Sciencemadness Discussion Board

help! lead contamination

UncleJoe1985 - 12-4-2015 at 03:46

Crap, I just messed up big time. I was making lead acetate to make PbO2 anodes by mixing PbO and acetic acid. Except I left the hot plate on for too long, causing it to decompose into this monstrosity :o

20150412_042023.jpg - 3.5MB

The hot plate temperature was set to 450F and left on for 2 hours. I guess the solution was already saturated at the beginning with about 160g Pb(CH3COO)2.

I had no idea lead acetate would decompose and generate PbO fumes or else I would've done it outside. Now my bathroom stinks with some bitter smell (not sure how to describe it exactly). How bad do you guys think it is and how should I go about decontaminating it?

blogfast25 - 12-4-2015 at 08:13

The level of contamination is probably quite low because most lead compounds are non-volatile. But droplets carrying lead compounds may have escaped the solution/slurry and ended up on the walls etc of your bathroom. Since as we don't actually know the level of contamination I would take ZERO chances here.

At a very minimum, wearing decent marigold gloves, sponge EVERYTHING down with soapy water, dry with kitchen towel or such like, then rinse with clean water and dry again. Any carpet should be thoroughly vacuumed. Anything like towels and the stuff used for the clean up I'd dispose of to be on the safe side.

Dealing with such quantities of lead based compounds in a domestic dwelling was never a smart idea to begin with, so learn from the experience.

[Edited on 12-4-2015 by blogfast25]

macckone - 12-4-2015 at 08:45

Most of your decomposition smell is probably from the acetic acid rather than lead. As blogfast suggested wipe everything down. Most lead salts are really insoluble. The nitrates and the acetates being the exceptions. After cleaning everything you should sprinkle baking soda over everything which should convert any soluble lead salts to insoluble carbonates. You will need to either use a wet solution of baking soda or let it sit long enough for atmospheric moisture to work on it. Then vacuum up the baking soda. You should get the area where you were working tested for lead contamination after the clean up. And you are required by law to disclose such contamination to your landlord and/or future purchasers of the property if you live in the US and contamination is found.

[Edited on 12-4-2015 by macckone]

violet sin - 12-4-2015 at 13:42

I would say: sponge TSP cleaner on all surfaces, in my experience there is *always* at least a a small layer of oil/dirt on the walls of an inhabited dwelling. release of this from the wall will hopefully dilute and contain the lead if any was present, but will definitely clean a lot better than soap and water. pre/post treatment with an ozone machine would deff help the smell and possibly oxidizing the lead if any was still there as the acetate.

@ macckone: don't forget about the sulfamate salt for soluble lead compounds :)

re-rocking (drywall) the bathroom would be fairly easy if you are capable; nice small room, only take a couple days short of repainting. if you clean the walls with a partially damp sponge and try to squeeze the residue into a container for testing, it would help to know if you just clean and call it good, paint over it, or deeper remediation like stripping the walls out.

save the solution, evaporate, leach with either sulfamic/acetic/nitric acid, and try to plate out the lead with small graphite electrodes( easier to see and insoluble).

obviously none of this came from a hazmat book, or lab procedure... and isn't a strictly legal protocol. but more from actual life experience, and what I would think might be workable. I do drywall for a living, so I clean walls regularly for remodels. standard soap and water is almost useless for me in that regard. for a small bathroom 8' x 8', you are probably looking at 200$ materials, + tools if you don't own them + a lot of frustration if you are new to it. but it would be substantially more to pay some one to do it for you in most cases. ~600$ around here depending on texture style, more or less based on where you are located.

UncleJoe1985 - 12-4-2015 at 17:42


The level of contamination is probably quite low because most lead compounds are non-volatile

Whew, that's a relief. Thanks everyone for their advice.

I'll never do that again in a residential area.

I understand the benefit of converting soluble lead compounds into insoluble ones to make it harder to get absorbed into your body. But then why all the fuss over lead paint, which contains insoluble lead carbonate and chromate. Is that fear mongering?

I'll try using TSP, but it seems to be doing the same thing as soap by dissolving oil that the lead might stick to. Vaguely, saponification seems more effective since it actively dissolves the oil instead of passively dissolving it like soap?

Save the solution, evaporate, leach with either sulfamic/acetic/nitric acid, and try to plate out the lead with small graphite

I'll try that too. But I don't think leaching will work because it will dissolve the TSP too. I think you mean to leach the TSP out with water, then dissolve the remaining insoluble lead in acid? Or does it not matter if you have TSP in the electrolyte?

I'm thinking about getting a lead test kit, but it says consumer ones only have a threshold of 2000ppm, well above the safe levels for long term contact, and not anywhere near the level for drinking water (15 ppb). I'll get one anyways and test it on the waste water I collect.

violet sin - 12-4-2015 at 19:09

nah, I meant to evaporate the solution to wax, oil, dirt, TSP( sodium metasilicate), prob sodium carbonate, lead acetate(?), lead carbonate(?), lead oxides(?) and a few others like maybe titanium dioxide from the paint. but the dried cake would only have sodium and maybe lead that would leach out with the acid extraction. personally I would use sulfamic acid, but I just like the stuff and have it on hand. when filtered and reduced in volume to electroplate it out on the graphite, only lead would plate out. the sodium would just be present as a spectator for the most part, other than maybe changing the pH.

sulfamic acid works great for electroplating lead. I have a bunch of papers on it, alas that mother board on that PC recently took ill, and the hard drives are waiting for a full desktop PC transplant... I have been left with the pittance of papers and patents I had dupes of on the lap top until the other one gets back from the shop :(

but a bought test seems WAY easier and and quantifiable. where the electrolysis would be more for curiosity and a rudimentary test that would have to be conducted with incredibly small electrode surface area in order to see a coating or crystals. and you would have to save as much of the solution as poss to see anything if it is a really low concentration, if at all.

jock88 - 13-4-2015 at 12:40

Wash the place down with a soluble sulphite if you can get one. Lead Sulphite is the least soluble of lead compounds. Sulphate is probably next best.
Lead is particularly dangerous to young things (animals and children).

blogfast25 - 13-4-2015 at 13:56

Quote: Originally posted by jock88  

Wash the place down with a soluble sulphite if you can get one. Lead Sulphite is the least soluble of lead compounds. Sulphate is probably next best.
Lead is particularly dangerous to young things (animals and children).

I think you meant sulph<b>ide</b>. As in PbS (lead sulphide). Water soluble sulphides stink of H<sub>2</sub>S though.

jock88 - 14-4-2015 at 11:49

Indeed I did, sorry about that.

Are there any common uses for a soluble 'xxx' sulphide sale or a soluble 'xxx' hydrogen sulphide salt?

Where might you purchase them OTC.

What happens when you mix a solution of soluble Lead compound and sodium Sulphite (thats sulphite not sulphide)

[Edited on 14-4-2015 by jock88]

violet sin - 14-4-2015 at 17:20

liver of sulfur for aging silver and copper is a mix of pollysulfides as far as I know.

"Liver of Sulfur is a poorly defined mixture of potassium sulfide, potassium polysulfide, potassium thiosulfate, and probably potassium bisulfide."
youtube vid of making it, not in english though.

AJKOER - 5-5-2015 at 17:48

On the thermal decomposition of Lead acetate, to quote from one source (see page 5 at ):

"The products from the acetoxy radical were found to be mainly C02 and methyl acetate by vapor phase infrared spectroscopy. Ethane, if formed, must be present in small proportions."

The author also further details the different reactions in the thermal decomposition of Lead acetate.

Now, with respect to methyl acetate (MA), Wikipedia comments ( see ):

"Methyl acetate is occasionally used as a solvent, being weakly polar and lipophilic, but its close relative ethyl acetate is a more common solvent being less toxic and less soluble in water. Methyl acetate has a solubility of 25% in water at room temperature. "

and also:

"A major use of methyl acetate is as a volatile low toxicity solvent in glues, paints, and nail polish removers."

Wikipedia also notes that MA is more soluble in a strong base, so you may wish to try Washing Soda and not NaHCO3.

[Edited on 6-5-2015 by AJKOER]