On: Unsafe levels of toxic chemicals found in drinking...

[bandushrew]

"Nothing measured in parts per trillion is "saturating the environment,""

citation needed.

There are a bunch of compounds whose effects are so harmful that a few parts per million are potentially lethal.

The fact you apparently are unaware of any of them, speaks volumes.

[hueving → bandushrew]

Ppm vs ppt is 6 orders of magnitude difference. To put that in context, 6 orders of magnitude the other way would be part per part.

[CamperBob2 → bandushrew]

citation needed.

Which do you prefer, Webster's or OED?

[Qwertious → CamperBob2]

If you're not sure, just provide both of them, instead of providing neither.

[CamperBob2 → Qwertious]

Fair enough. Looks like the OED has a paywall, but Webster covers the definition adequately:

http://www.merriam-webster.com/dictionary/saturate