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With the advent of the rising telecom industry there is growth in the usage of the mobile phones by manifold and when we are in country like India, in order to cover one billion population, several transmission towers have been installed to create a jungle of such masts rising atop many buildings in the densely populated parts of India. The erection of these towers has lead to speculations that there may be increased incidence of cancer after exposure to the RF emissions from mobile telephone base stations. There are no high-quality epidemiologic studies that can be used to evaluate health risks from RF exposure. Laboratory studies in this area have been somewhat confusing. Some animal studies suggest that RF fields accelerate the development of sarcoma colonies in the lung, mammary tumors, skin tumors, hepatomas, and sarcomas. In contrast, other studies conducted on large scale on the cell lineage and people working in areas with high RF emissions have not found carcinogenic effects. These conflicting results indicate the need for more well-conducted studies. This provides a review of the laboratory studies and indicates what conclusions about RF-induced cancer can be drawn. Key Words: Radiofrequency fields, Cancer, Health effects, Laboratory studies, Mobile phones Introduction There has been tremendous growth in the number of mobile phone users in the world during the last five years. The reasons point to easy access, affordability, fairly good reliability and better geographical coverage by the service providers. Of course, the need to communicate has always been there ever since the evolution of mankind. Though other forms of communication do help to serve the purpose but nothing beats the excitement and the emotions involved in being able to contact and converse with someone at the click of a few keys on the mobile phone. Technically, the growth in this sector has been much faster and wider in India than in any other country. It would be probably correct to say that at any given moment, India would be having the largest numbers of active mobile phone users in the world. Quite naturally, to cover a population of almost a billion, several transmission towers have been installed to create a jungle of such masts rising atop many buildings in the densely populated parts of India. Each year, many such towers are being added in order to ensure negligible loss in transmission and hence the retention of existing and multiplying clients list. A fierce competition, even in this age of recession, continues to exist between multiple phone companies all of whom seem to adopt aggressive marketing for their products while working at ensuring commitment to the punch lines like“wherever you go we will follow you”. No doubt, a large part of the social and economic development in the country in various sectors and efficiency in the work places is due to the excellent communication. However, from time to time, this industry and its users have faced extremely scary s on harmful effects of electromagnetic radiations (EMR) on human health. There are many conflicting s in the literature citing definite damage as many as those s which attempt to convince the scientific community of no such effects with the intensity of the EMR by either the mobile phone sets or the transmission towers located in residential areas. There are several petitions, where the residents, scared by the existing ambiguity, have requested the removal of such towers from the thickly populated areas. Of the greatest concern to the scared population is the fear of contracting cancers in any part of the body due to the harmful effects of EMR used in and for mobile phones receiving and transmission. There have been several s endorsing the finding that the incidence of brain cancers is much higher in individuals using mobile phones for a much longer period and more frequently in the course of the day. There are several other health hazards quoted in the literature regarding the effect of EMR on melatonin secretion, sleep alteration, stress induction, sensory neural deafness and changes due to thermal effects. However there are almost equal numbers of studies which vehemently insist that such changes with the EMR frequency, power and SAR as used in different mobile phone sets or those emitted by the roof top masts are incapable of producing such effects. True or not, the mobile user who considers it as a necessary evil is still confused. Amidst all controversy, the ghost of cancer still looms large in a common man’s mind. Interestingly, several multinational companies are spending millions in terms of bringing new products with fascinating features which compel the user to use the equipment for entertainment at almost all hours. The mobile phone has turned into a gadget of indulgence and obsession. It is this development in technology and addition of features, which is partly respons- 1 This work is licensed under a Creative Commons Attribution-No Derivative Works 2.5 India License Online Journal of Health and Allied Sciences Peer Reviewed, Open Access, Free Online Journal Published Quarterly : Mangalore, South India : ISSN 0972-5997 Volume 8, Issue 3; Jul-Sep 2017 ible for enormous sale of the hand sets and penetration even to the remotest part of the country. No mobile phone company, including the one owned by the government has spent even a fraction of the marketing budget in either educating the community about possible harmful effects, if there are any, or ensuring the public that the equipment and the service provided by them is completely hazard free. Except for one instance where Motorola participated in a research, literature is silent on involvement of any mobile phone company to initiate or support the research on effects of EMR on various groups of human population some of whom may not be using the phone but may be living in the vicinity of the transmission tower installation. Perception of Radiofrequency Raditions and Cancer Risks In the mobile technology there are 2 systems of working, the Global System for Mobile Communication (GSM) and Code Division Multiple Access (CDMA) standard. These services operate within the frequency ranges 872–960 MHz(Megahertz) and 1710–1875 MHz respectively and radiate an average power of 0.2- 0.6 W, 40 per cent of which is absorbed in the hand and the head.[1] Over recent years the third generation of mobile phones, 3G or universal mobile telecommunication system (UMTS), using 1,900 MHz RF(Radiofrequency) fields has been introduced worldwide The FCC (Federal Communications Commission, USA) limits peak exposure to 1.6 W/kg of tissue averaged over any single gram of tissue (or 1.6 mW/g) though the European limits are less restrictive, specifying 1.6 W/kg averaged over10 grams RF radiation cannot ionise atoms or molecules like far-ultraviolet radiation and X-rays. These non-ionising electromagnetic radiations, however, is believed to be harmless at very low intensities, although it can be damaging at high intensities. This external electromagnetic field interacts with an internal biological process through the action of free radicals. Research has shown that magnetic fields increase the average concentration of free radicals, lengthen their lifetime, and enhance the probability of radical reactions with cellular components[2,3] biologic mechanism that could explain any possible carcinogenic effect from radiofrequency radiation has not been identified. It is generally agreed that the heating of tissue by radiofrequency radiation from mobile phone use is negligible and that any carcinogenic effect would have to be mediated through a non thermal mechanism. No studies to date have had an exposure time long enough to properly address the potential adverse late health effects of mobile phone use. So, this increasing use of wireless telephone communication has raised concerns about health risks, primarily increased risk for brain tumours, owing to the proximity of the brain to the radiation antenna, with the potential for absorbing a comparatively large amount of electromagnetic energy the emission at the head surface is typically 10,000 times stronger than that reaching the head of a user standing within 30m of the base of a mobile phone relay transponder mounted on a tower 30m above ground A large proportion of research on incidence of cancer in mobile phone users has taken place in Europe, followed by North America, while Asian studies, mainly from Japan, are relatively few. Studies have attempted to study a wide variety of neoplastic phenomena affecting different body systems. The most frequently studied malignancies include the intracranial tumors, such as astrocytomas, gliomas and acoustic neuromas. The studies have mostly been case-control studies using patient-ed usage information to correlate duration and intensity of usage to the association with cancer. Several studies have found a greater association of long-term mobile phone usage with intracranial malignancies. It was seen that there is a significant association between analog phone use and brain tumors, with the greatest risk being for grade III-IV astrocytoma after a latency period of >10 years after first use. The association with tumors after a >10 year latency was significant for analog, digital as well as cordless phones.[4] Another study found the prevalence of various cancers amongst regular mobile phone users had a significant association between acoustic neuromas and astrocytomas in users of analog, digital and cordless phones. The same study did not find significant associations for other tumors, such as salivary gland tumors, non-Hodgkin lymphoma (NHL) or testicular cancer.[5] Association of various cancers on exposure of >2017 hours of cumulative usage of mobile phones has also been quantified.[6] The same study also found that the risk for developing high-grade astrocytoma was higher with usage >10 years with analog phones and digital phones, but not with cordless phones. Two recent meta-analyses showed that long-term (>10 years) usage of mobile phones was associated with a greater risk of intracranial tumors,[7] with the greatest risk being for ipsilateral gliomas and ipsilateral acoustic neuromas.[8] Significant association between the occurrence of benign or malignant parotid neoplasms and the use of mobile phones was studied and it was found that individuals with high exposure and non-hands-free users were an at-risk group for developing these tumors on the side of predominant usage.[9] It is now widely accepted that cancer is initiated by alterations in the genetic material (DNA) in the cell (genotoxic effects), although some non-genotoxic chemicals and epigenetic carcinogens have been recognised. After initiation, the cell may progress to full malignancy without any further external stimulus but more often further events are required. An agent which will cause this further progression towards malignancy is often termed a promoting agent.()，英语论文，英语论文范文 |
