PFAS Occurrence in North Carolina

Detlef KnappeProfessorDept. of Civil, Construction, and Environmental EngineeringNorth Carolina State Universityknappe@ncsu.edu

1NC Secretaries’ Science Advisory Board MeetingRaleigh, NC, December 7, 2020

Outline

• Brief introduction to per- and polyfluoroalkyl substances (PFASs)

• PFAS occurrence in NC drinking water sources• PFAS occurrence in blood serum of North Carolinians• Key observations

2

What are per- and polyfluoroalkyl substances (PFASs)?

• Class of synthetic chemicals that includes several thousand compounds

• Perfluoroalkyl substances: all C-H bonds replaced by C-F bonds

3

Perfluoroalkyl carboxylic acids (PFCAs) (e.g. perfluorooctanoic acid, PFOA or C8)

Perfluoroalkyl sulfonic acids (PFSAs)(e.g. perfluorooctane sulfonic acid, PFOS)

H

What are per- and polyfluoroalkyl substances (PFASs)?

• Polyfluoroalkyl substances: not all C-H bonds replaced by C-F bonds

4

Ø Perfluorooctane sulfonic acid (PFOS)

Ø 6:2 Fluorotelomersulfonic acid (6:2 FtS)

Perfluorinated(no C-H bonds)

Polyfluorinated(contains C-H bonds)

H

What are per- and polyfluoroalkyl substances (PFASs)?

• Per- and polyfluoro ether acids (“fluoroethers”) contain at least one ether oxygen atom

“GenX”PFMOAA

PMPA

PEPA

PFO2HxA PFO4DA

PFPrOPrA, HFPO-DA

Nafion by-product 2

Some common PFAS uses

Non-stick coatings

Grease- and oil- resistant coatings for paper products

Water repellent fabrics

Stain-resistant coatings for fabrics, carpets, and leather

Aqueous film forming foams

7

PFASs are known contaminants in some North Carolina drinking water sources

PFAS Sources:Ø Industrial wastewater discharges and air

emissionsFluorochemical production

Ø Municipal wastewater discharges and land application of biosolids

Landfill leachateIndustrial pretreatment

Ø Aqueous film-forming foam (AFFF)Military basesFirefighting training areasAirports

Impacts:Ø PFAS-impacted private and

public drinking water wellsØ PFAS-impacted surface waterØ Water treatment burdenØ Community concerns

Map courtesy of NC StateCenter for Geospatial Analytics(Vaclav Petras and Helena Mitasova)

Statewide sample collection

8

Raw drinking water sampled from every NC Public Drinking Water Provider for PFAS quantitation, 2 rounds

Ø 191 municipal surface water sitesØ 149 municipal ground water sitesØ 58 county water sites

Round 1 : COMPLETED

Round 2: In Progress

PFBS

APF

HxSA

PFO

SANM

eFO

SAA

NEtF

OSA

A4:

2 PF

S6:

2 PF

S8:

2 PF

S10

:2 P

FSPF

BAPF

PeA

PFHx

APF

HpA

PFOA

PFNA

PFDA

PFUn

DAPF

DoDA

PFTr

DAPF

TeDA

PFHx

DAPF

MOA

APM

PAPE

PAPF

O2H

xAPF

O3O

APF

O4D

APF

O5D

oDA

Gen

XNV

HOS

ADO

NAHy

dro−

EVE

acid

Nafio

n by−p

rodu

ct 1

Nafio

n by−p

rodu

ct 2

Nafio

n by−p

rodu

ct 4

F−53

B (M

inor

)F−

53B

(Maj

or)

PFBS

PFPe

SPF

HxS

PFHp

SPF

OS

PFNS

PFDS

PFDo

SN−

AP−F

HxSA

N−TA

mP−

FHxS

AN−

CMAm

P−6:

2FO

SA (6

:2 F

TAB)

1

2

5

10

20

50

100

200

500

Conc

entra

tion

(ng/

L)

% Detected

% ND

EPA HAL (PFOA & PFOS) = 70 ng/L

NC DHHS HAL (GenX) = 140 ng/L

Quantified PFAS Summary (n = 376)

Fluoroalkyl sulfonamides (FASAs)

Fluorotelomer Sulfonates

Perfluoroalkylcarboxylic acids (PFCAs)

Perfluoroalkylether Acids (PFEAs)

Perfluoroalkylsulfonic Acids (PFSAs)

Zwitterions

Concentration (ppt)

0 100 200 300 400

EPA PFOS+PFOA Health Advisory Level

Wat

er s

tatio

n (n

= 3

76 s

ites)

Summary of Round 1 Testing of 376 Drinking Water Supplies in NC

20 public water supplies with SPFAS > 70 ng/L

11

Comparison of Round 1 and 2: High temporal variability of PFAS levels in the Haw River at Pittsboro

Round 1 4/9/19ΣPFAS 54.3 ng/LDischarge 4,120 ft3/sPrecip. (14d) 1.66”

Round 2 9/5/19ΣPFAS 837.4 ng/LDischarge 119 ft3/sPrecip. (14d) 0.70”

Dominant PFASs in 57 private wells near Chemours

12

Median (ng/L)

GenX PEPA PFMOAAPFO2HxAPMPA

OH

OF

F

OF FF

OH

OFOFF

F

FFF

OH

OFO

F FFFFF

F

FFF

OH

OF

F

OF FOF

FF

OH

OFO

F FFF

F

FFF

GenX Exposure Study, NCSU, unpublished data

What were the PFAS levels in Wilmington drinking water?

PFMOAA

PFO2HxA

PFO3OAPFO4DA

PFO5DoA PMPA PEPA GenX Nafion by-product 2

NVHOSHydroEVEPFBA

PFPeA

PFHxA

PFHpA

PFOA

PFHxS

PFOS

S PFCAs: 120 ng/L

S PFSAs: 45 ng/L

S Fluoroethers: 130,000 ng/L

Zhang et al. (2019) ES&T Letters

July 2015 sample

PFAS occurrence in blood serum of North Carolinians

• NCSU/ECU GenX Exposure Study: Wilmington (Kotlarz et al., EHP, 2020)

• Duke University: Pittsboro

14

Wilmington, NC

15

PFHxSPFOSPFHpAPFOAPFNANafion BP2PFO4OAPFO5DoA

PFOS37%PFOA

19%

PFHxS19%NBP2

12%

PFO4DA12%

344 people living in Wilmington were recruited in November 2017

• 127 men, 216 women, 1 transgender• 289 adults, 55 children• Ages ranged from 6-86; median 50

PFNA5%

Kotlarz et al., EHP, 2020

Pittsboro, NC

16

PFAS in SerumPFHxA

PFHxS

PFHpA

PFOA

PFOS

PFNA

PFDA

PFOS:48%

PFOA:27%

PFHxS:12%

PFNA6%

49 people living in Pittsboro were recruited in November 2019

• 18 men and 31 women• Ages ranged from 33-86; median 60

Data from Heather Stapleton, Duke University

Key Observations

17

20 PFASs with highest detection frequencies and/or highest concentrations

18

Drinking Water Blood Serum

Perfluoroalkyl carboxylic acids PFBA, PFPeA, PFHxA, PFHpA, PFOA

PFHxA, PFHpA, PFOA, PFNA, PFDA

Perfluoroalkyl sulfonic acids PFBS, PFHxS, PFOS PFHxS, PFOS

Perfluoroalkyl ether carboxylic acids PFMOAA, PMPA, PEPA, GenX, PFO2HxA, PFO3OA, PFO4DA

PFO4DA, PFO5DoA, HydroEVE

Perfluoroalkyl ether sulfonic acids Nafion by-product 2

PFASs in both the drinking water and blood serum columns are important from an exposure perspective.

PFAS levels in blood serum of people living in Wilmington are higher than those of the general US population

19PFOA PFHxS PFNA PFDA PFOS

Bloo

d se

rum

con

cent

ratio

n(ng

/mL)

Kotlarz et al., EHP, 2020

NHANES (general US)

Wilmington, NC

PFAS levels in blood serum of people living in Pittsboro are higher than those of the general US population

20Data from Heather Stapleton, Duke University

Elevated PFAS levels in blood serum are likelyassociated with PFAS exposure through drinking water

21

Time (years)

Wilmington median

Seru

m P

FOA

(ng/

mL)

Predictedfor 18 ng/L PFOA in

drinking water

Data from Kotlarz et al. (2020) PFAS calculator: https://www.ics.uci.edu/~sbartell/pfascalc.html

Median fluoroether levels in blood serum of people in Wilmington decreased after levels in drinking water dropped

22

Nafion byproduct 2

PFO4DA

PFO5DoDA

Median blood serum concentration for 44 participants (ng/mL)

Nove

mbe

r 201

7

May

201

8

Kotlarz et al., EHP, 2020

23

PFASs occur as mixtures in water…

Cape Fear River: Chemours Impact PFSAs

PFOS

PFCAsPFOA

FASAs

FTSs

PFEAs

Lake Brandt:AFFF Impact PFSAs

PFOS

PFCAsPFOA

FASAs

FTSs

PFEAs

Cane Creek Reservoir:Biosolids Impact PFSAs

PFOS

PFCAsPFOA

FASAs

FTSs

PFEAs

Haw River: Industrial Wastewater Impact PFSAs

PFOS

PFCAsPFOA

FASAs

FTSs

PFEAs

… and in people

24

PFHxSPFOSPFHpAPFOAPFNANafion BP2PFO4OAPFO5DoA

PFOS37%PFOA

19%

PFHxS19%NBP2

12%

PFO4DA12%

PFNA5%

Kotlarz et al., EHP, 2020

Take-Home MessagesØ 20 PFASs are frequently detected and/or detected at high

concentrations in NC drinking water sources and/or blood serum of North Carolinians

Ø PFAS levels in blood serum of North Carolinians living in the Cape Fear River basin are substantially higher than in the general US population

Ø Drinking water is an important exposure route

Ø PFASs occur in mixtures

Ø Sources of PFAS contamination varyv Fluorochemical manufacturing (air emissions, wastewater, contaminated groundwater

discharging to surface water)v Industrially impacted municipal wastewater and biosolidsv Aqueous film-forming foam

25

Thank you for listening!

knappe@ncsu.edu

26

Acknowledgements:

Research Funding:• NIEHS (GenX Exposure Study)• NC Policy Collaboratory (PFAST)

Data Contributions:• Jane Hoppin (NCSU)• Heather Stapleton (Duke University)• Lee Ferguson (Duke University)