The following paper discusses how to detect mercury in a sink trap.  For the record, a sink trap is this thing:

The point of a sink trap is that there isn’t a straight, or even wavy line from the sink to the sewer.  I’ve lived in an apartment where a sink didn’t have one and, trust me, it’s not good.

In the lab, things can get stuck in the sink.  Mercury is pretty heavy, so it may get stuck down there.  Worse, it is volatile, so that it forms gas and is breathed in by people in the lab, messing up brains and bodies.

By extracting the fumes using a ‘vapour spare’ the authors were able to check for mercury contamination in the sink trap using absorbance.  They used an Ohio Lumex RA-915 Light Mercury Analyzer for the purpose.

The set up looks like this:

They found the following reading of mercury:

Here’s where I part company – that’s not a correlation, that’s a dartboard.  It’d be perfectly fine to stick with the statement “The detector found mercury – time to replace the trap”.

But even more basic – why are they detecting mercury like this?  According to the paper, because people sometimes break mercury containing thermometers and wash it down the drain.  One, thermometers should not be using mercury, period.  Two, no one should be putting this stuff down the drain.  In my lab, we enforce a rule that only soap and water go down the sink.

That said, the paper offers an interesting possibility of using this method to check for other contaminants. to see if people are following the rules and regulations.