DEQ-CFW_00074236

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
NATIONAL EXPOSURE RESEARCH LABORATORY
RESEARCH TRIANGLE PARK, NC 27711
July 13, 2017
OFFICE OF
RESEARCHAND DEVELOPMENT
MEMORANDUM
SUBJECT: Laboratory Results for GenX (Rounds 1-3) NC DEQ Cape Fear Watershed
Sampling
FROM: Timothy J. Buckley, Diesurements
Exposure Methods and Division
THRU: Jennifer Orme-Zavaleta, Director l�!/
TO: Linda Culpepper, Deputy Director
Division of Water Resources
North Carolina Department of Environmental Quality
Per your request of June 9, 2017, I am pleased to provide you with the laboratory analysis
results for the concentration of GenX in water samples collected by NC DEQ. These results are
for the first three weeks of sampling. Samples were received by our laboratory on June 23rd,
June 30th, and July 7th for each of these three rounds of weekly sampling. It is our
understanding that we will be receiving and analyzing samples from additional rounds of
sampling. Results from these additional sampling rounds will be reported separately as they
become available. We will also report semi -quantitative concentrations of additional PFAS
analytes in a later report.
Each round of sampling consisted of a number of sites selected by NC DEQ that included
a variety of water types: effluent, source, drinking, and well waters. Sampling rounds 2 and 3
also included field blanks and spikes that were provided by our laboratory for quality control
purposes. It is our understanding that duplicate samples were collected at each site. One of the
duplicates was provided to our laboratory with the second sample being provided to a contract
laboratory, Test America (Denver, Colorado), for GenX analysis. In rounds 2 and 3, Test
America was also provided with field blanks and spikes that were prepared by our laboratory
(round 2) and by an independent lab within EPA (round 3). Results from these QC samples will
provide the basis for comparing our results with Test America. Our laboratory methods for this
analysis are described in Sun et al., 20161 and Strynar et al., 20152.
1 Sun M; Arevalo E; Strynar M; Lindstrom A; Richardson M; Kearns B; Pickett A; Smith C; Knappe DRU: Legacy and Emerging
Perfluoroalkyl Substances Are Important Drinking Water Contaminants in the Cape Fear River Watershed of North Carolina, Environmental
Science & Technology Letters. 2016
ZStrynar M, Dagnino S, McMahen R, Liang S, Lindstrom A, Andersen E, McMillan L, Thurman M, Ferrer I, Ball C. Identification of Novel
Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs) in Natural Waters Using Accurate Mass Time -of -Flight Mass
Spectrometry (TOFMS). Environ Sci Technol. 2015
DEQ-CFW 00074236

July 13, 2017
The following provides a brief summary of results.
• GenX was observed above our detection limit of 10 ng/L in all but one sample.
• GenX concentrations ranged from 4 ng/L (DWR 3 PO Hoffer WTP Raw Water) to
21,759 ng/L (DWR #1-Chemours Outfall).
• Some samples exceeded our calibration curve (particularly week 1 where this was the
case for all but one sample). These samples were diluted and the analysis was repeated.
The dilution procedure introduces some additional uncertainty in our quantification. We
have flagged results for samples that required dilution.
• Quality control samples (included in rounds 2 & 3 only) indicated no field or laboratory
contamination and results accurate with about 5% of the expected values. Specifically,
QC samples showed:
o GenX was not detected in either of the two field blanks (round 2 & 3)
o Spiked field samples (n=4; round 2 & 3) were measured with an accuracy that
ranged from 96.7 to 106 percent.
Hence, we have high confidence in the concentration results reported here.
Thank you for inviting us to be a part of this effort that addresses a very important public
health concern in North Carolina. These results represent the effort of many within our lab but I
would especially like to acknowledge Dr. Mark Strynar and his laboratory conducting the
analysis, his Branch Chief, Dr. Myriam Medina -Vera who provided invaluable support and
coordination, and Ms. Sania Tong Argao who supported and oversaw quality assurance.
If you have any questions or concerns, do not hesitate to contact me at [phone] or
email buckley.timothanepa.gov. I look forward to our continued work together.
Attachment
CC: Becky B. Allenbach, Acting Deputy Director
Water Protection Division, EPA Region 4 — Atlanta
DEQ-CFW 00074237

July 13, 2017
Week
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
3
3
Flag
Concentration of GenX Measured in Cape Fear Watershed Samples
Conc.
Flag
Location / Sample Identifier
(ng/L)
DWR #1- Chemours Outfall
21,760
1
DWR #2 - Bladen Bluffs Raw water intake
501
2
NC DEQ#1- LCFWSA
629
2
NC DEQ #2 - CFPUA Sweeny
726
2
NC DEQ #3 - CFPUA ASR well
588
2
NC DEQ #5 - International Paper Raw
703
2
NC DEQ#6 - International Paper Finished
523
2
NC DEQ #7 - NW Brunswick WTP finished
695
2
NC DEQ #8 - Pender County 421 WTP Finished
269
2
NC DEQ #4 - Wrightville Beach Well 11
27
DWR #1 Chemours Outfall 002
15,250
1
DWR #2 Bladen Bluffs Raw water
31
NCDEQ 1 LCFWSA Raw water
72
NCDEQ 2 Sweeny Finished
100
NCDEQ 3 ASR well
336
3
NCDEQ4 Wrightsville Beach Well #11
28
NCDEQ 5 International Paper Raw water
41
NCDEQ 6 International Paper Finished water
111
NCDEQ 7 NW Brunswick WTP Finished
52
NCDEQ 8 Pender WTP Finished
112
DWR 1 Chemours Outfall 002
21,530
1
DWR 2 Bladen Bluffs Raw water
168
DWR 3 PO Hoffer WTP Raw Water
4
4
NCDEQ 1 LCFWSA Raw
119
NCDEQ 2 Sweeny Finished
87
NCDEQ 3 ASR Well
148
NCDEQ 4 Wrightsville Beach Well #11
24
NCDEQ 5 International Paper Raw
158
NCDEQ 5 International Paper Raw DUPLICATE
162
NCDEQ 6 International Paper Finished
80
NCDEQ 7 NW Brunswick WTP Finished
125
NCDEQ 8 Pender CO 421 WTP Finished
68
1 Sample diluted 20X; diluted sample still exceeded calibration
2 Sample diluted 5X
3 Sample diluted 2X
4 Below limit of quantitation
DEQ-CFW 00074238