Guest blog on SAR from Devra Davis of the Environmental Health Trust

These are comments, on the scientific issues that came up at BioEM2013, that Devra Davis submitted as a guest blog. The opinions expressed in it are of Devra Davis herself. Publication of these opinions in BRHP does not mean that BRHP agrees with or endorses these opinions.


It is inherently unfair to ask people who’ve spent their lives working on a problem to spend 10 minutes summarizing it, but that is the fashion nowadays with TED talks being crammed into ever shorter and shorter time periods.  One could imagine Immanuel Kant being told, ‘now you’ve got 10 minutes to explain the critique of pure reason and the critique of practical reason.  Just focus on the main message.  Keep it short and snappy.’

Brain modelling is nothing is not complex, so the challenge  CK Chou put to the assembled workshop panel on Specific Absorption Rate (SAR) testing of the head to keep it under 10 minutes on June 11 was remarkable on many counts.  If you think it is fascinating to watch brilliant engineers focus their attention on increasingly refined and irrelevant questions, then you really missed a great show during this rapid fire discussion of SAR modelling at the BEMS meeting June 11.  A panel featured many–but not all– of those involved in building and redesigning models of the head and body to estimate absorption of microwave radiation.  These included the renowned Niels Kuster (with backup by Andreas Christ, who has devoted 15 years to building the Finite Time Dimension Virtual Family). the irascibly brilliant Joe Wiart, who has created French variants that are more anatomically based, the skilled dosimetry expert Azadeh Peymann, the highly competent  Jianqing Wang,  who was able to explain where differences have arisen and how to resolve them, and the skilled dosimetry modeller Jashvar Keshvari.

Environmental Health Trust’s Lloyd Morgan provided color commentary noting the historic evolution of Standard Anthropomorphic Mannequin (SAM )based Specific Absorption Rate (SAR) computer simulation of exposure and highlighting some of the quaint assumptions used by the ANSI and IEEE reviewers through whose hands have passed every one of the approaches that have been applied to the testing of cellphone radiation over the past two decades.  Morgan added that the current SAM based SAR system rests on analyses developed in 1991 and 1992 and no one has a single copy of the 1992 document.  But since the overall framework has remained unchanged since 1996, that’s of no real consequence, although it might be of interest to those with a regulatory bent who care about historic records and foundations on which systems rely.

There was no rejoinder when he relayed that fact.

Excepting Morgan and Wiart,  the other BEMS speakers generally focused on why they concluded  that using the adult SAM results in the same exposure to the child head as to an adult.  Wiartt repeated his finding that the brain tissue  of  a child can absorb twice as much radiation as an adult.  Kuster added  that the bone marrow of the skull can, as he and Andreas Christ had shown in 2010, absorb ten times more radiation.

So the question remains, why does anyone  care about the total head  absorption of radiation in children and adults?  And why should we focus on the overall head rather than the targetted tissue? The answer was simple and had nothing at all to do with engineering and a lot to do with policy developments.   Some 17 years after first issuing standards for thinking about cell phone radiation, and a decade after suggesting what specific tests could be used, the FCC has recently formally called for advice on whether to change its approach to cell phones ..  Since in 1996 and 2003 cell phone users were mostly business and medical people and mostly male, the big head of SAM–weighing about 11 pounds–made sense then.  But today’s users are smaller and more diverse, with growing numbers of apps for toddlers and infants.

So showing that even small users get the same average Maximum SAR exposure to the entire head as larger ones might seem an important point to make at this time, excepting for one other undeniable fact.  Even if children were to absorb the same average amount of radiation into their heads, a child’s brain is not the same as an adults in many ways.   The unique qualities of the child brain was one point that Morgan ran out of time trying to make–

In the interests of fairness I should admit that this is also a central point of the work that he and I and modellers from the University of Porto Allegre are now making in our work with Environmental Health Trust.  We are also deeply engaged in explaining the impact of using a 1 gram volume into which one averages exposure as compared to using a 10 gram volume–as ICNIRP recommends and many other nations do.  We have found–and I presented at BEMS the day before–that the larger the averaging volume, the lower the average SAR will be.  Using 10 grams rather than 1 gram–think a raspberry compared to a plum–results in much higher exposures and higher temperatures within smaller areas.

To learn the reasons why this averaging volume is not merely an academic matter, skip to the last paragraphs here.

The speakers went to great pains to note that the original work on this topic by Om Gandhi in 1996–the year he was President of BEMS and awarded the D’Arsonval Medal–had relied on a scaled down model that simply reduced the adult fathead SAM to the estimated size of a 6  year old.  They offered more anatomically based models that they had created since 1996 pointing to refinements and advances in understanding curvature, and even more recently in modelling the fact that the hand can detune the antenna, thereby increasing exposure, and sometimes lessening it.  

At one point in the discussion, the issue of how SAR varied depending on where on the body phones were kept and how they were held was raised.  Gandhi and Kang had reported in 2002 that the SAR when a phone is in the pocket can be 4-8 times that when a phone is held at the head.  Niels Kuster shocked a few by conceding this point when asked about this and he repeated advice that few ever heed that appears in fine print or in online product specs, “The manufacturers tell you not to keep a phone in your pocket.”

But, the sticking point with a number of speakers was this–there’s really no need to  to change the FCC reliance on SAM because it protects children who get the same overall exposure to their heads as do adults.  But wait a minute.

I asked Michael Kundi, an epidemiologist and medical researcher with the Medical University of Vienna who knows a thing or two about basic biology and electronic engineering whether he thought  much could be made of the fact that Max average SAR exposure appeared comparable in children and adults.  He noted that

 “The most important point is: I’m not interested in max SAR. It usually occurs at the surface of the skin or in some other not very important tissue. I’m interested in SAR in vulnerable tissue!  That is: bone marow of the skull, meninges, brain, nerve sheets, ventricles.  And it is clear that concerning these tissues there is a difference between children and adults. So the question is: Do we measure the relevant exposure if regulations demand measuring max SAR, wherever this is?”

When asked about the biological importance of the SAR to children and adults, CK Chou said,  “We are not talking about biology here, only about exposure and the standards.”

A few jaws dropped at this statement, which proved too much for Luc Martens, one of the seasoned modellers who should have been on the panel,

“Are you saying that we should only be concerned about compliance with the standards and not about improving our ability to model real world exposures?” he asked.  “Isn’t that why we do this, after all?”

At that point the panel ended.

When pressed afterwards about whether he had an opinion about biological impacts of cell phones in a child compared to an adult, French telecom expert Wiart concurred.  “This is not my job.  My job is to provide the best dosimetry modelling about how exposure occurs.”

Indeed that was the position echoed by every one of the panel members who are experts in modelling exposure but not in the biological impact of exposure

The work that Alvaro de Salles and Claudio Fernandez are developing relies on modelling developed by the IT’IS group and Andreas Christ.  In preliminary simulations they report that average exposure estimates of SAR for the brain vary a great deal depending on the age of the head being modelled as well as the volume being used.  They also reported that using a 1 gram averaging sphere, as the U.S. does now, results in significantly less exposure than using a 10 gram sphere–or a cube, as do the ICNIRP and IEEE approaches respectively.

Now fast forward to the recent and long overdue call of the FCC for advice on cell phones and related matters.   As Louis Slesin pointed out in Microwave News last year, in 2003 when the FCC last issued proposed amendments to cell phones and related matters,  ” The number of cell phone subscribers in the U.S. was a tenth of what it is today and people used them, on average, less than four minutes a day.”

All of which makes the move toward loosening standards all the more curious.  At a time when users and uses have grown exponentially every few years, and when studies on safety are at an all time low, the idea the FCC might harmonize and adopt the 10 gram average cube used by the International Commission on NonIonizing Radiation Protection  (ICNRP) makes little sense.

But sense is hardly the guiding rule to government on this issue. 

If the commission were to follow the other standard-setting groups (IEEE and ICNIRP), it would increase exposures from cell phones by a factor of two or three or more.  In fact, the recent FCC Notice of Inquiry is part of a large effort to push America into harmonizing and thereby dropping what had been the most stringent standard for phones in the world, using a 1 gram average volume.Whether the FCC should be setting health based standards is a good and important question–especially in light of the fact the assembled world expert modellers on brain exposure all describe themselves as not biologists.  It is an irony that the bioelectromagnetics society in its annual meeting featured a discussion of head models that did not involve a single expert in human biology and focused solely on the narrow question of absorption of radiation into the brain as modelled by computer based simulations that do not reflect biological complexity of the brain itself. 

One can wonder as many FCC senior staff do whether they are the right agency to address the matter.  But, then all other agencies with health competence–like NIH and EPA– long ago lost their funding and training efforts in the field. So, with the exception of the large NIEHS animal study underway with results expected no earlier than 2014, and the rare study from NIH investigators like Nora Volkow, or reports of damage to male reproductive health from the prolific group at Cleveland Clinic led by Ashok Agarwal, there’s a huge vacuumn of expertise on the health impacts.  Then there’s the interesting matter of the pending confirmation as head of the FCC of Thomas Wheeler–the man who headed up industry decade-long multi-million dollar efforts to delay and diffuse science on cell phone dangers for the CTIA–as described by his former colleague George Carlo…  If this former industry lobbyist is confirmed to head the FCC, there is no way that he can lead the agency to set health standards against which he fought for so long.  The obvious conflict of interest could not be surmounted. 

The problem and it is a huge one is that currently in the U.S. there are few other expert groups regarding potential biological impacts of nonionizing radiation on which to rely–something the U.S. National Academy of Sciences Workshop noted in a report in 2008, calling for a major research program and investment in research and training that has never materialized.

A new paper by Carlo and others should send shock waves in the agency.  They argue that that the SAR should not be used as a primary dosimetric measure because it rests solely on avoiding heating, when the major health issues of concern relate to many other nonthermal effects such as the stimulation of reactive oxygen species and other markers of cell damage tied with cancer, inflammatory processes and degenerative diseases..  Seen in this light,  at its best the SAR is an imprecise measure which tends to bias statistical results toward the null, that is toward finding no effect when one is actually occurring. In other words, the SAR is loaded toward false assurances of safety or toward underestimating risks that are present. Yes, this has been a very controversial position that is inconvenient for people on both sides of the RF issue.

But, the time to look seriously at the question not answered at BEMS–is it time to move beyond the SAR and if so, what direction should be taken to come up with a biologically based approach?

Their conclusion should prompt major rethinking of the issue and is reprinted here:

SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict the biological effect due to non-linearity.

Citation: Panagopoulos DJ, Johansson O, Carlo GL (2013) Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects. PLoS ONE 8(6): e62663. doi:10.1371/journal.pone.0062663



6 thoughts on “Guest blog on SAR from Devra Davis of the Environmental Health Trust

  1. Even if we can say we decisively know the SAR, do we know that any SAR is safe, harmless?
    Do we know that any exposure level is safe?
    Exposure levels in power density are similarly impossible to measure and define as they are ever fluctuating. Lab studies are unlikely to duplicate real world exposures in every possible configuration and orientation in which people and other living things spend their lives. These exposure levels vary moment to moment and that also vary from one spot in space to another due to reflection, etc, etc. People may even have different thresholds of tolerance, further complicating the matter.
    So, I wonder at the end of the day, what do we really know other than that people are getting sick? We know that radio/microwave exposure in the near-field and far-field–from towers, wifi, smart meters, other people’s phones–is making people sick.
    When will we act?

    Here is a fascinating article from 1979:

    “Knowledge of mechanisms or physical laws explaining phenomena is obviously very important, particularly for its predictive value. But to say that there are no effects when effects are in fact observed, simply because the effects cannot be explained, is like saying no apples fell until Newton discovered the law of gravity.”

    When will we start protecting the public health? We have models, etc, but don’t even know a safe level exists.

  2. The head gets hot from other mechanisms: the phone itself produces heat because it uses power amplifiers, and its presence against the head prevents heat loss through thermoregulation. So yes it would be nice to show heating directly from a phone (and this can be done using MRI in phantoms) but it is not simple and comes with some strong provisos. For real people with real theormoregulation you’re unlikely to see any heating from the RF. You may see bioeffects from changes in blood flow and/or microthermal gradients, but that is even harder to quantify.

  3. It seems that all that is needed is to do thermal imaging while a cell phone is in use. Won’t this give us an accurate mapping of heating and how quickly it dissipates? Why do all of this modeling when we can so easily determine what is occurring in real usage? Everyone I talk to tells me that they get hot heads when they use their phone. While thermal imaging will not address non thermal effects, it would provide a simple method of determining the thermal effect.

  4. Because it is keyboard-out. Put it in your pocket keyboard-in and the SAR will be the same or less than in talk position. And the battery will last longer

  5. In fact SAM was nothing to do with IEEE, in 1991, 1992 or later. It was a European development which first was specified by CENELEC in 2001

  6. Why is the SAR somuch greater when the phone is in the pocket compared to the head?
    It makes the Newcastle NSW findings even more significant as regards reproductive health.

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