different insect families and functional groups, (ii) a better coverage of tropical regions, (iii) intraspecific variability between sexes, ages, castes, and individuals, and (iv) a larger tracking range via aerial surveys with helicopters and aeroplanes equipped with external antennae. Furthermore, field and laboratory studies, including observational and experimental approaches as well as theoretical modelling, could help to clarify the behavioural and energetic consequences of transmitter attachment. Finally, the development of commercially available systems for automated tracking and potential future options of insect telemetry from space will provide exciting new avenues for quantifying movement and space use of insects from local to global spatial scales.     

Hematological stress indices reveal no effect of radio‐transmitters on wintering Hermit Thrushes

ABSTRACT Radio‐telemetry is often used to track birds, and several investigators have examined the possible effects of radio‐transmitters on birds. One approach to this question is to determine if transmitters induce physiological stress. Using hematological indicators of stress (heterophil‐lymphocyte [H/L] ratios), studies of captive birds have revealed no evidence that radio‐transmitters cause stress. However, studies in captivity may not reflect conditions faced by birds in the wild, especially during energetically demanding times, such as the overwintering period. We examined the possible effect of backpack‐style transmitters on overwintering Hermit Thrushes (Catharus guttatus) in South Carolina by examining H/L ratios from blood smears made before and after transmitter attachment. We captured and recaptured eight thrushes in an early winter period and 11 in a late winter period, and in both cases found that H/L ratios did not change after 1 mo of carrying transmitters. H/L ratios also did not differ significantly (in either trial) between thrushes with and without transmitters. Furthermore, thrushes that carried transmitters during both of our trials did not have higher final H/L ratios than those that carried transmitters during just one trial (the late winter). These results indicate that carrying backpack‐style transmitters for 1 mo did not induce stress in overwintering Hermit Thrushes. These results are consistent with studies of captive birds, and provide support for the continued use of backpack radio‐transmitters in this species, as long as weight recommendations are met.     

Statistical analysis of personal radiofrequency electromagnetic field measurements with nondetects

Exposimeters are increasingly applied in bioelectromagnetic research to determine personal radiofrequency electromagnetic field (RF‐EMF) exposure. The main advantages of exposimeter measurements are their convenient handling for study participants and the large amount of personal exposure data, which can be obtained for several RF‐EMF sources. However, the large proportion of measurements below the detection limit is a challenge for data analysis. With the robust ROS (regression on order statistics) method, summary statistics can be calculated by fitting an assumed distribution to the observed data. We used a preliminary sample of 109 weekly exposimeter measurements from the QUALIFEX study to compare summary statistics computed by robust ROS with a naïve approach, where values below the detection limit were replaced by the value of the detection limit. For the total RF‐EMF exposure, differences between the naïve approach and the robust ROS were moderate for the 90th percentile and the arithmetic mean. However, exposure contributions from minor RF‐EMF sources were considerably overestimated with the naïve approach. This results in an underestimation of the exposure range in the population, which may bias the evaluation of potential exposure‐response associations. We conclude from our analyses that summary statistics of exposimeter data calculated by robust ROS are more reliable and more informative than estimates based on a naïve approach. Nevertheless, estimates of source‐specific medians or even lower percentiles depend on the assumed data distribution and should be considered with caution. Bioelectromagnetics. Bioelectromagnetics 29:471–478, 2008. © 2008 Wiley‐Liss, Inc.     

Radiofrequency exposure on fast patrol boats in the Royal Norwegian Navy—an approach to a dose assessment

Epidemiological studies related to radiofrequency (RF) electromagnetic fields (EMF) have mainly used crude proxies for exposure, such as job titles, distance to, or use of different equipment emitting RF EMF. The Royal Norwegian Navy (RNoN) has measured RF field emitted from high‐frequency antennas and radars on several spots where the crew would most likely be located aboard fast patrol boats (FPB). These boats are small, with short distance between the crew and the equipment emitting RF field. We have described the measured RF exposure aboard FPB and suggested different methods for calculations of total exposure and annual dose. Linear and spatial average in addition to percentage of ICNIRP and squared deviation of ICNIRP has been used. The methods will form the basis of a job exposure matrix where relative differences in exposure between groups of crew members can be used in further epidemiological studies of reproductive health. Bioelectromagnetics 31:350–360, 2010. © 2010 Wiley‐Liss, Inc.     

Radio‐transmitters have no impact on survival of pre‐fledged American Woodcocks

American Woodcocks (Scolopax minor) are a high priority species of conservation need across most of their breeding range due to long‐term population declines. Survival of juveniles may be key to understanding these population declines, but there have been few direct estimates of juvenile woodcock survival rates, and no recent assessment of the possible effect of radio‐tagging on juvenile survival. In 2011 and 2012, we radio‐tagged 73 juvenile American Woodcocks in west‐central Minnesota and compared survival rates of radio‐tagged (N = 58) and non‐radio‐tagged (N = 82) juveniles during the period from hatching to fledging. We compared survival rates of juveniles with known fates and used logistic‐exposure models to assess the potential impact of radio‐transmitters on survival. We evaluated variables related to juvenile survival including age, hatch date, maximum and minimum temperature, precipitation, and year to assess the possible effects of radio‐transmitters. The best‐supported model of survival rate of juvenile American Woodcocks included the interaction of age and year and a negative effect of precipitation (β = ?0.76, 85% CI: ?1.08 to ?0.43), but did not include a negative effect of transmitters. Our results suggest that radio‐transmitters did not impact survival of juvenile American Woodcocks and that transmitters are a reliable tool for studying survival of juvenile American Woodcocks, and perhaps other precocial shorebirds.     

Radiotagged fledgling Savannah Sparrows Passerculus sandwichensis at risk of entanglement in vegetation

Radiotelemetry is an essential method for studying the movements and survival of cryptic grassland bird fledglings. There is mixed evidence on the effects of wearing radio‐transmitters for passerines, with negative consequences probably under‐reported. In one season of a 2‐year study, we found 23% of radio‐transmitters and/or antennas deployed on fledgling Savannah Sparrows Passerculus sandwichensis had become entangled in vegetation, consequently harming the fledglings in two of seven cases. It is important for researchers to share their information on any negative consequences of attaching radio‐transmitters to songbirds in order to improve methods and to harm fewer individuals in future studies.     

Hypersensitivity to RF fields emitted from CDMA cellular phones: A provocation study

With the number of cellular phone users rapidly increasing, there is a considerable amount of public concern regarding the effects that electromagnetic fields (EMFs) from cellular phones have on health. People with self‐attributed electromagnetic hypersensitivity (EHS) complain of subjective symptoms such as headaches, insomnia, and memory loss, and attribute these symptoms to radio frequency (RF) radiation from cellular phones and/or base stations. However, EHS is difficult to diagnose because it relies on a person's subjective judgment. Various provocation studies have been conducted on EHS caused by Global System for Mobile Communications (GSM) phones in which heart rate and blood pressure or subjective symptoms were investigated. However, there have been few sham‐controlled provocation studies on EHS with Code Division Multiple Access (CDMA) phones where physiological parameters, subjective symptoms, and perception of RF radiation for EHS and non‐EHS groups were simultaneously investigated. In this study, two volunteer groups of 18 self‐reported EHS and 19 non‐EHS persons were tested for both sham and real RF exposure from CDMA cellular phones with a 300 mW maximum exposure that lasted half an hour. We investigated not only the physiological parameters such as heart rate, respiration rate, and heart rate variability (HRV), but also various subjective symptoms and the perception of EMF. In conclusion, RF exposure did not have any effects on physiological parameters or subjective symptoms in either group. As for EMF perception, there was no evidence that the EHS group better perceived EMF than the non‐EHS group. Bioelectromagnetics 30:641–650, 2009. © 2009 Wiley‐Liss, Inc.     

Survey of electromagnetic field exposure in bedrooms of residences in lower Austria

Previous investigations of exposure to electric, magnetic, or electromagnetic fields (EMF) in households were either about electricity supply EMFs or radio frequency EMFs (RF‐EMFs). We report results from spot measurements at the bedside that comprise electrostatic fields, extremely low‐frequency electric fields (ELF‐EFs), extremely low‐frequency magnetic fields (ELF‐MFs), and RF‐EMFs. Measurements were taken in 226 households throughout Lower Austria. In addition, effects of simple reduction measures (e.g., removal of clock radios or increasing their distance from the bed, turning off Digital Enhanced Cordless Telecommunication (DECT) telephone base stations) were assessed. All measurements were well below International Commission on Non‐Ionizing Radiation Protection (ICNIRP) guideline levels. Average night‐time ELF‐MFs (long‐term measurement from 10 pm to 6 am, geometric mean over households) above 100 nT were obtained in 2.3%, and RF‐EMFs above 1000 µW/m² in 7.1% of households. Highest ELF‐EFs were primarily due to lamps beside the bed (max = 166 V/m), and highest ELF‐MFs because of transformers of devices (max = 1030 nT) or high current of power lines (max = 380 nT). The highest values of RF‐EMFs were caused by DECT telephone base stations (max = 28979 µW/m²) and mobile phone base stations (max = 4872 µW/m²). Simple reduction measures resulted in an average decrease of 23 nT for ELF‐MFs, 23 V/m for ELF‐EFs, and 246 µW/m² for RF‐EMFs. A small but statistically significant correlation between ELF‐MF exposure and overall RF‐EMF levels of R = 0.16 (P = 0.008) was computed that was independent of type (flat, single family) and location (urban, rural) of houses. Bioelectromagnetics 31:200–208, 2010. © 2009 Wiley‐Liss, Inc.     

Accounting for tagging‐to‐harvest mortality in a Brownie tag‐recovery model by incorporating radio‐telemetry data

The Brownie tag‐recovery model is useful for estimating harvest rates but assumes all tagged individuals survive to the first hunting season; otherwise, mortality between time of tagging and the hunting season will cause the Brownie estimator to be negatively biased. Alternatively, fitting animals with radio transmitters can be used to accurately estimate harvest rate but may be more costly. We developed a joint model to estimate harvest and annual survival rates that combines known‐fate data from animals fitted with transmitters to estimate the probability of surviving the period from capture to the first hunting season, and data from reward‐tagged animals in a Brownie tag‐recovery model. We evaluated bias and precision of the joint estimator, and how to optimally allocate effort between animals fitted with radio transmitters and inexpensive ear tags or leg bands. Tagging‐to‐harvest survival rates from >20 individuals with radio transmitters combined with 50–100 reward tags resulted in an unbiased and precise estimator of harvest rates. In addition, the joint model can test whether transmitters affect an individual's probability of being harvested. We illustrate application of the model using data from wild turkey, Meleagris gallapavo, to estimate harvest rates, and data from white‐tailed deer, Odocoileus virginianus, to evaluate whether the presence of a visible radio transmitter is related to the probability of a deer being harvested. The joint known‐fate tag‐recovery model eliminates the requirement to capture and mark animals immediately prior to the hunting season to obtain accurate and precise estimates of harvest rate. In addition, the joint model can assess whether marking animals with radio transmitters affects the individual's probability of being harvested, caused by hunter selectivity or changes in a marked animal's behavior.     

A model for radiofrequency electromagnetic field predictions at outdoor and indoor locations in the context of epidemiological research

We present a geospatial model to predict the radiofrequency electromagnetic field from fixed site transmitters for use in epidemiological exposure assessment. The proposed model extends an existing model toward the prediction of indoor exposure, that is, at the homes of potential study participants. The model is based on accurate operation parameters of all stationary transmitters of mobile communication base stations, and radio broadcast and television transmitters for an extended urban and suburban region in the Basel area (Switzerland). The model was evaluated by calculating Spearman rank correlations and weighted Cohen's kappa (κ) statistics between the model predictions and measurements obtained at street level, in the homes of volunteers, and in front of the windows of these homes. The correlation coefficients of the numerical predictions with street level measurements were 0.64, with indoor measurements 0.66, and with window measurements 0.67. The kappa coefficients were 0.48 (95%‐confidence interval: 0.35–0.61) for street level measurements, 0.44 (95%‐CI: 0.32–0.57) for indoor measurements, and 0.53 (95%‐CI: 0.42–0.65) for window measurements. Although the modeling of shielding effects by walls and roofs requires considerable simplifications of a complex environment, we found a comparable accuracy of the model for indoor and outdoor points. Bioelectromagnetics 31:226–236, 2010. © 2009 Wiley‐Liss, Inc.     

Predators of Dusky Canada Goose goslings and the effect of transmitters on gosling survival

ABSTRACT The population of Dusky Canada Geese (Branta canadensis occidentalis) has been in long‐term decline, likely due to reduced breeding productivity. To identify causes of mortality, we monitored goslings marked with radio transmitters on the western Copper River Delta, Alaska, from 1997 to 1999. Almost all gosling mortality (96%; 81 of 84) was due to predation, with mink (Mustela vison) and Bald Eagles (Haliaeetus leucocephalus) the most important predators. Bald Eagles are also major nest predators and, thus, appear to play a key role in limiting the breeding productivity of Dusky Canada Geese. Daily survival rate for goslings to 28 d of age was lower (0.011; 95% CI 0.002?0.024) for those with transmitters than for those without, but did not differ for older goslings (29?45 d). Although finer resolution in the timing of the transmitter effect within the first 28 d was not possible, we found that, by limiting our sample to goslings that survived until after 2?3 d posthatching, support for a transmitter effect was much reduced. Younger, smaller birds are inherently more vulnerable than older birds to transmitter effects. In addition, the process of radio‐marking may have delayed the departure of goslings from nests and increased their risk of mortality shortly after hatching. Although radio transmitters may often be the only practical means for determining causes of mortality for young waterfowl, we suggest caution in using transmitters because of their potential negative effects, particularly during the first few days after hatching.     

Effects of external and surgically implanted dummy radio transmitters on mortality, swimming performance and physiological status of juvenile masu salmon Oncorhynchus masou

The effects of external and surgically implanted radio transmitters on juvenile masu salmon Oncorhynchus masou were examined. External attachment of transmitters significantly decreased the survival of fish and caused a decreased critical swimming speed compared with surgical implantation. Although plasma cortisol, plasma glucose and haematocrit values did not differ significantly among groups, it appeared that the most suitable transmitter attachment method for juvenile O. masou may be surgical implantation.     

No effects of a single 3G UMTS mobile phone exposure on spontaneous EEG activity,ERP correlates,and automatic deviance detection

Potential effects of a 30 min exposure to third generation (3G) Universal Mobile Telecommunications System (UMTS) mobile phone‐like electromagnetic fields (EMFs) were investigated on human brain electrical activity in two experiments. In the first experiment, spontaneous electroencephalography (sEEG) was analyzed (n = 17); in the second experiment, auditory event‐related potentials (ERPs) and automatic deviance detection processes reflected by mismatch negativity (MMN) were investigated in a passive oddball paradigm (n = 26). Both sEEG and ERP experiments followed a double‐blind protocol where subjects were exposed to either genuine or sham irradiation in two separate sessions. In both experiments, electroencephalograms (EEG) were recorded at midline electrode sites before and after exposure while subjects were watching a silent documentary. Spectral power of sEEG data was analyzed in the delta, theta, alpha, and beta frequency bands. In the ERP experiment, subjects were presented with a random series of standard (90%) and frequency‐deviant (10%) tones in a passive binaural oddball paradigm. The amplitude and latency of the P50, N100, P200, MMN, and P3a components were analyzed. We found no measurable effects of a 30 min 3G mobile phone irradiation on the EEG spectral power in any frequency band studied. Also, we found no significant effects of EMF irradiation on the amplitude and latency of any of the ERP components. In summary, the present results do not support the notion that a 30 min unilateral 3G EMF exposure interferes with human sEEG activity, auditory evoked potentials or automatic deviance detection indexed by MMN. Bioelectromagnetics 34:31–42, 2013. © 2012 Wiley Periodicals, Inc.