|07 Nov 2006
Disputes over mobile phones' impact on human health have been lasting for decades. Beginning with the 90 th every scientific research proving that using mobile phones can lead to irreversible health changes emerges a disproof elaborated by no less than other reputable scientists.
Actually there are no final data validating or disproving the harm of the mobile phones. Thus, in the year 2000 World Health Organization published their recommendations on items of security of mobile phones for European Parliament. The recommendations noted that there aren't any conclusive evidences about the association of using the mobile phones and the development of cancerous and other serious diseases. Final conclusions are assumed to be done in accordance with the subsequent researches in the years coming in some countries of the world.
Despite these statements, Great Britain was the first to treat a question on mobile phones' impact on children's health. In the same year, the report of the group of reputable British scientist on the study of mobile phones' impact on children's health was published, where was noted that children shouldn't use mobile phones due to the bigger susceptibility of children's organism to electromagnetic radiation influence. The research was carried out on the British Government order who immediately reacted to the received report. New rules of using mobile phones by children were developed where is stated the minimum age of users, the maximum duration of the conversation and quantity of the possible daily calls.
Canadian scientists carried out an investigation of radiation level of cellular transmission antennas situated on the roofs of the buildings. The researches were carried out on 118 objects and in 17 communities. The main researched objects were school buildings, where the population showed an advanced concernment on this problem. As a result the commission stated that inside all buildings the level of radiation was much lower to the permissible radiation level according to the British as well as to international standards. Essentially, schoolchildren get smaller radiation dose inside the building then outside at the distance of 300 m from antenna.
On the whole, according to the results of the investigations was concluded "that radiation (by radio-frequency field) of the type and intensity which is produced by wireless communication devices don't contribute to the apparition or growth of cancer at animals or people". Despite this, was noted a necessity of updating Canadian laws in the context of staff protection working in the field of cellular communications.
A criterion for determination of electromagnetic field intensity's permissible level of mobile phone is human body's temperature increase on 1° Ñ due to the electromagnetic field impact. To take into account mobile phone's impact on human health Association of Cellular Communication industry of the USA offered to introduce SAR index (Specific Absorption Rate), which determines the level of radiated energy (emission) on 1 kg of brain (W/kg). This value represents power overwhelmed by biological tissue of a certain mass for some period of time. The less SAR index is, the more secure the device is.
For the professional impact of electromagnetic field in the capacity of a permissible level was agreed on SAR index, equal to 0,4 W/kg by overall impact on human's body (for example, when a person is standing in the active zone of base station) and to 10 for the unprofessional impact of electromagnetic field SAR index is 0,08 W/kg and 2 W/kg respectively.
Besides, the testing parameter of electromagnetic field at an overall impact on human's body is field density of an equivalent plane wave. Permissible level of the given parameter is determined by different foreign agencies depending on the standard and working frequency.
Moreover, the legal framework of different countries in this field doesn't determine the degree of mobile phones' safety and rigorous measures of its guarantee. In the overwhelming majority of the developed foreign countries, in the USA in the first instance, EU member countries, in Japan is accepted to consider the biologically active electromagnetic field of such intensity which impact leads to the proved dangerous consequences for human's body functioning i.e. reversible. In the Great Britain is considered to be secure the level of SAR, that is equal to 10 W/kg. In Japan mobile phone's radiation levels standards were recently reviewed to the requirements strengthening (SAR index shouldn't exceed 2 W/kg).
In the course of the recently carried out research was placed on record the fact of mobile phone's electromagnetic field impact on the user's brain. In this case the results have shown that mobile phones of the NMT-450 and GSM-900 standards produce valid and noteworthy changes in the electrobiological activity of human's brain. These changes aren't outside the framework of the central nervous system competence and reflect its nonspecific protective response to the impact that is weak on its biological significancy at a single short-time action of electromagnetic field . Volunteers model study was used represented by mobile phone's users allowing to evaluate existence or non-existence of biological effect summation in conditions of long-term usage of mobile phones. Although, data received during the executed research wasn't enough to establish security criterions and to elaborate health rules.
Results received in the course of the experiment have shown two main aspects of electromagnetic field's influence on the human being :
- It is demonstrated that mobile phone's electromagnetic field is a bioactive factor.
- There is a significant influence on the human organism in the stage of its formation and development.
Let's consider the issue of the security of the mobile phones according to the results of the conducted researches. Thus, in the course of the researches were shown up different effects of mobile phone's impact.
Improvement of people's intelligence. Members of the experiment were offered to do a certain set of tasks on intelligence being under different conditions: under the influence of microwave radiation of digital phone, analog phone and without any influences. 36 people under the test showed the use of less time for the response for visual tests after 30 min. of radiation influence. According to the scientists this effect is connected to the enhancement of the brain's blood circulation, which can be produced by a slight heating. With that it is not impossible that short-term improvement under more lasting radiation influence can change to the irreversible harmful consequences.
Onset of the headache . The research carried out by the Swedish National Institute of Labour and Norwegian Administration on Radiation Protection showed that even people who use the phone less then for 2 min per day experience discomfort and side effects. The research lasted for 1 year and in it participated 11 thousand of volunteers. According to the received data 84 % mobile phone users felt skin heating back of the ear while talking on the phone, some even stated they had burns. Part of the users also experience blackout, dizziness, headaches and increased fatigability. Almost one forth of respondents have memory problems, a half suffer from heavy headaches, and about 65% experience drowsiness. One third of the respondents claimed degeneration of attention concentration during or immediately after the conversation; especially it was noticed among people under 30 years old who intensively use the phone. Subscribers who use the phone four or more times per day, in 3,6 times more frequently complained on headaches, in comparison to those who made less then 2 telephone calls per day.
Lack of major health complications. Researches published by a Royal Society of Canada, contains a conclusion about the thing that mobile phone's conversations can't provoke cancer or other diseases. A group of eight scientists examined numerous researches concerning the safety of using mobile phones, and didn't find any evidences in favor of apparition of diseases connected to the radio wave radiation. The scientists established that evidences "don't confirm conclusions that radio frequency field radiation of that type and intensity which is produced by wireless communication devices don't contribute to the apparition or growth of cancer at animals or people".
Pressure increase. German researchers found out that during the phone's work person's arterial blood pressure increases. The conversation that lasted for 35 min contributed to the increase of blood pressure on 5-10 mm of mercury column. It is supposed that the electromagnetic field provoked vasospasms which supply blood to the right hemisphere and namely this led to the blood pressure increase.
Influence on cardiostimulator's work. There are more than million people in the world who live with the implanted cardiostimulators. In cases when personal cardiac rhythm is discontinuous or too weak, this device sends electric impulses, necessary for the heart to work properly. German scientists examined whether mobile phone can provoke failure in the work of cardiac stimulator. During the experiment were tested three standards of cellular communications: NMT-450, GSM-900 and GSM-1800. In the experiment were also tested 231 cardiostimulators of different manufacturing firms. The results are as follows: 31 % of stimulators experienced disturbances from the mobile phones' radiation with the standard of NMT-450 and 34 % from GSM-900. There weren't registered any failures in the cardiostimulators' work when using GSM-1800 phones.
Despite the data presented above, it is not recommended to carry the phone next to the cardiostimulator, moreover it is not allowed to draw near this device a phone working in the active mode (i.e. during the conversation). This is way it is advisable to disconnect a phone when entering medical centers.
Increase of road accidents danger. Although many aspects of mobile phones' impact on human health still remain unclarified, the experts come to the agreement on one thing: telephone conversations while driving are very dangerous. The study case of 700 road accidents in Great Britain showed that telephone conversation increases the danger of getting into car accident in four times. Moreover it was noted that there is no difference between a phone a driver is holding in a hand, and a phone that leaves your hands free.
Creation of drawbacks to the radio navigation facilities on the plane. World's airlines don't allow using mobile phones while on the board of their planes.
Summarizing everything above mentioned, the following things can be noted:
1. Up to date can't be precisely said that using mobile phone is harmful or secure. The researches in the given field continue, although their results are sometimes ambiguous, the attempts are made to elaborate a unitary standard of permissible radiation level of SAR index.
2. As the overall conclusions come the following
- The longer time of the telephone conversation is, the more impact it has on a person;
- The phone of the modern digital standards (GSM-1800 and 3G) produce less impact on human's organism;
- In 3G standards should be expected lower level of mobile phone's radiation, despite the higher bandwidth (2GHZ). Substantial decline of phone's radiation level can be achieved for account of:
- a) less needed radiation level for 3G system functioning due t î the available energy advantage by using broadband radio signal;
- b) effective control of radiation level (its reduction to the baseline) of base stations and mobile phone under the certain conditions of a signal reception.
3. Using hands-free headset reduces the electromagnetic field effect to 92 %.