How dangerous is EtBr? - (Oct/01/2009 )

I recently added some EtBr powder to the EtBr solution to increase its concentration. I had on plastic gloves on top of latex gloves, so I suppose none of it got onto my hands. But I didn't put on the face mask, so I'm wondering if I could've inhaled some of those powder. How will I know if I did? I feel normal though so far...will there be any visible side effects? I'm pretty worried because of how serious people make EtBr sound. But in actual fact, how dangerous is it?

Thanks for reading this and your comments.

autumnhush on Oct 2 2009, 01:45 PM said:

http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do

Above is a link to the MSDS (medical safety data sheets) for Ethidium bromide. If you are feeling fine then probably it is ok- Ethidium bromide powder is an irritant. It is classed as highly toxic and has been shown to be a mutagen and tetragen so its important to follow the safety advice. As a liquid its doesn't penetrate seem to penetrate too far into the skin (or remain- due to the epidermal turnover). I can not comment on inhalation and absorbence of it into the mucosal epithelia. Were you working with this outside of the fume hood or in an enclosed space? these factors will change the risk....
Personally I've never used the powdered form- we ordered pre-made solutions so I can't comment thoroughly on the risk with powdered forms.

LostintheLab on Oct 2 2009, 03:59 PM said:

No, I wasn't working in a fume hood or enclosed place. The EtBr solution was in a container with a lid, so I opened the lid slightly, scooped a bit of the EtBr powder and dropped it into the solution. Some of it dropped onto the benchtop though but I wiped it off quickly with 70% ethanol. Thanks for the site, I'll look it up.

autumnhush on Oct 1 2009, 08:45 PM said:

The answer is not very. The LD50 of EtBr is about 1503 mg/kg for rat (oral). So you can imagine how much EtBr is required to do harm to a 50 kg researcher. Furthermore the EtBr molecule is rather large and has difficulties crossing the skin. And historically EtBr (aka hofnium) was used (For a brief period) to treat human infections of trypanosomiasis and is still used in africa to treat animals for the same. The risk of EtBr is over inflated.

All the same, you should have been working in a fumehood. While EtBr may not do you much harm, other chemicals such as SDS powder and antibiotic powder (via sensitization) can.

perneseblue on Oct 2 2009, 05:28 PM said:

Phew! It's a relief to know that, thanks! Yeah, I should've worked in a fumehood. From now on, I'd stick to the liquid EtBr.

also, look at this thread.

Anyway I'd be careful with EtBr, both as fluid and powder (that I never would use, if there's no absolute need for it). Cattle (and other animals that might got it or was used as test animal) have to some degree different metabolisms and most important, live (compared to us) very short. But a scientist might have an exposure time of 20-40 years depended when you started and how long you work in the lab. About this long-term chronic effects no data are available (and I guess will never be).
As PhD or postdoc it might be negligible as one works with this stuff for some years, and then have an office job, but a technician perhaps really works the 20-40 years with it...so I'd try to minimise the contact as far as possible.

I heared previously EtBr were used as a drug for parasitical worms treatment So it is not so dangerous as it considered to be.

gleb.kudr on Oct 3 2009, 12:56 PM said:

But there might be a difference between chronic and acute toxicity...a reason not to underrate EtBr. Better be careful today, than to suffer later. Even if you can not diagnose the ultimate cause for the disease later.
Better safe than sorry...

hobglobin on Oct 4 2009, 12:23 AM said:

But surely, by now, there will be workers from the 70's and 80's who have had very prolonged exposures (or would they have all been promoted out of the lab?). Perhaps someone should do an epidemiology study on molecular biologists and cancers that may be lab-induced...