[Sojourner26]

What is the proper storage of thorium nitrate and uranyl nitrate in a chemicals store of a college? A colleague of mine who oversaw our chemicals management system stored them in our poisons cabinet where compounds of mercury and arsenic are stored as well. These two chemicals are with us I believe more than 5 years. Will the radioactivity of the thorium nitrate and uranyl nitrate have affected the mercury and arsenic compounds? And how should these 2 compounds be disposed? Thorium nitrate has an expiry of 2 years while uranyl nitrate's is indefinite. Thank u to all in advance for the clarifications.

[billnotgatez]

Are the radioactive items stored in that cabinet have special containers to block the radiation?

[Sojourner26]

There are no special containers for the radioactive compounds inside the poisons cabinet.

[Borek]

From memory, so I can be wrong - both natural uranium and thorium are only a weak alpha emitters, and as such they don't require any special shielding (glass already absorbs most of the alphas and betas).

[Sojourner26]

Thank you for the comment. However, inside this poisons cabinet, there is no compartment to segregate the thorium and uranyl nitrates, not even a glass partition. These nitrates are  are put side by side with mercury, arsenic, and cyanide compounds. Is it logical to assume that in the absence of segregation, the latter compounds inside the cabinet are contaminated?

[billnotgatez]

@Sojourner26
Are the containers for thorium and uranyl nitrates in tightly sealed glass bottles?
Are the other items in tightly sealed glass bottles?
Have you looked at the MSDS for thorium and uranyl nitrates?

[Hunter2]

I got the expierence with Thorium nitrate in our university. It was stored together with other analytical chemicals in a cabinet. The bottle are made of  PE. The result was as I measured with a Geiger counter that the board of the cabinet got radioactive where the bottle of Thorium nitate was stored.

[Borek]

Thank you for the comment. However, inside this poisons cabinet, there is no compartment to segregate the thorium and uranyl nitrates, not even a glass partition.

If they are in glass bottles, you won't need additional glass partition.

These nitrates are  are put side by side with mercury, arsenic, and cyanide compounds. Is it logical to assume that in the absence of segregation, the latter compounds inside the cabinet are contaminated?

Contaminated? As long as you treat your chemicals seriously, you should not contaminate one with another, although during normal usage some traces can be transferred between bottles, as a dust for example. That's unavoidable, unless you follow very tight procedures (which would be nonsensical in this case).

To some extent if other substances are irradiated with alpha particles from the U and Th compounds, they can have some traces of induced radiation (not sure what is the correct English term). But we are talking about radiation levels orders of magnitude lower than the original samples.

I wonder which of these two was responsible for the effect Hunter reported.

Please remember it is not radiation presence that is dangerous, it is the amount of radiation that is important. Just because we can measure the sample as being more active than the background doesn't mean much. Compare http://xkcd.com/radiation/

[billnotgatez]

I am assuming that @Hunter2 experience was due to someone at some point getting the radioactive chemical on the bottom of its container. Thus transferring a minute amount to the cabinet shelf.

[Sojourner26]

Thank you for all the comments. I've browsed through the Sigma Aldrich SDSes of the nitrates. A special respirator is needed to handle Th which we don't have. I wouldn't dare open the cabinet without this respirator & other required PPEs. That means I haven't seen the nitrates in person so I have no idea what the actual packaging is for both. I have no clue too if they have been used previously, brought to the labs, and opened. These two are declared in our stocklist as early as 2010.  They're not used in any practicals now. However, this new guy probably did the shifting to the cabinet when he got assigned to the chem store last academic year.

I guess the correct term is "irradiated", not contaminated.

I would like to suggest to my HoS to tap a radioactive processor to handle the Th and U compounds. Or maybe tap someone with expertise from a nearby university to guide us handle the matter. We can do initial inspection using a Geiger counter from our Physics unit.

Again many thanks. I'm floored by the responses. I had my first post in another forum about using the Thermo AQ 4000 colorimeter for COD analysis. I got zero responses. It's now more than a week since I made the post.