Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

  1. Peter J Hore  Is a corresponding author
  1. University of Oxford, United Kingdom


Prolonged exposure to weak (~1 µT) extremely-low-frequency (ELF, 50/60 Hz) magnetic fields has been associated with an increased risk of childhood leukaemia. One of the few biophysical mechanisms that might account for this link involves short-lived chemical reaction intermediates known as radical pairs. In this report, we use spin dynamics simulations to derive an upper bound of 10 parts per million on the effect of a 1 µT ELF magnetic field on the yield of a radical pair reaction. By comparing this figure with the corresponding effects of changes in the strength of the Earth's magnetic field, we conclude that if exposure to such weak 50/60 Hz magnetic fields has any effect on human biology, and results from a radical pair mechanism, then the risk should be no greater than travelling a few kilometres towards or away from the geomagnetic north or south pole.

Data availability

All data generated during this study are included in the manuscript and supporting files. Code files have been provided for Figures 2 and 4.

Article and author information

Author details

  1. Peter J Hore

    Department of Chemistry, University of Oxford, Oxford, United Kingdom
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8863-570X


The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Anant Paravastu, Georgia Institute of Technology, United States

Version history

  1. Received: December 6, 2018
  2. Accepted: February 2, 2019
  3. Accepted Manuscript published: February 25, 2019 (version 1)
  4. Version of Record published: March 14, 2019 (version 2)


© 2019, Hore

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.


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  1. Peter J Hore
Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs
eLife 8:e44179.

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