Introduction
There have been several deliberations about the biological effects of exposure to electric and magnetic fields (EMF) and their possible detrimental effects on the health of humans and animals over the years. Illnesses attributed to power lines include abnormal heart pulses, leukaemia, cancers, miscarriages, birth defects, and other conditions that might lead to premature death. Regardless of the conclusions of many studies that find no evident risks, many people remain uncertain about the safety of power lines. The aim of this investigation is to determine and discuss the ethical issues behind power lines in residential areas and whether there are dangers that should be seriously considered.
Research Question
Are electromagnetic fields around power lines harmful to people living in close proximity to them?
Hypothesis
Those exposed to power lines in close proximity for long periods of time may obtain health problems however the power lines are not the main cause of the health issue but rather a factor. The reason for this is that there is not sufficient research conducted to prove that power lines are dangerous and that no health programmes have advised people to refrain from living near power lines or protected them from them either. There are many possible risks associated with electromagnetic radiation as it is not only available from power lines but also from apparatus such as microwave ovens, computers, wireless networks and cell phones. However these are more powerful forms of electromagnetic fields that are essentially more detrimental to human health than power lines.
Data Research
All electricity is generated, transmitted, or used and electric and magnetic fields are created due to the existence and motion of electric charges. (Gledhill, 2014) An electromagnetic field (EMF) has two components: an electric field and a magnetic field. When two objects have a voltage difference between them, an electric field is created. There is an electric field between a power line and the ground below because the power line is at a large voltage relative to the ground. (Nedlands, 2006)The electric field is measured in volts per meter (V/m) or in kilovolts per meter (kV/m). (See Figure 1 below) A magnetic field exists when electric current flows through a wire. Thus magnetic fields surround the power lines conducting current from the power station to residential areas. (Geoff Cackett, 1979)Transformers decrease these high voltages for local distribution to homes and businesses.
Figure 1 – Graph indicating the relationship between the Magnetic Field and Distance from the High-Voltage Power Line (Runge, 2011)
The magnetic field from a power line can vary extensively because the current in the wires depends on the amount of power expended. In contrast, the electric field from a power line varies very little because the voltage fundamentally remains constant. In general, these fields are time-varying vector quantities categorised by a number of constraints which include their frequency, phase, direction, and magnitude. (Portier, 1998)
Electric and magnetic fields (EMFs) are areas of energy that are invisible and connected with the usage of electrical power(Birnbaum, 2014)EMFs are characterized by wavelength or frequency into one of two radioactive categories: non-ionizing and ionizing.( See Figure 2 below) High-voltage power lines that transmit electricity expose anything nearby to electromagnetic radiation as they create electromagnetic fields around them. (Goldberg, 2014) Electromagnetic radiation is any form of energy that is sent as waves or rays between two places. Electricity and magnetism are both jointly responsible for many kinds of radiation. (Knapp, 2002)
Radiation Type
Definition
Forms of Radiation
Source Examples
Non-Ionizing
Low to mid-frequency radiation which is generally perceived as harmless due to its lack of potency.
Extremely Low Frequency (ELF)
Radio frequency (RF)
Microwaves
Visual Light
Microwave ovens
Computers
House energy smart meters
Wireless (wifi) networks
Cell Phones
Bluetooth devices
Power lines
MRIs
Ionizing
Mid to high-frequency radiation which can, under certain circumstances, lead to cellular and or DNA damage with prolonged exposure.
Ultraviolet (UV)
X-Rays
Gamma
Ultraviolet light
X-Rays ranging from 30 * 1016Hz to 30 * 1019Hz
Somegamma rays
Figure 2 – Table indicating differences between ionizing and non-ionizing radiation types (Gledhill, 2014)
The strongest EMFs are found around those major transmissioned lines that carry the highest voltages and currents. EMFs are also present around suburban distribution systems that carry large currents but at much lower voltages,. (Nedlands, 2006)
Electric and magnetic fields are also different in the way they interact with our bodies. Electric fields have very little penetration, while magnetic fields can penetrate to our inner organs. (Toufexis, 1989)
A biological effect is any change that could occur either short term or long term in the physical state of the human body. (Runge, 2011) EMF’s are able to induce the conductive matter of the human body and may result in observed changes in the human health. The epidemiological studies have inspired laboratory research into how EMFs could be associated with cancer. It is generally recognised by researchers that EMFs cannot initiate a cancer. They suggest instead that EMFs may play a part in promoting the growth of an existing cancer.
Researchers from the University of Tasmania and Britain’s Bristol University(See Figure 3 below) found that in a study of 850 lymphoma, leukaemia and cancer related conditions that living for an elongated period near high-voltage power lines increased the risk for these conditions much later in life (Zeman, 2011). However, the British Medical Journal published a paper on the investigation of the effect of 50 Hz magnetic fields on the existence of several types of cancer and concluded by stating that the extremely low frequency magnetic fields of high voltage power lines at typical residential levels do not appear to be associated with an increase in cancer among various adults; this also pertains for the haematological malignancies and for tumours of the nervous system as well as for the male and female hormone related cancers in genitals. (Verkasalo., 1996) As for specific cancer types, the presence of extremely low frequency magnetic fields remains indefinite. Numerous studies appear to display a weak association between incidence of some cancers and the exposure to power-frequency magnetic fields. The reason for this is that the electromagnetic energy from power lines are of extremely low frequency and therefore low energy. They are evidently different in frequency from ionizing radiation such as X-rays and gamma rays and are non-ionizing. Biological material absorbs the energy from higher-frequency more readily. In contrast, extremely low frequency EMF does not have enough energy to heat body tissues or cause ionization. Generally, the evidence that power line fields cause or donate to cancer is weak to non-existent according to most scientists.
Figure 3 – The study conducted by the University of Tasmania and Britain’s Bristol University produced these results. (Zeman, 2011)
According to ESKOM and several other studies, electric fields of the intensity encountered close to power lines, cannot damage crops. (See Figure 4 below) Laboratory studies that expose animals to electromagnetic fields, looking for variations in body function, chemistry, behaviour or general health and have also concluded that they have no effect on the fertility, behaviour, carcass quality, reproduction, meat, milk and egg production or the development of their offspring. (Rayleigh, 2006)
Crop
Setting of study
Authors
Finding
Sunflower seeds
5 kV/m electric field
Marino et al, 1983
Reduced germination rates in a minority of the tests
Corn
500 kV power line
Hilson et al, 1983
Lower yields, but explanation not clear (suggested that it could reflect less spraying near power line)
Cotton, soy beans, clover
500 kV power line in Tennessee
Hilson et al, 1983
No effects
Various
765 kV power line in Indiana
Multiple reports
No effects
Various
1200 kV power line in Oregon
Multiple reports
No effects
Wheat
7.7 kV/m field, Japan
Endo et al, 1979
No effects
Pasture grass
1200 kV power line, USA
Rogers et al, 1983
No effects
Figure 4 – Table indicating results of various investigations conducted on the effects of power lines on crops (Rayleigh, 2006)
Disadvantages of power lines in residential areas:
Recent studies approve a reported association between eminent long term health risks (e.g. cancer) and proximity to residential power lines, but it is not certain if the observation is coincidental or not. Physical impossibility of any health effect has been argued by scientists due to weak levels of EMFs, while others uphold that the potential health risks should not be terminated. (Zeman, 2011)
The World Health Organization (WHO) publications state that EMF such as those from power lines, can also cause short term symptoms such as headaches, fatigue,anxiety, insomnia, prickling and/or burning skin, rashesand muscle pain. (Verkasalo., 1996)
Power lines are not visually appealing in residential areas and are more prone to external damage as they are exposed to people living around them.
Advantages of power lines in residential areas:
House prices are less expensive closer to power lines as people usually look for homes without obstructions.
Any technical or maintenance problems are fixed as soon as possible as many people depend on the residential power lines.
There is no compelling evidence of health hazards from power lines as many forms or research indicate that some health risks are associated with power lines in close proximity but it does not prove that they are the direct cause of any biological dangers. (Goldberg, 2014)
CONCLUSION
Therefore there are known health risks that appear to relate to power lines and their electromagnetic fields emitted but no evidence completely proves that biological effects have been conclusively demonstrated to be caused by living near high-voltage power lines. Many scientists believe that exposure to the low-level EMFs near power lines is safe, but some scientists continue research to look for possible health risks associated with these fields. The risks are clearly small if there are any risks associated with living near power lines.
References
Birnbaum, L. S., 2014. Department of Health and Human Services. [Online] Available at: http://www.niehs.nih.gov/about/od/index.cfm [Accessed 2 August 2014].
Geoff Cackett, R. K. A. S., 1979. Core Physics. In: C. Ratray, ed. Oxford: Oxford University Press, p. 211.
Gledhill, M., 2014. Electromagnetic fields (EMF). [Online] Available at: http://www.who.int/peh-emf/about/WhatisEMF/en/ [Accessed 2 August 2014].
Goldberg, R. B., 2014. Environment, Health and Safety. [Online] Available at: http://www.ehso.com/ehshome/emf.htm [Accessed 2 August 2014].
Knapp, B., 2002. Visual Science Encyclopedia. In: M. Sanders, ed. Heat and Energy. Danbury: Grolier Educational, pp. 13-14.
Nedlands, 2006. Powerlines, Electromagnetic Fields and Health. [Online] Available at: http://www.public.health.wa.gov.au/cproot/1372/2/Powerlines_Electromagnetic_Fields_and_Health.pdf [Accessed 2 August 2014].
Portier, C. J., 1998. National Institute of Environmental Health Sciences. [Online] Available at: http://www.niehs.nih.gov/health/assets/docs_a_e/emf1.pdf [Accessed 2 August 2014].
Rayleigh, R., 2006. EFFECT OF ELECTRICAL FIELDS, IONS AND NOISE. [Online] Available at: http://oregonstate.edu/dept/coarc/sites/default/files/publication/88 DC lines cattle crops (’88).pdf [Accessed 2 August 2014].
Runge, K., 2011. Eskom Fact Sheet. [Online] Available at: http://www.niehs.nih.gov/emfrapid. [Accessed 3 August 2014].
Toufexis, A., 1989. Health: Panic Over Power Lines. Times Magazine, 127 July , pp. 40-42.
Verkasalo., D., 1996. British Medical Journal. [Online] Available at: http://www.bmj.com/content/313/7064/1047.abstract [Accessed 3 August 2014].
Zeman, G., 2011. Health Physics Society. [Online] Available at: http://hps.org/hpspublications/articles/powerlines.html [Accessed 3 August 2014].
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