Geomagnetic Fields
A �Magic Bullet� Mechanism
It is well established that whilst epidemiology has linked exposure to magnetic fields and power lines to numerous health effects, definitive explanations of such links have remained elusive. Literature has previously linked exposure to other environmental sources such as light and power-frequency magnetic fields, with increased risks of certain cancers amongst other health effects.
This area of research is exciting as it incorporates the influence of light, geomagnetic and power frequency fields. The primary candidate mechanism is the Radical Pair Mechanism (RPM).
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The Earth�s Magnetic Field
Fluctuations in the level of the Earth�s Geomagnetic Field (GMF), a quasi static magnetic field, and geomagnetic storms have been associated with a number of health effects and disorders in scientific literature spanning more than 50 years.
- Magnetic fields are ever present in our lives. They exist wherever there is a flow of charged particles.
- The GeoMagneticField is roughly akin to a bar-magnet running from pole to pole.
- There are contributions to this field from solar winds, the Earth�s core, local crust variations, and the atmosphere.
- Values of the field range from 20�T-70�T. In Bristol the value of total intensity is~45�T.
Why Look at Magnetoreception?
- Humans have long utilised the GMF for navigation using compasses.
- Humans were not thought to be able to detect the GMF in any meaningful way.
- Now there are several competing theories to show that biological reactions in animals arise with GMF interaction.
- Some reactions may have a profound effect upon human health.
Aldrich, Andrews and Liboff (2001) � The results � offer evidence that a metric of EMF�s, incorporating a geomagnetic component, may finally provide some clarification on the protracted quandary about EMFs and cancer risk.�
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How does the GMF interact with life on Earth?
- Three suggested mechanisms for animals: Induction, RPM and magnetite.
- Most of the work on magnetoreception in animals has been concentrated on birds and turtles � obvious migratory participants.
- Wiltschko (2005) -The available evidence suggests that birds use a magnetite mechanism and RPM to navigate. The RPM is light dependent and is thought to be influenced by magnetic fields.
- Magnetite, (Chemical Formula: Fe3O4, Iron Oxide) mechanism in the upper beak provides on position as component of a �map�.
- Magnetite is present in the human brain.
What are the Reported Effects of GMF Interactions with Humans?
Literature has suggested links to
- Sudden death
- Seizures
- Hallucinations
- Heart attacks
- Strokes
- Depression
- Suicide
- Visual acuity � light perception
- Melatonin suppression
Semm 1980 � Effects of an Earth-strength magnetic field on electrical activity of pineal cells. After initial exposure to 50�T and diminished pineal electrical activity was observed, it was possible to depress activity again with a low stimulus of 0.10�T.
The pineal gland is the adrenal gland responsible for the synthesis of the hormone melatonin which is a well-established free-radical scavenger. It also plays an important part in establishing and controlling the �body-clock� or circadian rhythm.
There is evidence from Norway of exposure to temporal changes of the GMF and Melatonin Suppression:
- Weydahl 2001 � Geomagnetic activity influences the production of melatonin at latitude 70�N.
- Changes in the geomagnetic activity had to be of a certain magnitude to affect the daily amplitude of melatonin.
- If large enough (>80nT/3h), changes in GM activity also significantly decreased the concentration of melatonin in saliva.
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