Monday, June 23, 2014

What's Wrong with Cell Phone Radiation Exposure Limits?

In 1996, the Federal Communications Commission (FCC) adopted a cell phone radiation exposure limit based upon a measure called the Specific Absorption Rate or SAR.  A SAR testing procedure was developed that is applied to all cell phones sold in the U.S.

In the U.S and about a half dozen other countries, cell phones are allowed to have a maximum SAR of 1.6 watts per kilogram of tissue averaged over one gram of tissue.  Many countries, however, adopted a more permissive standard, that was developed by a self-appointed body, known as the International Commission on Non-Ionizing Radiation Protection or ICNIRP. The ICNIRP standard allows for up to 2.0 watts per kilogram of tissue averaged over ten grams of tissue. 

Recent studies have determined that the head can absorb 2-3 times the radiation from a phone based on the ICNIRP standard as compared to the U.S. standard. Nonetheless, the cell phone industry in the U.S. has been lobbying the FCC to adopt the ICNIRP standard using the euphemism, "harmonization," to justify this weakening of the regulatory standard.

Considerable research, however, suggests that both the U.S. and ICNIRP standards do not adequately protect us from health risks due to exposure to cell phone radiation. The Specific Absorption Rate (SAR) and testing procedures are based upon four fallacies:

1) The SAR standards assume that a thermal (or heating) effect is the only way that microwave radiation emitted by cell phones can harm tissue.

However, many studies have found that exposure to low-intensity, microwave radiation at non-thermal levels where there is no measurable temperature change can produce DNA damage, reactive oxygen species, and stress proteins, and can alter brain activity and open the blood-brain-barrier. The SAR standards do not protect mobile device users from these non-thermal effects.

2) The standards are based upon averaging cell phone radiation exposure over one or ten grams of tissue and over time.

However, peak exposures and/or "hot spots" which damage tissue are not considered.

3) The standards only consider the immediate, acute effects of cell phone radiation exposure.

However, chronic effects due to long-term exposure are ignored.

4) The SAR test procedure uses a Specific Anthropomorphic Mannequin (SAM) which simulates a very large man's head and body.

The standards do not address exposure to fetuses, children, or women, different tissue types, or metallic objects worn on the body that influence the absorption of radiation (e.g., metal eye glasses or dental braces).  Research indicates that a child's brain absorbs 2-3 times the radiation of an adult's brain.


Evaluation of Specific Absorption Rate as a Dosimetric Quantity 
for Electromagnetic Fields Bioeffects

DJ Panagopoulos, O Johansson, GL Carlo. Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects. PLoS One. 2013; 8(6): e62663. Published online 2013 Jun 4. doi: 10.1371/journal.pone.0062663


Purpose  To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment.

Methods  We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect.

Results  We find that: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured.

Conclusions  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.


For further information about the FCC review of the SAR exposure limits in the U.S. see ...

FCC Needs Input on Radio Frequency Radiation

Does The FCC Plan To Rubber Stamp Outdated Cell Phone Radiation Standards?

Comments submitted to FCC re: "FCC Proposes Changes in the Commission's Rules and Procedures Regarding Human Exposure to RadioFrequency Electromagnetic Energy" (Proceeding Number 03-137), Feb 5, 2013

What's Wrong with the GAO Report on Cell Phone Radiation?