I accomplished a number of small tasks this weekend – working on a plate polishing holder, charging up an iodine box – but the little exercise I thought I would post on was the test I did for mercury fumes. I wanted to test the new Mercury Indicator Powder I got from Lab Safety Supply. A while ago a dear friend gave me some mercury in support of my dagurreian passion. It was an item he had picked up out of curiosity many years ago as a young man and had carted around with him from place to place. I don’t know how he had it stored when he had it, but it came to me in a polyethylene eye wash bottle sealed inside a gasketed Army surplus ammo can. I was curious to discover if polyethylene is mercury vapor proof.
I put some of the indicator powder in a plastic jar lid and closed it in the ammo can. For a control I put a second measure of the indicator it in a duplicate jar lid and left it in the fume hood. The test setup was carried out with the fume hood running, and with me gloved and wearing a full face gas mask with appropriate cartridge. Well to cut to the chase – the indicator powder passed and the polyethylene likely failed. The powder turns brown when exposed to mercury fumes. Although I can’t absolutely rule out mercury contamination inside the ammo can, there are no visible mercury droplets of any size to be seen. Whatever. The reality is that the ammo can has mercury vapor in it and the point is brought home to me (again) that you have to be darn careful with poisons you can’t see. I already knew that a lot of plastics are permeable to varying degrees, but I think many people would have looked at this setup as a safe way to store mercury. It’s not. Here are a few pictures.
I would encourage anyone looking to use the process to try some of this indicator powder. It is cheaper than many of the more sophisticated ways to detect Hg vapor, and it has a long shelf life. It is possible to make it yourself, but the chemicals involved are fairly expensive bought in small quantity from a retail supplier. It is cheaper to buy from LSS unless you feel like making a very large quantity.
In any case – for now the ammo can is hanging out doors in a closed bucket. I will be ordering a proper bottle – the kind that comes packed in a can with a vermiculite filling. I would also welcome other storage ideas from the more experienced.
Be careful out there.