DEQ-CFW_00042467

NCDENR
Dexter R `4@tt,1,,ews, Director Division of Waste Management
June 25, 2004
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. Michael E. Johnson
Environmental Manager
DuPont Fluoroproducts - Fayetteville Works
22 828 NC Highway 87 W
Fayetteville, NC 28306-7332
'�Jic,�ae! F Easley, ";overrior
,NNIiarq , G. Ross j,,. Sece`ary
IN
Re: NOTI for Phase I Supplemental RCRA Facility Investigation Repo (5/27/04)
DuPont Fluoroproducts - Fayetteville Works
EPA ID # NCD 047 368 642
Dear Mr. Johnson:
The North Carolina Hazardous Waste Section (HWS) has reviewed the document titled Phase I
Supplemental RCRA Facility Investigation Report. The report does not constitute an adequate RF1 report.
Comments developed to offer guidance and aid with revisions to the report are attached to this letter.
DuPont -Fayetteville should submit responses to the Hazardous Waste Section's comments and/or
revisions to the referenced document within ninety (90) days of the receipt of this letter. The 14WS will
need three copies of the responses to comments and document revisions. If your office has questions
concerning this correspondence, please call me at [phone] extension 236.
Sincerely,
Larry Stanley
Hydrogeologist
NC Hazardous Waste Section
cc: Jon Johnston, EPA Region 4
Bobby Nelms
Larry Stanley
cv/
4W Bud McCarty
Bob Glas#&
Karim Pathan /44P
Larry Stanley/4�py
1646 Mail Service Center, Raleigh: North Carolina 27699-1646
Phone [phone] \ FAX [phone] Internet http Ywaste notric org
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Fayetteville, North Carolina
EPA ID # NCD 047 368 642
Hazardous Waste Section's Comments on
Phase I Supplemental RCRA Facility Investigation Repo (5/27/01
Executive Surninary
SWMU 6
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standards. The Hazardous Waste Section believes all exceedances of applicable groundwater
standards identified at locations doAmgradient of SWMU 6 should be mentioned in the executive
summary. The executive summary seems to limit discussion to releases potentially originating at
the common sump area of SWMU 6.
Section 2.3
Plant Site Operations
2) Area IV (Ammonium Perfluorooctanoate Area) is not shown on Figure 3. The other three
areas, however, are labeled on this figure. DuPont -Fayetteville should show the part of the plant
where ammonium perfluorooctanoate (C-8) has been manufactured or used.
Section 2.5.5
Ammonium Perfluorooctonate..(C-8) SaInDling
3) DuPont -Fayetteville should indicate the date when ammonium perfluorooctanoate (C-8) was
introduced at the plant --either first manufactured or first used..
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4) The RFI report states that eight shallow piezometers were installed as part of the Phase I
supplemental RFL Figure 3 also seems to show eight piezometers. However, the piezometer
designations (i.e., PZ-1 1 through PZ-20) cited in the text of Section 3. 1.1 indicate ten
piezometers were installed. DuPont should resolve this apparent discrepancy.
Section 4.4.1
Analicaj Results -Groundwater Samples
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methylene chloride is exceeded in NAF-03 and not NAF-02. Constituent exceedances in
groundwater are depicted on Figure 6 and not, as stated in the text, on Figure 7. DuPont -
Fayetteville should revise the text ♦I Section 4.4.1 to show this information.
Section 4.4.1
Anal3lical Results -Surface Water Sam I A
6) Surface water sample locations and analytical results are depicted on Figure 7 and not, as
indicated in the text, on Figure 8. The analytical results for the surface water samples are in
Table 5. Rce wtits of constituett conce-ttration aroiallot shown o-t Table 5.
7) DuPont -Fayetteville should consult with the Water Quality Section to confirm that the
reported concentrations of chloride and fluoride do not exceed their respective Subehapter 2B
surface water quality standards. If the sampled stream is a Class C surface water body, the 2B
surface water standards for chloride and fluoride are exceeded.
Section 4.4.2
Fire Training Area-AnalZical Results
8) The analytical results for the groundwater samples collected at the fire training area are
summarized in Table 6 instead of Table 5 and displayed on Figure 8 rather than Figure 9.
DuPont -Fayetteville should make the appropriate revisions to the text of the RFI report.
• In addition to the analytical methods mentioned in this section, TPH-DRO analysis by Methojo
8015 (Modified) was also performed • the groundwater samples. This analysis and •f
qhould be listed in the text along with the others.
10) Analytical results for groundwater samples collected at the former fire training area report a
detection limit of 250 ug[L for TPH-DRO. The samples were not diluted. On the other hand,
equipment ► analyzed for the same constituent ► the same method • a detection limit
of 26 ug/L. DuPont -Fayetteville should explain the apparent disparity in the two detection limits.
11) The water table surface in the area of the former fire training area exhibits very little relief.
When the data collected for the Phase I RFI report and the more recent supplemental Phase I RF1
report are compared, the interpreted groundwater flow direction can vary significantly. The
HWS suggests that DuPont -Fayetteville discuss the apparent variability of the groundwater flow
direction and the implications for further investigations posed by this variability.
Section
12) In some parts of the mapped area, the contour lines shown on Figure 13 (Top of Clay
Contour Map) do not honor the data points. For example, data points C-3, C-4, D-4, and F-3 are
• the wrong • • contour lines. Assuming the data are correct, such "undulations" in the
surface • the clay unit could mean that the unit is faulted • that there are stratigraphic variations
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in the unit. DuPont -Fayetteville should discuss the validity of the data points mentioned above
and, if the data are considered "real," their significance.
Section
Contaminant Distribution-SWMU6 (Common Sumv)
13) The distribution of different constituents and variations in their concentrations implies there
may be more than one release originating at SWMU 6. DuPont -Fayetteville should discuss the
possibility of point sources other than the common sump at SWMU 6. As you are aware,
SWMU 6 includes all of the process sewer system in the Nafion area.
Section 6.2
Recommendations and Path Forward
14) The monitoring wells in the area of SWMIU 6 have been sampled twice. White the analytical
results showed similar constituents, the concentrations reported for these constituents varied
significantly. The HWS recommends DuPont -Fayetteville continue to sample these wells until
baseline concentrations can be established with some degree of confidence. The wells should be
sampled on a quarterly basis for at least a year.
15) The HWS recommends that DuPont -Fayetteville submit a work plan for future
characterization tasks. Without a work plan the facility will be proceeding with the RFI on 7
"voluntary" basis. Depending upon the scope of work proposed in the work plan, DuPont -
Fayetteville may be able to reference the elements mentioned in Section 6.2 (i.e., Data
Management Plan, Project Management Plan,
Erl rd ffal "M
16) The HWS requests that DuPont -Fayetteville review the facility's SWMUs with the Section.
(The RFA was conducted over ten years ago.) Similar efforts to review and prioritize units at
other DuPont facilities have been fruitful. The review could be submitted in writing or, as
suggested by DuPont, done during a meeting at the facility.
17) The HWS recommends that DuPont -Fayetteville conduct an EI evaluation as part of their
proposed formal risk evaluation. In the Handbook of Groundwater Protection and Cleanup
Policies for RCRA Corrective Action, EPA has explained in detail the context in which
environmental indicator evaluations are appropriate. As indicated in the EPA handbook, the
HWS believes El evaluations should be performed at all TSDs, and not just the GPRA facilities.
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