Fifteen years ago Om Gandhi pointed out that children are exposed to higher levels of radiation from cell phones than adults. He was right then and he is right today. Yet, no one could blame you for thinking otherwise.
In an article published in the May issue of Harper's, Nathaniel Rich uses this putative controversy, among a number of other examples, to make the case that confusion reigns in all aspects of cell-phone research. "The brain of a child absorbs a much greater amount of radiation from a cell phone than does the brain of an adult," he writes, adding immediately after, "No, it does not."
The truth is that there should be no controversy. Children do have higher radiation exposures and if cell phones are indeed doing us harm, then children are at greater risk than their parents.
"There is nothing complicated about why children absorb more radiation than adults," Gandhi told Microwave News from his office at the University of Utah not long ago. Children have thinner skulls and smaller ears than adults, he explained, and so the radiation has a shorter distance to travel from the phone to the brain. (Every millimeter of separation makes a big difference.) Because more radiation gets to the brain, the specific absorption rate (SAR), the preferred way to measure the radiation dose, increases. That's it. You don't need any complicated equations, or even a computer to see the big picture. "The higher SARs have nothing to do with sophisticated models," Gandhi said, "It's all about separation distance. This is something you can explain to your mother-in-law."
Gandhi's original 1996 graphics showing that 5-year-old and 10-year-old children have higher SARs than adults (reproduced below) have achieved iconic status. Ronald Herberman, the former director of the University of Pittsburgh Cancer Institute, and his colleague Devra Davis fashioned a three-dimensional model of Gandhi's pictures —with Gandhi's assistance— to emphasize the higher SARs and the deeper penetration of the radiation in a child's brain. They have exhibited it at Congressional hearings, on various TV shows and during myriad lectures and presentations. Their message, summarized by Herberman in a memo distributed to the some 3,000 members of the cancer institute's faculty and staff in July 2008, calls for precaution, especially with respect to children (see MWN, July 2008). "Do not allow children to use a cell phone, except for emergencies," Herberman advised because, "The developing organs of a fetus or child are the most likely to be sensitive to any possible effects of exposure to electromagnetic fields."
Much of the cell-phone industry is still in denial, however, and disputes the increased risk for children. In a brochure released earlier this year, the Mobile Manufacturers Forum (MMF), a leading cell-phone industry trade group, continues to insist that others have been unable to find support for Gandhi's conclusion. MMF's argument is tautological: It cites Gandhi's 1996 paper as evidence that that same 1996 paper is wrong. Then again, perhaps it does make sense. if industry's objective is to sow seeds of confusion, using Gandhi against Gandhi would be entirely appropriate.
Some of those who should be trying to set the record straight are dragging their feet. Take, for instance, Michael Thun, the American Cancer Society's (ACS) point man on cell phones. Last month, Thun told Parade magazine and its 75 million readers that, "If cell phones were harmful, then it is conceivable that children might be more vulnerable." Conceivable? No, it's a fact. As Gandhi points out: It's simple high school geometry.
Today, Gandhi has many supporters. Research groups in Brazil, France, Japan, Spain and Switzerland have all published papers showing that children have higher SARs. Joe Wiart of France Telecom, a major mobile-phone operator, should have put the issue to rest two years ago when he announced that he agreed with Gandhi. (The MMF neglects to cite Wiart's paper in its brochure.) "Children are not simply small adults," Wiart told us at the time. "Their skin and their skulls are thinner than those of adults, and their ears are smaller too. Given these differences, the higher SAR for children is not surprising" (see MWN, July 2008). The industry does not speak with one voice: One large company says Gandhi is right, while others fight on.
Even Niels Kuster, the director of the IT'IS Foundation in Zurich, who has feuded with Gandhi for more than a decade, has decided that he can no longer turn back the tide (see MWN, N/D01, p.8, and MWN, M/J02, p.1). Kuster's work is often been cited to make the case that children are no different than adults. One example: The MMF brochure points to two Kuster papers to bolster its argument. Kuster counters that he has been misunderstood. "In the 1990s, we were talking about compliance," he told Microwave News, "My position was never about whether or not children get more radiation exposure in the brain, but whether the phones meet exposure standards when used by children." Kuster told us that Gandhi's revelation is "trivial" —which is what Gandhi has been saying all along.
Children’s Brains Are Different
And there's more: Children also have a greater sensitivity to cell-phone radiation. For years, some have argued that young children are more vulnerable because their brains are still developing. This is Herberman's argument in favor of precaution, and, while plausible, there wasn't much hard data to back it up. Now, Andreas Christ of Kuster's lab has reported that the SAR in the bone marrow of children is more than ten times higher than that in adults. Or, to put it bluntly, the same amount of radiation packs ten times the punch inside a child's bone marrow as in his mother or father's bone marrow. The new paper came out last month in Physics in Biology and Medicine.
Christ and Kuster's finding could not have been a big surprise to those who follow the field. Last year, Azadeh Peyman and Camelia Gabriel, another veteran RF researcher who runs MCL Technology Ltd., a testing firm in London, showed that some children's tissues have very different electrical properties than those of adults. These are known as dielectric properties and, in this context, refer to the conductivity (σ) and the permittivity (ε). (The SAR is directly proportional to the conductivity.) Peyman and Gabriel worked with samples from freshly killed pigs of different ages, which, they said, "are regarded as a good substitute for human tissues." They reported that the conductivity of a piglet's bone marrow was ten times higher than that of an adult pig. The reason for the big difference is that bone marrow has a higher water content in early life. The more water, the higher the conductivity, which in turn leads to a higher SAR. Christ and Kuster then used Peyman and Gabriel's new numbers to calculate the relative SARs in children and adults. (Follow this link for a look at the SAR arithmetic.)
If Gandhi's contribution is about the importance of separation distance, the lesson from the Swiss and U.K. groups is about the importance of biophysical properties. Each tells us that the SARs are higher in children.
One remarkable aspect of the Peyman/Gabriel paper is that, having measured the dielectric properties, they did not take the next step and show that the SAR in a child's bone marrow would be higher. Peyman and Gabriel were working under a ~$600,000 (£408,000) research grant from the U.K. mobile phone research program, known as MTHR. They could have done the same SAR calculation as Christ and Kuster, or at least pointed to and compared the conductivities. Yet, Gabriel and Peyman did neither. When asked why not, Gabriel replied that this would have required "speculation." Maybe so, but that was the problem they were hired to study. Another peculiar disconnect is that Peyman and Gabriel only looked at RF exposures from walkie-talkies, not cell phones. This too doesn't make much sense. When was the last time you saw a child talking into a walkie-talkie?
Gabriel and Peyman's decision not to draw the obvious inference about the higher SARs is all the more surprising because they had long known that the dielectric properties of bone marrow change with age. Back in 2001, they had reported a similar change in rat tissues —that time too, they didn't say a word about how it might raise the SARs. Yet, Gabriel realized its significance. "Children are not little adults," she told a meeting in Rome on children and cell phones the following spring. "We cannot afford not to do more research," she said (see MWN, M/J02, p.10).
At about the same time that Gabriel was delivering her talk in Rome, Gandhi published a new paper that showed what Gabriel and Peyman must have already known but had not stated in print: The higher conductivity found in baby rats means higher SARs in young children. Gandhi minced no words about the necessity to follow up. These results point to "an urgent need" to validate the finding for rats in children, he pleaded.
Still, seven years later when Gabriel finally had the better data from pigs to support everyone's long-held suspicions that children might be at greater risk, she once again held back.
While Christ and Kuster have shown that the SAR is higher in a child's bone marrow, we still don't know the dose (the SAR). It may be ten times higher than in adults, but we need the actual number, or at least a range of SARs. "That's coming," Kuster said. "We have a new research grant from the Swiss National Science Foundation to look at SARs induced by phones in specific tissues."
National WorkerRF Safety Crisis Video Our nations’ workers and the welfare of their families
are at risk! Watch the video to see how.
Children and Cell Phones: Time To Start Talking Sense
Source: MicrowavesNews.com
Date: 05/03/2010
