Electronic gadgets proliferating without risk assessment
by Someshwar Singh
Geneva, June 30 -- A whole range of electro- magnetic devices are being added to the existing list of appliances such as mobile phones, electronic cards and security devices - without their health effects being ascertained, the World Health Organization (WHO) said Wednesday.
Releasing a new WHO fact-sheet on "Electromagnetic field and public health - Radars and Human Health," Dr Michael Repacholi, scientist at the WHO's office of Global and Integrated Environmental Health, said most of the electronic devices were being brought into the market even before their health effects were clearly established.
RADAR is an abbreviation for Radio Detection And Ranging System. Radars usually operate at radio frequencies (RF) between 300 MHz and 15 GHz. They generate electromagnetic fields (EMF) that are called RF fields.
A second world war time invention, RADAR which began to be used for military, aeronautic navigation and weather forecast and other purposes, has now spread to other uses ranging from police traffic control, including police hand-held speed radars, to computer-controlled uses in motor transport etc. But some of these like hand-held police radars have very low output power, a few milliwatts, and are not considered hazardous to health.
Most studies have examined health effects, other than cancer. And while some epidemiological studies have addressed possible links between exposure to RF and excess risk of cancer, the differences in design and execution of these studies have made it difficult to interpret their results, the WHO said.
A recent Swedish study, by Prof Hardel of Stockholm University (a report on which was published in the British media) about effects of use of mobile telephones on risks of cancer in human brains, when peer reviewed did not bear out the results, Repacholi said, adding WHO itself had not reviewed it.
While the WHO does not set health standards that should accompany these electronic devices, it encourages international and national work in this area. It is addressing this important health concern through its International EMF Project launched in 1996.
EMFs are defined as electromagnetic fields with frequencies from 0 to 300 GHz.
Exposure limits for RF fields are developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), an NGO formally recognised by the WHO. The Commission uses health risk assessments developed in conjunction with WHO to draft their guidelines on exposure limits.
However, the ICNIRP guidelines protect against all established RF health effects and are developed following reviews of all the peer-reviewed scientific literature, including reports on cancer and non-thermal effects.
The latest WHO concern has been aroused because some research suggests that exposure to EMF may produce health effects such as cancer, changes in behaviour, memory loss, Parkinson and Alzheimer's diseases.
According to the WHO, while insufficient research has been conducted to substantiate these effects, sufficient concerns and perceptions of risk have been raised and there is an urgent need for an accelerated programme to provide scientific consensus and clarification of these issues.
Dr Repacholi said that though the health effects had not been substantiated, a lot of research was currently going on to ascertain the health effects of mobile phones. Research funding in this area was of the order of $100 million. The WHO was not itself funding any research but only had a coordinating role, Dr Repacholi pointed out.
Current mobile telephone systems operate at frequencies between 800 and 1800 MHz. Systems using 2100 MHz and higher frequencies are likely to be introduced soon. These frequencies fall into the range between 1 MHz and 10 GHz (1 GHz = 1 thousand MHz).
Adverse healh effects of RF exposure within this range have been researched over the past forty-five years.
RF fields within this range are known to penetrate exposed tissues and produce heating due to energy absorption - similar to the working of a microwave machine. The depth of penetration of the RF field into the tissue depends on the frequency of the field and is greater for lower frequencies.
Even very low levels of RF energy produce a small amount of heat, but the body's normal thermal regulatory processes dissipate this heat away. However, international technical standards, according to which mobile telephones are made and their base stations are constructed, do not allow them to cause any significant heating. (SUNS4467)
The above article first appeared in the South-North Development Monitor (SUNS).
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