We're so used to being at the top of the food chain, we sometimes forget... "You don't know... what you don't know"...
At the U of A, a team lead by Dr. Holt made their discovery while conducting experiments on a human enzyme that is the target for drugs to treat Parkinson's disease.Remember... it wasn't all that long ago, we were using lead pipes to transport drinking water.
The researchers were trying to inhibit the activity of the enzyme with ammonium chloride. They were surprised to find that even when they only added one part per million of the ammonium chloride, an amount that is so minute it was expected to have little effect, some mystery substance was still blocking the enzyme function.
The team initially suspected contaminants in the chemicals they were using, but eventually they determined that biologically active substances were leaking from the plastic tubes they used to transfer liquids in the experiment.