SAR (Specific Absorption Rate)

Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.

Sunohara T, Hirata A, Laakso I, Onishi T · 2014

Characterization of personal RF electromagnetic field exposure and actual absorption for the general public.

Joseph W, Vermeeren G, Verloock L, Heredia MM, Martens L · 2008

This study characterized personal radiofrequency electromagnetic field exposure of the general public from 12 different sources. Indoor office exposure from WiFi reached 95th-percentile field values of 0.36 to 0.58 V m(-1), while DECT reached 0.33 V m(-1), and outdoor GSM and DCS downlink signals reached up to 0.52 V m(-1). The researchers proposed a method to relate measured field exposure to actual whole-body absorption and applied it to a GSM downlink signal, finding Fiftieth, 95th, and 99th percentiles of whole-body SAR of 0.58 microW kg(-1), 2.08 microW kg(-1), and 5.01 microW kg(-1) for a 95th percentile of 0.26 V m(-1).

Between-country comparison of whole-body SAR from personal exposure data in urban areas.

Joseph W et al. · 2012

Researchers measured personal radio frequency electromagnetic field exposure in Belgium, Switzerland, Slovenia, Hungary, and the Netherlands across microenvironments such as homes, public transport, and outdoors. From those field measurements, whole-body absorption values were calculated for a 1-year-old child model and an adult male model and compared for the five countries. The maximum mean whole-body absorption was 3.4 µW/kg for the child and 1.8 µW/kg for the adult, both well below the ICNIRP basic restriction of 0.08 W/kg for the general public.

GSM 900 MHz cellular phone radiation can either stimulate or depress early embryogenesis in Japanese quails depending on the duration of exposure.

Tsybulin O et al. · 2013

Japanese quail embryos were exposed in ovo to GSM 900 MHz radiation for 38 hours or 158 hours with a 48-second on, 12-second off cycle at an average power density of 0.25 μW/cm(2) and a specific absorption rate of 3 μW/kg. The number of differentiated somites was assessed microscopically and DNA damage was assessed by an alkaline comet assay. After 38 hours the number of differentiated somites increased and DNA strand breaks decreased, while after 158 hours the number of differentiated somites decreased and DNA damage increased.

Calcium-ion movement and contractility in atrial strips of frog heart are not affected by low-frequency-modulated, 1 GHz electromagnetic radiation.

Schwartz JL, Mealing GA · 1993

Researchers investigated the effects of AM or CW modulated 1 GHz exposure on calcium efflux and contractile force of isolated atrial muscle stripes of frog heart in vitro. Calcium efflux from electrically stimulated, 45Ca(2+)-preloaded atrial strips of the frog heart was measured from perfusate samples collected at 2-min intervals for 32 min while contractile force was simultaneously monitored. The atrial strips were exposed for 32 min to constant or amplitude-modulated 1 GHz fields at SAR ranging from 3.2 microW/kg to 1.6 W/kg with modulation at 0.5 Hz or 16 Hz. Neither unmodulated nor 0.5 Hz or 16 Hz modulated 1 GHz waves affected the movement of calcium ions or the contractile force in isolated atrial strips of the frog heart.

Estimation of whole-body SAR from electromagnetic fields using personal exposure meters.

Joseph W, Vermeeren G, Verloock L, Martens L. · 2010

Researchers converted personal electromagnetic field measurements into whole-body specific absorption rates (SAR) for members of the general public. Among the body types compared, the highest SAR values at 950 MHz were found for the 1-year-old child, followed by the 5-year-old child, 10-year-old child, average woman, and average man. All calculated values remained below the basic restriction of 0.08 W/kg for the general public.

Microwave induced alteration in the neuron specific enolase gene expression.

Verma M, Dutta SK. · 1993

The study aimed to investigate microwave induced alteration in neuron specific enolase gene expression. Researchers exposed pNGE7 cells containing the neuron specific enolase gene to 915 MHz, 16 Hz AM radiation at SAR 0.05 mW/kg. Exposure resulted in elevation of neuron specific enolase, a diagnostic marker for neuron and lung cancer. Ion-exchange chromatography separated neuron specific enolase activity from non-neuronal enolase activity and showed altered expression of both.

Effect of low level microwave radiation exposure on cognitive function and oxidative stress in rats.

Deshmukh PS et al. · 2013

Researchers exposed rats to extremely low-level 900 MHz microwave radiation (similar to cell phone frequencies) for 2 hours daily over 30 days. The exposed rats showed significant cognitive impairment and increased oxidative stress (cellular damage from harmful molecules called free radicals) compared to unexposed control rats. This suggests that even very weak microwave radiation can affect brain function and cause cellular damage.

Effect of low level microwave radiation exposure on cognitive function and oxidative stress in rats

Deshmukh PS et al. · 2013

Researchers exposed rats to extremely low-level 900 MHz microwave radiation (similar to cell phone frequencies) for 2 hours daily over 30 days. The exposed rats showed significant memory and learning problems, plus increased oxidative stress (cellular damage) in their blood. This matters because the radiation level was about 1,000 times lower than current safety limits, yet still caused measurable brain and cellular effects.

Effect of low level microwave radiation exposure on cognitive function and oxidative stress in rats

Deshmukh PS et al. · 2013

Assessment of Public Exposure From WLANs in the West Bank-Palestine.

Lahham A, Sharabati A, ALMasri H. · 2017

Researchers conducted 271 measurements at 69 indoor sites in the West Bank to assess public exposure to radiofrequency emissions from wireless local area networks. Power density levels varied from 0.001 to ~1.9 μW cm-2 with an average of 0.12 μW cm-2, and the highest levels were found in university environments. The maximum measured value of ~4.5 μW cm-2 at 20 cm from an access point transmitting large files was 221 times below the ICNIRP general public exposure limit, which was never exceeded. At 1 meter from a laptop, power density was lower than from the access point in both transmit and idle modes, and the estimated specific absorption rate for the user's head ranged from 0.1 to 2 mW/kg.

Effects of chronic exposure to radiofrequency electromagnetic fields on energy balance in developing rats

Pelletier A et al. · 2013

Researchers examined the effects of chronic RF-EMF exposure (900 MHz, 1 V m(-1)) on the main functions involved in body energy homeostasis, including feeding behaviour, sleep, and thermoregulatory processes. Thirteen juvenile male Wistar rats were exposed to continuous RF-EMF for 5 weeks and compared with 11 non-exposed animals. The frequency of rapid eye movement sleep episodes was greater in the exposed group independently of ambient temperature, with increases of 42.1% at 24 °C and 31.6% at 31 °C. Exposure also increased daytime food intake, and the researchers concluded that RF-EMF exposure can induce energy-saving processes without strongly disturbing the overall sleep pattern.

Using medaka embryos as a model system to study biological effects of the electromagnetic fields on development and behavior.

Lee W, Yang KL. · 2014

Researchers exposed fish embryos to extremely low frequency electromagnetic fields (3.2 kHz) at various intensities to study developmental effects. They found that EMF exposure accelerated embryonic development across multiple measures including eye formation, brain development, and hatching time. Fish exposed to the highest EMF levels also showed increased anxiety-like behavior after hatching.

Increased blood-brain barrier permeability in mammalian brain 7 days after exposure to the radiation from a GSM-900 mobile phone.

Nittby H et al. · 2009

Rats were exposed in TEM-cells for 2 hours at non-thermal specific absorption rates of 0, 0.12, 1.2, 12, and 120 mW/kg, and albumin extravasation over the blood-brain barrier, neuronal albumin uptake, and neuronal damage were assessed. Albumin extravasation was enhanced in the mobile phone exposed rats compared to sham controls after a 7-day recovery period, with a significant result at the SAR value of 12 mW/kg. There was a low but significant correlation between the exposure level and the occurrence of focal albumin extravasation.

Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones.

Eberhardt JL, Persson BR, Brun AE, Salford LG, Malmgren LO. · 2008

Swedish researchers exposed rats to cell phone radiation at 900 MHz for 2 hours and examined their brains 14 and 28 days later. They found that the radiation compromised the blood-brain barrier (the protective shield around the brain) and caused nerve cell damage. The blood-brain barrier leaked proteins into brain tissue within 14 days, while actual nerve cell death appeared after 28 days.

Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones

Eberhardt JL, Persson BR, Brun AE, Salford LG, Malmgren LO · 2008

Researchers exposed rats to GSM microwave signals in the 900 MHz band and measured blood-brain barrier permeability and signs of neuronal damage after recovery periods of 14 or 28 days. Non-anaesthetized rats were sham exposed or exposed to microwaves for 2 hours at whole-body specific absorption rates of 0.12, 1.2, 12, or 120 mW/kg. Albumin leakage and its uptake into neurons was enhanced after 14 days but not after the 28-day recovery period, while the occurrence of dark neurons was enhanced after 28 days.

Electromagnetic fields at a mobile phone frequency (900 MHz) trigger the onset of general stress response along with DNA modifications in Eisenia fetida earthworms

Bourdineaud JP et al. · 2017

Researchers exposed Eisenia fetida earthworms to electromagnetic fields at 900 MHz and field levels ranging from 10 to 120 V m-1 for a period of two hours. All exposure treatments induced significant DNA modifications, and the number of probe hybridisation sites showed a significant two-fold decrease even after 24 hours of recovery. Genes involved in general stress, oxidative stress, and immune defence were up-regulated after exposure, and Western blots confirmed an increased quantity of HSP70 and MTCO1 proteins.

Electromagnetic fields at a mobile phone frequency (900 MHz) trigger the onset of general stress response along with DNA modifications in Eisenia fetida earthworms.

Bourdineaud JP et al. · 2017

Scientists exposed earthworms to cell phone radiation (900 MHz) for two hours at levels far below safety limits. The worms showed DNA damage and stress responses that lasted over 24 hours after exposure ended, suggesting even brief, low-level mobile phone frequencies cause lasting biological harm.

DNA synthesis and cell proliferation in C6 glioma and primary glial cells exposed to a 836.55 MHz modulated radiofrequency field.

Stagg RB, Thomas WJ, Jones RA, Adey WR · 1997

Researchers exposed transformed and normal rat glial cells to an 836.55 MHz packet-modulated RF field at power densities of 0.09, 0.9, and 9 mW/cm2, with SARs from 0.15 to 59 muW/g. Primary rat glial cells showed no significant differences in DNA synthesis between sham and RF-exposed conditions for either log-phase or serum-starved cultures. C6 glioma cells exposed at 5.9 muW/g SAR showed small but significant increases in thymidine incorporation in 38% of experiments. Growth curves showed no differences between sham and RF-exposed cultures for either cell type, and doubling times of C6 glioma cells did not differ significantly.

Focus formation of C3H/10T1/2 cells and exposure to a 836.55 MHz modulated radiofrequency field.

Cain CD, Thomas DL, Adey WR · 1997

The study tested whether a TDMA-modulated RF field and the tumor promoter TPA together increase focus formation of transformed cells cocultured with parental C3H/10T1/2 murine fibroblasts. Cell cultures were exposed to an 836.55 MHz TDMA-modulated field at specific absorption rates of 0.15, 1.5, and 15 μW/g in a repeating cycle of 20 minutes on and 20 minutes off continuously for 28 days. RF exposure did not significantly alter TPA-induced focus formation at any of the tested exposure levels across multiple independent experiments.

Exposure of frog hearts to CW or amplitude-modulated VHF fields: selective efflux of calcium ions at 16 Hz.

Schwartz JL, House DE, Mealing GA · 1990

Exposure to ELF-pulse modulated X band microwaves increases in vitro human astrocytoma cell proliferation.

Pérez-Castejón C et al. · 2009

Researchers exposed human astrocytoma cells (Clonetics line 1321N1) to a 9.6 GHz carrier wave amplitude-modulated by extremely low frequency pulses in a GTEM cell. The exposure parameters included pulse widths of 100-120 ns, pulse repetition frequencies of 100-800 Hz, power of 0.34-0.60 mW, electric field strength of 1.25-1.64 V/m, and a SAR of 4.0 x 10-4 W/Kg. Cells were exposed for 15, 30, 60 minutes, and 24 hours using a double-blind method with sham controls. Cytoskeleton proteins, cell morphology, and viability were unchanged, but cell proliferation rate increased significantly after 24 hours of exposure. Hsp-70 and Bcl-2 antiapoptotic proteins were present in both control and exposed samples, while connexin 43 protein expression increased in exposed samples.

Electromagnetic radiation (Wi-Fi) and epilepsy induce calcium entry and apoptosis through activation of TRPV1 channel in hippocampus and dorsal root ganglion of rats

Ghazizadeh V, Nazıroğlu M · 2014

Effect of Low Level Subchronic Microwave Radiation on Rat Brain

Deshmukh PS et al. · 2016

Researchers exposed male Fischer rats to microwave radiation for 90 days at 900, 1800, and 2450 MHz to investigate effects on cognitive function, heat shock protein 70 (HSP70) levels, and DNA damage in the brain. Cognitive function was tested using the elevated plus maze and Morris water maze, HSP70 levels were measured by ELISA, and DNA damage was assessed using alkaline comet assay. The results suggest that low-level microwave exposure at these frequencies may lead to hazardous effects on the brain.

Effect of Low-Intensity Microwave Radiation on Monoamine Neurotransmitters and Their Key Regulating Enzymes in Rat Brain.

Megha K et al. · 2015

Researchers exposed Fischer rats to 900 MHz and 1800 MHz microwave radiation for 30 days at 2 hours per day, 5 days per week, with specific absorption rates of 5.953 × 10−4 and 5.835 × 10−4 W/kg respectively. Levels of dopamine, norepinephrine, epinephrine, and serotonin were measured in the hippocampus using LC–MS/MS. Exposed animals showed significant reductions in DA, NE, E and 5-HT, and significant downregulation in mRNA expression of TH, TPH1, and TPH2 compared with sham-exposed animals (p < 0.05).