C A RY, N O RT H C A R O L I N A A N N U A L WAT E R Q U A L I T Y R E P O R T 2 0 2 3 14
S U M M A RY O F D E T E C T E D P FAS I N 2 0 2 3
MAXIMUM
CONTAMINANT
LEVEL (MCL)*
AVERAGE
DETECTION
RANGE
DETECTED (PPT)
Perfluorooctanoic acid (PFOA) 4 ppt 2.1 ppt ND–3.2
Perfluorooctane sulfonate (PFOS) 4 ppt ND ND
Perfluorohexanesulfonic (PFHxS) 10 ppt ND ND
Perfluorononanoic acid (PFNA) 10 ppt ND ND
Hexafluoropropylene Oxide Dimer Acid (HFPO-DA or GenX) 10 ppt ND ND
Perfluorobutanesulfonic acid (PFBS) No individual MCL 3.5 ppt 2.5–4.7
Mixture of two or more: PFHxS, PFNA, HFPO-DA, and PFBS
1.0 (unitless)
Hazard index
< 0.1 (unitless)
Hazard index
No range
Perfluorohexanoic acid (PFHxA) N/A 6.4 ppt 4.1–9.1
Perfluoropentanoic acid (PFPeA) N/A 7.3 ppt 5.3–11
Perfluoroheptanoic acid (PFHpA) N/A ND ND–2.9
Perfluorobutanoic acid (PFBA) N/A 4.3 ppt ND–10
*MCLs will become effective in 2029.
1, 4 - D I OX A N E
SUBSTANCE
(UNIT OF
MEASURE)
YEAR
SAMPLED
HEALTH
ADVISORY
AVG.
AMOUNT
DETECTED
RANGE VIOLATION
TYPICAL
SOURCE
1,4-Dioxane (ppb) 2023 35 ND ND–0.15 No
Byproduct in paint strippers,
dyes, greases, antifreeze,
aircraft deicing fluids, deodorants,
shampoos, cosmetics, manufacture
of pharmaceuticals, and
manufacture of PET plastic
