After thousands of studies, the most that experts worldwide can determine is the radiation used for wi-fi networks, digital devices, cordless phones and cell phones is a "possible" cause of cancer. With such uncertainty, OLIVIA WANNAN asks if we are using this technology with enough caution.
As in many countries around the world, the debate about long- wave radiation has come to a head in New Zealand through the recent introduction of wi-fi networks in schools.
The energy waves have been harnessed for more than a century to bring radio and television to our home, track objects by radar, microwave our food, and connect us through texts, phone calls and the internet.
Yet the World Health Organisation lists this radiation as a "possible" cause of cancer, based on research showing a link between heavy cellphone use and an increased risk of developing brain tumours.
Kapiti Coast parent Damon Wyman is a vocal advocate for caution. He became aware of the possible health effects of wireless technology after losing his son Ethan, 10, to cancer in August 2012.
Ethan died 11 months after being diagnosed with two brain tumours. Four months before the diagnosis, he had been given a wi-fi connected iPad.
His parents later discovered he had been falling asleep with the device under his pillow.
Even though it was on standby, it was still emitting bursts of radiation as it tried to connect to the router, Mr Wyman said.
Doctors who saw Ethan said the tumours appeared to be about three months old, Mr Wyman said. "We're not saying that caused it, but it seems like a bit of a coincidence."
Children were rarely exposed to most of the other potential cancer- causing agents such as coffee and lead, Mr Wyman said.
Until recently, parents could limit exposure to the energy waves, deciding what age their child received a cellphone or digital device and setting restrictions on their use. But new bring-your-own-device initiatives introducing wireless networks running all day in school classrooms had suddenly taken away that control.
"Schools have to be neutral. They have to have a safe environment," he said.
Mr Wyman has campaigned to have the technology turned off in the junior classrooms at Te Horo School. The board of trustees decided to switch it off after surveying parents, who were concerned about the possible health effects.
This month the Government reiterated its belief that wi-fi in schools was safe, backed by the result of a study at Te Horo School and one in Canterbury.
Associate Health Minister Jo Goodhew said the study confirmed wi-fi in schools was not a health risk to pupils or staff, with exposures thousands of times lower than recommended levels.
Mr Wyman remains sceptical.
He said many parents falsely believed a classroom's wi-fi station emitted no more radiation than an at-home router. But new school wi- fi systems were "industrial- grade", emitting a lot more than a residential version. Professional measurements of the classroom's wi-fi station at Te Horo School showed similar radiation levels to those of some commercial cellphone network towers.
"This goes way beyond what a child would see normally."
Mr Wyman obtained the figures from measurements taken by radiation expert and Ministry of Health adviser Martin Gledhill.
The ministry called in Mr Gledhill to assess the levels of radiation in Te Horo School classrooms with wi-fi after the board switched it off. He disagreed that school systems emitted significantly more radiation than at-home routers. "There might be some variation, but it's not going to be hugely different.
"What they're getting at home and what they might get at school is a bit of a red herring. Really, what's important is where it sits with what's considered a safe limit." Mr Gledhill said the radiation emissions in the classroom were, at the most, still 250 times less than the maximum New Zealand safety limits allowed.
The wi-fi base station and the electronic devices also communicated in pulses, so averaged out over time, overall radiation was even lower, he said.
Mr Gledhill, a physical sciences expert, is the Health Ministry's only expert spokesman on the safety of the emissions. Requests from The Dominion Post to the ministry to additionally speak to a specialist with a background in biology were unsuccessful.
Mr Gledhill said the maximum safety levels prescribed in New Zealand were set in 1999, based on guidelines established by an international panel of experts. Many nations took their guidance from the same group, including Australia and Britain. Nothing since has moved the panel to make any new recommendations.
"The only effect that showed up with any consistency was the effects of heat stress and the limit was set based on that.
"You get people who say it ignores all sort of other [health] effects, but an awful lot of work has gone on for the last 30 years looking for effects at exposure levels much lower . . . but nothing has shown up with any clarity."
Britain's Health Protection Agency echoed this when it looked at studies up until 2010, noting "findings still remain divergent with no obvious reason as to why some researchers find effects and others do not".
Yet a biologist specialising in radiation spoken to by The Dominion Post last year said things were becoming a little more clear cut at the cellular level.
"Of late there has been more evidence there are certain changes in the biochemistry within cells and tissues exposed to radio frequencies [long-wave radiation]," said Sophie Walker of the Institute of Environmental Science and Research.
"It's quite a new area really in terms of science. And translating those changes in the biochemistry through to experienced short-term changes is a difficult link to make - one that will be made with more work."
Dr Walker said conclusive evidence on radiation's risks and safety was still years away.
"[The radiation] has only been used in the wider population for the last 30 years so true long-term studies are still under way."
She provided twice-yearly reports to the Health Ministry on the latest scientific findings. A spokesman for the Crown research institute said Dr Walker was unable to comment for this article, citing the institute's contractual obligations to the Health Ministry.
The uncertainty around the radiation's effect should mean we treat the technologies using it with kid gloves rather than abandon, Monash University radiation researcher Mary Redmayne said.
The Melbourne-based scientist said there was not enough research for us to know what a safe level of exposure was.
"The research has looked at a narrow range of possible problems," she said. "For instance, I'm going to set up a breast cancer study. There hasn't been a breast cancer study - no- one's considered that."
Many studies have focused on the technology's link with brain cancers and leukemia in children, and DNA damage in sperm.
Dr Redmayne has studied the effect of long-wave radiation, particularly on the young.
She said young people have thinner skulls, and the brain's protective defences - a protein that covers nerve cells called myelin - were only fully developed in middle age. This combination meant children's brains were poorly insulated from outside interference, such as radiation.
Their bodies also grew more new cells than adults. The damage that led to cancer happened more commonly as cells were divided into new ones. "This pulsed radiation is very new to mankind, very recent. There really hasn't been time to know for sure how much effect it has."
However, the ministry remained certain of its policies, based on the advice of experts such as Mr Gledhill and backed up by a broad international consensus, environmental health manager Sally Gilbert said.
"The internationally recommended values for maximum exposure for radio- frequency [radiation] and electromagnetic fields provide good protection against harm."
When it came to wi-fi in schools, the Education Ministry was confident it was safe, based on Mr Gledhill's report on Te Horo School and advice from health officials, Education deputy secretary Andrew Hampton said.
The ministry would continue to monitor international developments, and allow school boards to make their own decisions on installing wireless technology.
While Mr Wyman might wish for moves like those in the German state of Bavaria, which promotes the use of wired internet networks in schools, he is a pragmatist.
He would like to see policies minimising children's exposure in schools until the data became more conclusive. Rules requiring teachers to switching off wi-fi bases when not in use, asking their pupils to use flight mode on their devices, and encouraging them to place electronics on desks rather than on their laps could all significantly reduce exposure.
Many education providers already have policies to minimise pupils' exposure to a similar type of radiation, ultraviolet light, Mr Wyman said.
Even the chance that wi-fi technology was dangerous should be enough to have such initiatives.
"Who bears the risk until this is known? Let's take the precautionary principle and reduce exposure as much as possible."
CUT BACK ON YOUR EXPOSURE
MOBILES AND DEVICES
Before buying a cellphone or internet-capable device, check out its SAR (specific absorption rate) rating - though in New Zealand you'll likely have to go online for this information. The SAR measures how much the device's emissions are absorbed by the body. Lower ratings indicate lower absorption.
Ensure your mobile has flight mode and use this as often as you can, including overnight, and when carrying it close to your body.
For long computing tasks, select a wired desktop or plugged-in laptop, rather than a wireless tablet.
Avoid holding a laptop or device on your lap or stomach - use a table instead, unless it's in flight mode.
When you can, choose a text over a call. Keep phone calls to a minimum or use a hands-free kit.
Keep calls to a minimum where reception is bad - when a mobile is far from a cell tower, it has to boost its signal to connect.
Choose a wired mouse and keyboard.
If possible, choose corded devices, or purchase one with speaker-phone capabilities.
If using a cordless, keep the main transmitting base of the cordless phone away from bedrooms and desks.
Keep calls short.
When installing a transmitting unit, ask for it to be put up high, such as on the wall or a shelf, away from bedrooms or where people sit.
Only turn the system on when you're using it. Make sure the router is turned off overnight, especially.
Choose software on a laptop rather than cloud-computing technology such as Google Docs, if you're using wi-fi. Typing in a Google Docs word processing means a wi-fi signal is sent with every single keystroke.
It may have serious health consequences, but without radiation, we wouldn't be alive at all. Light and radiating heat are the same sort of energy waves that power wi-fi and cellphones, Victoria University physicist Melanie Johnston-Hollitt says. What differs is the size of the waves.
Higher energy waves, such as those used in X-rays and CT scans, have the power to interfere with atoms and are known to be dangerous. These rays are emitted constantly by the Sun, but the Earth's protective magnetic "shield" stops many of these from reaching us, Dr Johnston-Hollitt says. One form of this "ionising" radiation that does, though, is ultraviolet light - well-known to cause cancer.
"There's also background ionising radiation from the Earth at low levels. Natural processes in rocks will produce some small levels of ionising radiation."
As the energy of the waves gets lower, it loses the ability to damage our atoms. Light, radiating heat, microwaves, and those powering TV and radio, wi-fi and cellphone communication are all mid- or low-energy radiation, also known as long-wave.
However, that doesn't mean all long-wave radiation is completely safe for humans. Enough of it can cause the body to heat up, causing damage. However, these levels are well-known and maximum safety levels are set far below. New Zealand's safety standards are 50 times lower than the radiation amount known to cause heating.
- The Dominion Post
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