A long-running US study has found there is “clear evidence” that mobile phones could cause cancer in rats.
The results of the National Toxicology Program (NTP) found male rats develop cancerous heart tumours when exposed to high levels of radio frequency radiation (RFR). This is usually seen in 2G and 3G mobile phone devices, while further evidence saw male rats develop tumours in the brain and adrenal gland.
The research didn’t investigate the impacts of WI-FI or 5G networks and although alarming, researchers said the studies could not be compared directly to the human experience when using a mobile phone.
“In our studies, rats and mice received radio frequency radiation across their whole bodies,” senior scientist John Bucher said in a statement. “By contrast, people are mostly exposed in specific local tissues close to where they hold the phone. In addition, the exposure levels and durations in our studies were greater than what people experience.”
In the series of studies, the lowest exposure level used was equal to the maximum local tissue exposure currently allowed for humans who use mobile phones. The highest exposure level in the study was four higher than what is permitted. Still, researchers of the study said the link between RFR and tumours in rats is real.
The studies cost US$30 million (AU$41.6 million, UK £23.09 million) and more than a decade to complete. They also make up the most comprehensive assessment study analysing the impact RFR exposure has on animals.
Researchers were able to control the amount of radio frequency the animals received – something that isn’t possible with humans. During the tests, animals were housed in chambers specially designed for the studies and RFR exposure began for rats when they were five-weeks-old, while mice were exposed from six-weeks-old. For two years, the animals were exposed to RFR for up to nine hours a day.
Experts have warned the results of the studies aren’t likely to reflect 5G technology as it is still emerging. The NTP will provide the results of the studies to FDA and the Federal Communications Commission, who will review the information to monitor the potential impacts of RFR.
The findings have been widely discussed in the medical community, with many experts offering their thoughts on the research. Some claim the data wasn’t clear of the impacts RFR has on humans.
“This report provides an incremental contribution to understanding of the interaction between radio frequency radiation and cancer, although it is not at all clear that the results have applicability to humans using mobile phones in any realistic manner,” Flinders University Lecturer Dr Paul Gardner-Stephen said in a statement. “Of course, people who are concerned about the risk can always choose to use a headset or similar device when using a mobile phone, so that any possible risk – however small or unlikely – can be completely avoided.”
Others said the latest findings do little to strengthen evidence surrounding RFR.
“In a nutshell, the present results serve only to add a little strength to the evidence available following the first report on the rat studies,” Consultant for Cancer Causes and Prevention at the University of Western Australia Bruce Armstrong said. “That report has stood up to very careful scrutiny. The new results from the mice studies serve to strengthen the findings from the rat studies only a little. I remain of the view that IARC classification of ‘possibly carcinogenic to humans’ remains correct for the present.”