A thought on oils - and again I will beat a dead horse about using honey
when foreign materials are used in the hive - but at least most of the
oils are things we consume in other ways -  oil and water do not mix, but
oils and oils do.  Several years ago, we tried to feed bees PCBs, the oils
in old electric transformers.  Every bee we have ever tested had a trace
of PCB.
 
Put PCB in water, it floats to the surface, same in syrup.  And the bees
seemed to be able to avoid it.  Mix it in a grease patty, went right in,
and the bees took it just like a TM patty.  Don't know wheter they eat
because they like it   or    want to get rid of it, but they got the dose.
 
Jerry Bromenshenk
The University of Montana-Missoula