March 27, 2004

BEFORE the twentieth century, mankind was exposed only to a variety of naturally created electrical energy such as lightning, solar radiations, ground-induced electric emissions, and certain caves of specific geological structures. But since we harnessed electricity and learned to produce and use it so extensively, our environment has become the victim of the vicious electromagnetic radiation generated by innumerable man-made electrical systems, such as transmission wires, transformers, power cords, television sets, computer monitors and and other electrical devices, signal antennas, automotives, etc.

Huge pylons are constructed to support the high tension (HT) transmission lines meant to reduce the loss of power over long distances. They form an essential component of the transmission and distribution system, which comprises lines carrying electric power through extra-high voltage (EHV) and ultra-high voltage (UHV) lines, and, of course, the substations. The EHV lines had taken a start in the 1940s while the UHVs were introduced in the 1960s. The third option, the underground cable system, is highly capital intensive and does not form part of our grids.

A typical transmission-grid-power-plant uses transformers, as a component of the distribution system, to step up the electric power to high voltage alternating current (AC) for transmission over long distances to substations, which then step down the voltage and supply electricity to local power lines. These transformers transfer energy from one electrical circuit to another by means of magnetic coupling.

A power transformer has a set of at least two coils where the primary induces current in the secondary through changing magnetic field. This changing magnetic field causes mechanical flux that vibrates the iron core of the transformer, causing a hum that is not only an annoying noise, but also casts a electromagnetic radiation (EMR) that affects the whole surrounding.

Electrical hazards are caused by strong electromagnetic fields that generate electric current in other metal objects by induction. The induced current can cause an electric shock to all living forms and can overload or destroy electrical equipment. The typical EMR hazards may be:

1. Fires caused by electromagnetic induction resulting from strong EMF setting off electric currents to flow across an air gap to ground and produce sparks, which can then ignite flammable materials or gases, leading to fire and explosion.

2. Biological hazards caused by heat produced in biological materials by electromotive force (EMF) can be many. Touching an antenna while a transmitter is in operation can, for example, cause severe burns. Heating effect varies with the frequency of EMR.

Eyes are particularly vulnerable to the RF energy in the microwave range. Prolonged exposure to microwaves can lead to cataracts. Each frequency in the electromagnetic spectrum is absorbed by living tissues at a different rate, called the Specific absorption rate (SAR). The health and safety institutions of many governments (except the government of Pakistan — which seems to be insensitive to issues of health and hazards to the life of common people) have established safety limits for exposure to various frequencies of electromagnetic energy based on SAR.

3. Health hazards caused by exposure to EMF were not known when the use of electrical energy was being extensively promoted and high tension lines were being laid in the 1950s. EMFs have now been found to cause cancer. It can double the risk of leukaemia among children who are consistently exposed to fields above 4mG milligauss. The safe limit for exposure is below 2 mG.

According to estimates by the Electric Power Research Institute in USA, only about 25 per cent homes exceed 2 mG of overall background EMR. However, EMFs from appliances, particularly those which are faulty and/or have outlived their lives, have been found to cause localized fields well in excess of 2 mG.

An idea on impact of EMF on the living environment can be had from its measurements in the surrounding. It is estimated that the EMF directly underneath power lines carrying 200Kv at the ground level is 15mG, while at 50 feet (about 15m) from the power lines it is 8mG and at 200 feet (about 60m) it is less than 2mG. That’s why the right of way granted to high tension line extends to 200 ft (60m) and no habitation or human activity is allowed within this high impact zone. The fields directly underneath the ordinary electrical overhead lines at ground level are reported at 35-40mG which is much higher than those produced by the ominous-looking high-tension lines.

It may be interesting for you to note that EMR field at the usual distance you keep from your computer monitor (two feet) is 6-12 mG. The field in a typical office is between 2mG and 8mG, and even much higher, specially under fluorescent lights. The field at the handle of an electrical iron when it is on, is as much as 35mG. At the driving seat of a car it is more than 4mG while that at the passenger seat is over 2 mG.

The impact of EMR on health resulting from high voltage current remained unnoticed till the 1970s when an increasing number of cases related to hazards of exposure to high-tension wire started pouring in. It was the time when many of the lifestyle-related diseases, through use of materials and methods not quite compatible with nature, had come into limelight. There were reports of serious cases of linemen and radio-antenna technicians getting various forms of cancer but the information was not considered sufficient to attribute the incidence to exposure to EMFs.


Public debate

Electrical energy dominates the lifestyle of modern society although scientific studies have shown that EMR is linked to cancers of various kinds. Health hazards due to exposure to EMR from high-tension electrical transmission lines have been caught up in official denial in most countries. A change is nevertheless imminent, since citizens and scores of groups in many countries are opposing the construction of these transmission lines and powerful radio antennae near homes, schools and communities. They are winning court cases to have lines rerouted or are instigating investigations.

Cases of abnormal health, leukaemia and cancer related to exposure to EMR under high power transmission lines were reported in the 1970s and catching the headlines in the late 1980s.

An unexplained iron deficiency was observed in a number of patients from a small northern French village, Coutiches, during 1993-1994. This prompted evaluation of iron profile and iron metabolism in the affected population living in the village in the proximity of high-voltage transmission lines. A detailed study on changes in iron profile led to the conclusion that the diminution of iron levels among those exposed to high EMF was not only due to the intensity of the EMFs but also to the cumulative dose and to the number of hours of exposure per day. It was suggested that EMFs modify iron metabolism in populations subjected to 2mG or more with a high bone marrow incorporation of the iron which explains the low iron level, and a rapid utilization for the metabolism of hemoglobin.

Other observations reported around the same time were reported in Clifton, New Jersey, where an abnormally high rate of cancer was noted among police officers working in an office within 20 or 30 feet of a radio tower giving off EMR. This led to a great deal of disturbance among the community. A front-page story in the Dateline Journal (New Jersey) reported two officers dying of cancer, a third having cancer of the testicles and two more retiring with another form of cancer. No direct evidence linking the cancer to EMR from the antenna was found. Residents there were also battling with cellular phone companies to remove antenna towers from their neighborhoods.

The Australian senate conducted an inquiry in 2001 to assess the effects of EMR on public health. They invited an expert on the effects of EMR from the University of California to testify. The expert, while making a conservative statement opined, “There is some statistical correlations between proximity to power lines and leukaemia in children. There have been some studies in recent years which make it look like there is a weak correlation with breast cancer and possibly other tumors.”

This is the type of conservative non-committal scientific view that one gets when facts are required to be concealed.

The public health debate in the United States and elsewhere has prompted the emergence of an international organization called “The EMR Alliance” to fight the construction of high powered transmission lines and the exposure to health hazards associated with radiation.

The Alliance’s mission statement is: “EMR is hazardous to life and constitutes a significant threat to public health.”

It states further: “exposure to electromagnetic fields has been linked to a host of illnesses and diseases including brain cancer and tumors, breast cancer in both men and women, various forms of leukemia and lymphoma, spontaneous abortions, birth defects, Alzheimer’s disease and other life threatening health disorders.”

Recent studies indicate that the concern about the impact of EMFs on health is not unfounded. EMFs exceeding 2mG can induce differences in magnetism in the two moieties of haemoglobin molecule such as haemoglobin. This disbalance is cause for leukaemia, beside other blood related diseases, and also for cancer.

Childhood cancer studies have noted that the EMF directly below 400Kv power lines has a level exceeding 40mG and that the safe limit of 2mG is found at 100 metres from the system.

The nature of financing and unsatisfactory terms of foreign aid left the country with no choice of technology when the National Grid was created in Pakistan. It had to act according to the desires of the donors when Mangla and Tarbela dams were constructed.

The EMF under the supply lines installed by KESC, WAPDA and local suppliers has not been measured but going by the data reported in the literature it can be assumed that the level is higher than that recommended even under the low voltage overhead lines.

Housing schemes, amenity plots for schools, hospitals and marriage halls were allotted without considering the hazards of their location near or under the HT transmission systems.

A number of kacthi abadis in Karachi are located right under HT lines. It is common to see transformers that have outlived their age being surrounded by settlements and overloaded pole-mounted transformers installed in the housing schemes.

Old transformers are a potential source of high EMF. The Karachi Electric Supply Corporation (KESC), for instance, admits that 75 per cent of its transformers are old and in order to reduce their tripping due to overloading that it has to resort to load shedding. Things are not any different elsewhere in Pakistan.

The start up of generators during load shedding causes an increased incidence of high EMR at the user premises while restoration of power after load shedding causes a momentary higher than normal EMR around the transformers.

Household electrical appliance, computer monitors, automobiles and power generators are similar sources that emit radiation beyond the recommended level in Pakistan, particularly since they are old versions.

The living environment is thus highly vulnerable to the hazards of high EMF. Already the hitherto unknown diseases that can be related to electrical energy installations e.g. leukemia, are taking their toll.

It is high time for Pakistan to: (a) initiate monitoring of EMF at all electrical energy installations, (b) ensure that the limit for exposure to EMR at 2mG is duly observed and (c) phase out the hig-tension electricity transmission system, and living under or near them declared hazardous. All installations and offices should be mandated to adopt safety measures to restrain the exposure of the concerned population in residential areas and workers in installations or work places to all equipments, including computers, photocopiers and printers to levels below the said limit.

The writer is a former director-general, Pakistan Council of Scientific and Industrial Research

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