Power Lines and Electrical Devices

The ever-increasing use of electrical appliances, along with the consequent demand for electric power, have greatly increased awareness of possible risks from electric and magnetic fields at extremely low frequencies. In particular, concern has been raised about power lines. This concern has, in some cases, led to strong opposition to the installation of transmission facilities, which has delayed or even prevented their licensing. The proximity to power lines in suburbs usually means less demand for the properties and lower real estate values due to concerns about raising families near these powerful sources of electromagnetic radiation.

The idea that such fields might be deleterious has been seriously considered only since 1979, when researchers suggested, on the basis of a case-control study conducted in Colorado, that the fields associated with power lines and domestic electric wiring might cause cancer in children. At the time the idea seemed bizarre—power lines were such a normal part of everyday life and they had not been shown in laboratory experiments to have any effect that appeared to be even remotely connected with the development of cancer. During the past 25 years, however, numerous epidemiological studies have suggested a link between leukaemia and brain cancer in adults and exposure to similar and higher frequency fields at work places. Residential-based studies have found similar links. The findings are, however, difficult to interpret. One reason for this is that neither leukaemia, nor brain cancer, is a single entity; each consists of a variety of conditions that differ in childhood and adult life and may—and in some cases definitely do—have complex causes.

Residential studies do not always directly measure exposure, but frequently use surrogates. These surrogates might include the distance of the residence from overhead power lines or electrical transmission stations or the wiring configurations in the vicinity of the residence, which could be classified as “high” or “low” according to the presence or absence of transformers and the characteristics of the local electricity supply cables. However, in three Scandinavian studies in 1993, children who lived in houses within broad corridors around power lines had higher than normal rates of leukaemia and brain cancer. Other studies have shown similar results: the incidence of leukaemia with residential exposure equal to or greater than 0.2 uT (or 0.25 uT in the Danish series) was 2.1 times that in the unexposed population. A recent study in Canada, in which participants wore personal monitoring devices, supports a link between magnetic field exposure and an increased risk of childhood leukaemia. Evidence of a carcinogenic effect in adults has been supported by studies that have suggested occupational hazards for leukaemia and cancer of the brain. Magnetic fields and childhood cancer—a pooled analysis of two Scandinavian studies

In a three-year study of some 570 people in Auckland, New Zealand researchers found that people living within 20 metres of high-tension power lines were three times as likely to have asthma, twice as likely to experience major depression, twice as likely to suffer from immune deficiencies (including allergies and dermatitis) and more likely to have diabetes than those who did not live within such proximity to power lines. http://aktinovolia.net/wp-content/uploads/Evidence-that-EMFs-are-hazardous.pdf

Researchers have also found significant evidence that occupational exposure to electromagnetic fields may reduce melatonin levels. Melatonin levels appear to be affected by the intensity and length of exposure as well as time of day it occurred; levels did not return to normal when workers were away on weekends. Melatonin, produced by the body, regulates sleep cycles and is a potent antioxidant that protects us from cancer. http://aje.oxfordjournals.org/content/150/1/27.short

The magnetic field strength produced by overhead lines depends mainly on the current flowing and distance from the line. Unlike the voltage, the current may change considerably during the day according to the demand for energy and, therefore, the magnetic field from power lines will be highly variable, reaching its maximum values when the load is highest—that is, when many people are using electrical appliances. Objects and buildings provide little or no screening for the magnetic field. In other words, even though it is safer to be farther from power lines, buildings don’t block out the magnetic field.

Exposure to electromagnetic radiation from appliances in buildings is also an area of growing concern. The results from measurements in some offices show that magnetic induction levels are within the range 0.2 3.2 uT close to typical office devices such as personal computers and photocopiers, while at the writing desks and in usual conditions the mean value is equal to 0.37 uT, with a maximum value of 1.4 uT. Most new computers have a screening device on the front but unfortunately not behind the computers so don’t sit behind a computer. In a few buildings we have investigated, wiring ran inside internal columns in the buildings, with people working right next to the columns. The exposure was extremely high and resulted in many health complaints. Devices to measure electromagnetic radiation are relatively cheap and can be obtained from some electrical stores.

In the home environment, the most significant exposure is likely to come from electrical equipment, clocks and lights in the bed head or near where people sleep. In addition, exposure can be considerable if the bed backs onto a wall that has a circuit board behind it. In general the bedroom should not have too many electrical devices in it and none near the area where one’s head is during sleep.