Do you know at what level PCE concentrations are of concern? Is 8,300 PPB a major problem?

Answer 1

Go to the second post. I forget to add the link here but I did there.
I googled PCE and came up with all kinds of things that PCE can stand for; i.e., from professonal organizations and none of them came close to what I assume you are asking about. I assume perchloroethylene. Here are a number of articles I found. Perhaps there will be something there that will give you some indication of the toxicity and at what levels. Or perhaps PCE stands for something different.
http://www.google.com/search?hl=en&client=firefox-a&hs=Xwx&rls=org.mozilla:en-US:official&ei=aOeOS8nIDsyttgez55y7Cw&sa=X&oi=spell&resnum=0&ct=result&cd=1&ved=0CBcQBSgA&q=perchloroethylene&spell=1

Answer 2

OK. The link shows. Take you pick from the many sites.