NC PFAST Quantitative Screening Results for Raw Drinking Water


Disclaimer: The PFAS measurements reported here represent initial laboratory findings that have not been subjected to full validation and quality assurance/quality control procedures and should be considered preliminary.

As part of the North Carolina Per and Polyfuoroalkyl Substances Testing (PFAST) Network statewide sampling effort (, a raw water sample collected from INTERNATIONAL PAPER COMPANY (NC0424820) on 2019-05-29 by the Ferguson Lab was analyzed for 15 PFAS chemicals by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Concentrations of individual PFAS are reported in units of parts-per-trillion (ppt, i.e., nanogram of chemical per liter water).

PFAS compounds are not currently regulated as drinking water contaminants by the United States Environmental Protection Agency (US EPA) or the North Carolina Department of Environmental Quality (NC DEQ) and thus the measurements reported here are not intended to be used in enforcement actions. The US EPA has established a lifetime health advisory level (HAL) of 70 ppt for combined perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in drinking water. In addition, the NC DHHS has established a provisional health goal based on risk assessment for GenX in drinking water of 140 ppt. These advisory levels can serve as reference values when evaluating PFAS concentrations reported below for raw drinking water.

Reporting Limit (RL): This is the lowest concentration that can be confidently quantified in water samples for an individual PFAS chemical. This level is a function of instrument sensitivity, reproducibility, and precision. The RL typically (but not always) represents the lowest concentration point on the calibration curve, and it is always higher (often much higher) than the method detection limit (MDL) for a given PFAS analyte.

Sum of PFOS and PFOA

PFOA and PFOS were both below their respective reporting limits.


The concentration of GenX was 14.9 ppt. This represents 10.6% of the NC DHHS health goal for GenX.

Total PFAS

The total PFAS concentration was 72 ppt.

Summary of findings

Figure 1: Concentrations of individual PFAS compounds.

Table 1 Concentrations of PFAS compounds detected in parts-per-trillion (ppt). Gray values indicate compounds below the reporting limit (RL). Bold rows indicate occurence in excess of the EPA Health Advisory Limit (HAL) for PFOS + PFOA of 70 ppt.

Analyte Name Abbreviation CAS Registry Number Concentration (ppt) RL (ppt)
Perfluoroalkylether Acids (PFEAs)
Perfluoro-2-methoxyacetic acid PFMOAA 674-13-5 <RL 5
Perfluoro-2-methoxypropanoic acid PMPA 377-73-1 18.9 1
Perfluoro(3,5-dioxahexanoic) acid PFO2HxA 39492-88-1 26.7 1
Perfluoro-2-ethoxypropanoic acid PEPA 267239-61-2 5.8 1
1,1,2,2-tetrafluoro-2-(1,2,2,2-tetrafluoro-ethoxy)ethane sulfonic acid NVHOS N/A 3.7 1
Perfluoro(3,5,7-trioxaoctanoic) acid PFO3OA 39492-89-2 <RL 1
Perfluoro-2-propoxypropanoic acid GenX 13252-13-6 14.9 1
Perfluoro(3,5,7,9-tetraoxadecanoic) acid PFO4DA 39492-90-5 <RL 1
Dodecafluoro-3H-4,8-dioxanonanoic acid ADONA 958445-44-8 <RL 1
Propanoic acid, 3-[1-[difluoro(1,2,2,2-tetrafluoroethoxy)methyl-1,2,2,2-tetrafluoroethoxy]-2,2,3,3-tetrafluoro- Hydro-EVE acid 773804-62-9 <RL 1
Ethanesulfonic acid, 2-[1-[difluoro[(1,2,2-trifluoroethenyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2-tetrafluoro- Nafion by-product 1 29311-67-9 <RL 1
Perfluoro(3,5,7,9,11-pentaoxadodecanoic) acid PFO5DoDA 39492-91-6 <RL 2
Ethanesulfonic acid, 2-[1-[difluoro(1,2,2,2-tetrafluoroethoxy)methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2-tetrafluoro- Nafion by-product 2 749836-20-2 2 1
9-chlorohexadecafluoro-3-oxanonane-1-sulfonate F-53B (Major) 73606-19-6 <RL 1
11-chloroeicosafluoro-3-oxanonane-1-sulfonate F-53B (Minor) 83329-89-9 <RL 1