Saturday, October 17, 2009

Now there's BPA in cash register receipts?

I haven't posted about bisphenol A (BPA) at all, even though there's been A LOT of coverage on the health concerns of this chemical. First it was in polycarbonate baby bottles, then in the epoxy liners for food cans. Now we find out it's in cash receipts. What's the concern? BPA is an endocrine disruptor (estrogen mimic), and some studies suggest that human exposure to the chemical could lead to negative health effects, such as reproductive problems, obesity, and cancer. Back when I was working in industry, I used BPA quite regularly as a monomer, but of course I was handling it safely, with gloves and in a fume hood.

Apparently, the carbonless copy papers that are used for most credit card receipts and the thermal imaging papers used by most cash registers both rely on BPA chemistry. How does it work? A powdery layer of BPA combined with an invisible ink is coated onto one side of the paper so that when heat or pressure is applied, the BPA and ink molecules react to produce color. Not surprisingly, the quantities of BPA on these receipts are at the milligram level (60-100 mg) -- compare that to the nanogram amounts of BPA that can leach out of polycarbonate baby bottles. Yikes. TIP: Wash your hands well before you lick your fingers...

What's next, BPA in polycarbonate CDs and DVDs? Maybe we're better off going back to vinyl records and VHS tapes.

Monday, October 12, 2009

Detecting cancer during surgery in real time

This is cool. Researchers at Justus-Liebig University in Germany have developed a way to detect cancerous cells during surgery, by using a combination of mass spectrometry and an electroscalpel. Mass spectrometry is already used to distinguish between healthy and cancerous tissue, but samples have to be ionized before analysis by way of a high-voltage nitrogen jet -- a procedure that would most certainly not sit well with the patient...

However, the researchers found that the "surgical smoke" emitted by the electroscalpel can be collected and used as a sample for mass spectrometry. Analyzing the samples takes only a fraction of a second. By taking multiple samples within the surgical area, doctors could map out the healthy parts and unhealthy parts, which could make tumor removal more effective and reduce the number of subsequent surgeries.

The technique has already been tested in animals, and human clinical trials will begin soon. The only drawback is that a commercial mass spectrometer is very expensive (6 digits!), but the researchers believe that the cost could be reduced to about $20,000 with lower-performance mass spectrometers, which should work fine for this purpose.

Monday, October 5, 2009

The best and worst cellphones in terms of radiation output

Here's a post that caught my eye from Engadget, pointing out a list of best and worst cellphones based on the amount of radiation they put out. A quick glance at the list made me jump, as my cellphone -- the Motorola W385 -- is among the worst. Great. However, nothing in the list indicates anything about the quality or performance of the phones. My phone works extremely well in terms of sound quality and reception, and I'm not sure I would trade it in for one that emitted less radiation but had crappy reception and sound quality. And seriously, how much radiation are we talking about here?

It would take some work to dig out all the studies about the health effects of cellphone radiation that are out there, but so far, the conclusion is... inconclusive. Research is still on-going. But until then, it might be wise to not chat for hours with the cellphone next to your head. Or chat while driving -- this is a little off-topic as it has nothing to do with radiation, but it's probably more dangerous. I guarantee that if you see someone driving erratically on the road, weaving and driving much slower than the speed limit, it's not because they're intoxicated. It's because they're talking on their cellphone.

Getting back to the list of phones... If you pay closer attention to the source of this list, it's from the Environmental Working Group, an environmental advocacy group. While their website is nice in that it compiles a lot of useful information, be wary that this group tends to sensationalize science to suit their agenda. Do your research and use your common sense.