Debates over the safety of mobile phone technologies continue as evidence on health impacts remains inconclusive and experts have different opinions on the need for regulatory action to reduce potentially damaging exposures to non-ionising radiation.

 

Adding their voice to the debate with an article¹ published online ahead of print in Environmental Health Perspectives, Mike Dolan and Jack Rowley argue against applying the ‘precautionary principle’ to impose more stringent regulations of exposure to electro-magnetic field (EMF) radiation.

 

“In the absence of a scientifically plausible hazard from exposure to low level RF [radio-frequency fields], application of the PP [precautionary principle] is not appropriate to policy on the use of mobile phones and the siting of base stations,” write Dolan, Executive Director of The Mobile Operators Association and Rowley, Director of Research and Sustainability at the GSM Association, both based in the UK.

 

The precautionary principle has featured prominently in environmental policy decisions; most strikingly in REACH, the recently implemented EU chemicals regulation which essentially shifted the responsibility to prove chemical safety from government to industry. Though difficult to define with precision, it favours protective actions where there is reasonable concern that a particular exposure might cause harm, and in the absence of certainty about the extent of the risk.

 

Mobile phone technologies are already “inherently precautionary”, argue Dolan and Rowley, who are affiliated with institutions that represent the mobile communications industry. Standards are conservative and subject to regular review, they point out, technical features minimise unnecessary exposures to non-ionising radiation, and consumer information is available, allowing people and organisations to take “common sense measures” to address any health concerns.

 

Dolan and Rowley’s view counters that put forward in an editorial² published online ahead of print in Pathophysiology. In the editorial, Cindy Sage and David Carpenter call for action to reduce EMF exposures, invoking the precautionary principle and citing "sufficiently strong" exposure-effect associations. Existing safety standards are obsolete, they say, because they are based only on effects from short-term exposure at relatively high levels of radiation. The authors are affiliated with The BioInitiative Report, through which a group of scientists have put across a “rationale for a biologically-based public exposure standard for electromagnetic fields”.

 

“New ELF [extremely low frequency fields] limits are warranted based on a public health analysis of the overall existing scientific evidence,” write Sage, an independent consultant, and Carpenter, Director of the Institute for Health and Environment at the University of Albany in New York, USA. “These limits should reflect environmental levels of ELF that have been demonstrated to increase risk for childhood leukemia, and possibly other cancers and neurological diseases.”

 

Dolan and Rowley cite a lack of convincing scientific evidence that would justify a precautionary approach to regulating the technology, or a change in how exposure is assessed. But they admit that more needs to be learnt about potential effects of the exposure. “The possibility of some unknown long term adverse effect (including possible effects on children) has been left open by the reviews and is the subject of ongoing research.”

 

 

The precautionary principle is not defined robustly enough to give clear guidance for policy decisions on this issue, says Robert Goble, Research Professor at Clark University in Massachusetts, USA. “But I think that the evidence is sufficient and confusing enough to justify a ‘precautionary stance’,” he adds.

 

Peter Wiedemann, Head of the Human, Environment and Technology Program Group at the Research Center Jülich in Germany, says the precautionary principle is the right approach to take in regulating mobile phone technologies. “It is already applied in Switzerland, Germany, as well as in the EU.” But different measures can be used to apply it, he points out, echoing Goble’s view.

 

Wiedemann’s research suggests that the precautionary principle can trigger a perception of risk. “This calls for caution,” he says. Dolan and Rowley share this view, saying that taking more measures to re-assure the public could backfire by increasing concern.

 

Goble agrees that there’s more to precaution than setting standards. “Placing a portion of the burden on the creators, producers, and sellers of mobile phone technology is appropriate, but... more of a framework is needed for a legitimated precautionary approach,” he says. “The phone industry can’t do it themselves.”

 

In the case of REACH, which placed the burden of proof of chemical safety with manufacturers, scientists could reach “some sort of very rough” consensus about what it means to “demonstrate safety,” explains Goble. Wiedemann doesn’t find the analogy useful, arguing that demonstrating safety is impossible even for chemicals. “It cannot be taken for granted that RF-EMF is a hazard,” he adds. “On the other side, it cannot be excluded.”

 

“Different [protective] measures require different amount[s] of evidence,” says Wiedemann, though all need some evidence of potential harm. “However, there is no and there will [be] no consensus [over] how much evidence should be available in order to apply some (well-defined) precautionary measure.”

 

 

According to Sage and Carpenter, putting protective actions in place is necessary and especially important for children who might be more susceptible to the potential harmful effects of EMFs. Evidence from studies by a team led by Lennart Hardell, one of the scientists involved in The BioInitiative Report, suggest a higher risk of malignant brain tumours for young people who began to use mobile phones before the age of 20, note the authors.

 

In a review³ of mobile-phone health risks published today in the Emerging Health Threats Journal, Florence Samkange-Zeeb and Maria Blettner find that although the use of mobile phones among kids is on the rise, most studies have looked at health risk among adults, and found no evidence of adverse health effects.

 

The conclusion is shared by scientists who see bias in evidence that back calls for lower exposure standards. Maria Feychting, Professor in Epidemiology at the Karolinska Institute in Stockholm, Sweden, says a recent review of epidemiological evidence published by Hardell and colleagues reaches conclusions with which the majority of the scientific community disagree.

 

“Hardell [and colleagues] disregard several potential sources of errors in the studies,” says Feychting. She points out that in September 2008, the Health Council of the Netherlands questioned the scientific value of The BioInitiative Report in an advisory letter sent to the Minister of Housing, Spatial Planning and the Environment.

 

But an assessment of the available research by Michael Kundi, who is affiliated with the BioInitiative Report, examined the biases and methodological problems in some 25 studies and found that the evidence favours a slightly higher risk of brain tumours.

 

Samkange-Zeeb and Blettner point to knowledge gaps where future research could help to resolve these differences. “Studies covering different age groups as well as pregnant women and capable of incorporating the rapidly changing technology and exposures should be conducted,” they conclude. “As the use of mobile phones is now so widespread, with almost everyone in industrialised countries having access to them, further studies should focus on exposure gradients rather than exposed versus non-exposed groups.”

 

 

The groups of scientists with opposing views on whether exposure standards should be revised “put more weight on data that support their own prior beliefs,” says Wiedemann. “This problem refers to selection and interpretation biases. My impression is that this [is] especially the case with respect to the Hardell group.”

 

Goble believes that methodological differences and politics come into it too. “There is both scientific disagreement and policy disagreement and it is all too easy for these to get mixed together,” he points out.

 

Differences in interpreting the science are partly explained by differences in disciplinary backgrounds, adds Goble. When it comes to policy, each group tends to pick the interpretation that suits their interests. “The overall impression created is that ‘scientists never agree on anything,’ when there is a lot of agreement on the actual science, just not what to make of the ambiguities.”

 

Uncertainty confuses the debate, he explains, as each group can argue that the other cannot prove their position.

 

Drawing from his work on EMFs emitted from power lines, Goble says one could think of mobile phones as a controversy that is still “fresh” — one for which new information could come up to clarify important issues. “However, I think it prudent to prepare for the possibility that the uncertainties will not be resolved any time soon,” he suggests. “That will require developing practical approaches to ‘coping with uncertainty’.”