Cell phones and DNA damage: again, no link found.

[elfs]

Hot off the news that the measles-mumps-rubella vaccination does not and never did cause autism, it now turns out that the authors of two papers showing that cell phone electromagnetic fields cause DNA damage are under investigation for scientific misconduct. Among the most important parts of the investigation are notes from a technician indicating that the supposedly double-blind study of EMF damage was not double-blind; she knew for each experiment which cell lines had been exposed to EMF and which had not. Both papers, the only two showing actual DNA damage, came out of the same lab, and all eight of the papers to come out of this lab since 2003 are now considered suspect.

The lead author of the papers claims that the investigation was motivated by the cell-phone company, and is standing by his findings even without the technician's results. But it's not looking good; right now, any results showing genotoxic EMF from cell phone radios ought to be considered invalid.

[Edit: I'd add attribution, but the original LJ post is friends-locked.]

Comments

[elgatocurioso.livejournal.com]

Have you ever had someone put their cell phone or blackberry next to their telephone while talking to you and heard the audible interference it creates? My own cell phone even makes my alarm clock speaker emit audible "computer noises" when it is just sitting next to it on the nightstand!

I'm not a scientist, and I continue to use my cell phone, but knowing that it is putting out enough energy to cause audible interference in other devices makes me feel uneasy about putting it up next to my head!

I've made an open version by request

[dakiwiboid.livejournal.com]

here

By the way, you weren't one of the influential bloggers I was shooting at towards the end of that post. I appreciate your take on science very much, and I've learned a lot from what you post on all facets of scientific stories.

[en-ki.livejournal.com]

Honestly, it really does help to have a basic understanding of electromagnetic radiation and circuits when thinking about this stuff. You don't have to be a scientist to do that; there are good books you can pick up that will tell you useful things in lay terms—or you can skim the science books intended for undergraduates, which don't require serious math and which do have a lot of careful explanation.

To create audible interference, the Blackberry just has to emit a signal that is fairly close to what the device is receiving on purpose in frequency and in power. The phone then receives the (faint) signal and amplifies it so you can hear it, the same as it amplifies the faint signal from the phone company's central office.

(1) That doesn't mean the Blackberry is putting out a lot of energy—modern electronics are very sensitive, because power costs money and sensitive receivers make transmission cheaper.

(2) The energy output grows with both the frequency (which determines the energy of each individual photon) and the number of photons. The kind of damage it can do to you depends on the frequency: X-rays have a high frequency and a high energy per photon and can easily damage DNA with a single photon, while radio waves have a lower frequency and a lower energy per photon and absolutely can't. Standing right next to a very powerful radio source like a transmission tower may well kill you, but only by heating you up with the sheer number of low-energy photons you're getting hit with.

Scientists hedge this a little bit and do studies because, if there's a subtle and unexpected way for these things to affect people after all (for example, a huge number of low-energy photons coincidentally hit the same pocket of water in your body at the same time and heat it up enough to do DNA damage), it's a big deal; so even if it's unlikely, it's worth looking for. But the phenomenon you're describing isn't evidence of that, because it's perfectly consistent with our existing, well-understood model that makes extremely sound predictions and is the foundation of all kinds of medical and communications technology.

[acelightning.livejournal.com]

[en-ki.livejournal.com]

Hm, 50 kW at 1 meter should be about 4 kW/m^2 if it's spherical, right? I know I'd feel a 100 W light bulb at that distance, so I would have figured you'd get at least some warmth from RF. Go figure. (Certainly for "that might kill you", I was thinking more in the megawatt range, but maybe you have to be working with microwaves anyway.)

[acelightning.livejournal.com]

[theerik.livejournal.com]

The issue with standard light bulbs is not their normal output, but their efficiency. An incandescent bulb is only about 2-4% efficient, and most of the other 95% of its power is given off as heat instead of light. This is why flourescent bulbs both use so much less energy for the same amount of light output, and are so much cooler to the touch. Radio antennae are much more efficient than either, and there is virtually no loss to heat energy. The amplifiers are a different story. :-)

[en-ki.livejournal.com]

When you say "heat", what form do you suppose the heat is in? My understanding is that the light bulb is giving off light by something close to blackbody radiation, so the "heat" it is radiating is mainly in the form of photons in the infrared spectrum. If it were in the microwave spectrum, since I'm mostly water, I'd still feel heat. If it were in the radio spectrum, apparently, it would affect me very little.