Could be lead in soil, paint, dust, or water. I'm starting up an effort focused on this in a hand...
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by read_holman |
August 13, 2018 22:22 |
Could be lead in soil, paint, dust, or water. I'm starting up an effort focused on this in a handful of cities and am looking to connect with folks in this area.
Hi @read_holman, I added the tag question:lead to this great question in order to link this to some previous postings and a bit of discussion.
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I've done a lot of lead testing. This was mostly by atomic absorption (AA), in an industrial situation.
The specs have changed. The lead levels are much lower than they used to be. A lot of the testing is now done by ICP. But, I have some experience with water testing, sample testing, incoming raw material testing ( the most common was clay), etc.
It can get nasty, with hydroflouric acid digestions. For water work, you usually don't have to deal with HF. But if you are dealing with lead in silicates, you do.
Excited that you might create a wiki page for "lead" !
You can create it by clicking the button on https://publiclab.org/tag/lead that says "Add one now".
While editing this new page, you can add this single line of text in the text area:
and it will automagically display all the questions asked so far about lead in a cute grid.
If you want to do more, you can add:
...all the research notes posted so far will display in another grid.
@Ag8n I'd love to pick your brain about the technologies. I am familiar with the general trends, but only bc I've read about them, have worked with labs that have used them, and have spoken with an analytical chemist. AKA, I've never actually used them.
BUT I'd like to know them better. I'm also exploring what a low-cost / DIY testing kit might look like that doesn't involve fancy lab-based equipment like ICP-MS, AA, XRF (though that's more portable), and others...
I've thrown together this spreadsheet that has tech on the Y axis and sample-types + variables on the X. Do you mind taking a look at this and providing reactions? Certainly feel free to jump into that file, but even comments on whether I have the file structured appropriate and if I have all the main technologies listed would be helpful. I'll be chipping away at this over time...
Lead Testing Technologies Pros/Cons Matrix
And for a bit more background...
Here's a writeup of this effort I'm working on: https://publiclab.org/wiki/the-lead-data-collaborative-overview
Is this a question? Click here to post it to the Questions page.
I'd be happy to help. Give me some time to look it over.
I've worked extensively with EDXRF, but mostly the desktop (read R&D) variety. Only a little with the handheld units. Did a lot of AA work. Again, only a minor amount of ICP.
Did a lot of the USP tests for lead and heavy metals, but those often use hydrogen sulfide or other not so nice reagents.
I took my own advice and created publiclab.org/lead, linking to the Lead Data Collaborative at the top
Hi @liz -- Cool. The aggregate page (for lack of a better word) is super helpful! Seeing all the related content / questions now and will check those out.
I'm also just seeing that you posted a couple tips above for me to incorporate into my wiki. Sorry for missing those. I added them as tags, and see questions now appearing on top. Is that what you were suggesting? Or do i put it in the content of the wiki itself. (Or does the new page you created obviate this suggestion?)
Hey Read, your page is looking great! The new tags look good, and i added another one parent:lead so that people can kind of navigate through this research area more easily.
Huh... Sorry about the duplicate questions. The page stalled on me and I didn't realize that the first one posted. (edit: I just deleted said duplicates.)
I believe you can delete your own duplicate comments, if not, however, and if you'd like me to (as site admin) just let me know and i can clean this up. <3
Thanks :) Some bumps here as I learn the quirks of the platform... So I just did delete a couple of the comments to clean up this thread.
One of those now deleted comments though had the following line in there, which I'll just restate here. After I added the questions:lead and notes:lead tags, I saw the questions appear on top of the page. I actually didn't like the presentation / location; it makes it harder to find the wiki itself and distracts the reader. So I removed those tags. I added a link to the top-line lead wiki at the bottom instead.
(I found the github repo where site issues can be posted. I hesitate to just jump into that stream blindly, but I'm checking it out now to get a sense as to what's going on there.)
Read- ICP-MS is the premier method.no doubt. But you pay for it. I'm second place is ICP-OES (ICP-optical emission spectrometry). Pretty much the same thing you call ICP-AES. Third place for me was GFAA (graphite furnace AA). You could get an adapter for an AA to convert it to GFAA. It still gave ppb resolution, but cost was between ICP and AA. Flame AA ( it can also do AE) is still popular. It is required for many methods.
The microwave methods weren't popular when I retired. Maybe they are now. As for XRF, there are two base methods, EDXRF and WDXRF. You want to go with EDXRF under most situations. WDXRF has many more regulatory requirements. More to follow...
As for difficulty:
Worst is ICP- ME
Many of the wet chemical methods can only detect heavy metals as lead. They usually detect this as the sulfide and produce a dark or black color. These often use hydrogen sulfide and can be dangerous. Other color methods are out there, though.
To give you an idea of what you are dealing with, let's look at flame AA. It takes the solution you are analyzing, mixed it with acetylene and air, and sends the mixture through a lot torch. The torch has a beam of light bedding through it from a hollow cathode lamp.
The air and acetylene is mixed before the flame, so if anything should happen to cause flashback, you get a big bang ( and other bad effects). Now imagine if you are analyzing gasoline for any lead. Sometimes the results were very nasty.
As for what method can do soil, paint, water, etc. Edxrf has a big problem with water. Water absorbs xrays. You can get around this by evaporating the water, if you want. It's advantage is in paint and dust analysis. Lead shows up well in by edxrf. I was analyzing soot dust from a natural gas heated plant and found some strange elements (radioactive ones from natural gas).
One the other hand, for most environmental work, ICP-MS , is a much better way to go. It is just much more expensive and takes extensive training.
Thanks @Ag8n - Really appreciate the time you spent typing all of this out. I'm going to try to convert your comments into the spreadsheet format, in a likely oversimplified format that gets the main points across to a less technical audience. Again: huge thanks!
This is part of: