DEQ-CFW_00083941

W,flTED SIATE',S E--INWRONNHINTAL
July *13, 2017
MEMORANDUM
SUBJECT: Laboratory Results for GenX (Rounds I-3)NC DEQ Cape Fear Watershed
Sampling
FROM: Timothy J. Buckley- Dire c6./N
Exposure Methods and UpAurements Division
THRU: Jennifer Orme-Zavaleta, Director
TO: Linda Culpepper, Deputy Director
Division of Water Resources
North Carolina Department of Environmental Quality
Per your request of June 9, 2017, 1 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
f'or 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.
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 &Tcchuolo,-4Y Letters. 2016
,=Strynar M, Dagnino S, McMahen R, Liang S, Lindstrom A, Andersen E, McMillan L, Thurman M, Ferrer 1, Ball C. identification of Novel
Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs) in Natural Waters Using Accurate Mass Ti nle-of- Fl i.-ht Mas;
Spectrometry (TOFMS). Environ Sci Technol. 2015
DEQ-CFW-00083941

July 13, 2017
The following provides a brief summary of results.
* GenX was observed above our detection limit of 10 ng/f. in all but one sample.
* GenX concentrations ranged from 4 rig/l, (DWR 3 PO Hoffer WTP Raw Water) to
21,759 ng/l, (DWR #I-Chemours Outfall).
* Some samples exceeded our calibration curve (particularly week I where this was the
ease 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:
• GenX was not detected in either of the two field blanks (round 2 & 3)
• Spiked field samples (n=4; round 2 & 3) were measured with an accuracy that
ranged 1rom 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 M". I look forward to our continued work together.
.. . ............... ­�I,.,,-----
Attachment
CC: Becky B, Allenbach,Acting Deputy Director
Water Protection Division, EPA Region 4 — Atlanta
DEQ-CFW-00083942

July 13, 2017
Conc.
Flag
Week
Location / Sample Identifier
(n /L)
1
DWR #1- Chemours Outfall
21,760
1
1
DWR #2 - Bladen Bluffs Raw Water intake
501
2
1
NC DEQ #I- LCFWSA
629
2
1
NC DEQ #2 - CFPUA Sweeny
726
2
1
NC DEQ #3 - CFPUA ASR well
588
2
1
NC DELI #5 - International Paper Raw
703
2
1
NC DEQ #6 - International Paper Finished
523
2
1
NC DEQ #7 - NW Brunswick WTP finished
695
2
1
NC DEQ #8 - Pender County 421 WTP Finished
269
2
1
NC DEQ #4 - Wrightville Beach Well 11
27
2
DWR #1 Chemours Qutfall 002
15,250
1
2
DWR #2 Bladen Bluffs Raw Water
31
2
NCDEQ 1 LCFWSA Raw water
72
2
NCDEQ 2 Sweeny Finished
100
2
NCDEQ 3 ASR well
336
3
2
NCDEQ 4 Wrightsville Reach Well #11
28
2
NCDEQ 5 International Paper Raw water
41
2
NCDEQ 6 International Paper Finished water
111
2
NCDEQ 7 NW Brunswick WTP Finished
52
2
NCDEQ 8 Pender WTP Finished
112
3
DWR 1 Chemours Qutfall 002
21,530
1
3
DWR 2 Bladen Bluffs Raw water
168
3
DWR 3 PO Hoffer WTP Raw Water
4
4
3
NCDEQ 1 LCFWSA Raw
119
3
NCDEQ 2 Sweeny Finished
87
3
NCDEQ 3 ASR Well
148
3
NCDEQ 4 Wrightsville Beach Well #11
24
3
NCDEQ 5 International Paper Raw
158
3
NCDEQ 5 International Paper Raw DUPLICATE
162
3
NCDEQ 6 International Paper Finished
80
3
NCDEQ 7 NW Brunswick WTP Finished
125
3
NCDEQ 8 Pender CO 421 WTP Finished
68
Flag
1
Sample diluted 20X; diluted sample still exceeded
calibration
2
Sample diluted 5X
3
Sample diluted 2X
4
Below limit of quantitation
DEQ-CFW 00083943