— Is Wi-fi dangerous?
THERE IS A STORY about an experiment by a group of Danish schoolgirls, involving watercress seeds in two adjacent rooms. In one room the seeds germinate and thrive; in the other room, which has Wi-fi routers in it, the seeds fail to germinate.
This is cited as proof that electromagnetic fields (EMF) generated by Wi-fi kill things.
We’ll come back to the watercress in a minute, but first let’s address the big question to which it leads. Can Wi-fi technology damage humans?
Good science rarely, if ever, comes up with an unassailable yes-or-no answer, and scientific investigation always remains open to new data. So far, however, after scores of studies, there is no uncontested evidence electromagnetic fields cause any damage to human tissue.
This didn’t appear to be the case, however, in 2011, when the World Health Organisation’s International Agency for Research on Cancer (IARC) announced it had “classified radiofrequency electromagnetic fields as possibly carcinogenic to humans based on an increased risk for glioma, a malignant type of brain cancer, associated with mobile phone use”.
Headlines based on this one sentence were startling. The agency’s own report, however, noted evidence linking phone use and gliomas was “limited”, and evidence for links with any other kind of cancer “inadequate”. Even with these qualifications, however, some researchers suggested the IARC’S position was based on poorly designed studies.
The IARC position was not supported by a 2012 study published in the British Medical Journal. Researchers from the US National Cancer Institute found no change in US glioma rates between 1992 and 2008 – “a period coinciding with a substantial increase in mobile phone use from close to 0% to almost 100%”. One of the main studies used by the IARC had predicted a 40% rise with widespread mobile phone use.
A 2011 British study did find a slight increase in temporal lobe cancers, but that trend began in the 1970s, long before mobiles and Wi-fi were invented. Overall it found no increase in brain cancers with the spread of mobile phones.
The largest investigation into the matter – published in 2013, looking at almost 80,000 middle-aged British women over seven years – found “mobile phone use was not associated with increased incidence” of brain cancers.
Despite these (and many other) studies, fears about Wi-fi and EMF continue to flare up from time to time. Why might this be so? One clue comes from a study, published in February 2018, by scientists at the National Cheng Kung University in Taiwan. It found the number of people presenting to doctors with self-diagnosed Emf-related symptoms rose and fell with media reports about EMF dangers. In other words, the likely cause of EMF symptoms was fear.
Now, briefly, back to the watercress experiment. The mark of any good experiment is that other researchers can replicate it, right? In 2016 a Canadian scientist who is also a consultant to a company that sells EMF ‘protection’ devices repeated the work of the Danish schoolgirls. She reported the routerexposed cress grew just as well as the stuff in the other room.