Childhood cancer and powerlines : distinguishing between `magnetic field` and `airborne electroactivity` unterpretations.
Results of the study by Draper et al have been considered mainly in
terms of electric and magnetic field influences. The `indirect` ion
hypothesis of Fews et al (1) relating to health hazards of electrically
enhanced airborne particulate pollutant deposition was briefly discussed,
but the possible relevance of `direct` biological activity (2) by
powerline associated air ionization has not been considered.
In general, the extent of corona activity at overhead powerlines may
have been underestimated, but has become apparent recently following the
introduction of the daytime ultraviolet corona detection camera. As
illustrated on the "Daycor" website (3), corona activity is particularly
associated with support insulators and other overhead line junction
Groom & Chalmers (4) reported that negative space charge, near a
132 kV powerline, was liberated at line support insulators and could be
detected principally near transmission towers. Unlike magnetic field
effects therefore, any health impacts attributable to airborne
electroactivity would be expected to show some non-random distribution
along the axis of an electricity utilization line corridor, with a
tendency for `health impact` sites to be clustered near support towers or
poles. As the Draper et al study obtained grid references for all
relevant high voltage line pylons in England & Wales, the study data
could provide the basis for evaluating the relative importance of
`airborne electroactivity` and `magnetic field` interpretations of health
impacts. A linear non-random distribution of adverse health impacts would
support the view that some airborne products of electrical corona
discharge may be biologically active.
1. Fews AP, Henshaw DL, Wilding RD, Keitch PA, 1999. Corona ions from
powerlines and increased exposure to pollutant aerosols. Int. J. Radiat.
Biol. 75 1523-1531.
2. Sidaway GH, 2008. Environmental and social impacts of electricity
utilization : broadening the debate. The Environmentalist, in press : DOI
4. Groom KN, Chalmers JA, 1967. Negative charges from high-tension
power cables in fog. J.Atmos. Terr. Phys. 29 613-615.
Competing interests: No competing interests