Testing Wood for Lead: Help Finding an Effective Method

[Andre]

Lead in the form of -for example- Tetra ethyl lead has long been used as fuel additive, ultimately causing soil pollution. There is concern that this lead ultimately settled in wood during the growing process, which may have led to unacceptable concentrations of lead in wood.

So, it would be desirable to test wood on lead contents. It appears that this is being done with hand held http://www.niton.com/Portable-XRF-Technology/how-xrf-works.aspx.

So I attempted to google for a chemical testing method of wood for lead concentrations but with underwhelming success. So my question is...help.

 

[chemisttree]

Do you want to destructively test or swipe test?

 

[Andre]

anything goes, destructive is fine, thanks.

 

[turbo]

You might enjoy reading this, Andre.

http://www.damninteresting.com/?p=932

 

[chemisttree]

You could carefully combust a weighed sample of the wood in a covered crucible using a muffle furnace set to about 400C. Remove and cool then quantitatively transfer the ash (using DI water only) into a large beaker. Add some hydrochloric acid and boil gently until only a moist residue remains. Add some nitric acid and boil gently until only a moist residue remains.
Cool and take up the moist residue into some DI water. Dilute the water to a known volume (100 mL, for example).

Test the aqueous sample using an over the counter lead test kit for testing water samples. The amounts of nitric and hydrochloric acid you use are not too important but you should have a clear solution at the end of the process.

You should treat a blank in the same way and subtract any reading you obtain from that of your sample.

Good luck with it.

 

[alxm]

I'm not entirely sure why you think wood would be an issue. Lead is a heavy metal and tends to bioaccumulate in fatty tissues. (not something wood has a lot of) Wood is also very far down the food chain, meaning low levels in general of bioaccumulated toxins. I've never heard of it anyway.

In any case, you're talking about looking for trace amounts, in which case the 'classical' method of analysis chemistree mentioned may not be usable and/or practical and/or reliable.

X-ray fluorescence, or ICP-AES would be the typical methods used in the Real World. Both are indeed pretty expensive. That's why there are lab and testing companies.