November 18, 2007

Ethidium Bromide: How bad is it really?

Posted by Eric at 12:45 am | Category: In the Lab, Personal

When I was in college, my biology friends would all mutter “ethidium bromide” in hushed tones, as if discussing the devil incarnate. It was the evil-but-necessary chemical, the mutagen that would cause dozens of cancerous masses all over your body with the slightest bit of contact. Meanwhile, I happily worked my hours away in a chemistry lab using pyrimidine, benzene, toluene, and plenty of more mutagenic stuff than that. Pansies.

But when I started working in biology, again, safety training indoctrination told me: Ethidium Bromide is hazardous stuff. Use a fume hood. Any spill must be cleaned immediately, and so on. It’s dangerous.

Well, apparently not. (via Life of a Lab Rat) Eh. Guess I shouldn’t worry so much that we heat our running buffers with EtBr already it in. I probably do worse things to my body by being lazy about sunscreen in the summer.

Follow the comments thread by the RSS 2.0 feed. You can leave a response, or trackback from your own site.

3 Responses to “Ethidium Bromide: How bad is it really?”

  1. pluto Says:
    November 18th, 2007 at 1:06 pm

    Sybr Green was only cytotoxic in one strain of Salmonella (It had no effect in the other one they tested).

    Also, when the dyes were first mixed with liver enzyme extract (to mimic what happens if you actually get it into your body), EtBr was 7-1000 times more toxic than the other dyes.

    Further, keeping cows alive a few more years longer before you send them to market is a little different than living a complete human life cancer-free.

    I use EtBr all the time and have no plans to switch to an alternative dye. I think it is fine as long as you take the necessary precautions. However it is certainly not as innocuous as you make it out to be, and promulgating misleading information about its safety only makes it more dangerous as people will not treat it with the respect it deserves.

  2. pluto Says:
    November 18th, 2007 at 1:10 pm

    Sorry, I meant to edit that last post before I posted it. Anyways, that’s the post I made to BK’s site. If you read the whole study he links to, there are 3 other figures which don’t support his argument that EtBr is harmless. EtBr is not killer-deadly, but it should definitely be treated with respect.

  3. Eric Says:
    November 18th, 2007 at 10:04 pm

    I guess I made my post sound more flippant than I meant it to. It isn’t harmless, as you said. And inevitably it is most likely mutagenic to some degree, just like many other flat, planar molecules. So of course, it gets treated like any other potentially hazardous chemical: I don’t drink it, I don’t eat where I work, I use gloves when I handle the stuff, and I don’t just spill the stuff everywhere.

    On the other hand, the little amount that gets into the air from, say, microwaving a bottle of gel-solution is unlikely to be 1) acutely toxic, 2) mutagenic over background. It’s been about thirty years since people started running gels, and famous biologists aren’t dying of horrible cancers the way early 20th-century physicists did in the 1970s and 1980s. This is just crude epidemiology (if one can call it that), but that tells me that radiation safety is far, far more important than the rampant paranoia of ethidium.

    And as for cancer…I eat chargrilled meat, I’m not all that cautious around bright sunlight, and the UV box probably will give me cancer sooner than the ethidium will.

Leave a Reply