Monday, May 2, 2011

Non-ionising Electromagnetic Radiation

There is so much confusion nowadays about the pros and cons of radiation I thought it best to try and clarify it as best I could. People are exposed to non-ionising radiation through natural sources such as the sun as well as human-generated sources: computers, microwaves ovens, mobile phones, radar systems and power lines. From the sun, UV radiation is a major concern related to sunburn, skin damage and skin cancer. Too much sun can have a negative effect on one’s immune system. On the other hand, without enough exposure to the sun, the body does not produce vitamin D. But more on that at a later date.

Microwave radiation or Microwaves are extremely high frequency radio waves on the electromagnetic radiation spectrum. While some microwaves and radiofrequency radiation occur naturally—the sun, the earth and the ionosphere create natural sources of low-level RF and MW radiation fields—the incidence of non-naturally occurring radiation has increased dramatically with the advance of technology. Microwaves can be used to carry satellite signals for communication in televisions, AM and FM radio, computers, global positioning systems and mobile phones. Microwaves can also be used to generate heat through the extremely rapid reversal in the polarity of electrons affected by magnetic and electric fields via a tube called a magnetron—this occurs in almost every kitchen and restaurant throughout the industrialised world, with the ubiquitous microwave oven.

Microwaves and radiofrequencies represent one of the most common and fastest growing environmental influences about which anxiety and speculation are spreading. Yet very little is known about the results of exposure to microwaves; even less is known about the relative dangers of different sources of microwaves. We do, however, know that microwaves can be reflected, transmitted or absorbed by matter in their path. Absorption occurs in matter that contains moisture, including human beings.

Living organisms absorb microwaves and radiofrequency energy at the molecular, cellular, tissue and whole-body levels. Heating of internal organs is a consequence of the absorption of energy. The energy is absorbed by water within the tissue; therefore, tissues with high water density and low blood density—such as the eyes and testes—are particularly vulnerable.

Scientists have known for a long time about the capacity of RF radiation to cause this type of heating and have discovered that prolonged exposure to RF radiation can lead to health problems such as fatigue, reduced mental concentration and, in the case of very high levels, cataracts. These effects are similar to subjecting a person to an extremely warm environment. Other possible thermal effects include foetal abnormalities, decreased thyroid function, cardiovascular mortality, impaired ability to perform complex tasks and the suppression of behavioural responses, gonadal function and natural killer cell activity. Studies have shown that environmental levels of microwaves and radiofrequency energy routinely encountered by the general public are far below levels necessary to produce significant heating and increased body temperature. However, there is concern for whole body heating amongst the elderly and those on specific medications that affect thermoregulatory function. Also of concern are people with cardiac and circulatory problems, those with implanted medical electronic devices (e.g., heart pacemakers), fever sufferers, infants and pregnant women.

The majority of studies in this area are concerned with cataracts, arguably the major hazard associated with microwave radiation. A cataract is a clouding of the lens within the eye. Authorities concerned with producing safety standards agree that little is known with any real certainty about the effects of microwave radiation beyond its thermal effects. However, microwave studies contain too many shortcomings to rule out the possibility that microwaves cause adverse health effects.

The recognition of non-thermal effects has been highly controversial, due to conflicting and inconclusive studies. Studies are complex, investigating possible effects of microwave radiation—from cancer to effects on the operation of all systems and parts of the human body. Cancer studies have examined cancers of the breasts, lungs, testicles and brain, as well as ocular melanoma and leukaemia. Other studies have included assessments of the relationships between radiation and cardiovascular disease, birth defects and hormone secretion rates. Research has also shown the effect of microwaves on reducing a cell’s ability to perform apoptosis, that is when the cell terminates its own life as a part of the life cycle of the cell, increasing the risk of spontaneous mutations, including cancer.

An example of the controversy surrounding microwaves occurred with a 1990 leaked draft EPA report in the USA, recommending that radiofrequency microwave radiation be considered a “possible human carcinogen.” The White House moved quickly to suppress the draft and commissioned another report, which stated that there was no EMF cancer risk. Unfortunately, politics has its influence in too many places it should not.

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