Sunday, December 07, 2008

Lead in plastic

A few weeks back, shortly before my job with Uramet terminated, the chief geo and I were doing some work out at the Geoscience Australia core library. I took the opportunity to grab the portable XRF analyzer, and check the old, peeling paint on out railings for lead. The good news is that they were not Pb paint- the Pb content was measured in ppm, not percent.

Not content to turn the machine off with my peace of mind intact, I decided to move on to the windows. When we bought the house, we replaces all the old, leaky, single-pane aluminum windows with swish double-glazed uPVC windows. I’d head something about metals such as lead being used in some plastics, so I figured I’d take a look. A spectra is shown below:


The dominant peak is the chlorine peak. Since PVC stands for polyvinyl chloride, this is not surprising. The Ti is probably related to the white pigment. And there is also substantial calcium and lead. I don’t have a standard to compare this to, but the instrument’s built-in, assume-it’s-a-crustal-rock firmware estimates 1-2% Pb.

So from now on, LLLL is not allowed to chew on the windows. Aside from that, though, I don’t really know what to make of this. I know fuck all about plastic stabilization, much less how it is regulated. So I don’t have the environmental knowledge required to calibrate my level of parental worry. If anyone better educated than I wants to pitch in, that would be great.

5 comments:

Chris Phoenix said...

Lead is very often used in wire-insulation plastic. Some Christmas light strings come with a warning to wash your hands after handling them! I think the lead makes the plastic softer.

Another thing to be aware of is bromine as fire retardent in casings of computer equipment.

on-the-rocks said...

Sorry about your un-employment.

I don't know why this post triggered this memory, but years ago, there was a minor scandal at UT El Paso because of an over-abundance of uranium samples in an old store room. One of the professors had made repeated visits to the Sierra Peña Blanca uranium mining district, in Chihuahua, and had brought back too many samples.

I don't know what happened to the materials removed from the store room. You could probably find an abundance of interesting particulates in those store rooms, radioactive and otherwise.

Bob said...

We got one of those portable XRF guns last summer. The boss loves it. How is the regulation of such devices in your part of the world. Here the regulations date to when the phrase "portable X-ray device" was an oxymoron. To properly qualify to use it we need to go through far too much administrative nonsense.

Sorry to hear about your unemployment. I hope yu find something better.

Chuck said...

Regulation here is state-based, which is kind of a pain in the ass, if the vendor, the HQ, and the tenements are all in different states.

Qld regs are particularly cumbersome, so we found that since all of our Qld ground was adjacent to NT stuff, it was easier just to collect the rocks, and hop over the fence to do the analyses. All of our drill programs were in NT, so it was usually with the team on the rig anyway.

Our scintillometers had low energy filters low enough to pick up the primary X-rays, so actually BEING safe (as opposed to meeting safety regs) was easy and fun to demonstrate to contractors, as direct beam exposure set off the rad hazard alarms on the scints. And even at sub-alarm doses, we could use the uptick in counts to detect and define the scattered X-ray zone, and improvise shielding to reduce exposure BDL.

As for official badge exposure, everything was background except the radiation badge of a drill contractor who took his badge off-site and sent it through the X-ray machine at the airport.

UPVC said...

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