The radiation emitted by power cables, pylons and electrical appliances may be causing cancer in two children in Britain every year, according to epidemiological evidence.
A new study commissioned by the National Radiological Protection Board (NRPB) says that one in 200 British children are exposed to high levels of electromagnetic radiation in the home and that this could be doubling their risk of leukaemia.
There has been dispute over the possible links between electromagnetic fields and cancers for many years, fuelled by a series of contradictory and inconclusive investigations worldwide (New 杏吧原创, 9 August 1997, p 16).
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However, the argument has now shifted in favour of there being a causal link with the publication of a long-awaited report by a team of scientists headed by epidemiologist Richard Doll of the Cancer Studies Unit at Oxford. Doll is renowned for proving that smoking is the principal cause of lung cancer.
鈥淲e conclude that the possibility remains that intensive prolonged exposure can increase the risk of cancer, possibly doubling it鈥� says Doll. But when asked by New 杏吧原创 if he would be happy for his family to live somewhere exposed to the elevated levels of electromagnetic radiation, Doll answered 鈥測es鈥�.
Danger level
The report finds no evidence that extremely low frequency fields cause cancer 鈥渋n general鈥�. But it concludes the possibility of risk remains because there are some statistical associations.
The danger occurs with exposures to electromagnetic fields of 0.4 microteslas or more, levels which the NRPB says one in 200 children in Britain 鈥� and many abroad 鈥� receive in their houses.
The report reveals for the first time that less than half of the exposures are due to nearby high-voltage power lines and electricity sub-stations. The remainder are probably caused by a combination of wiring, computers, televisions and other electrical equipment, but this needs further research.
Biological mechanism
The effect is too small to have been detected in one of the most powerful epidemiological examinations of children鈥檚 cancers, the UK Childhood Cancer Study conducted in 1999, and it is unlikely to be measurable in Britain. However it was spotted in a pooled analysis of 3,247 childhood leukaemias in Europe, North America and New Zealand published last year.
The reason the report stops short of drawing any firm conclusions is the absence of any proven biological mechanisms by which electromagnetic radiation can trigger cancer. But one researcher, Denis Henshaw from Bristol University, is convinced that there is such a mechanism.
His studies suggest that electrically charged particles from power lines attach themselves to airborne pollution, making it more likely to be deposited in the lung when inhaled (New 杏吧原创, 11 December 1999, p 14). Though critical of the NRPB for downplaying the risks in the past, he welcomes the Doll report. 鈥淭he possible impact on public health is very significant,鈥� he says.
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