[TherapyforGlencross]

Originally Posted by timun

Water can be treated to remove these chemicals. You can actually go look at concentrations of all sorts of chemicals in Calgary's water supplied from the Glenmore Water Treatment Plant (south Calgary, from the Elbow River) and the Bearspaw Water Treatment Plant (north Calgary, from the Bow).

Health Canada guidelines are such that 200 ng/L (0.0002 mg/L) of PFOA is acceptable, and the City doesn't even report levels below 10 ng/L. I would wager they don't report values below that because they can't measure concentrations lower than that; certainly not down to the picogram (0.001 ng, or 0.000000001 mg/L)...

Yes, when water quality parameters are that low in concentration, most labs will reduce the concentration as <0.0001 mg/L (or “insert below threshold concentration here mg/L”) on their lab reports. In essence, the concentration was too low to correctly measure.