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Wrong. The EPA limit is 4 ng/L for PFOA and PFOS: https://www.epa.gov/system/files/documents/2024-04/drinking-water-utilities-and-professionals-technical-overv

Wrong. The EPA limit is 4 ng/L for PFOA and PFOS: https://www.epa.gov/system/files/documents/2024-04/drinking-water-utilities-and-professionals-technical-overview-of-pfas-npdwr.pdf https://www.epa.gov/system/files/documents/2024-04/drinking-... An off the shelf Agilent spectrometer with EPA approved methods can detect PFOA at .28 ng/L and PFOS at .78 ng/L: https://www.agilent.com/cs/library/applications/application-analysis-legacy-and-emerging-pfas-water-1290infinity-6495btriplequad-5994-0919en-agilent.pdf https://www.agilent.com/cs/library/applications/application-... This limit is not even the lowest EPA limit in drinking water. Radium is limited to ~5 picograms per liter, 1000x lower that the PFOA/PFOS limit. Dioxin is 0.03 ng/L. https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations https://www.epa.gov/ground-water-and-drinking-water/national...

mensetmanusman 2y ago
I see, their prior recommendation in 2022 was 0.004 ppt or ng/L, so they backed away from being an order of magnitude below the detection limit. Thanks for the update!
- hwillis 2y ago
  It was a health advisory in 2022, and it was revised from .004 ppt (note that you are off by an order of magnitude) to zero. Per the EPA: > Drinking water health advisories (HAs) provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. *EPA's HAs are non-enforceable and nonregulatory* and provide technical information to drinking water system operators The update was because of additional evidence of cancers. The EPA always acknowledged that .004 ppt is not reasonably detectable, but the point of an advisory is to note the level that is evidenced to be dangerous. Its a goal, and the new goal is "as good as possible". It should be obvious why the EPA should set requirements to reduce toxins while also noting what is a safe level. https://www.epa.gov/system/files/documents/2022-06/technical-factsheet-four-PFAS.pdf https://www.epa.gov/system/files/documents/2022-06/technical...

mensetmanusman 2y ago

I see, their prior recommendation in 2022 was 0.004 ppt or ng/L, so they backed away from being an order of magnitude below the detection limit. Thanks for the update!

hwillis 2y ago
It was a health advisory in 2022, and it was revised from .004 ppt (note that you are off by an order of magnitude) to zero. Per the EPA: > Drinking water health advisories (HAs) provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. *EPA's HAs are non-enforceable and nonregulatory* and provide technical information to drinking water system operators The update was because of additional evidence of cancers. The EPA always acknowledged that .004 ppt is not reasonably detectable, but the point of an advisory is to note the level that is evidenced to be dangerous. Its a goal, and the new goal is "as good as possible". It should be obvious why the EPA should set requirements to reduce toxins while also noting what is a safe level. https://www.epa.gov/system/files/documents/2022-06/technical-factsheet-four-PFAS.pdf https://www.epa.gov/system/files/documents/2022-06/technical...