The Trump WH looks to be trying to slow-walk or downplay the effects here, but it looks bad. The entire US water supply may be contaminated at unsafe levels with a pair of substances that causes thyroid problems, cancer risks, problems in pregnancy and reduce effectiveness of child vaccines.
If you know anyone pregnant or breastfeeding, it’s probably a smart move to recommend they move away from tap-water. The risk might be small, but it appears to be there.
Acceptable levels were previously thought to be 70 parts per trillion, the new study is suggesting that even levels below 1/6th of 70 parts per trillion is still dangerous.
As for treatment at local sources:
“The WRF found that aeration, chlorine dioxide, dissolved air flotation, coagulation, flocculation, sedimentation, granular filtration, and microfiltration were all ineffective for removing PFASs including PFOA and PFOS. Anion exchange was moderately effective in treating PFOA, highly effective for PFOS, and failed to remove several other PFASs. Nanofiltration and reverse osmosis proved to be the most effective methods of removing even the smallest PFASs. Granular activated carbon (GAC) was shown to be adept at removing most PFASs and it may be the average utility’s best bet for PFOA and PFOS contamination.”