DEQ-CFW_00075091

t I -
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Hazardous Waste Section
File Room Document Transmittal Sheet
17
Larry Stanley
N C D 0 4 7 3 6 8 6 4 2
DuPont Fayetteville
Corrective Action (CA)
RCRA Facility Investigation (RFI)
Phase III RFI - Request for supplemental information (recent releases)
11/18/2011
DuPont-CRG
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NCD047368642
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DEQ-CFW 00075091

DuPont Engincering
6324 Fairview Road
Charlotte, NC 28210
Tel. [phone]
Fax [phone]
aUP .
DuPont Engineering
November 18, 2011
Mr. Larry Stanley
NCDENR
Hazardous Waste Section
Division of Waste Management
1646 Mail Service Center
Raleigh, NC 27699-1646
Re: Revised Phase III RCRA Facility Investigation Work Plan
Request for Supplemental Information
DuPont Fayetteville Works
Fayetteville, North Carolina
EPA ID No. NCD 047 368 642
Dear Mr. Stanley:
In a letter dated October 5, 2011, the NC Hazardous Waste Section (HWS) recommended that
supplemental information be added to the Phase III RCRA Facility Investigation (Phase III
RFI) Work Plan (Rev. 1), which was submitted to SCDHEC on April 5, 2011. The
supplemental information was requested to address three potential releases to the environment
since March 2011, about which DuPont Fayetteville Works (Site) has submitted notifications to
the HWS. Information in the notifications and, in some cases, subsequent geochemical data
suggested that impacts resulting from the releases did not require immediate actions.
The HWS has asked that the risks posed by these incidents, as evaluated by DuPont's CRG's
"Risk -Based Prioritization System," be further discussed in the work plan, and corrective action
activities designed to further investigate or remediate impacts resulting from the releases, if
any, be presented in the plan. The DuPont CRG project team has reviewed the available data
for the three releases reported at the facility and has evaluated the potential risks associated
with these releases in accordance with the Risk -Based Prioritization System described in the
Phase III RFI Work Plan. The SWMU Prioritization Worksheets for the affected areas have
been reviewed and updated to include the newly -reported releases (see attached with changes
highlighted). A summary of the review is presented below.
Risk -Based Prioritization System Review
The releases from the compromised process wastewater trench and from the failed underground
process wastewater pipe are included in SWMU 6 (the Process Sewer System and Common
Sump). Soil data collected after the releases confirm that there are no unacceptable risks to
DEQ-CFW 00075092

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Page 2 of 2
November 18, 2011
human health or the environment because the soil results are all either below method detection
limits or below applicable soil screening levels (Table 1). While no additional investigation of
this SWMU has been proposed as part of the Phase III RFI or as a result of the additional
releases, the unit will be included in the site -wide groundwater monitoring investigation (as
part of AOC GW), which will monitor potential impacts of site operations on the shallow
groundwater at the site.
The area where the new release of perfluorooctanoic acid (PFOA) to the ground from the
Polymer Processing Aid (PPA) Manufacturing Building's stack occurred is already included in
the proposed Phase III RFI as part of the investigation of SWMU 7. The monitoring wells in
the vicinity of the new release (SMW-05 and SMW-05P) have had previous detections of
PFOA, and further investigation of the area (and of the area downwind) was proposed in the
work plan. Because additional data is needed to determine the extent of impact of PFOA (from
the historical and the new release) on shallow groundwater, the Phase III RFI activities will
include an investigation to determine the perimeter of the clay layer underneath the PPA
manufacturing area and further investigation of groundwater quality to the west and northeast
of the PPA area. These activities will adequately address any concerns in the area because the
2011 release is in the same area as the previously reported release and because no new
constituents were identified in the new release.
Based on this review, impacts from the three releases do not change the conclusions presented
in the revised Phase III RFI Work Plan nor do the releases require additional investigation at
this time. As such, no updates to the work plan are necessary, and no additional corrective
action activities designed to further investigate or remediate impacts resulting from the releases
will be required.
DuPont looks forward to working with you through the completion of the RFI. If you have any
questions or need additional information please feel free to contact me at 704-362-6626.
Sincerely,
X/ , ff
Jamie VanBuskirk
Project Director
DuPont Corporate Remediation Group
cc: Mike Johnson — DuPont Fayetteville Works
File
Enclosures
DEQ-CFW 00075093

DUPONT — FAYETTEVILLE WORKS - SWMU PRIORITIZATION WORKSHEET
SWMU 6 _ Process Sewer System (and Common Sump)
Description: This unit is a system of underground sewer pipes, manholes, and sumps that convey process
wastewater from the main plant areas to the site's wastewater treatment plant system. Plant personnel and
site sewer maps indicate that the pipes are constructed of vitrified clay or steel. There are five process sewer
sumps throughout the plant and all are in -ground and constructed of reinforced concrete. These include the
following: 1 %Butacite® sump; 2. PVA sump; 3. Nafion® Vinyl Ethers North sump; 4. Semiworks sump; 5.
Nafion® Common Sump. All sumps are concrete -lined, and the Nafion® Common Sump is also polylined.
The Nafion® Common Sump was removed from process wastewater service in 2001; the other sumps are all
still active. The former Common Sump received waste from the Nafion® process, which included process
wastewater, cooling water, and steam condensate from the various manufacturing units.
Low. Organic constituents were detected in soils during the CS and Phase I RFI above MDL values but the
total concentration of the constituents is less than 1 % by weight.
':1�•J.ea.-..Cs
Low.-
h k^
Low. Organic constituents were detected in soils during the CS and Phas..e I RFI above MDL values, but
were below EPA Regional Screening Levels (RSLs) industrial soil concentrations. Detected constituents are
located in subsurface soils (more than 2 feet below grade) where exposure via this pathway is not expected.
Although volatile organic compounds have been detected in groundwater, a preliminary evaluation of the air
pathway resulted in a low potential for exposure.
yr
Low. Organic and inorganic constituents were detected in soils during the CS, Phase I RFI and supplemental
soil sampling in 2011- above MDL values, but below RSL industrial soil concentrations. The 2011
supplemental sampling was conducted to determine the potential for releases associated. with a
compromised wastewater trench near the Butacite® Flake Manufacturing Building. Most of the detected
constituents are located in subsurface soils (more than 2 feet below grade) where exposure potential is low
and institutional and operational controls exist to prevent excavation without taking proper measures and to
minimize the potential for exposures via this pathway.
Low. Methylene chloride, benzo(a)pyrene and iron were detected in soils slightly above NC Csoil
concentrations (soil concentrations protective of groundwater). Several constituents were detected in the
groundwater at levels above the DENR 2L groundwater quality standards. Groundwater flow is expected to
be towards the Cape Fear River therefore, there are no potable sources for down gradient groundwater use.
The presence of the underlying clay layer reduces the potential for vertical groundwater migration.
Low. This unit is designed to operate with a freeboard and as such would not overflowtoa surface water
body. A wet weather channel is present approximately 400 feet to the northeast of the unit. Sample results
from surface water drainages were below NC 2B concentrations, and the unit is overlain by a thick cover of
soil and ties on relatively flat ground that does not promote runoff, leading to no exposure via this pathway.
�. ...-._. .._-. _...__::r. ..--_,:.Ss.�✓`�. .-r�x>�... �. {m .�._�-..mob:
No Further Investigation/Corrective Measures Needed
Repairs to the Common Sump were made, and it has since been taken out of service. The unit will be
included in the site wide groundwater monitoring program (AOC GW) to monitor potential impacts to the
shallow groundwater.
Phase III Activities:
1) Confirm unit location with GPS.
2) Long-term monitoring as part of AOC GW.
November 2011
DEQ-CFW 00075094

" M J
DUPONT — FAYETTEVILLE WORKS - SWMU PRIORITIZATION WORKSHEET
SWMU 7 — Storm Sewer System
Description: This unit collects stormwater through a system of sumps, drains and ditches located
throughout the plant which are routed to the Cape Fear River. The stormwater collection system is designed
to handle a combined rate of approximately 13,900 gallons per minute (gpm). Rainfall accumulated in
bermed chemical containment areas and other engineered spill containment structures are routed through
the process sewer system after the waters have been tested and approved for such discharge. During
construction of the APFO manufacturing facility, a temporary rain water retention basin and associated
drainage channel were constructed. The basin operating by allowing collected rain water to infiltrate and
evaporate. The storm sewer system became operational in 1972 when the plant was started -up. It is still in
use; however, the stormwater retention basin associated with the APFO manufacturing area was closed in
2007.
�-+.:
Low. Engineering control devices are in place to prevent the mixture and/or% contact with plant process
constituents.
x �.
Low. Engineering control devices are in place to prevent the mixture and/or contact with plant process
constituents. �+
61
Low. Engineering control devices are in place to prevent the mixture and/or contact with rplant process
constituents. Evidence of a release was identified in the vicinity of the former rain water retention basin north
of the APFO manufacturing facility and a .second, similar release occurred on June 23, 20.11 from the PPA
stack in this same area. APFO has been identified in shallow groundwater as a result of air deposition in the
immediate. vicinity of the APFO manufacturing area being carried via runoff and infiltrating into the
subsurface. Potential for exposure to APFO via direct contact with surface soils is considered to be low.
Insufficient Data. Evidence of a release was identified in the vicinity of the former rain water retention basin
north of the APFO manufacturing facility and a second, similar release occurred on June 23, 2011 from the
PPA stack. APFO has been identified in shallow groundwater as a result of air deposition in the immediate
vicinity of the APFO manufacturing area being carried via runoff and infiltrating into the subsurface. Extent of
the shallow groundwater contamination has not been determined.
44
Insufficient Data. Evidence of a release was identified in the vicinity of the former rain water retention basin
north of the APFO manufacturing facility and a second, similar release occurred on June 23, 2011 from the
PPA stack. APFO has been identified in shallow groundwater as a result of air deposition in the immediate
vicinity of the APFO manufacturing area being carried via runoff and infiltrating into the subsurface. The
groundwater quality near Willis Creek has not been determined.
Insufficient Data.
Need additional data to determine extent of impacts of APFO on shallow groundwater and near Willis Creek.
Phase III Activities:
1) Confirm location/boundaries of the unit using GPS.
2) Determine the perimeter of the clay layer underneath the APFO manufacturing area.
3) Further investigate groundwater quality to the west and northeast of the area.
November 2011
DEQ-CFW 00075095

Table 1. Summary of Soil Analytical Results
DuPont Fayetteville Works
Fayetteville, North Carolina
CAS No.
Analjt_i:::4
Iii
Industrial
Health -Based
O.s-R—G .-Water
re Sceningi
Cril . te Criteria
Protection
of Ground
PSRG
Screening
Criteria
Location
Top (ft)
BUT-Soiil
—BUT-Soil-WW-2
3/25/11
11
Bottom (ft)
Duplicate
7439:92-1 Lead MG r1(3 800 270. MG KG
7440-39-3 Barium MG/KG 3800 580INd/KG
_�4_4047-T MG/KG 36000l -Wdlkd
74 9-97-6 . Mercury MG/KG_ 1 3.1 MG/Rd
7440 02-0 MG/KG 4006_'_.._ 136 MG/KG1_
7440-36-0 Antimony MG/KG E__
�2 0.9 MG/KG
Y4_4C-38-Y—.ArsenicMG/KG " 1.6 5.8
4441-4 Beryllium 1M4G KG 400 63M&/KG
7440-43-9 Cadmium G/KG i Y6 M0' 3 MG/KG
7482-49-2 Selenium MG/KG 10001 2.1
'Sliver MG/KG 10001 3-.4 Mijffid
. ..............
.. ..... ...
J - Indicates the reported result is an estimated value (analyte is
detected and the result is less than the adjusted Reporting Limit but
equal to or greater than the Method Detection Limit.
. ..........
scre-e'—ning Criteria are Preliminary Solt Remediation Goals (PSRGs),
North Carolina —Inactive Ha"z*a*rd'o*-us Sites Branch, updated August 2011
2.48
3."
< . 6. .. 72
2.45 J
<6.16
<0.00797
0.00..9.9.J
.1
1.401
.,-<1.93
<0.537
,
<0.5371
<0.189:
<0.155
<0.189
<0.155
<0.6121
<0.612
<0.1951
NC Preliminary Soil Remediation Goals 2011 Soil data Comparision.xis:Sheetl
< = Non detect at stated reporting limit Page 1 of 1 11/18/2011: 9:24 AM