Why would Clark say to use a conductivity meter to test water sitting in a stainless steel pot? The light would turn on if the water was contained in a plastic bottle, or just a puddle on the ground. This is due to the fact that even "clean" water would have ions in it (ions permit electricity conduction in water). If the pot was indeed leaching metal, then you could leave it outside on a humid day, and at the end of the day, wipe your finger across it.
Ruthenium may be harmless, but one would have some trouble finding a real case of ruthenium poisoning.
I would appreciate it very much if you could refer me to some of her scientific publications.