Radioligand binding - safety concerns ?

[Eypeka]

Hi everybody :D (try no.3 to post this, huh, so I'll be short)!
It was great reading your discussions, now I have one question for you, I hope you can help me.

I started working in a lab that uses radioligand binding assays routinely.
We use tritium labeled steroid hormones. I know that tritium is weak source of radiation (electrons, let's forget anti neutrino here ;)).

Thing that happens sometimes (usually during disposal) is that I can feel the odor of scintillating fluid in the air. Radiolabeled hormones are dissolved in that fluid.
Inhaling tritium is unsafe if my knowledge is good.

But I was told that everything is safe because steroids do not evaporate from solution, only solvent evaporates. It makes sense, but I'm still concerned about it, I'm thinking that there is a chance that some (possibly very small quantity) of steroid hormones can evaporate from solution. And I do not like the notion of inhaling them even if it's few radiolabeled molecules (and that's 2-3 times monthly).

I hope that some of you are familiar with this method and it's safety procedures, so you can give me some advice about this. Thanks !

 

[Andy Resnick]

The main issue here is one of general lab safety, and it appears that your lab is in gross violation. One problem is the tritium, but the other is handling and disposal of the relevant chemicals.

We haven't used tritium in quite some time, but during a move someone discovered a 'hot' spill (which somehow turned out to be tritium), requiring decontamination of the affected room.

If I were you, I would notify the safety office- not to place blame, but to ensure everyone is working in a safe environment.

 

[Moonbear]

I have a LOT of experience with tritium hormone assays. There is NO reason you should be smelling scintillation fluid during disposal, because you should NEVER be opening the scintillation vials after you have filled them (and this should be done in a hood). Every institution I've worked at has required scintillation vials to be disposed of still closed with the fluid in them.

However, your risk of exposure from the tritium itself is minimal. The actual amount used in the assays is very small. You still should practice as much safety precaution as possible, but it's not something to freak out about. Work in a hood, wear gloves, eye protection and a lab coat, and you will be fine (with tritium, technically, you don't even have to work in a hood). Tritium is a beta-emitter, and won't penetrate skin, but you still should wear all the proper protective gear anyway.

The biggest concern would be the scintillation fluid itself. Depending on which cocktail you're using, the scintillation fluid can be more hazardous than the tritium.

However, any time that you're in doubt with regard to radiation safety, contact your radiation safety officer. They are MORE than happy to check if everything is within safe limits and being done within regulation and if there's anything you can do to work more safely with those materials.

 

[Cincinnatus]

Every institution I've worked at has required scintillation vials to be disposed of still closed with the fluid in them.

I can corroborate Moonbear's post. I've also done radioligand binding experiments. We never opened the scintillation vials after initially filling them and disposed of them still closed. I don't think I recall ever smelling scintillation fluid.

 

[Eypeka]

Thank you all for your replies.

Just to clarify some things [I wrote my first post in hurry], we don't open scintillation vials after the reading, they are disposed closed.
There's another lab using the same method, and we dispose vials in the same room. As a newbie I had to dispose all the waste [mainly scintillation vials] form that room. There were a large number of vials in bags, I think that those on bottom opened up under the pressure, nevertheless I've could feel strong acrid odor of scintillation fluid. It was scintillation cocktail used by that other lab (highly hazardous, Moonbear's point), cocktail we use is almost odorless (and much less toxic).

Primarily I was worried about possibility of inhaling tritium, and forgot all about hazards of scintillation fluid itself. But they convinced me that it was rare mishap.

When we're preparing samples for binding, we keep samples on ice, but we do not work under the hood.
I stopped freaking ;), but I;m still thinking about rate of evaporation of steroids :).

Well, thank you again for advices.

 

[Moonbear]

Even if it is an accident that the vials are opening, that is a safety hazard. Contact your radiation safety department, or even the chemical safety department, and notify them there is a potential hazard. It's much better to report things like that when you notice them and let them dispose of it promptly, as well as insure that any spilled fluid isn't leaking past the primary containment (there should be secondary containment, but you shouldn't be relying on that once spilling is noticed).

As for the steroids themselves, no worries. Those aren't particularly volatile. Steroids themselves are more of a contact hazard. The only time they are an inhalation hazard is if you're working with them in the powdered form.