Genotoxic effects of electromagnetic field radiations from mobile phones

Highlights

• Electromagnetic field radiation exposure has increased from manmade electronic devices in addition to natural sources.

• A few studies indicated that electromagnetic field radiation does not cause harmful effects.

• A greater number of studies show that mobile phone use causes genotoxic effects.

• Electromagnetic field radiations induce reactive oxygen species causing mutagenesis genotoxicity leading to cancer.

Abstract

The use of wireless communication technology in mobile phones has revolutionized modern telecommunication and mobile phones have become so popular that their number exceeds the global population. Electromagnetic field radiations (EMR) are an integral part of wireless technology, which are emitted by mobile phones, mobile tower antennas, electric power stations, transmission lines, radars, microwave ovens, television sets, refrigerators, diagnostic, therapeutic, and other electronic devices. Manmade EMR sources have added to the existing burden of natural EMR human exposure arising from the Sun, cosmos, atmospheric discharges, and thunder storms. EMR including radiofrequency waves (RF) and extremely low-frequency radiation (ELF) has generated great interest as their short-term exposure causes headache, fatigue, tinnitus, concentration problems, depression, memory loss, skin irritation, sleep disorders, nausea, cardiovascular effects, chest pain, immunity, and hormonal disorders in humans, whereas long-term exposure to EMR leads to the development of cancer. The review has been written by collecting the information using various search engines including google scholar, PubMed, SciFinder, Science direct, EMF-portal, saferemr, and other websites from the internet. The main focus of this review is to delineate the mutagenic and genotoxic effects of EMR in humans and mammals. Numerous investigations revealed that exposure in the range of 0–300 GHz EMR is harmless as it did not increase micronuclei and chromosome aberrations. On the contrary, several other studies have demonstrated that exposure to EMR is genotoxic and mutagenic as it increases the frequency of micronuclei, chromosome aberrations, DNA adducts, DNA single and double strand breaks at the molecular level in vitro and in vivo. The EMR exposure induces reactive oxygen species and changes the fidelity of genes involved in signal transduction, cytoskeleton formation, and cellular metabolism.

Introduction

The first wireless communication (WC) came into existence in the year 1899 when Guglielmo Marconi sent a telegraphic message from a ship docked at New York Harbor to the Twin Lights in Highlands, New Jersey. Since then, telecommunication has advanced rapidly due to many new inventions that enabled wire-free communications, such as mobile telephony (MT) and the Internet as we know it today. The first commercially available mobile phone was launched in October 1983 since then the MT has accelerated rapidly with the addition of new features over time. The twenty-first century can be regarded as the age of cell/mobile phones (Bento, 2016; Harris and Cooper, 2019). Mobile phone use has increased tremendously in the past twelve years globally, reaching a level approximately 1.5 times greater than the global population at the time of writing this article. It is predicted that the number of mobile phones will continue to grow in the coming years. (Source: https://www.bankmycell.com/blog/how-many-phones-are-in-the-world). Mobile phones act as a two-way radio i.e., they can receive and send information (calls, messages, images, videos, emails and allow internet access). This is made possible by the use of wireless technology involving electromagnetic field (EMF) and electromagnetic radiation (EMR) waves (Aly and Crum, 2016; Zothansiama et al., 2017).

EMFs in the form of EMR are self-propagating radiation generated due to the movement of charged particles. EMRs consist of both electrical and magnetic components that oscillate normally (at 90°) in the direction of wave propagation. EMR can travel in air different media and vacuum. The EMFs/EMR are of two types 1. Ionizing radiation with a wavelength range of 10 to 10⁻⁴ nm and a frequency range of 10¹⁶–10²⁴ Hz and 2. The non-ionizing radiations, which have a wavelength between 1 mm and 100 km and a frequency range from 3 kHz to 300 GHz (Norgard and Best, 2020). The EMFs/EMRs used by WC technology have the “pulsed” character and may pose an additional risk even if the exposures are well below the limit set by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) (ICNIRP, 1998, 2020; Martynyuk et al., 2016; Liu et al., 2019). Manmade EMFs/EMRs are generated by microwave ovens, mobile phones, mobile tower antennas, radars, radio/television stations, electric power stations, and various commonly used electronic devices including those, which are used for diagnostic and therapeutic purposes. MT uses radiofrequency (RF) carrier waves with wavelengths between 1 mm and 100 km and frequencies from 3 kHz to 300 GHz and traveling at the speed of light (Joshi and Kumar 2003; Kelsh et al., 2011; Buckus et al., 2017).

Human exposure to manmade EMF/EMR depends on the density of base stations/square kilometer, the distance between two base stations, the amount of power transmitted by the base stations, the number of cell phones/km², and call traffic. There are typically more base stations per square kilometer in cities due to greater population density/km² and a large number of users to service. The power density (PD) of EMR is low just near the base stations (1000 μW/cm²) and is 10–100 μW/cm² at 100 m from the base stations and decreases linearly with distance thereafter. However, this may not be possible in the cities where mobile towers are closely located (Haumann et al., 2002; Aly and Crum, 2016; Marinescu and Poparlan, 2016).

MT uses mainly 2nd generation Global System for mobile communication digital technology (GSM) that employs TDMA (Time Division Multiple Access) system and 3G/4G Universal Mobile Telecommunications System (UMTS) that uses CDMA (Code Division Multiple Access) pulsing/modulation system. Carrier frequencies range between 900 and 2200 MHz, with pulsations at 8 and 217 Hz (GSM) or 100 and 150 Hz (UMTS). In addition to MT, other sources of WC-EMFs are domestic cordless phones (DECT: digital enhanced cordless telecommunications), and internet wireless connection (Wi-Fi: wireless fidelity). All these technologies utilize combine RF carrier signals with extremely low frequency (ELF: 0–3000 Hz) pulsations and modulation (Pedersen, 1997). In addition to mobile phones, human exposure to manmade EMFs/EMRs arises from electrical lines, transmission towers, 5th generation technology (5G), diagnostic, therapeutic, and other electronic devices that have added an extra burden to the electromagnetic pollution of the global environment (Gosselin et al., 2013; Panagopoulos, 2019a; Moon, 2020; Paolucci et al., 2020; López et al., 2021).

All manmade EMFs are coherent and polarized and pose a greater risk to human health due to their ability to disrupt the electrochemical homeostasis in the cells than natural EMFs emanating from the sun, the cosmos, geomagnetic/geoelectric fields, atmospheric oscillations, and other sources (Wolf, 2003; Geffrin et al., 2012; Panagopoulos et al., 2015; Pall, 2021).

The increased use of cell phones for extended durations, and the installation of MT base antennas/towers for communication, have raised concerns about potential health risks to humans as electromagnetic emissions may put an additional burden on the environment beyond several other types of pollution humans are exposed daily such as air and ware pollution, chemicals, pesticides etc. As early as 2000/2001 mobile phone users and individuals residing close to MT base antennas/towers complained of different non-specific symptoms like headache, fatigue, tinnitus, concentration problems, depression, memory impairment, skin irritation, cognitive function, cardiovascular effects, and hormonal disorders. The term “microwave sickness”/“Electrohypersensitivity” has been coined to describe these symptoms as a consequence of WC-EMF exposures (Augner et al., 2009; Yakymenko et al., 2016; Deniz et al., 2017).

Apart from the above WC-EMF exposures cause tactile hallucinations, dry eyes, De Quervain's tenosynovitis, nomophobia, computer vision syndrome, weakness in thumbs, rigidity of hands, and wrist, stiff neck, insomnia insecurity, delusions, auditory and sleep disturbances, insomnia, hallucinations, reduced self-confidence, anxiety, stress, and mobile phone addiction disorders (Parasuraman et al., 2017; Amjad et al., 2020; Al-Khlaiwi et al., 2020). All of these effects occurred without increasing tissue temperature.

The short-term effects of WC-EMF exposure include muscle and nerve stimulation, shock or burn after touching conducting objects. The absorption of EMF energy leads to a rise in tissue temperatures, which is known as the thermal effect (Van Leeuwen et al., 1999; Wainwright, 2000; Dilli, 2021). However, most of the manmade WC-EMF exposures at environmentally relevant levels are non-thermal as they do not induce any tissue heating (Goodman et al., 1995; Israel et al., 2013; Wust et al., 2021). WC-EMF exposures cause alteration in the permeability of the blood-brain barrier, immunity system, and changes in cell membrane fidelity due to flow of current (Aly and Crum, 2016). The MT increased the activation of HSP27 and p38MAPKinase in EA. hy926 cells and rat brain and stabilization of endothelial stress fibers indicating that it changes the permeability of the blood-brain barrier (Leszczynski et al., 2002; Kesari et al., 2014). These studies confirm that WC-EMF exposure is not safe for humans.

The report of WC-EMF on adverse effects of human health are with mixed results. Many studies report the negative effects of WC-EMF exposure on human health as epidemiological studies are insufficient to prove the adverse effect on human health. This may be due to rapidly changing mobile technology and the research on the adverse effects of WC-EMF exposure on human health is unable to keep pace with the fast-changing mobile technology (Russell, 2018). However, studies with the adverse effects of WC-EMF exposure on human health are numerous and outnumber the negative reports. These investigations indicate that WC-EMF radiation has adverse health effects on humans/animals (Yakymenko et al., 2016).

The time taken by the human cells to respond to WC-EMF arising from mobile phones and mobile tower stations/antennas is approximately 2.5 min indicating the health risk posed by radiofrequency radiation to humans is real (Hardell et al., 2002). A study conducted in Sweden between 2007 and 2009 in humans of either sex between the age of 18–75 years revealed an increased risk of malignant brain tumors and ipsilateral use was associated with a higher risk of tumors than contralateral mobile and cordless phone use. The use of the mobile phone for 30 min/day for 8–10 h/day by an individual has a double to quadruple risk of brain tumors (Hardell et al., 2013; Miller et al., 2019). The incidence of neuroepithelial brain tumors in children, adolescents, and young adults in the age group from birth to 24 years has increased between 2010 and 2017 in the USA. The glioblastoma multiforme increased among all ages in the UK, whereas pituitary tumors and schwannoma (nerve sheath tumors) in the age group of 20–85 years (Miller et al., 2019; Pareja-Peña et al., 2020). This indicates that there is a close relationship between WC-EMF exposure and the induction of brain tumors.

Exposure of pregnant rats on gestation day (GD) 7 and 14 to 1800 MHz EMF-RF (SAR 0.048 W/kg) for 2 h/day reduced the number of live embryos and increased the number of dead and resorbed embryos and hematoma, malformed, and edematous fetuses. The exposure on 20th GD resulted in congestion, hematoma, malformation, short tail, and growth retardation, and reduced glutathione peroxidase (GPx) in the pregnant rat serum receiving EMF-RF for 14 and 20 days (Alchalabi et al., 2016). The exposure of mouse follicles to WC-EMF reduced the developmental capacity of the follicles in vitro (Cecconi et al., 2000). Rats exposed to EMF-ELF to 30 Hz (4 kA/m) sinusoidal magnetic field for 2 h/day for 10 weeks led to the alleviation in the follicle stimulating hormone in the proestrus and progesterone in the estrus phase and defect in the structure and function of the ovaries (Alekperov et al., 2019).

The exposure of WC-EMF from mobile phones and mobile base stations has increased spontaneous abortions in pregnant women and also the pregnant women exposed to EMF-RF (SAR 1.07–1.16 W/kg) gave birth to boys (5%) with low birth weights (Mahmoudabadi et al., 2015). The use of mobile phones for more than half our/day reduced fetal growth and infant birth weight (Lu et al., 2017; Ren et al., 2019; Boileau et al., 2020). An epidemiological study of 55 507 pregnant women who used cell phones in Denmark, Netherlands Spain, and South Korea showed an association between preterm delivery and cell phone use (Tsarna et al., 2019).

Excessive exposure to WC- EMF for a longer duration adversely affected male and female reproduction (Dilli, 2021). The exposure of human semen samples to 800 MHz EMF-RF < 1 W or 0.001–2000 μW/cm² from a laptop reduced semen quality, sperm motility, and viability (Erogul et al., 2006; Avendaño et al., 2012; Okechukwu, 2020). However, a recent study conducted in Denmark (751) and the USA (2349) on human volunteers who kept their mobile phones in their pant pockets did not find any adverse effect on semen quality (Hatch et al., 2021).

The 900 MHz exposure from mobile phones at a SAR of 2 W/kg reduced the fertilizing capability of the rat sperms (Yan et al., 2007). Exposure of rats to 200 MHz pulse-modulated WC-EMF (PD 50 W/m²) for 1 h/day for 30 days decreased sperm quality, reduced serum testosterone, and increased Bax/Bcl2 ratio, cleaved caspase 3 and caspase 3 in testis (Guo et al., 2019). The review aims to make the reader aware of the adverse effects of manmade WC-EMF, whose consistent use causes mutagenicity, genotoxicity, and cancer. The genotoxic effects of WC-EMF on humans and mammalian preclinical models are only reviewed here.